BR0108899A

Method and apparatus for participating in group communication services in an existing communication system

Abstract

"METHOD AND APPLIANCE FOR PARTICIPATION IN GROUP COMMUNICATION SERVICES IN AN EXISTING COMMUNICATION SYSTEM". It is an apparatus for forming a group of communication devices through a distributed network (10). A first node (22) establishes a first channel with a first communication device (12). At least a second node establishes at least a second channel with at least a second communication device. A controller (18) electrically connected to the first node (22) and at least one second node (24) comprises a database module. The database module comprises identification information for each of the communication devices (12, 14, 16, 17 and 20) in the group. The controller is dynamically configurable, so that any single communication device in the group is able to send packet data through its respective channel to the other communication devices in the group.

BR0108899A, drawing sheet 1 — Sheet 1 of 12

Term

Term ended

Projected expiry passed 2 March 2021, 5.6 years ago.

60 claims: 4 independent, 56 dependent

1
REIVINDICAÇÕES 1. Em um sistema de comunicação, aparelho para formar um grupo de dispositivos de comunicação através de uma rede distribuída, o aparelho compreendendo:um primeiro nó configurado de modo a estabelecer um primeiro canal com um primeiro dispositivo de comunicação;* pelo menos um segundo nó configurado de modo a estabelecer pelo menos um segundo canal com pelo menos um segundo dispositivo de comunicação;e um controlador conectado eletricamente ao primeiro nó e a pelo menos um segundo nó, o controlador compreendendo também um módulo de banco de dados, em que o módulo de banco de dados compreende informações de identificação de cada um dos dispositivos de comunicação do grupo, em que o controlador é configurável dinamicamente de modo que qualquer dispositivo de comunicação único do grupo seja capaz de enviar dados de pacote através de seu respectivo canal a todos os demais dispositivos de comunicação do grupo.
2
Aparelho, de acordo com a reivindicação 1, onde os dados de pacote contêm informações sensíveis ao tempo.
3
Aparelho, de acordo com a reivindicação 1, onde pelo menos um dos dispositivos de comunicação é um dispositivo de comunicação sem fio.
4
Aparelho, de acordo com a reivindicação 1, onde o controlador compreende também um módulo de núcleo e um módulo de rede, em que o módulo de núcleo é configurado de modo a estabelecer a identificação de cada um dos dispositivos de comunicação e redirecionar as informações dos dispositivos de comunicação para o módulo de rede, em que o módulo de rede é configurado de modo a operar e 2/12 gerenciar informações transmitidas entre o grupo de dispositivos de comunicação.
5
Aparelho, de acordo com a reivindicação 4, onde o módulo de banco de dados é configurado de modo a ser uma parte do módulo de núcleo.
6
Aparelho, de acordo com a reivindicação 4, onde o módulo de núoleo compreende também um módulo de registro de tarifação, em que o módulo de registro de tarifação mantém um histórico da atividade entre os dispositivos de comunicação.
7
Aparelho, de acordo com a reivindicação 6, onde o módulo de rede compreende também um módulo de registro local, em que o módulo de registro local é configurado de modo a manter um histórico da atividade entre os dispositivos de comunicação e transfere a história para o módulo de registro de tarifação.
8
Aparelho, de acordo com a reivindicação 4, onde o módulo de núcleo e o módulo de rede são ligados à rede distribuída.
9
Aparelho, de acordo com a reivindicação 1, onde o controlador compreende também um servidor de nível superior, em que o servidor de nível superior é configurado de modo a enviar e receber dados de pacote dos dispositivos de comunicação.
10
Aparelho, de acordo com a reivindicação 9, onde os dados de pacote compreendem pelo menos um dos dados de identificação do dispositivo de comunicação, dados de localização do dispositivo de comunicação e dados de controle para estabelecer, modificar ou terminar comunicações em grupo.
11
Aparelho, de acordo com a reivindicação 1, onde o primeiro canal compreende também um canal de 3/12 protocolo de iniciação de sinais (SIP), um canal de sinalização de meios e um canal de tráfego de meios.
12
Aparelho, de acordo com a reivindicação 1, onde o controlador compreende também um primeiro cronômetro (timer), em que-o primeiro cronômetro é configurado de modo a medir um primeiro período de tempo decorrido no qual qualquer um dos dispositivos de comunicação não transmitiu informações ao controlador, em que o controlador é configurado de modo a enviar uma mensagem aos dispositivos de comunicação de modo a introduzir um modo dormènte se o tempo decorrido ultrapassar um período de tempo predeterminado.
13
Aparelho, de acordo com a reivindicação 12, onde o controlador compreende ainda um segundo cronômetro, em que o segundo cronômetro é configurado de modo a medir um segundo período de tempo decorrido, em que, se qualquer um dos dispositivos de comunicação não tiver transmitido informações ao controlador dentro de um período de tempo predeterminado, o controlador é configurado de modo a enviar uma mensagem aos dispositivos de comunicação para omitir uma resposta dos dispositivos de comunicação de modo a se determinar se os dispositivos de comunicação desejam permanecer participantes ativos.
14
Aparelho, de acordo com a reivindicação 1, onde o controlador compreende também um arbitrador, em que o arbitrador é configurado de modo a atribuir um nível de prioridade a cada um dos dispositivos de comunicação, em que o nível de prioridade determina uma hierarquia de privilégio de transmissão dos dispositivos de comunicação, de modo que os dispositivos de comunicação com um nível de prioridade mais elevado possam interromper a transmissão dos dispositivos de comunicação com um nível de prioridade mais baixo. 4/12
15
Aparelho, de acordo com a reivindicação 14, onde a atribuição do nível de prioridade é configurável dinamicamente.
16
Aparelho, de acordo com a reivindicação 1, onde o controlador compreende também uma memória buffer, em que a memória buffer é configurada de modo a armazenar os dados de pacote até que o dispositivo de comunicação esteja pronto para receber os dados de pacote.
17
Aparelho, de acordo com a reivindicação 16, onde a memória buffer é configurada de modo a reduzir ao mínimo a latência percebida de um usuário.
18
Aparelho, de acordo com a reivindicação 1, onde pelo menos um dos dispositivos de comunicação opera em infra-estruturas de comunicação diferentes.
19
Aparelho, de acordo com a reivindicação 1, onde o controlador é configurado de modo a atualizar as informações de identificação do dispositivo de comunicação quando as informações de identificação do dispositivo de comunicação tiverem se alterado ou estiverem para se alterar.
20
Aparelho, de acordo com a reivindicação 1, onde o controlador é configurado de modo a enviar informações para o primeiro dispositivo de comunicação referentes ao pelo menos um segundo dispositivo de comunicação.
21
Aparelho, de acordo com a reivindicação 1, onde o primeiro dispositivo de comunicação é identificado por um primeiro identificador e o pelo menos um segundo dispositivo de comunicação é identificado por pelo menos um segundo identificador, e onde o controlador é configurado de modo a manter o identificador de cada um dos dispositivos de comunicação e permite a transferência de 5/12 dados de pacote entre o primeiro dispositivo de comunicação e o pelo menos um segundo dispositivo de comunicação.
22
Aparelho, de acordo com a reivindicação 1, onde os dispositivos de comunicação operam através de um modo protegido.
23
Em um sistema de comunicação, aparelho para formar um grupo de dispositivos de comunicação aperta-parafalar sem fio através de uma rede distribuída, o aparelho compreendendo:um primeiro nó configurado de modo a estabelecer um primeiro canal com um primeiro dispositivo de comunicação aperta-para-falar sem fio;pelo menos um segundo nó configurado de modo a estabelecer pelo menos um segundo canal com pelo menos um segundo dispositivo de comunicação aperta-para-falar sem fio;e um controlador conectado eletricamente ao primeiro nó e ao pelo menos um segundo nó, o controlador compreendendo também um módulo de banco de dados, em que o módulo de banco de dados compreende informações de identificação de cada um dos dispositivos de comunicação sem fio do grupo, em que o controlador é configurável dinamicamente de modo que qualquer dispositivo de comunicação aperta-para-falar sem fio do grupo seja capaz de enviar dados de pacote através de seu respectivo canal para os demais dispositivos de comunicação aperta-parafalar sem fio do grupo.
24
Em um sistema de comunicação, aparelho para formar um grupo de dispositivos de comunicação através de uma rede distribuída, o aparelho compreendendo:um dispositivo para estabelecer um primeiro canal com um primeiro dispositivo de comunicação;6/12 um dispositivo para estabelecer pelo menos um segundo canal com pelo menos um segundo dispositivo de comunicação;e um dispositivo para controlar o primeiro nó e o pelo menos um - segundo nó, o dispositivo para controlar compreendendo também dispositivos para proporcionar um módulo de banco de dados, em que o módulo de banco de dados compreende informações de identificação de cada um dos dispositivos de comunicação do grupo, em que o controlador é configurãvel dinamicamente de modo que qualquer dispositivo de comunicação do grupo seja capaz de enviar dados de pacote através de seu respectivo canal aos demais dispositivos de comunicação do grupo.
25
Aparelho, de acordo com a reivindicação 24, onde os dados de pacote contêm informações sensíveis ao tempo.
26
Aparelho, de acordo com a reivindicação 24, onde pelo menos um dos dispositivos de comunicação é um dispositivo de comunicação sem fio.
27
Aparelho, de acordo com a reivindicação 24, onde o dispositivo para controlar compreende também dispositivos para proporcionar um módulo de núcleo e um módulo de rede, em que o módulo de núcleo estabelece a identificação de cada um dos dispositivos de comunicação e redireciona as informações oriundas dos dispositivos de comunicação para o módulo de rede, em que o módulo de rede opera e gerencia as informações transmitidas entre o grupo de dispositivos de comunicação.
28
Aparelho, de acordo com a reivindicação 27, onde o módulo de banco de dados é uma parte do módulo de núcleo.
29
Aparelho, de acordo com a reivindicação 27, onde o módulo de núcleo compreende também dispositivos para 7/12 manter uma história da atividade entre os dispositivos de comunicação.
30
Aparelho, de acordo com a reivindicação 29, onde o módulo de rede compreende também dispositivos para enviar e receber uma história da atividade entre os dispositivos de comunicação e transfere a história para um módulo de registro de tarifação. onde o controlador compreende também dispositivos para enviar e receber dados de pacote dos dispositivos de comunicação.
31
33. Aparelho, de acordo com a reivindicação 24, compreendendo também medir um primeiro período de tempo decorrido no qual qualquer um dos comunicação não tenha transmitido dispositivos de informações ao dispositivo para controlar, em que o dispositivo para uma mensagem aos dispositivos de comunicação para entrarem em um modo dormente se o tempo decorrido ultrapassar um período de tempo predeterminado.
32
34. Aparelho, de acordo com a reivindicação 33, compreendendo um dispositivo para medir um segundo período de tempo decorrido, em que, se qualquer um dos dispositivos de comunicação não tiver transmitido informações ao dispositivo para controlar dentro de um período de tempo predeterminado, o dispositivo para controlar envia uma mensagem aos dispositivos de comunicação para omitirem uma resposta dos dispositivos de comunicação de modo a se determinar se os dispositivos de comunicação desejam permanecer participantes ativos. controlar envia 8/12
33
35. Aparelho, de acordo com a reivindicação 24, compreendendo também um dispositivo para atribuir um nível de prioridade a cada um dos dispositivos de comunicação, em que o nível de prioridade determina uma hierarquia de privilégio de transmissão dos dispositivos de comunicação de modo que os dispositivos de comunicação com um nível de prioridade mais eleva da possam interromper a transmissão dos dispositivos de comunicação com um nível de prioridade mais baixo.
34
36. Aparelho, de acordo com a reivindicação 35, onde o dispositivo para atribuir nível de prioridade é configurável dinamicamente.
35
37. Aparelho, de acordo com a reivindicação 24, onde o controlador compreende também dispositivos para proporcionar uma memória buffer, em que a memória buffer armazena os dados de pacote até que o dispositivo de comunicação esteja pronto para receber os dados de pacote.
36
38. Aparelho, de acordo com a reivindicação 37, onde o dispositivo para proporcionar memória buffer é usada para se reduzir ao mínimo a latência percebida de um usuário.
37
39. Aparelho, de acordo com a reivindicação 24, onde alguns dos dispositivos de comunicação operam em infra-estruturas de comunicação diferentes.
38
40. Aparelho, de acordo com a reivindicação 24, onde o dispositivo para controlar é configurado de modo a atualizar as informações de identificação do dispositivo de comunicação quando as informações de identificação do dispositivo de comunicação tiverem se alterado ou estiverem para se alterar.
39
41. Aparelho, de acordo com a reivindicação 24, onde o dispositivo de controle é configurado de modo a enviar informações ao primeiro dispositivo de comunicação 9/12 referentes ao pelo menos um segundo dispositivo de comunicação.
40
42. Aparelho, de acordo com a reivindicação 24, onde o primeiro dispositivo de comunicação é identificado por um primeiro-dispositivo para identificar e o pelo menos um segundo dispositivo de comunicação é identificado por pelo menos um segundo «dispositivo para identificar, e onde o controlador mantém o identificador de cada um dos dispositivos de comunicação e permite a transferência de dados de pacote entre o primeiro dispositivo de comunicação e o pelo menos um segundo dispositivo de comunicação.
41
43. Aparelho, de acordo com a reivindicação 24, onde os dispositivos de comunicação operam através de um modo de segurança.
42
44. Em um sistema de comunicação, um método para formar um grupo de dispositivos de comunicação através de uma rede distribuída, o método compreendendo:estabelecer um primeiro canal com um primeiro dispositivo de comunicação;estabelecer pelo menos um segundo canal com pelo menos um segundo dispositivo de comunicação;e proporcionar um controlador conectado eletricamente ao primeiro nó e ao pelo menos um segundo nó, o controlador compreendendo também proporcionar um módulo de banco de dados, em que o módulo de banco de dados compreende informações de identificação de cada um dos dispositivos de comunicação do grupo, em que o controlador é configurável dinamicamente, de modo que qualquer dispositivo de comunicação do grupo seja capaz de enviar dados de pacote através de seu respectivo canal aos demais dispositivos de comunicação do grupo.
43
45. Método, de acordo com a reivindicação 1, onde os dados de pacote contêm informações sensíveis ao tempo. 10/12
44
46. Método, de acordo com a reivindicação 1, onde pelo menos um dos dispositivos de comunicação é um dispositivo de comunicação sem fio.
45
47. Método, de acordo com a reivindicação 44, 5 onde o controlador compreende também estabelecer a identificação de cada um dos dispositivos de comunicação e redireciona as informações oriundas dos dispositivos de comunicação para um módulo de rede, em que o módulo de rede opera e gerencia as informações transmitidas entre o grupo 10 de dispositivos de comunicação.
46
48. Método, de acordo com a reivindicação 44, compreendendo também manter uma história da atividade entre os dispositivos de comunicação.
47
49. Método, de acordo com a reivindicação 44, 15 onde o controlador compreende também proporcionar um servidor de nível superior, em que o servidor de nível superior envia e recebe dados de pacote dos dispositivos de comunicação.
48
50. Método, de acordo com a reivindicação 49, 20 onde os dados de pacote compreendem pelo menos um dos dados de identificação do dispositivo de comunicação, dados de localização do dispositivo de comunicação e dados de controle para estabelecer, modificar ou terminar comunicações em grupo. 2 5
49
51. Método, de acordo com a reivindicação 44, onde o primeiro canal compreende também proporcionar um canal de protocolo de iniciação de sinais (SIP) , um canal de sinalização de mídia e um canal de tráfego de mídia.
50
52. Método, de acordo com a reivindicação 44, 30 medindo um primeiro período de tempo decorrido, no qual qualquer um dos dispositivos de comunicação não transmitiu informações ao controlador, em que o controlador envia uma mensagem aos dispositivos de comunicação para entrarem em 11/12 um modo dormente se o tempo decorrido ultrapassar um período de tempo predeterminado.
51
53. Método, de acordo com a reivindicação 52, compreendendo também medir um segundo período de tempo decorrido, em -que, se qualquer um dos dispositivos de comunicação não tiver transmitido informações ao controlador dentro de um período de tempo predeterminado, o controlador envia uma mensagem aos dispositivos de comunicação para omitirem uma resposta dos dispositivos de comunicação, de modo a se determinar se os dispositivos de comunicação desejam permanecer participantes ativos.
52
54. Método, de acordo com a reivindicação 44, compreendendo também atribuir um nível de prioridade a cada um dos dispositivos de comunicação, em que o nível de prioridade determina uma hierarquia de privilégios de transmissão dos dispositivos de comunicação, de modo que os dispositivos de comunicação com um nível de prioridade mais elevado possam interromper a transmissão dos dispositivos de comunicação com um nível de prioridade mais baixo.
53
55. Método, de acordo com a reivindicação 54, onde a atribuição do nível de prioridade é configurãvel dinamicamente.
54
56. Método, de acordo com a reivindicação 44, onde o controlador compreende também proporcionar uma memória buffer, em que a memória buffer armazena os dados de pacote até que o dispositivo de comunicação esteja pronto para receber os dados de pacote.
55
57. Método, de acordo com a reivindicação 56, onde a memória buffer reduz ao mínimo a latência percebida de um usuário.
56
58. Método, de acordo com a reivindicação 44, onde pelo menos um dos dispositivos de comunicação opera em infra-estruturas de comunicação diferentes. 12/12
57
59. Método, de acordo com a reivindicação 44, compreendendo também atualizar as informações de identificação do dispositivo de comunicação quando as informações de identificação do dispositivo de comunicação 5 tiverem se alterado ou estiverem para se alterar.
58
60. Método, de acordo com a reivindicação 44, compreendendo também, enviar informações ao primeiro dispositivo de comunicação referentes ao pelo menos um segundo dispositivo de comunicação. 10
59
61. Método, de acordo com a reivindicação 44, compreendendo também proporcionar um primeiro identificador para o primeiro dispositivo de comunicação, proporcionar um segundo identificador para o segundo dispositivo de comunicação, e ondeo controlador mantém o identificador de 15 cada um dos dispositivos de comunicação e permite a transferência de dados de pacote entre o primeiro dispositivo de comunicação e o pelo menos um segundo dispositivo de comunicação.
60
62. Método, de acordo com a reivindicação 44, 2 0 onde os dispositivos de comunicação operam através de um modo de segurança. / / (S.S d$ 1/12 LU _ Ü I—H LU 2/12

Independent claims60

466 paragraphs in 5 sections, as filed

(54) Title: METHOD AND APPARATUS FOR PARTICIPATION IN GROUP COMMUNICATION SERVICES IN AN EXISTING COMMUNICATION SYSTEM (30) Unionist Priority: 03/03/2000 us 09 / 518,622 (71) Depositor (s): Qualcomm Incorporated (US) (72) Inventor (s): Mark Maggenti, Douglas M. Crockett, Eric Rosen (74) Attorney: Montaury Pimenta Machado & Liôpe, S / CUda— (86) International Request: pct usoi / 06739 of 02/03/2001 (87) International Publication: wo 01/67787 of 13/09/2001 ( 57) Abstract: METHOD AND APPARATUS FOR PARTICIPATION IN GROUP COMMUNICATION SERVICES IN AN EXISTING COMMUNICATION SYSTEM. It is an apparatus for forming a group of communication devices through a distributed network (10). A first node (22) establishes a first channel with a first communication device (12). At least a second node establishes at least a second channel with at least a second communication device. A controller (18) electrically connected to the first node (22) and at least one second node (24) comprises a database module. The database module comprises identification information for each of the communication devices (12, 14, 16, 17 and 20) in the group. The controller is dynamically configurable, so that any single communication device in the group is able to send packet data through its respective channel to the other communication devices in the group.

Invention Patent Descriptive Report: METHOD AND APPARATUS FOR PARTICIPATION IN GROUP COMMUNICATION SERVICES IN AN EXISTING COMMUNICATION SYSTEM.

BACKGROUND OF THE INVENTION

I. Field of the Invention *

The present invention relates to multi-point communication systems. More specifically, the present invention relates to an apparatus and method for enabling group communication services that employ standard Internet Protocol in an existing communication system.

II. Related Technique Description

Multi-point communication systems have been employed to provide communication generally between a central location and multiple users of the system. For example, dispatch systems that employ Land Mobile Radios (LMRs) have been used on trucks, taxis, buses and other vehicles in order to communicate planning information between a central dispatch center and one or more corresponding fleet vehicles. Communications can be directed to a specific vehicle in the fleet or to all vehicles simultaneously.

Another example of a point-to-point communication system is a wireless push-to-talk system. Such a system allows a group of individuals, each with a wireless communication device, to communicate with other members of the group. Typically, a push-to-talk system has a unique frequency, or dedicated channel, through which communications are received by wireless communication devices. In most systems, only one member can transmit information to

2/98 other members at once. However, all members can listen to the dedicated broadcast channel in order to receive communications from the single member that is transmitting. Members who wish to transmit to other members of the system typically send an access request by pressing a push-to-talk button on their respective communication device that allows the user unique access to the dedicated channel.

Squeeze-to-speak systems are typically employed in outdoor environments, where a group of people, or members, need to communicate with each other from point to point. Examples of uses of the push-to-talk system include workgroup communications, security communications, construction site communications, and localized military communications. 0 A group of people who need to communicate with each other is commonly known as a network, each member of the network being sometimes called a member of the network.

In a typical push-to-talk system, a dedicated channel, sometimes called a broadcast channel, is used to transmit communications from one member to several members of the network simultaneously. The dedicated channel can comprise a single channel or frequency, or a group of individual channels administered by a controller, in order to mimic the single channel. In either case, only one member can transmit voice and / or data communications to another member's users at any given time. If another member tries to transmit over the broadcast channel while another member is transmitting, there will be interference between the two competing communications, resulting in the reception of intelligible communications by the other members of the network.

3/98

SUMMARY OF THE INVENTION

In order to implement a push-to-talk communication system in a conventional wireless communication system, expensive infrastructure modifications are generally required.

In addition to the high costs associated with current wireless point-to-multiple-point communication systems, communications are generally limited to members who operate in relatively close proximity to each other using the same or similar technology. In other words, point-to-point communications do not extend to other communication networks or technologies, such as the Public Switched Telephone Network (PSTN), data networks, such as the Internet, or communication systems via satellite, such as the GlobalStar satellite communication system.

Thus, the present invention is an apparatus for forming a group of communication devices through a network distributed in an existing communication system. The apparatus comprises a first node for establishing a first channel with a first communication device. At least a second node establishes at least a second channel with at least a second communication device. The channel connecting the communication devices with the controller, or communication manager, comprises a signal initiation protocol (SIP) channel, a media signaling channel (media) and a media traffic channel. A controller, also called a communication manager, electrically links the first node with at least one second node. The controller also comprises a database module. The database module comprises identification information for each of the communication devices of the

4/98 group. The controller is dynamically configured so that any single communication device in the group is able to send packet data through its respective channel to the other communication devices in the group. In one embodiment, the packet data contains time-sensitive information. In another embodiment, at least one of the communication devices is a wireless communication device.

The controller also comprises a core module and a network module, or MCU module. The core module and the network module are connected to the distributed network. The core module establishes the identification of each of the communication devices and redirects the information from the communication devices to the network module. The network module operates and manages information transmitted between the group of communication devices. In one embodiment, the database module is a part of the core module. The core module also comprises a charging record module. The charging record module maintains a history of the activity between the communication devices.

The network module also comprises a local registration module. The local registration module maintains a history of activity between the communication devices and transfers the compiled history to the charging registration module. The controller also comprises a top-level server. The top level server sends and receives packet data from the communication devices. The packet data comprises information such as identification data of the communication device, location data of the communication device and control data in order to establish, modify or terminate group communications.

5/98

The controller also comprises a first timer (timer), which measures a first period of time elapsed. If any of the communication devices has not transmitted information to the controller before the time period has elapsed, the controller sends a message to each of the communication devices before going into sleep / sleep mode. The controller also comprises a second timer that measures a second period of time elapsed. If any of the communication devices has not transmitted information to the controller within a predetermined period of time, the controller sends a message to each of the communication devices for the purpose of omitting a response from the communication device in order to determine whether the communication device wants to remain active.

The controller also comprises an arbitrator that assigns a priority level to each of the communication devices. The priority level determines a privilege hierarchy for communication devices, so that communication devices that have a higher privilege level can interrupt the transmission of communication devices that have a lower priority level. The priority level assignment is dynamically configurable.

The controller also comprises a buffer memory that stores the packet data until the communication device is ready to receive packet data. Temporary storage memory is used to minimize a user's perceived latency.

Communication devices can work on the same network despite working on

6/98 different communications, which include, but are not limited to, CDMA, TDMA and GSM.

Therefore, it is another aspect and another advantage of the invention to provide an arbitration that allows one or more users to pass over the authority to transmit voice or data with an access priority over that of the other users of a squeeze-to-speak network.

It is another aspect and another advantage of the invention to reduce the perceived latency for users of a squeeze-to-talk network to a minimum.

It is another aspect and another advantage of the invention to allow the communication device to terminate data frames to reduce latency to a minimum.

It is another aspect and another advantage of the invention to allow the communication device to anticipate the guarantee of an order in order to minimize latency.

It is another aspect and another advantage of the invention to temporarily store voice data in one or the other user until a given user is ready to receive the data.

It is another aspect and another advantage of the invention to allow a user to multicast through a single broadcast channel to several listeners.

It is another aspect and another advantage of the invention to allow a communication device to recognize and report that its identification address has changed or is about to change.

And another . aspect and another advantage of the invention to guide the user to determine if the user is still an active part of the squeeze-to-talk network.

7/98

It is another aspect and another advantage of the invention to allow the user to switch between several push-to-talk networks.

It is another aspect and another advantage of the invention to allow the user to dynamically determine the members of a given squeeze-to-talk network.

It is another aspect and another advantage of the invention to provide the user with a list of squeeze-to-speak networks of which the user can be a part.

It is another aspect and another advantage of the invention to give the user geographical information and other specific information about the other users of the press-to-speak network.

It is another aspect and another advantage of the invention to provide point-to-point voice communications via the Internet protocol.

It is another aspect and another advantage of the invention to provide end-to-end voice communications via the Internet protocol.

It is another aspect and another advantage of the invention to provide wireless squeeze-to-talk communications to a group, transmitting voice as packet data via an Internet protocol.

It is another aspect and another advantage of the invention to present a squeeze-to-speak system through an existing communication infrastructure without the need to modify the existing underlying communication infrastructure.

It is another aspect and another advantage of the invention to allow a group of connected or wireless communication devices to transmit and receive voice data mutually via the Internet protocol.

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It is another aspect and another advantage of the invention to present a rest mode for an inactive pinch-to-speak network.

It is another aspect and another advantage of the invention to present a communications manager to manage and control one or more press-to-talk networks.

It is another aspect and another advantage of the invention to present a dedicated media control unit for a squeeze-to-speak network.

It is another aspect and another advantage of the invention to present complete duplexing through packet data.

It is another aspect and advantage of the invention to present a signaling channel for configuring and maintaining a push-to-talk network.

It is another aspect and another advantage of the invention to provide security for voice in Internet protocol transmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the present invention will become evident with the detailed description presented below, taken in conjunction with the drawings, in which the same references identify the same members and in which:

Figure 1 illustrates a network broadcast system.

Figure 2 illustrates an NBS network and how communication devices interact with a communications manager (CM), indicated by reference number 104.

Figure 3 illustrates a functional block diagram of the CM.

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Figure 4 illustrates an example of the NBS SIP signaling protocol stack.

<td>THE signaling</td><td>figure 5 illustrates of NBS media.</td><td>an</td><td>battery</td><td>in</td><td>protocols</td><td>in</td>

<td>THE voice means</td><td colspan="2">figure 6 illustrates a time protocol</td><td>battery real.</td><td>in</td><td>protocols</td><td>in</td>

<td>THE voice means</td><td>figure 7 tillustrates UDP.</td><td>an</td><td>battery</td><td>in</td><td>protocols</td><td>in</td>

<td colspan="2">Figure 8 illustrates media traffic.</td><td>an</td><td>battery</td><td>in</td><td>protocols</td><td>in</td>

<td>THE</td><td>figure 9 illustrates</td><td>an</td><td>battery</td><td>in</td><td>protocols</td><td>in</td>

DNS client.

Figure 10 illustrates the high-level functionality of the group 500 module of the CD.

Figure 11 shows a SIP call signal, indicated by reference number 350.

Figure 12 illustrates a sequence of media signaling messages,

Figure 13 illustrates the sequence of media signaling messages with respect to the resting condition.

Figure 14 illustrates a sequence of signaling messages from NBS media.

Figure 15a illustrates a diagram of

CM 104.

Figure 15b is a continuation of figure 15a, which illustrates a CM 104 condition diagram.

Figure 16 illustrates a diagram of

CD 352.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS network broadcast service system (NBS) allows communication devices to participate in a group voice and data conference. NBS is basically a Voice over IP (VoIP) application. Communication from

10/98 Voice is transmitted from a speaker endpoint communication device to one or more listeners by encapsulating voice frames in IP datagrams. Voice data can also be transmitted in this way. The NBS system is described in U.S. Patent Application Serial No. 09/518 985, entitled Method and Apparatus for Providing Group Communication Services in an Existing Communication System, filed on March 3, 2000, Attorney's Protocol No. 000212, and in US patent application No. 09/518 776, entitled Method and Apparatus for Participating in Group Communication Services in an Existing Communication System, filed on March 3, 2000, Attorney's Protocol No. 000211, and are specifically incorporated in this report by way of reference.

Figure 1 shows a functional block diagram of a group communication system, 10. The group communication system, 10, is also known as a push-to-talk system, a network broadcast service (NBS), system dispatch or point-to-multi-point communication system. A defining characteristic of such an NBS system is that, generally, only one user can transmit information to other users at any given time. In NBS 10, a group of users of communication devices, individually known as members of the network, communicate with each other using a communication device assigned to each member of the network.

network means a group of users of communication devices authorized to communicate with each other. Generally, a central database contains information that identifies the members of each particular network. More than one network can work on the same

11/98 communication system. For example, a first network that has ten members can be defined and a second network that has twenty members can be defined. The ten members of the first network can communicate with each other, but usually not. with members of the second network. In other situations, members of different networks can monitor communications between members of more than one network, but they can also transmit information to members within their own network.

The network operates through an existing communication system, without the need for substantial changes to the existing infrastructure. In this way, a controller and users on a network can operate on any system capable of transmitting and receiving packet information through the Internet protocol (IP), such as a Code Division Multiple Access (CDMA) system , a Time Division Multiple Access (TDMA) system, a Global System for a Mobile Communication System (GSM), satellite communication systems, such as Globalstar (or Iradium (, or several other systems.

The members of a network communicate with each other using an assigned communication device, shown as a communication device (CD), embodied as the communication devices 12, 14, 16 and 17. CDs 12, 14, 16 and 17 can be connected or wireless communication devices, such as land-based cordless phones, connected phones with squeeze-to-talk capability, satellite phones equipped with squeeze-to-talk functionality, video cameras. wireless video, fixed cameras, audio devices such as recorders or music players, lap or desktop computers, radio broadcast devices, or any combination thereof. For example, CD 12 may comprise a cordless landline phone that

12/98 has a camera or video screen. In addition, each CD can send and receive information either in a protected (security) mode or in an unprotected (released) mode. Throughout the following description, the reference to an individual CD can be expressed as being made to a cordless press-to-talk phone. However, it should be understood that it is not intended to limit the reference to a CD as such, and it may include other communication devices that have the ability to transmit and receive packet information in accordance with the Internet Protocol (IP).

In the NBS 10 system in figure 2, a transmission privilege is defined as that which allows a single user to transmit information to other members of the network, depending on whether the transmission privilege is currently assigned to another member of the network when the request is made. Received. The process of securing and denying transmission requests is known as arbitration. Other arbitration schemes assess factors such as the priority levels assigned to each CD with regard to determining whether the member of the group making the request is granted the transmission privilege.

To participate in the NBS 10 system, CDs 12, 14, 16 and 17 can request transmission privileges from a controller or a communications manager (CM), 18. In general, CM 18 manages the operation in real time and administrative networks. The CM is any type of computer-type device that has at least one processor and memory. In one embodiment, the CM is a Sun Workstation Netra TI (.

CM 18 maintains a list of networks defined, defined either as released or as protected. Moving from a released network or networks to a protected network or networks is generally not allowed. A protected network

13/98 has the encryption presented by the individual CDs to provide authentication and protection against intrusions. Encryption for protected networks is implemented on an end-to-end basis, which means that encryption and decryption takes place within each CD. The CM 18 works, in general, without the knowledge of algorithms, keys or security policies.

CM 18 manages remotely through either a communication service provider, members of the network or networks, or both, assuming authorization is given by the service provider. The CM 18 can receive network settings through an external administration interface, 226. Network members can request administrative actions through their service provider or administer network functions through defined systems, such as a member-operated security manager (SM), 20, which conforms to a CM 18 administration interface CM 18 can authenticate to high-grade business standards any party that attempts to establish or modify a network.

SM 20 is an optional component of the NBS 10 system that performs key management, user authentication and related tasks to support protected networks. A single group communication system can interact with one or more of an SM 20. 0 SM 20 is generally not involved in real-time control of a network, including network activation or PTT arbitration. Õ SM 2 0 may have administration features compatible with a CM 18 interface to automate administration functions. 0 SM 20 can also act as a data entry point for purposes of participating in a network, broadcast network keys, or simply monitoring network traffic.

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In one embodiment, the device for requesting the privilege of a CD comprises a push-to-talk key or switch. When the user on NBS 10 wishes to transmit information to other network members, the push-to-talk switch located on his CD is pressed, resulting in the sending of a request or request to obtain privilegetof transmission of CM 18. If no other member of the network is currently assigned the transmission privilege, the transmission privilege is granted to the requesting user, and the requesting user is notified by an audible, visual or tactile alert via the CD. After the requesting user has been granted the transmission privilege, the information can be transmitted from that user to another member of the network.

In an embodiment of the present invention, each member of the wireless network establishes a broadcast link and a reverse link with one or more base stations 22 or satellite port 24, as the case may be. Base station 22 is employed to describe a communication channel from base station 22 or satellite port 24 to a CD. Satellite port 24 is used to describe a communication channel from a CD to a base station 22 or port 24. Voice and / or data data are converted into data packets by means of a CD, the data packets suitable for a specific distributed network 26, through which communications with other users occur. In one embodiment, the distributed network 26 is the Internet. In another modality, a dedicated broadcast channel is established in each communication system (that is, a terrestrial communication system and a satellite communication system) to disseminate information from each member of the network to other members of the network. Each member of the network receives communications from other members of the network through the dedicated channel. In yet another

15/98 modality, a dedicated reverse link is established in each communication system to transmit information to the CM 18. Finally, a combination of the above invention schemes can be used. For example, a scheme may be establishing a broadcast broadcast channel, but which requires wireless motorcycle CDs to transmit information to the CM 18 through a reverse link assigned to each CD.

When a first member of the network wants to transmit information to other members of the network, the first member of the network requests transmission privilege by pressing a key on his CD, which generates a formatted request for transmission through the distributed network 26. In the case of CDs 12, 14 and 16, the request is transmitted over the air to one or more base stations 22. A mobile communication center (MSC), 28, comprises a well-known interoperational function (IWF) for processing data packets, including the order, between the MSC 18 and the distributed network 26. For CD 17, the order is transmitted to the Public Switched Telephone Network (PSTN), 30, then to a modem bank, 32. The modem bank 32 receives the request and sends it to the distributed network 26. An NBS terminal, 34, monitors NBS system traffic through your internet connection 26. Since the NBS 34 terminal is connected to the Internet 26 ', geographic proximity to network participants is not necessary.

If another member currently maintains the transmission privilege when the request for transmission privilege is received by the CM 18, the CM 18 transmits a message to the member of the network making the request, notifying him that the transmission privilege has been granted. Audio, visual or other information from the first member of the network can then be transmitted to other members of the network by sending the information to the CM 18, using a

16/98 of the transmission paths just described. In one embodiment, CM 18 then provides information to members of the network by duplicating the information and sending each duplicate to members of the network. If a single network channel is used, it is necessary that the information be duplicated for each broadcast channel in use.

THE

In an alternative modality, CM 18 is incorporated into MSC 28 so that data packets from base stations are routed directly to CM 18 without being routed to distributed network 26. In this modality, CM 18 is still connected to the distributed network 26 so that other communication systems and devices can participate in group communication.

CM 18 maintains one or more databases to manage information related to members of the network, as well as to each defined network. For example, for each member of the network, a database may comprise information such as the user's name, account number, a telephone number or dialing number, associated with the member's CD, a Mobile Identification Number assigned to the CD, the current condition of the member on the network, such as whether the member is actively participating in the network, a priority code to determine how the transmission privilege is assigned, a data phone number associated with the CD and an IP address associated with the CD and an indication of which or which networks the member is authorized to communicate with. Other related types of information can also be stored by the database for each member of the network.

As part of the NBS infrastructure, the communications manager (CM) forms connections from

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individual communications in order to form a group, or network, of conversation. The CM comprises several hardware and software resources that are configurable in different ways to accommodate different applications. In general, the CM presents a resource to manage real-time, administrative and network authenticity (NBS) operations, shake-to-talk (PTT) order arbitration, maintenance and distribution of association and registration lists, configuration of calls and disruption of required CDMÁ system and network resources, as well as full control of network condition.

The NBS network can be within a stand-alone cellular system, or within a large multi-site configuration. In the case of a large configuration, several

CMs can be installed to form a single integrated network.

Each works as a connection module in an existing cellular infrastructure. Therefore, new features introduced by the NBS networks are available to cellular users without the need to modify the existing cellular infrastructure.

A function of the CM is to maintain a list of defined NBS networks. Each network definition includes a network identifier, a list of members or partners, including phone numbers or other identifying information, information regarding user or user priority or priorities, and other general administrative information. Networks are statically defined as either being released or protected and transitions between released and protected are not allowed. A protected NBS network typically uses media encryption to provide authentication and protection against intrusion. Encryption and decryption of media

18/98 are implemented on an end-to-end basis, which means that encryption and decryption take place within the communication device. CM works without knowledge of algorithms, keys or security policies ...

The CM receives network definitions through an external administration interface. Customers can request administrative actions through their service provider or administer network functions through systems

10 'defined, such as, for example, a security manager operated by the customer who conforms to the CM administration interface. CM authenticates in accordance with business standards for any party attempting to establish or modify a network.

Before an embodiment of the invention is explained in detail, it should be understood that the invention is not limited in its application to the details of the construction and arrangement of the components presented in the following description or illustrated in the drawings. The invention

0 it may have other modalities and is implemented in several ways. It should also be understood that the phraseology and terminology used in this report are for the purpose of description and should not be understood as limiting.

Figure 2 illustrates an NBS network, 100, and how communication devices interact with a CM 104. Several CMs 104 can be installed as desired for large-scale NBS networks, indicated by reference number 100. In figure 2, the communication device

108, or CD 108, is allowed to transmit media to the network. In this case, the CD 108 is known as the speaker and transmits media through a channel. When CD 108 is designated as the speaker, network participants

19/98 remaining, communication devices 112 and 116 (or CD 112 and CD 116) are not allowed to transmit media to the network. Therefore, CD 112 and CD 116 are designated as listeners and so on.

As described above, each of the CDs 108, 112 and 116 is connected to the CM 104 via a channel. In one embodiment, the channel is divided into separate channels comprising a session initiation protocol (SIP) channel, 120, an NBS media signaling channel, 124 and a media traffic channel, 128. The session initiation protocol (SIP) channel 120 and the media signaling channel 124 can be used at any time as the bandwidth allows, regardless of whether they are designated as a speaker or listener, by any of the CDs 108 , 112 and 116. SIP is an application layer protocol defined by the Internet Engineering Task Force (IETF), which describes control mechanisms for establishing, modifying and terminating multimedia sessions that operate in accordance with the Internet Protocol (IP). 0 SIP provides a general solution to call signaling problems for Internet telephony applications by devices supporting user registration and location, a mechanism that defines user capabilities and describes means parameters, mechanisms for determining user availability, configuration of calls and call handling.

SIP channel 120 is used to start and end the participation of a CD within the network 100. Optionally, a session description protocol (SDP) signal can also be used within the SIP channel 120. When the participation of the CDs within a NBS network is configured through the SIP channel 12 0, the control and signaling of calls in real time between the CD and the CM 104

20/98 occur through the media signaling channel NBS 124. Specifically, among other tasks, the media signaling channel NBS 124 is used for handling orders and press-to-talk releases, for arbitration between conflicting requests, or floor control, announce the start and end of the transmission of information, manage the idle condition of the network, track the connectivity of the

At the terminal point, request and change the network condition, notification and error messages. The protocol of the media signaling channel -NBS reduces the length of the most common messages to a minimum and simplifies the task of interpreting responses and responding to requests, while retaining the flexibility for future improvements. The NBS 124 media signaling channel protocol also allows requests to be resent without affecting the protocol condition differently.

Signaling traffic on media channel 124 can also be differentiated into two categories: call setup and control signaling, which basically consists of requests and acknowledgments for receiving SIP requests and media signaling, which basically consists of control requests for real-time floor and similar asynchronous messages. The media traffic in the media traffic channel 128 is made up of voice broadcasts and / or point data to various points in real time. Both categories of sending and receiving messages have unique functional attributes. In addition, each CD can issue requests from Domain Name Service customers to facilitate the mapping of fully qualified DNS primary names to Internet network addresses.

The call setup and call control signaling are performed according to the

21/98 SIP semantics. Although the SIP can be transported using either the User Datagram Protocol or the Transmission Control Protocol (UDP), notoriously known, in a preferred mode each. CD performs signaling functions based on SIP through UDP, as shown in figure 4. In addition, each CM expects to receive all requests for SIP signaling through the

THE

UDP. Real time signaling takes place via dynamic UDP / IP interfaces on the CM and on each CD. Other signals can occur through a fixed TCP / IP interface between the CM and the CD using SIP.

Figure 3 shows the modules and physical reprocessing of the CM 104. The CM 104 comprises a CM core module or complex, 204, at least one network module, or media control unit (MCU), 208 and 212, a DNS server 216, a redirect server 220 and an administrative workstation, 224. The CM core complex 204 provides administration capabilities for a Java-enabled web browser (. One or more DNS servers 216 may also be included in the core complex 204 of the CM. The core complex 204 of the CM also comprises a node, 228, of the CM, and a database service 232. The CM 104 is separable into at least two parts, the core complex 2 04 of the CM and each node 208 of the MCU. The MCU node 088 sends and receives information, as needed, from the core complex 204 of the CM. The separability of the CM 204 core complex provides versatility in the sense that, once a specific network has been established, the network is operated by a dedicated node, 208, of the MCU. This allows the CM core complex 204 to make initial connections to other potential networks, regardless of the type of communication structure on which the network wishes to operate. In addition, the CM core complex 02 04 can be moved

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It is geographically from node 208 of the MCU. For example, a single-core complex, 204, of the CM can be located in the central part of the United States, and a series of nodes 2 08 of the MCU can be located regionally in order to operate networks from their given region. Thus, the CM core complex 044 can route the user to a specific node, 208, of the MCU based on the user's location. In addition, information can be sent to a user or group of users based on location, such as, for example, broadcast, directions or the identification of boundary marks based on location.

CM node 228 provides centralized functionality associated with NBS networks. CM node 228 comprises a user-initiation protocol agent (SIP UAS) server, 236, and a CM communications manager, 240, a central billing registry, 244, and an administration server, 248. The UAS 236 SIP server supports user requests for lists of networks and handles SIP request messages for networks. When a SIP request message, 229, is received from a communication device, the network assigns the communication device to an appropriate node 208 of the MCU and directs the communication device to node.208 of the MCU.

The CM 240 manager monitors the condition of all MCU nodes within a network and assigns network execution to data MCU nodes, such as MCU node 2 08. 0 CM 240 manager handles administrative functions relating to the administration of networks, including creating and deleting networks, defining new users and deleting existing users, adding and removing users as members of the network and adjusting operational parameters on a user-wide basis, network or CM.

23/98 pricing information.

central billing register 244 maintains time and identification for the purposes of The central billing register receives information relating to the billing record from a local logging server, 260, at node 208 of the MCU. Detailed registration information for each user, such as which communication devices are active on the network, for how long, from where and when and for how long each CD is a speaker or listener, is maintained. 0

Administration Server 248 supports an interface that allows the Administration workstation 224 to retrieve information regarding conditions, initiate database administration and system management functions through the network condition interface 280.

The CM implements both the SIP 236 user agent server and the SIP MCU 252 server. To support NBS, each CD implements a user agent agent client. The CM receives incoming SIP calls on an advertised node or port. When a connection occurs, the SIP 236 server receives and processes requests according to SIP call signaling conventions. The SIP 236 server is capable of processing several call signaling connections in parallel.

To conserve network resources, the CD can release its UDP connection to the SIP 236 server after it has successfully (or unsuccessfully) associated itself with the NBS 100 network. The UDP connection can be reinstalled later to send signaling requests from SIP calls (for example, to leave the network or switch to another network).

Figure 4 illustrates an example of an NBS SIP signaling protocol stack. The stack is a collection of protocol layers that implements network communication. 0

24/98 protocol associated with each layer communicates with the layers immediately above and below it and assumes the support of underlying layers. Since UDP is less secure connectionless transport, application-level security is preferable in order to ensure robust communication, which is achieved by implementing through SIP-compliant endpoints. Generally, signaling of SIP 302 calls on UDP 304 streams is encapsulated within the IP 306 protocol. No special formatting is required. The SIP call signaling IP packets, indicated by reference 306, are exchanged between, for example, a CDMA based cell CD or a dialing PSTN based CD, which are encapsulated within point-to-point frames (PPP), indicated by reference 308. Therefore, no special formatting is required. In addition, the SIP 308 call signaling PPP frames exchanged between a CDMA cell-based CD and a base station are encapsulated within a radio-link protocol (RLP), 310. For users based on dialing PSTN, a appropriate modem standard, such as ο V, 32bis or ο V90, can replace the RLP 310. In both cases, special handling is generally not necessary and an error-free physical link is not assumed.

Figure 5 illustrates an NBS media protocol stack, 312, which carries voice and data traffic via UDP 304 datagrams over IP 306. NBS 314 media signaling is layered on UDP / IP 306 traffic and is handled similarly with respect to the description in figure 4.

Figure 6 illustrates a stack of real-time protocol voice media protocols, 320. In this embodiment, the payload data of the voice encoder

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322 are layered in real-time protocol (RTP) 324. RTP 324 is then layered in UDP 304 and IP 306. In an optional embodiment, real-time protocol header compression (CRTP) 330 is also used to encapsulate media traffic through RTP 322 in the application layer. Header compression techniques can be applied as appropriate to all incoming and outgoing UDP / IP traffic shown in figures 4-9. Media signaling requests and responses are encapsulated within UDP datagrams. When available, CRTP header compression can be applied to reduce the impact of sending uncompressed UDP / IP headers. In figure 6, CRTP compresses the layer of RTP 324, 324, the layer of IP 306 and the layer of PPP 308. In figures 4, 5 and 7-9, CRTP 32 0 compresses the layers between, and that include, UDP 304 and PPP 3 08.

In operation, each CD dynamically selects a UDP port on which it is intended to listen for NBS signaling requests and communicates the port number to the SIP server 236 as part of the SIP request it transmits when trying to join a network. The destination address of the network's CM media signaling (including the UDP port number) is described in the session description of the transmitted network, as part of a successful response to the SIP INVITE request, to the CD. Unlike SIP signaling addresses, media signaling destination addresses are network specific and can change between occurrences of a CD that joins a network. Several networks hosted by the same CD generally operate independently and do not share media signaling ports or traffic signaling ports. However,

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Θ ιθ

Ο the possibility of several networks sharing media signaling or media traffic ports is considered.

Referring to figure 6, voice traffic is encapsulated by grouping one or more voice encoder frames within an RTP / UDP 324 or UDP 304 payload. The use of RTP 324 with CRTP 330 enabled is intended to reduce end-to-end media latency to a minimum and provide interoperability with IP telephony applications and services. Both in one. in each case, the CD dynamically selects the UDP port on which it expects to receive media traffic and communicates the port number to the SIP server 236 as part of the SIP request it transmits when trying to join a network.

The voice and transport encapsulation protocol, as well as its media traffic destination address (including the UDP port number), are described in the session description response to a successful SIP request request from the SIP server 236 Like media signaling addresses on the network, media traffic destination addresses are not network specific and may change between occurrences of a CD that is associated with a network.

Typically, as shown in figure 6, voice traffic is encapsulated in the application layer via RTP 324, which segments each UDP datagram 304 into an RTP header, 324, and a voice encoder payload, 322. The figure 7 illustrates a stack of UDP voice media protocols, 332. Voice traffic can optionally be encapsulated simply via UDP 304 datagrams, without RTP encapsulation, typically when CRTP 330 header compression is not available or is not supported by a member of the network. Figure 8 illustrates a stack of

27/98 media traffic protocols, 334. The media traffic protocol stack 334 is used for use by network participants that do not have application-level RTP encapsulation. The 336 data is encapsulated in the UDP304 datagrams.

The structure of the UDP payload 304 follows the definition given for a corresponding RTP payload 324, without the RTP header fields. The decision to encapsulate media directly in UDP 304 is configured by the network administrator 248 and announced by the announcement of the network session. In addition to voice media, NBS networks can also support arbitrary data broadcasts. If a network supports a data broadcast channel, the SIP 236 server announces the type of media in the description of the network's SIP sessions when a CD formally joins the network.

Figure 9 illustrates a stack of DNS client protocols, 338. Each CD includes the ability to resolve Internet domain names to Internet addresses using the Domain Name Service (DNS) protocol 340. The CD functions as a client DNS. The CD encapsulates DNS requests via UDP 32 6, as shown in figure 9. In order for the CD to resolve primary names, the CD is provided with the DNS 216 server's network address, as shown in figure 3. The DNS address is also configurable by the service provider and, optionally, by the user.

<td></td><td>Beyond the</td><td>means</td><td>in</td><td colspan="2">voice, networks can support</td>

<td colspan="2">also broadcasts</td><td>in</td><td colspan="2">arbitrary data,</td><td>such as</td>

<td colspan="2">rekey</td><td>network</td><td colspan="2">protected mail</td><td>electronic,</td>

<td>files</td><td>of data,</td><td>etc.</td><td>If</td><td>a network supports</td><td>a channel</td>

<td>broadcast</td><td colspan="2">data, the</td><td>CM</td><td>announce the type</td><td>of means in</td>

<td>description</td><td colspan="2">SIP sessions</td><td>gives</td><td>network when the CD</td><td>associates with</td>

network. Like traditional media broadcasts, broadcasts operate under the RLP in one mode (or

28/98 a corresponding physical layer), but are generally considered less secure transport.

The CD includes the ability to resolve Internet domain names to Internet addresses using the Domain Name Service (DNS) protocol, defined in RFC 1034. Alternatively, the CD functions as a DNS client or resolver, as described in RFC 1035.

and

In order for the CD to resolve DNS main names, the CD is pre-programmed with the IP network address of „10. DNS server. .0 DNS address is also configurable by the CD service provider and, optionally, by the user.

The CM 104 can optionally be configured to function as a DNS server, 216. Although it can respond to DNS requests from external entities using TCP as the transport protocol, in order to fulfill requests that originate with the CD, the SIP 236 server encapsulates DNS messages through UDP 304 according to figure 8.

NBS also takes advantage of the development of a cellular multicast channel. Such a channel generically allows a broadcasting station to address N listening stations directly through a broadcasting channel, without the need for N rebroadcasts separate from the transmitted data. The presence of a cellular multicast channel implies changes in the NBS media stack basically below the IP network layer. To take advantage of the efficiencies provided by a cellular multicast channel, the destination addresses of signaling and media traffic on a network are conventional IP multicast channels and signaling broadcasts and data traffic originating from the CM are multicast broadcasts. Each signaling broadcast and media traffic originated

29/98 of the CD and the SIP signaling remain as point-to-point communications.

The Radio Link protocol (RLP) 310 shown in figures 4-9 can be modified within each CD in order to minimize the latency experienced when loss of link-layer (frame RLP) occurs. Such modifications are optional and do not necessarily affect the transport operation of the application layer protocols, since neither TCP nor UDP 3 04 assumes a network (IP) or link-layer service.

Several modification strategies for the RLP 310 are possible. For example, the RLP 310 can be modified to send multiple messages, such as NAK responses, after an initial RLP timeout, thereby directing the remote end to transmit multiple copies of the lost RLP 310 frame and increasing the opportunities for successful recovery of the RLP 310. 0 RLP 310 can also be modified so that it never sends a NAK response (after the RLP has expired) and allows canceled frames from the RLP 310 to force higher levels of the protocol stack to generate errors. Any application-level protocols based on TCP perform routine recovery through TCP error recovery mechanisms. 0 traffic that relies on UDP

5 3 04 for transport already faces the potential for loss.

Again with reference to figure 2, once the CD establishes participation within the NBS 100 network using the SIP channel 12 0, the CD is prepared to send and receive media from network 100 on a specific media port of the CD through the communication channel. media traffic 12 8. If the CD gains control of the floor by signaling media, as is the case with CD 108 in figure 2, the CD transmits media to the network

Destination 30/98 and transport addresses as indicated in the network 100 session description. The CD decodes media received at its media ports according to the speech encoder and media format defined in the · network 100 session description. received in a request response when the CD joined the 100 network. 0 CD encodes and encapsulates the media sent to network 100 according to the voice encoder and the media format defined in the session description of network 100 received in a request response when the CD joined network 100.

Each CD that participates in a network determines the destination network and the transport address for each media channel of the session description received from the CM 104 SIP 236 server and which was acknowledged during the configuration of SIP calls and used them for address corresponding media sent within network 100. Each CD provides a packet data link with the CM. Changes can be made to the CD implementation of this interface in order to improve NBS performance.

Changes to the infrastructure side of this interface are generally not necessary. The CD can optionally support most NBS activities using Quick Network Connection (QNC), as described in this report.

When sending to a service provider, the CM 240 manager goes through a basic administrative setup before supporting NBS activities. Initial setup includes basic system setup, such as assigning passwords to operating system-level accounts for root-level system administration and configuring the CM 240 manager's network interfaces to work properly on the wireless infrastructure network place.

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Once the CM 104 is configured, general network administration can take place. The network administration functions take place via HTML or another network interface built using TCP / IP. The administration workstation 224 interacts with the core complex 204 of the CM employing a World Wide Web (WWW) browser. Administration can take place locally or remotely (anywhere on the Internet, or via manual dialing). However, the underlying transport path for administrative access is typically TCP / IP. In addition, several (at least three) simultaneous administration connections are allowed.

When connected to the CM core complex 044 for network management purposes, the workstation

224 The administrator authenticates himself / herself successfully to ensure that only authorized administrative actions are accepted. Different levels of access are accommodated; for example, authorized members of the network can connect directly with the CM administrative interface (248) to modify specific network membership lists. More general administrative privileges are generally reserved for specific administrative explanations / reports. For the sake of clarity, administrative actions are generally separated into those that specifically deal with user definitions and those that define networks. A user definition comprises information such as the user name, the unique identifier of the CD cellular system, the CD telephone number and the user's electronic address. A unique user identifier is defined that can be passed to the CD and used to uniquely identify the user in signaling messages. A network definition comprises information such as network address,

32/98 suspension of the network, waiting time for private dispatch and list of members. A list of members of the network comprises information such as a list of member records, which individually contain a user identifier and the priority level. A member with the minimum priority level typically has listen-only privileges.

The CM 248 administrator can monitor the current condition of networks for which they have administrative privileges. In particular, the CM administrator 248 can determine the current list of network participants, as well as monitor the condition (active, inactive, at rest, waiting, awakening, etc.). Whenever the network is active, the CM 248 administrator can also monitor the identity of the current speaker. Additional statistics and condition, such as the duration of the current session, total talk time, average number of registrants, etc., may also be available to administrators through the administrative interface.

The administration server interface 248 comprises at least two network nodes, or ports. One is a Hypertext Transfer Protocol (HTTP) interface based on TCP / IP that supports administrative access through a conventional Java ™ capable web browser. The second is an NBS-specific Command Line Interface (CLI) based on TCP / Ipihiehe.

The administration server 248 makes all administrative functions available to a generic web browser through an HTTP web server interface with one or more formatted pages using a readable medium over the Internet, such as a syntax of Hypertext Complement Language (HTML). At least one of the administrative pages can include a

33/98 reference to a Java ™ utility. Some administrative functions can optionally be performed using the HTTP GET (GET) and POST (POST) commands by the Web browser through authorization mechanisms administrative functions subset of functions

Conventional HTACCESS. The supported ones are generally supported by the CLI interface.

The HTTP interface can be used to send a Java ™ utility to the web browser. The utility can then rely on the CLI interface of the administrative server 248 to provide additional administrative functionality to the user through a web browser interface. access to the CLI interface, a potential administrative workstation, 224, connected to the CLI interface of the administrative server 248 is authenticated. In a preferred embodiment, the CLI interface can be reached at a notoriously known fixed TCP port address and is capable of simultaneously managing multiple CLI sessions.

The database server 232 is responsible for storing information and network parameters, information about the network user, information about conditions associated with MCUs 208 and 212 and node 228 of the CM. The database server 232 also serves this information to the rest of the ÇM 104, such as, for example, the SIP 236 server and other modules that need such information. Database server 232 maintains databases that capture information that supports NBS network activities, including an NBS network database part and an NBS user database part. Information that supports activities and administration privileges can be stored in one or the other database, or in a third database functionally

34/98 distinct. The database server can also be divided into a user part and a network part.

The CLI interface supports administrative functions such as create user / network, delete user / network, modify user / network, list / show user, list / show network, condition and help from CLI.

The Create User function allows the administration server 248 to create new users in the user part of the database, including specifying all user registration fields. The Suppress User function allows the administration server 248 to suppress existing user records in the user part of database 232. The Modify User function allows the administration server 248 to modify existing user records in the user part of database 232, including modifying all record fields for a specific user.

The Create Network function allows the administration server 248 to create new networks in the user part of database 232, including specifying all definition parameters. The Suppress Network function allows the 248 administration server to suppress existing networks in the 232 database user part. The Modify Network function allows the 248 administration server to modify existing networks in the 232 database user part. The Modify Network function allows the administration server 248 to modify the existing networks in the user part of database 232, including modifying all network definition parameters for a specific network. The List User function allows the 248 administration server to list all users, for example

35/98 username, dialing number and user identifier, in the user part of database 232.

The List Network function allows the administration server 248 to list all networks, by network address and network identifier, in the network portion of database 232. The Show User function allows the administration server 248 to show all fields for a specific user identified by the user's user identifier. The Show Network function allows the administration server 248 to show all fields for a specific network identified by the network identifier or network address of the network. The Condition function allows the administration server 248 to consult a static condition report for a specific network. The Condition function can also allow the administration server 248 to see reports in real time (updated). In real time, the condition function identifies the current list of network participants, the current speaker, the presence or absence of media traffic, and identifies any and all media signaling messages sent or received by the CM. The Help function allows the administration server 248 to consult a summary summary, readable by the user, of each supported CLI command, including description of use and syntax.

The NBS user portion of database 232 tracks individual NBS users. User records contained within the 232 database may or may not necessarily be members of networks defined in the network portion of the 232 database CM.

Each record in the user part of database 232 consists of fields such as user name, user ID, list of voice encoders, dialing number, user type, CRTP support,

36/98 CD user address and very good privacy public key (PGP) on the CD. The list of voice encoders is a list of voice encoders supported by the subscriber's CD. The list may include voice encoders not supported by NBS. The dialing number is the dialing number of the subscriber's CD. This field is empty, or null, for generic Internet users. The user type is a type field that describes whether the user is a CDMA cell phone or a generic Internet user. Users who connect via PSTN dialing are considered generic Internet users. CRTP support is a signal that indicates whether the CD supports and attempts to negotiate CRTP Header Compression via PPP when connecting. This signaling is valid for cell phones, as well as for users based on PSTN. 0 CD user address will have several corresponding entries in the user part of database 232. The public key PGP is the key associated with the CD user address.

NBS network database defines the network set known to the CM. The network part of database 2.32 also lists the defined members of each network; that is, users who can ask to join and become participants in a network. Each record in the network part of database 232 consists of several fields. The fields include a network identifier, which is a unique integer that identifies the network within the context of the CM. The fields also include a network address, which is the network's SIP-compliant network address. The network owner (s), a non-empty list of users, is (are) identified by user identifiers who have administrative privileges (defined separately) for the network. In addition, the condition

37/98 protected from the network is a field for a flag that indicates whether the network is released or protected.

The fields also include an arbitration scheme, which is a unique value that identifies the arbitration scheme used in resolving PTT arbitration conflicts between network participants. The network voice encoder describes a field that has a unique value that identifies the voice encoder shown in the description of announced network sessions. Defined network members have this voice encoder listed in their list of supported voice encoders. The PTT fail-safe wait time is the maximum number of seconds that a network participant can transmit media to the network before the CM revokes floor control with the PTX deny message. The standby timeout value is the maximum number of seconds that the network can remain inoperable before the CM puts it in the idle condition. The PTX Sleep Response timeout value is the maximum number of seconds the CM waits after determining that the floor of a resting network can be guaranteed before the transmission of the PTX warranty response to the requesting CD. The wake-up time value is the maximum number of seconds that the CM waits for network participants to respond to the AYT wake-up message before securing an important PTT request. The late wake-up time value is the maximum number of seconds that the CM waits for a CD to respond to the CM's AYT wake-up message before the CM removes the unresponsive CD from the list of active network participants. The AYT timeout value is the maximum number of seconds that the CM waits for a CD to respond to an AYT message from the CM before the CM removes the CD from the playlist.

38/98 active participants in the network. The media channel list is a list of media channels, including payload specifications, for the network (networks list at least one media channel, which carries voice).

The list of members of the network defines the set of users who can request membership in the network as participants and the specific privileges of the related network. Each entry in the list contains fields such as user identifier, which is a unique identifier for a user listed in the network's 232 user database. The fields also include the network priority level, which is the user priority level to be used by the network's PTT arbitration algorithm when resolving PTT conflicts. A priority level of zero indicates that the user has only listening privileges and may never have secured control of the network. The fields can also include a user authorization list, which details the authorization privileges, if any, that the user has for the network. Privileges can include the ability to add, edit or modify entries in the list of network members and the ability to modify other network parameters.

Each CD maintains a database, also known as the list group, that identifies the known networks to which the CD can request membership. Each entry in the CD database includes fields such as network address, network security advisory signaling, network traffic encryption key and ama-dry stopwatch. The network address is the formal network SIP network address that the CD uses to request network membership as an active participant. The network security advisory signaling is the released / tied advisory signaling distributed by the CM SIP 236 server in its list of available networks or established

39/98 by the user to indicate a network defined to carry Type IV tied media traffic. The network traffic encryption key is the traffic encryption key used in the encryption and decryption of all media traffic for type IV strung networks. The ama-dry inactivity timer is the duration of the interval, * in seconds, during which the CD will wait when in the Idle condition between switching to the Connected condition, which confirms that the packet data call remains valid and that the base station did not drop the link unilaterally.

node 208 of the MCU comprises a media control unit (MCU), 252, a node manager, 256, of the MCU and the local registry server 260. Nodes 208 and 212 of the MCU can optionally also comprise an additional MCU , 264. MCU node 212 is substantially identical to MCU node 2,088. For purposes of description, only node 2 08 of the MCU is addressed in this report. The MCU 252 is responsible for controlling a single active network. The MCU supports SIP, media signaling and media interfaces for the network and provides the functionality associated with normal network operation. Each node 208 of the MCU can have a group of 252 MCUs that can be instructed to manage the networks, as appropriate. Each MCU 252 features an MCU management interface, 268, to support functions such as start, stop and report condition.

MCU node manager 2 56 monitors the health of MCU node 208 and manages the health of each MCU 252 on its MCU node 256. The node manager 256 of the MCU also presents an external interface, 272, with the core complex 204 of the CM, in order to provide

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starting and / or stoppage, assigning a network to the node and sharing information regarding conditions.

Local logging server 260 logs all occurrences locally for node 208 of the MCU. Local logging server 260 also responds to requests from local logging server 244 through its occurrence logging interface 276. Requests include loading certain classes or occurrence priorities. To prevent loss of occurrences, messages are stored on the local logging server 2 60 until an acknowledgment of receipt is received by the central billing logging server 244.

DNS server 216 provides name services to NBS communication devices. The DNS server 216 can handle SRV record requests. The DNS server 216 can be located anywhere on the network. In one embodiment, the DNS server 216 is a part of the core complex 204 of the CM.

Each CD maintains a list of networks, or a groupist, which internally represents the set of known networks in which the CD can participate. The list is non-volatile, but can be updated as needed, or through interactions with a CM, 104, or interactively by the user. The user is also able to determine who and how many users are either active or inactive on the network. 0 NBS list group maintained internally by a CD is analogous in function of the list of names and dialing numbers maintained in the telephone directory and used to facilitate voice services. The NBS directory group can be integrated with the conventional telephone directory of the telephone. In both cases, the act of selecting a network from the list group instructs the phone to try to join the selected network.

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In order to participate in a specific NBS network, each CD initially requests that the CM add itself to the list of active network participants for a specific network. In this way, each CD is initially aware of, or is able to learn, the network address of any networks in which it wishes to participate. In addition, each CD initially knowsando, or can be configured with, the address of a top-level SIP server, 236, to which SIP requests can be sent.

Network addresses can be presented to, or learned from, a CD in many different ways. For example, in one embodiment, the CD can initially be supplied with the address of a known or predefined top-level SIP server, 236, which provides a current list of networks in which the CD can participate. The CD can also be supplied with a list group, which defines at least one network address in which the CD is a member. The CD can later send a request for the top level 236 SIP server to update its group member. In the event that no explicit provision of NBS has occurred for the CD, the user can be provided with a top-level SIP server, 236, and a network address to enter the CD interactively before using NBS. The user can also interactively enter additional network addresses in a list group that has already been provided with entries. This configuration step is analogous in terms of entering personal names and dialing numbers in the conventional phone book.

Note that, although users can enter a network address in the CD list group, the corresponding top level SIP server and network 236 are preferably existing and the user must be

42/98 listed as a member of the network so that the CD is able to successfully participate in the network.

The CD can also be provided with the IP network address of the Domain Name Service (DNS) 216 server, to which the CD can send DNS queries. Typically, the address of the DNS server 216 operated by a CDMA cellular carrier is provided. The CD can also be provided with the IP network address of an alternate DNS server.

In order to support SIP authentication, the CD can be provided with a PGP user identifier and a unique secret key which it can use to sign SIP transactions when requested by CM 104. The PGP user identifier can be used as the address of CD user for generic SIP transactions.

Figure 10 illustrates the high-level functionality of the group 500 module of the CD. Typically, the group services module starts up in a predefined idle condition, 504, when the CD is activated. From the 504 inactive condition, the CD can move on to other conditions that allow it to actively participate in NBS networks.

The user may wish to temporarily disable NBS services via a menu option within the CD user interface. If the user has deactivated NBS services, the group services module goes into a predefined deactivation condition, 508, when the CD is activated. When disabled, the CD does not attempt to automatically associate with any NBS networks. In addition, the CD does not perform any NBS-specific SIP transactions (the CD can maintain records or perform other SIP transactions for other IP-based telephony applications that reside within the CD).

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Optionally, group services can be hidden entirely from the user by providing group services within the DC in a condition of not equipped, 512. The condition of not equipped disables group services, whereas a condition of equipped enables services of group. Once not equipped, the DC requires administrative provision to equip <group services. When group services are not equipped, NBS group services functionality and related user interface features are not available to the user.

The CD can support provision by air in order to equip NBS group services. In case the CD list group contains more than one network address, no more than one network address can be identified as a predefined network, 514. If a network address is selected, the CD tries to automatically switch from inactive condition 504 for attempting to associate with this selected network shortly after the CD is activated.

When the CD is connected, CD goes from a rest condition, 516, a listening condition, 520, a speech condition, 524 and an inactive condition, 528, based on where the user is in the push-to-stop system. speak as described in relation to figure 16.

NBS has a call signaling syntax and semantics defined by the SIP to announce available network addresses and provide mechanisms by which an individual CD can formally associate with networks or formally leave networks. CM 104, along with other functional entities, includes the top-level SIP server 236, one or more multi-point control units (MCUs), 252, and related SIP user agent servers, in addition to user parts and administration database network 232. 0 level SIP server

44/98 superior 236 acts as a known meeting point for participation in the system. Each MCU 252 switches media signaling and media traffic to one or more networks. Database 232 stores and provides user, administration and network address settings and can serve multiple CM installations or be accessed remotely.

Each CD is provided with a list of network addresses and one or more addresses from the top level SIP server 236. If the list group is empty, the user can interactively specify the address of an existing network. If no 236 top-level SIP server is defined, the user can interactively specify the address of a 236 top-level SIP server. Once the 236 top-level SIP server address is known, the CD can request an updated list of networks available to it by making a call, using the SIP INVITE method, to a predefined SIP destination.

The top-level SIP server 236 can redirect the request to an internal destination or respond to it directly. The INVITE response to this call includes the current list of networks available for the CD. The CD uses this list to update its internal list group.

Once the network has been selected, the CD attempts to join the network using the SIP INVITE method by specifying the network address as the request destination and by sending the request to the top level SIP server 236. The level server superior 236 attempts to map the network address to a known destination and, if successful, redirects the CD to the corresponding SIP agent user server on the MCU 252. If no mapping is available, the request usually fails.

Typically, the MCU 252 target SIP user-agent server confirms that the CD is a member of the network

45/98 selected and responds to the request, embedding a description of the traffic parameters and signaling means to be used to participate in the network in the content of its response. The MCU 252 SIP user-agent server can also respond with an error if it is unable to confirm the CD as a legitimate member of the network or if some other error condition arises, such as a failure that prevents it from functioning normal network. If the request is accepted, the CD acknowledges receipt of the response by means of a message, such as, for example, the SIP ACK (ACCEPT RECEIPT) method. Note that other transient response codes, which indicate the progress of the call, can also be received by the CD while the request is being processed.

The CD is responsible for updating its group member for the set of networks in which it can participate. The user can command the CD in order to consult the database 232 of the CM 104, even when no network address is selected, in order to receive updates for its list group. If the CD determines that it has been added to or removed from a network, it displays to the user, for a brief period of time, an appropriate message (for example: Added to group X) and / or possibly guides towards interaction with the user. If the CD determines that it is not a member of any network, it will likewise inform the user. The CD can automatically incorporate new

<td>network addresses in your list group,</td><td>but</td><td>can</td><td>guide the</td>

<td>user before deleting addresses</td><td>in</td><td>nets</td><td>in which</td>

<td>ceased to be a member of the list group.</td><td></td><td></td><td></td>

<td>In general, no more</td><td>in</td><td>an</td><td>network in one</td>

CD list group can be identified as selected at once. A predefined network can be selected

46/98 initially, or the user can select a network from the list group.

The response of the MCU 252 CM SIP user-agent server to an INVITE request to join a network includes, as embedded content, the destination addresses of the network's media signals and real-time media, as well as other network parameters (such as media payload format descriptors). Once confirmed, the CD displays, for a short period of time, feedback to the user, indicates whether the user has privileges to listen only and activates group service functions. If the CM 104 determines that the CD is not a member of the selected network, or if an error or other exceptional condition occurs, the SIP 252 server responds with a response to the corresponding error. When such registration is refused, the CD displays, for a short time, a corresponding error message, and the group service functions remain inoperative. If no network is selected, the group services within the CD remain inoperable.

As part of the activation of the group services, the CD initializes and opens its RTP 128 media traffic channel and the NBS 124 media signaling channel distinct from the CM destination addresses presented in a successful request response. Once these channels are initialized, group services are activated on CD 108, and it introduces the 516 group service rest condition with the ability to receive voice traffic from the network and request permission to send voice traffic to the network.

With group services active, CD 108 monitors its media traffic channel 12 8 and signaling channels 124 for the CM. The voice data received in the media traffic channel 128 is decoded and presented via a long-range speaker,

47/98 or an earpiece accessory, from CD 108, according to the current user configuration. CD 108 displays the speaker identity as identified by means of real-time media signaling 124. If speaker identity- is not available, CD 108 displays the current selected network name as listed in the group . CD 108 can also table media traffic statistics (for example, the total time spent talking, listening and monitoring, estimating the loss of media traffic packets) and making them available to the user as a diagnostics via a menu option. Although it receives traffic from the network, the CD 108 goes to the listening condition of the group services 520, returning to the resting condition 516 when the voice traffic is interrupted.

At any time, the user can request permission to speak to the network by pressing the PPP button and causing the CD 108 to signal the CM 104 (specifically, the MCU 252) with a floor control request. The PTT button can be any type of activation command, including, but not limited to, pressing a key or key sequence, voice activation, a switch, a toggle device, or disks. MCU 252 responds either by guaranteeing or denying the request. If the CD has listen-only privileges, such as CD 112 (ie, the CD has a priority level of zero within the selected network), the request is denied. If denied, CD 112 alerts the user with an error tone, displays an error message or explanatory message, and returns to the idle condition 516. The CD insists that the PTT be released and pressed again before attempting another request for control of floor. If guaranteed, the CD 112 introduces the speech condition of group services 524, signals the

48/98 user with a brief audible peep, for example, and starts transmitting voice traffic to the CM 104 while the PTT is pressed. The CM 104 can signal asynchronously to the CD 112 (while the PTT is pressed) that it has lost control of the floor. Upon receipt of such a signal, the CD 112 aborts the transmission of voice traffic and alerts the user with an error tone until the PTT is released, at which point it returns to the resting condition 516. Otherwise, once the PTT is released, the CD 112 signals the CM 104 that it has released the floor and returns to the resting condition 516.

The user can switch to a different network by selecting another network from the list group whenever the group services within CD 108 are in the idle condition 516, in the listen condition 520 or in the idle condition 528. When a new network is selected, the CD 108 signals the CM 104 to remove it from the current network through call setup mechanisms and then follows similar procedures to join the new network. If the process of joining the new network fails, CD 108 is no longer a member of any networks, and the group services within CD 108 return to 504 inoperative status.

If CM 104 determines that the CD 108 requesting the floor of a specific network is the only registered member of the network in question, the CM 104 denies the floor control request and signals an error message, such as an user error alone, which CD 108 displays to the user. Although there may be a network with only one registered member, a network cannot relay voice traffic unless there are at least two registered members.

The application of NBS is based on two distinct application-level protocols: call signaling

49/98 of the Login Protocol (SIP), described with reference to figure 11, and the NBS Media Signaling, described with reference to figures 12-14. SIP is used exclusively for signaling calls and configuring calls. Media signaling transports PTT requests (figure 12), manages network downtime (figure 13) and resolves PTT arbitration conflicts (figure 14).

The signaling of SIP 350 calls is illustrated in figure 11. The Session Initiation Protocol provides control (signaling) of the NBS application layer to discover, associate with NBS networks and leave them via the SIP 236 server interface of the CM 104. To join a network, a CD 352 invites network 100, by name, to join a call, through the top-level SIP server 236. To leave network 100, CD 352 sends one up to logo corresponding to the network.

The CD 352 determines the IP address of the top level SIP server 236 using DNS 216 to resolve the primary or secondary SIP server addresses provided in Internet network addresses, if necessary. As an optional alternative approach, SIP conventions allow CD 352 to query DNS 216 service records associated with the domain part of the NBS main system of the network address and contact the SIP 236 server at ( s) returned.

By default, CD 352 attempts to contact the SIP 236 server using a predefined SIP port, unless alternative port information is determined using DNS 216. Before attempting to join a network, CD 352 you can make a call, using the SIP INVITE method, to request an updated list of available networks.

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For example, CD 352 that has created a connection over the air is assigned an IP address, and CD 352 wants to determine its current list of available networks. This opens a UDP / IP connection to the IP server port and issues a request. The request to obtain an updated list of networks is addressed to a special destination. Where appropriate, CD 352 also includes additional application-specific headers that identify the CDMA network and system from which a CDMA cell-based CD 352 is obtaining service.

CD 352 may also include a header to indicate that CD 3 52 expects the SIP 23 6 server to understand and support NBS services. The option value distributed with the header can also be used by CD 352 to inform server 236 of a specific version or type of NBS services that CD 352 expects server 236 to support.

The top level SIP server 236 of the CM can redirect a request request, 356, through SIP redirect mechanisms, to a destination specifically defined to receive and respond to requests for information about networks. Upon receiving such a redirection, CD 352 acknowledges receipt (ACK) of the 357 response and resends the request to the redirected destination.

It may be necessary for CD 3 52 to determine the appropriate SIP contact point for the redirected address, through DNS mechanisms. In order to simplify this process for CD 352, server 236 can specify the redirect destination using its Internet network address explicitly. Once the INVITE 354 message, which requests a list of networks, is successfully received and accepted by server 236, server 236 transmits a response, 356, to the INVITE request.

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Response 356 to the INVITE request includes, in its content, a list of records that define the set of networks that the CD 352 can then associate with. The server 236 queries its database 232 to find out about the networks that list the requesting CD 352 as a defined member in order to form the response 356 to the INVITE 354 request. The networks are identified within the content using a defined record format by the application that includes the formal network address of the network. Networks can be listed in any order.

Server 236 may be unable to successfully respond to CD 352 for several reasons. In such circumstances, server 236 transmits an appropriate SIP condition code in place of the INVITE 356 response. CD 3 52 must be prepared to accept and interpret such condition codes, taking appropriate action (such as displaying a message error message on the CD 352 user interface screen) in case of any fatal errors. Server 236 can also preface a successful INVITE 356 response with informational condition responses that indicate the progress of the records. The CD 352 can accept and interpret informational condition codes that preface successful registrations.

CD 352 asks to join a network by issuing a SIP INVITE request, 358, to the CM 240 manager through server 252. If CD 352 does not have a UDP / IP connection to the SIP server 252, it will open a new one UDP / IP connection to the SIP server port.

The CD 352 is prepared to be redirected by the top level SIP server 236 and to reissue the request to the redirected destination, if necessary The top level SIP server 236 of the CM redirects any incoming INVITE requests, as appropriate, to

52/98 the MCU SIP 252 server currently associated with the network in question. The CD 352 can be redirected more than once.

The INVITE 358 request may include a description (as content - of message) of the media sources that originate with the CD 352, assuming that the request is successful. If included, the description is included as message content and described using field constructions.

The session description is transmitted in a format compatible with the Session Description Protocol (SDP). After defining the SDP version (v), the session description includes a mandatory source description (o). The CD 352 can employ any suitable mechanism to choose the values for the session identifier and session version. Presenting an estimate of the current moment is a possible way to define the session identifier. Connection data (c) is specified by defining the network type, address type and connection address. CD 352 uses the IP address with which it labels media (or source) traffic as the connection address. The CD 352 uses the name portion of the network address as the session name (s). CD 352 specifies the session lifetime (t) by providing your best estimate of the start or current moment, preferably in Network Time Protocol (NTP) format and indicates that the session is unlimited, (0). The media format description (m) defines the media type, source port, transport protocol and payload format that the CD 352 intends to use to transmit to the network. Finally, the session description uses an attribute type definition (a) to indicate that CD 352 expects the session to function as an NBS conference. The server 236 must confirm that the requested address is

53/98 indeed a valid NBS network address before securing the request.

In order to indicate a successful request, and specifically inform CD 352 that it has been added to the list of participants for the requested network, server 236 sends an INVITE 360 response.

A successful INVITE response, 360, includes the primary session description for the guest network, which describes ports and media traffic formats supported using SDP syntax. The session description includes a connection description (o) that defines the network address to which signaling and media traffic are to be sent. 0 The destination's network address is not necessarily identical to the network address of the SIP user-agent server resolved using the DNS of the network's network address.

The session description describes all media ports and destination media. The session description must also include an identifier assigned to the CD 352 by the MCU 252 for the purpose of identifying media signaling messages transmitted by the CD 352 as part of its subsequent participation in the network. The value of this identifier is unique among all active participants in a given network and must therefore be generated dynamically. CD 352 does not necessarily cache this identifier between 'successful SIP requests.

The session description can also include an NBS protocol version announcement that indicates the level of revision to which the network media signaling adheres. Such an announcement can be implemented by extending. the value of the type attribute field (type) or defining a new attribute, whose value is the protocol version number.

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After receiving an INVITE response, CD 352 confirms the request by sending an acknowledgment request (ACK), 362, back to the network MCU's SIP agent user server 252. After transmitting the ACK request 3 62, CD 3 52 can close its TCP connection to the SIP server. Before the ACK 362 request is transmitted, the CD 352 initializes its signaling and media traffic ports according to the session description transmitted in the INVITE 360 response.

At any time after CD 3 52 has transmitted the SIP ACK 3 62 message in response to a successful INVITE 360 response, CD 352 can formally terminate its participation in the network by sending a SIP BYE 364 message to the user-agent server 252 from the Web. Before sending the BYE message (UNTIL SOON) 3 64, the CD may need to open a TCP connection with the user server agent 252. The BYE message 364 is acknowledged by the CM with a reply message BYE, 366. Once it acknowledges receipt of the BYE 366 response message, CD 352 can close its UDP connection to the user-agent server 252. Before acknowledging receipt of the BYE 366 response message, the user-agent server 252 removes the CD 352 from the list of active participants in the indicated network.

In general, a SIP user agent agent on CD 3 52 can use the OPTIONS method to query the capabilities of a SIP server. In particular, CD 352 may wish to query an arbitrary SIP destination to determine whether the destination provides NBS call signaling support.

CD 352 may wish to abort an INVITE (REQUEST) request, 358, pending before receiving the INVITE 360 response and ending receipt confirmation 362. In

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Ο 10 ©

In such circumstances, the CD 352 may employ a SIP CANCEL method (not shown) in order to gracefully abort the call. Both the top-level SIP redirect server 236 and the user-agent server SIP 252 of the CM support the CANCEL method.

For example, CD 3 52 can employ the CANCEL method to abort an INVITE, 358 message, in progress if the user decides to make a voice service call and press send before the INVITE 358 message is completed. In such a circumstance, instead of waiting for the INVITE 360 response to complete and immediately send the BYE 3 64 message, CD 3 52 can simply CANCEL the INVITE 358 message immediately and proceed to make the requested voice services call.

After the CD 108 has successfully negotiated the entry into the current membership of an NBS network using SIP, all real-time call control takes place through point-to-point application level media signaling messages exchanged between each CD 352 and the network MCU SIP 252 server.

The media signaling messages are carried through the protocol stack shown in figure 4, and according to the sequence shown in the figure

12. Figure 12 illustrates a sequence of media signaling messages 368. A PTT request message 370 is sent by CD 352 to the user-agent server SIP 252 of node 208 of the MCU and signals the user's desire to broadcast media, usually voice , for the network. Normally, the PTT 3 70 order message is sent for each press of the CD 352 push-to-talk button to denote a floor control order. In addition, a PTT release message is sent by CD 352 to the SIP 252 user-user server

56/98 in order to denote the normal release of the floor when the user releases the CD 352 push-to-talk button.

The PTT message consists of fields such as opcode (operational code), id, src and reserved. The opcode field defines whether the PTT message is a floor control request or a release message. The id field has a unique message identifier that allows PTT and PTX release messages to refer to a specific PTT request. The id must be unique within the registration session for a specific CD, 352. The src field uniquely identifies the CD 352 that sends the PTT 370 request to the SIP 252 agent user server. The reserved field reserves space in the PTT 370 message for future capabilities.

CD 352 expects to receive at least one PTX response message, 372, for each transmitted PTT 370 request. If a PTX 372 response is not received within a predetermined timeout period, CD 352 assumes that the PTT 370 request was lost in transit and retransmits the PTT 370 message using the same PTT id.

If the PTX 372 response message is never received from the SIP 252 user-agent server within a predetermined number of retransmissions, CD 352 assumes that the SIP 252 user-user-agent server is no longer reachable, it passes to the NBS idle mode and indicates an error condition to the user. In a preferred embodiment, CD 352 employs a different PTT id for order and release messages.

The PTX 3 72 message is sent by the SIP 252 user-agent server to a CD 352 in order to acknowledge receipt and respond to a previous PTT 370 request, as well as signal asynchronous floor control occurrences. The SIP 252 user-agent server employs the PTX 372 message in order to respond to a request or

57/98 release of PTT floor control. The PTX 372 message includes information such as whether the referenced floor control request was granted or denied. When responding to a PTT 3 70 floor control release, the PTX message

372 is used to indicate receipt confirmation only. The SIP 252 user-agent server can also employ the PTX 372 message to asynchronously deny a * previously guaranteed floor control request (when a higher priority CD 3 52 issues a floor control request, the PTX guarantee expires ( that is, it becomes invalid), or if there is any other occurrence that requires the control of the network floor to be revoked).

The PTX 372 message comprises fields such as opcode, id, action, condition and expires. The opcode field defines whether the PTX 3 72 message is an asynchronous response to an important PTT request, or whether it is an asynchronous message that indicates an error or priority arbitration conflict. The id field refers to a previously received PTT request. The action field indicates whether the PTX 3 72 message is guaranteeing, denying, revoking or confirming the control of the network floor. The condition field provides additional information that explains the PTX action, especially in cases where the PTX 3 72 message denies, revokes or cannot act on the previous PTT request. The condition field may indicate that a higher priority speaker has been granted control of the network, or that the CD 352 is not listed as a network participant and hence it is not allowed to submit media signaling requests to the network. The expiring field represents the maximum duration, in total seconds, for which the network floor control is guaranteed to the receiving CD 352. The user server agent SIP 252 starts its timer from the moment it sends the response from the PTX 372 message - not when the

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CD 3 52 begins to send media traffic. The expiring field value is a configurable network parameter.

CD 352 does not explicitly acknowledge receipt of the PTX 372 message response. Instead, if the transmitted PTX 372 message response is lost, the CD 3 52 PTT retransmission timer expires and CD 3 52 retransmits its PTT 370 request. Since the retransmitted PTT 370 has the same id as the lost PTX 3 72 response, the SIP 252 user-agent server responds by resending the lost PTX 3 70 message response, and does not treat the retransmitted PTT 372 message request as one. distinct press-to-speak request occurrence.

A PTA message, 374, is sent by the user-agent server SIP 252 to each CD 352 currently participating in a network, in order to announce the identity of the source of the pending media traffic. A PTA 374 message is also used to formally announce the end of a spurt of speech.

The PTA 374 message comprises fields such as opcode, speaker and reserved. The opcode field indicates whether the message PTA 374 is announcing the guarantee (or release) of the floor to (or by) the CD 352 identified by the speaker. The speaking field identifies the CD 352, which causes media traffic to the network until the next PTA 374 message is sent. The reserved field reserves space in message PTA 374 for future capacities.

The CD 352, whose PTT 370 floor control request was successful, may or may not receive a PTA 374 message that announces that it has control of the floor. The message can arrive before or after it receives the corresponding PTX 372 response, since UDP does not necessarily preserve the ordering of datagrams. However, the SIP 252 user-agent server sends the PTA 374 announcement

59/98 before waiting for it to start sending media (in the case of a PTA warranty announcement). It is recommended that the requesting CD 352 ignore incoming PTA 374 messages that announce that it has gained control of the floor and that it only relies on receiving a PTX 374 warranty message response in order to determine whether it can initiate transmission of means, to the network.

AYT message are you there ?, 404 (figure

13), is sent by the SIP 252 user-agent server to an individual CD 3 52 in order to confirm that the CD 3 52 in question is reachable via IP. A meeting of AYT 4 04 messages can be sent to a group of network participants in order to signal that a network is no longer in idle mode.

The AYT 404 message comprises fields such as opcode, id and reserved. The opcode field indicates whether node 208 of the MCU is sending the AYT 4 04 message in order to determine whether the CD 352 is still reachable or whether the user-agent server 252 is using AYT 4 04 message traffic to take the channels network-related CDMA cell traffic out of sleep mode. The id field has a unique message identifier that allows a subsequent IAH I am 408 response message to refer to a specific AYT 404 request message. The id can include a timestamp reference to generate latency estimates. The reserved field reserves space in the AYT 404 message for future capabilities.

The CD 352 may or may not be in sleep mode when an AYT 404 message is sent. In all cases, CD 3 52 responds to an AYT 4 04 message received with an IAH 408 reply message.

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The SIP 252 user-agent server assumes that the CD 352 generally responds to an AYT 404 message with an IAH 408 response. If an IAH 408 response is not received within a reasonable time, the SIP 252 user-agent server transmits a new AYT 408 message with a new id. If after a configurable number of retransmissions, a reply to the AYT 408 message is not received from CD 352, it is assumed that CD 352 is unreachable, and the SIP 252 user-agent server removes it from the current list of network participants . Future media signaling messages from the removed CD 352 will be ignored (or will generate an error response) until the CD 352 successfully joins the network again.

The IAH 408 message is sent by CD 352 to the SIP 252 user-agent server in order to acknowledge receipt of a previously sent AYT 404 message. The IAH 408 message comprises fields such as id, src and reserved. The id field refers to an AYT 408 message received whose receipt CD 3 52 is confirming. The src field uniquely identifies the CD 352, which sends the response from the IAH 408 message to the user server agent SIP 252. The reserved field reserves space in the IAH 408 message for optional capabilities.

The SIP 252 user-agent server assumes that CD 352 acknowledges receipt of all AYT 408 messages received with an IAH 408 reply message. If the referred AYT 408 message was sent in order to confirm that a CD 352 remains connected in the NBS rest condition, passively monitoring the traffic and signaling of NBS media, the user-agent server SIP 252 observes the moment of receipt IAH 4098 for future reference.

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Since the SIP user agent server 52 is responsible for setting the value of the id field, the SIP user agent server 252 can use the id to determine and track whether a specific CD 352 remains reachable.

The ZZZ or standby message (shown in figure 13 as reference number 412) is sent by the user-agent server SIP 252 to encourage the CD 352 to release its resources over the air and enter sleep mode. The CD 352 can choose to ignore this message (especially if it is supporting other package applications concurrently).

The ZZZ message comprises fields such as id and reserved. The id field has a unique message identifier to allow the CD 352 to differentiate between multiple ZZZ message receipts. The reserved field reserves space in the ZZZ message for optional or future capabilities.

The CD 352 does not acknowledge receipt of the ZZZ message. Error recovery is generally not attempted if the ZZZ message is lost. To protect against the loss of a ZZZ message, the user-agent server 252 can send multiple copies of the same ZZZ message to an individual 352 CD. The SIP 252 user-agent server ensures that copies of the same wait message are sent within a defined interval, and CD 352 expects a longer period than this interval from the moment the first message (with a new id) is received before releasing your connection through the air and going into a rest condition.

As illustrated in figure 15, an ASK message, 382, is sent by CD 352 as a query, 384, to the user-agent server 252 in order to confirm the

62/98 connectivity to the SIP 252 user-agent server. The ASK 382 message also allows CD 352 to determine whether CD 352 remains listed as a network participant. The CD 352 can confirm your participation after a period of service disruption or - another period in which you may have temporarily lost connectivity with the user server agent SIP 252. »

The ASK 382 message comprises fields such as id, src and reserved. The id field has a unique non-zero message identifier to allow a subsequent FYI reply message to refer to a specific ASK request message. The src field uniquely identifies the CD 352 that sends the ASK 382 message request to the SIP 252 user-agent server. The reserved field reserves space in the ASK 382 message for optional or future capabilities.

CD 352 assumes that the SIP user agent server 2 52 responds to an ASK message 3 82 received with an FYI 386 response message. If an FYI 386 response is not received within a predetermined timeout period, the CD 352 transmits a new ASK 3.82 message with a new id. If after a configurable number of retransmissions, a reply to the ASK 382 message is not received from the user-agent server 252, it is assumed that the user-agent server SIP 252 is unreachable, and the CD 352 goes into idle condition. group service.

The FYI 386 message is sent by the SIP 252 user-agent server to CD 352 in order to acknowledge receipt of a previously sent ASK 382 message, or is sent asynchronously by the SIP agent user server 252 to inform CD 352 of a condition exceptional.

The FYI 386 message comprises fields such as operational code, action, condition, id and reserved. 0 field

63/98 operational code defines whether the FYI 386 message is a synchronous response to an important ASK 382 request, or whether it is an asynchronous message indicating an exceptional condition. The action field indicates whether the message FYI 386 is confirming participation in the network, informing CD 352 that it has been administratively deleted from the list of network members, or performing some other function to be defined. The condition field provides additional information that explains the FYI 386 response, especially in cases where

<td>the message</td><td>FYI</td><td>386 indicates that the</td><td>CD</td><td> 352</td><td>it is not</td><td>one</td>

<td>participant</td><td>or</td><td colspan="2">network member. 0 field</td><td>id</td><td>refers</td><td>an</td>

<td>ASK message</td><td> 382</td><td>previously received</td><td>gives</td><td>which one</td><td>CD 3 52</td><td>it is</td>

acknowledging receipt. The value of the id field is undefined for asynchronous FYI responses. The reserved field reserves space in the IAH 408 message for optional or future capabilities.

CD 352 generally does not acknowledge receipt of responses from the FYI 386 message. If a synchronous FYI 386 message is lost, CD 3 52 sends a new ASK 382 message request. Since CD 352 does not request asynchronous responses to the FYI message 386, in a preferred mode the SIP 252 user-agent server makes at least three alternate transmissions of any asynchronous responses to the FYI 386 message.

A participating CD 352 signals a user's desire to broadcast media to the network by issuing a PTT 3 76 message request to the SIP 252 user-agent server. The SIP 252 user-agent server responds to the PTT 3 76 request with a 378 response to the PTX message, which can either guarantee or deny the request. If the order is guaranteed, a PTA 380 announcement message is broadcast to all participants in the network. The user interface of the requesting CD 352 can indicate to the user that permission

64/98 to speak to the network was guaranteed as soon as the guarantee response 378 to the PTX message is received. The CD 352 normally broadcasts media traffic until the user releases the PTT button, at which point it signals the end of the speech spurt by issuing a release message, 376, to the SIP 252 user-agent server. 0 user-agent server SIB 252 responds with a PTX 378 confirmation message and broadcasts an announcement that signifies the end of the spurt of speech to all participants in the network.

When any CD 352 has the floor (the right to speak) of a network, the network is said to be active; otherwise, it is inactive. If a network is inactive for a period that exceeds the network suspension time, the SIP 252 user-agent server can put the network to sleep by individually signaling all registered mobile stations to release their traffic channels over the air. A condition is maintained that allows a floor control request or other traffic to bring the network out of sleep relatively quickly. Network members can ignore messages going to sleep mode. The SIP 252 user-agent server does not explicitly or implicitly trace the idle condition of individual members of the network.

As shown in figure 15, the SIP 252 user-agent server will wake up a network and bring it out of sleep mode 616 when a successful floor control request, 704, is received during the sleep condition. Once the control request has been granted, the SIP 252 user-agent server will signal each registered 352 CD requesting the response you are there (AYT) 716 through the media signaling channel and start an internal alarm clock, 724. Each CD

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352 acknowledges receipt of the AYT 716 response to the SIP 252 user-agent server if it wishes to remain registered on the network. Optionally, a CD 3 52 at rest can temporarily store media traffic 740 from the moment the user presses PTT until the CD 352 traffic channel is (re) connected. 0 user-agent server SIP 252 can temporarily store media traffic 470 received from the talking CD 3 52 until the wake timer 724 exceeds the wake up time, at which point it starts sending media traffic to each registered CD 352 - including any members who have not yet responded to the AYT 716 request. In this way, both the CD 3 52 and node 2 08 of the MCU have the capacity to temporarily store data until the recipient is ready to receive the temporarily stored information. In one embodiment, pieces of data are stored on both the CD 352 and node 208 of the MCU.

The SIP 252 user-agent server periodically retransmits AYT 716 requests to any registered 352 CDs that have not acknowledged receipt of the AYT 716 request. the SIP 252 user-agent server will unregister any member 352 CD whose confirmation of AYT receipt is important and interrupt the 724 wake-up timer. The SIP 252 user-agent server ignores duplicate AYT responses.

If CD 352 tries to join a network that is currently in sleep mode, the SIP 252 user-agent server processes the request normally and then signals CD 352 to enter sleep mode. The signaled CD 352 can ignore the command go to sleep mode.

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During periods of prolonged network inactivity, NBS allows a packet data service call to be made in the idle condition 528 (see figure 11). The SIP 252 user-agent server facilitates transitions into and out of the 528 sleep condition by independently managing a similar sleep concept for each NBS 100 network.

Figure 13 illustrates the sequence of media signaling messages with respect to inactivity 400 between CD 252 and the user-agent server SIP 252. In general, a message is passed to the condition of inactive for all CDs in the network based on a control signal sent from the CD, based on a timer on each CD. Therefore, the resources allocated to the network are released and can be used for other users. In configurable planning, the user-agent server SIP 252 sends a message request (AYT), 404, to each CD 352 in order to confirm that the CD 352 in a rest condition can still be reached. In this way, CM 104 maintains centralized interrogation of current network users and their condition. This also allows individual CDs to dynamically join the network or leave the network dynamically. CD 3 52 responds to AYT request 04 04 with a message response (IAH) 408. AYT 404 messages are not necessarily broadcast to each CD 352 at the same time. The SIP 252 user-agent server can alternate sending AYT 404 messages to each network participant in order to avoid receiving a flood of simultaneous IAH 408 message responses.

After the network has been idle long enough for the configurable network downtime to expire, the SIP 252 user-agent server broadcasts a ZZZ, 412 request message to each participant in the network.

67/98 network. In response, each CD 352 can release its resources over the air and enter idle mode. Network participants do not necessarily have to respond to the ZZZ 412 order message.

A successful PTT 416 request from CD 352 takes the network out of idle. In one embodiment, a predetermined threshold number of users is required to respond in order to take the network out of idle. Before securing the request with a PTX 42 0 message, the SIP 252 user-agent server sends an AYT 424 message request to each CD 352 in order to force each CD 352 that previously participated out of the idle condition. This is done if CD 352 chooses to release its resources over the air in response to message ZZZ 412 and confirms that participating CD 3 52 can still be reached. In another mode, after a configurable but fixed delay, defined as a PTX inactivity response timer, the SIP 252 user-agent server transmits the PTX 420 guarantee message response to the requesting CD 352. Once a second wake-up timer has expired (whose value is generally not less than the PTX inactivity response timer), the SIP 252 user-agent server announces the speaker, via a PTA message, 428, to all participants in the network and can start sending media.

Node 208 of the MCU is responsible for receiving incoming data packets from the transmitting CD 352 and sending duplicate copies of the received data packets to other members of the network to which the transmitting CD 352 belongs. As each data packet is received by node 2 08 of the MCU, it is stored in memory (not shown). The transmitting CD 352 can be identified by querying the data packet. In one embodiment, a

68/98 IP address representing the transmitting CD is included in each data packet as a way of identifying it.

Once the transmitting CD 352 has been identified, the MCU .256 node manager retrieves a list of network members belonging to the network associated with the MCU node 208 from local memory (each MÇU is typically assigned to only one network). A destination address is associated with each active member of the network, that is, members of the network that are currently registered with node 2 08 of the MCU in local memory. In one embodiment, the destination address is an IP address. 0 MCU node manager 2 56 then creates a duplicate of the original data packet, except that the destination address identified within the data packet is modified to reflect the destination address of the first member of the network. Then, MCU 2.08 creates a second duplicate data packet, addressed to the second member of the network. This process continues until the original data packet has been duplicated and sent to all active members of the network in local memory. During the termination of any temporarily stored media, the CM 104 treats the network as active, even though the speaking CD 3 52 has cleared the floor. Consequently, CM 104 does not allow a CD 352 to interrupt the termination of temporarily stored media, unless the interrupt CD 352 has a higher priority than the source of the temporarily stored media.

Note that the SIP 252 user-agent server can receive IAH message responses, 432, for an extended period after the network is taken from idle, and that the SIP 252 user-agent server does not expect all network participants respond before securing the pending PTT 416 request. Respondents

Late 69/98, whose IAH 432 response arrives after the PTX 420 warranty message response is transmitted, remains listed as network participants, but may not receive all initial media traffic and signaling. It is assumed that any CD · 352 that does not respond to the AYT 424 request after a third (and configurable) third delay can no longer be reached and is removed from the list of active network participants.

Figure 4 illustrates a sequence of NBS media signaling messages, 440, which demonstrates a higher priority CD 442 interrupting a lower priority CD 444 with network floor control.

Initially, a lower priority CD, 442, submits a PTT message request, 446, to the SIP 252 user-agent server, which is guaranteed by the SIP 252 user-agent server. The SIP 252 user-agent server announces that the CD 442 has control of the network floor.

While the lowest priority CD 442 is transmitting media 443, a second ÇD, 444, tries to interrupt by sending a PTT message request, 448, to the SIP user agent server 252, to the same network. The SIP 252 user-agent server determines that the second CD 444 has a higher priority than that of speaking CD 442 and immediately revokes control of the network floor of speaking CD 442 by sending him an asynchronous PTX denial message, 450 . 0 SIP 252 user-agent server then secures PTT request 448 to the highest priority CD 444 with a response from the normal PTX guarantee message, 452, and announces that the highest priority CD 444 has control of the network floor .

If the SIP 252 user-agent server determines that interrupt CD 444 has no higher priority, the SIP 252 user-agent server rejects

70/98 immediately requests PTT 448 with a response from the PTX message, 454, and continues to distribute media 456 from the talking CD to network participants without interruption.

Although the priority assigned to a specific CD is a fixed value defined in the database maintained by the SIP 252 user-agent server, the SIP 252 user-agent server can employ other arbitration algorithms that do not always necessarily guarantee the floor to the requesting participant, as shown here. The PTT arbitration algorithm used to arbitrate conflicts can be configured individually on a per network basis.

At a minimum, the SIP 252 user-agent server supports an arbitration policy that allows a CD to interrupt the current speaker if the CD has a priority level that exceeds that of the current speaker. A minimum priority CD can listen to media traffic, but never gain control of the network floor.

Figures 15 and 16 illustrate the operation of CM 104 and CD 352, respectively, during different conditions. The CM 104 maintains a sleep timer for each network, or the sleep time timer 62 0. When the sleep timer 620 reaches a configurable setpoint, the timer triggers the CM 104 to put the network in a sleep condition. inactivity, 616, by broadcasting a media signaling message, 696, to all network participants. Upon receipt of the message, a participating CD 352 may release its traffic channel and enter a rest / inactivity condition, 844, or CD 352 may ignore the message and remain in a connection condition, 820. In particular, network participants who are not operating through a channel, such as PSTN users of

71/98 dialing, should ignore the media signaling messages.

The network suspend time timer 62 0 does not advance for the duration that a response from the PTX warranty message, .632, is an effect. Stopwatch 620 is reset to zero when the PTX 632 warranty message is transmitted and remains at zero until the PTX 632 warranty expires or CD 352 clears the floor 872 of the network. Once the floor is cleared, the suspend time timer advances until the response to the next 632 warranty message is transmitted.

If a participating CD 3 52 enters the idle / idle condition 844, it remains at rest until either package data addressed to the CD 352 reaches the cellular infrastructure MA of the CD 352, or the CD 3 52 generates data to be sent using the service of packet data. The first case can be triggered by the traffic sent to the CD 352 by the CM 104 (908). The last case can be triggered by the user pressing the PTT button in order to request permission to broadcast, 824, to the network. Other shots not related to NBS are also possible.

The network itself remains inactive until one or more participants initiate the transmission of a PTT request, 704. If CM 104 determines that it can guarantee the PTT request message 704 (including the execution of any arbitration necessary to handle multiple requests) , it sends a request, 716, to each listed network participant in order to trigger a transition out of the 844 rest / inactivity condition. For any specific CD 352, triggering may or may not be necessary, but each CD 3 52 nevertheless responds to the request. In this circumstance, when a network is transiting out of the 616 resting condition, CM 104 abstains from sending the

72/98 initial PTX warranty response message 756 until a fixed but configurable delay, the PTX 728 idle response timer, expires. After the stopwatch 728, whose default value is typically zero, expires, the CM 104 sends the PTX 756 warranty, as usual. In the meantime, CM 104 continues to refrain from sending media to the network until a second, similar * timer, the network's 724 wake-up timer, expires. Both timers reset when the CM 104 determines that the floor of the inactive network can be guaranteed. The value of the 724 wake-up timer should not be less than the value of the PTX 728 inactivity response timer. After the 724 wake-up timer expires, the CM 104 starts sending media, and media signaling and traffic flow normally. Both timers are configurable on a per network basis.

If CM 104 determines that it cannot guarantee the PTT 704 request, it immediately signals the requesting CD 352 accordingly with a PTX denial message, 708, and the network remains inactive.

A CD 3 52, which has entered the Sleep / Inactivity 844 condition, may require a system change, change service options or experience some other service disruption, which makes it never receive and respond to the AYT wake-up message 908. The CM 104 maintains a third longer timer, which also resets with the PTX wake-up and inactivity response timers. This longest late wake timer (not shown) is also configurable on a per network basis. After the late waking time has expired, any CD 352 whose IAH 916 response to the AYT 908 wake-up message has not been received is removed from the list of active network participants by CM 104. Any CD 352

73/98 removed it registers itself with the SIP 236 server in order to become once again a participant in the network.

Due to potential delays related to the passage of a CD 3 52 from the Sleep / Inactivity condition 844 to the connected condition, both the CD 352 and the CM 104 can effect temporary voice storage in order to mitigate the transition delay perceived by the user.

Typically, the CD 352's user interface signals the user, through visual or aural mechanisms, at least two milestones when processing a PTT button press. First, the CD 352 signals that it has detected a PTT keystroke. Subsequently, CD 352 signals that it has received response 868 to the PTX message from CM 104. If the 868 response to the PTX message grants permission to broadcast media, the CD 352 user interface provides an indication that the user can start talking to the network; otherwise, the CD 352 user interface indicates that the user has been denied permission (856) to speak to the network.

When the network is not idle, the latency between the transmission of the PTT request message and the receipt of the corresponding PTX response message is relatively small, and the user becomes accustomed to being granted permission to speak shortly afterwards the PTT button is pressed. However, when the network is down, a relatively significant delay can separate the transmission of the PTT 852 request and the receipt of the corresponding PTX 856 or 868 message. The delay may occur because the CD 352 may have freed its traffic channel and experiences a delay in restoring the packet data service. The delay can also occur because the CM 104 waits until the network wake-up timer has expired before sending the message response

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ΡΤΧ 856 or 868. In this circumstance, the CD 352 can optimistically assume that the CM 104 will finally respond with a PTX 868 guarantee response and signal the user that the PTT 876 request has been guaranteed. To allow the user to start talking early, the CD 352 temporarily stores the voice internally, until either the PTX order arrives, or consumes all the existing internal temporary storage space.

If the response from the PTX message arrives and the request is guaranteed, the CD 352 can start transmitting the voice (temporarily stored), and operation continues normally. If the response from the PTX message arrives and the request is denied, the CD 352 signals the user that permission to speak to the network has been denied. Once the user has started talking, this last denial may seem like a conflict of priorities. Special care is taken in this circumstance in order to avoid unnecessarily confusing the user. The CM 104 signals the PTX 858 denial message as soon as possible to limit the length of time for which the user can speak under the assumption that the important PTT request will finally be secured.

If the PTX message does not arrive before all the existing internal intermediate storage space

5 is consumed, the CD 3 52 can simulate a PTX 856 denial message and signal the user to stop talking (856). If the CD 352 has not been able to reestablish service, it may also need to take further action on error at this point and inform the user accordingly.

Alternatively, if at that time the packet data service is reestablished, the CD 352 may, in this situation, start transmitting voice media to the CM 104 without receiving a reply to the PTX 868 guarantee message.

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While waiting for the wake-up timer to expire, the CM 104 temporarily stores any voice media received on media channels on a CD 352 network, which sent the important PTT 852 request, and finally sends a corresponding PTX guarantee response, 868, . Once the wake-up timer has expired, the CM 104 transmits the PTX 868 guarantee response to the requesting CD 352, broadcasts a PTA announcement to the network, and begins to broadcast the temporarily stored voice media. If the CM 104 internal voice intermediate storage is consumed before the wake up timer expires, the CM 104 immediately transmits a denial message 856 to the requesting CD 352. The temporarily stored voice treatment is undefined, but the CM 104 can transmit the contents of your intermediate voice storage to the network after the wake-up timer has expired. Once the wake-up timer has expired, the network continues to function normally.

size of the intermediate storage of voice media on CD 3 52 is chosen based on the maximum time that is expected to pass to the Connected IS707.5 condition, indicated by reference number 812, of the IS-707.5 rest / inactivity condition, indicated by reference number 844. Similarly, the size of the intermediate media storage on the CM 104 should be chosen based on the (maximum) value of the network wake timer specified in the CM 104 network database 232.

A more complete description of the conditions of the CM 104 follows. CMCSTICDDR182 The CM 104 implements the NBS 600 Media Signaling condition diagram shown in figure 15 for each example of a network. The CM 104 is initCMCSTICDDR183 initialized in an inactive condition,

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604, when a network is created. The network remains inactive 604 as long as no network participant asks for PTT 608, or as long as no network participant is guaranteed floor control (612) and the network is not inoperative (616). The CM 104 resets the suspend time timer 62 0 to zero when entering the inactive condition 604. CMCSTICDDR184 CM 104 transitions from inactive condition 604 to guarantee condition 612, when a PTT request, 606, from a network participant is received. CMCSTICDDR185 The CM 104 transitions from the idle condition 604 to the idle condition 624 when the suspend time timer expires.

CMCSTICDDR186 0 CM 104 transitions from guarantee condition 612 to inactive condition 604 and sends a PTX denial response, 626, to the requesting CD 352 if the arbitration algorithm denies control of the floor to the requesting CD 352. CMCSTICDDR187 CM 104 transitions from guarantee condition 612 to the condition of announcing 628 and sends a guarantee response PTX 632 to the requesting CD 352 if the arbitration guarantees control of the floor to the requesting (or interruption) CD 352. After sending the PTX 632 warranty response, the CM 104 considers the requesting (or interruption) CD 352 to be the current speaker of the network. CMCSTICDDR188 0 CM 104 transitions from the condition of announcing 62 8 to the condition of speaking 63 6 and sends a message PTA, 64 0, announcing the new speaker to all participants in the network upon entering the condition of announcing 628. 0 Current speaker remains in speech condition 636 as long as no PTT 644 request or release message 648 is received from a network participant and the network failure protection timer 652 on the network has not expired. The CM 104 resets the network's fail-safe timer 652 upon entering speech condition 636. While

77/98 is in speech condition 636, CM 104 broadcasts media from the current speaker of the network to the network.

CMCSTICDDR189 CM 104 transitions from speech condition 636 to arbitration condition 656 when the PTT 644 request message is received from a network participant. CMCSTICDDR190 The CM 104 transitions from speech condition 636 to release-confirmation condition 660 when the PTT 64 8 release message is received from CD 352 with the network floor control. CMCSTICDDR191 The CM 104 transitions from speech condition 636 to fault-recovery condition 664 when the fail-safe timer 652 expires. The user is typically given the amount of time remaining before the fail-safe timer expires. CMCSTICDDR192 The CM 104 broadcasts the media traffic received from the current speaker of the network to the network while remaining in the 636 speech condition. CMCSTICDDR193 If the intermediate media storage of the network is not empty, the CM 104 continues to temporarily store the media received from the current network speaker while broadcasting media traffic to the network.

CM 104 enters arbitration condition 656 as a result of receiving the PTT request message 644 while in speech condition 636. The CD 352 that originated the PTT request message is known as the interrupt participant. If the interrupt participant and the current speaker are identical, the guarantee message PTX 668 from CM 104 has been lost and the current speaker resends his PTT 644 request. CMCSTICDDR194 The CM 104 transitions from arbitration condition 656 to speech condition 636 and sends the guarantee message 668 to the interrupting participant if the interrupting participant and the current speaker of the network are identical. CMCSTICDDR195 O

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CM 104 applies the arbitration algorithm to the current speaker of the network and to the interrupt participant immediately upon entering arbitration condition 656 if the interrupt participant and the current speaker of the network are distinct.

CMCSTICDDR 196 CM 104 transitions from arbitration condition 656 to speech condition 636 and sends the interrupt participant a PTX denial message, 672, if the arbitration algorithm legislates in favor of the current speaker. CMCSTICDDR197 0 CM 104 transitions from arbitration condition 656 to guarantee condition 612 and sends an interruption message PTX 676 to the current speaker of the network if the arbitration algorithm legislates in favor of the interruption participant. CMCSTICDDR198 The CM 104 transitions from the release-confirmation condition 660 to the release-announcement condition 680 and sends a confirmation message PTX, 684, to the current speaker when entering the release-announcement condition 680.

CMCSTICDDR199 0 CM 104 transitions from fault-recovery condition 664 to release-announcement condition 680 and sends a PTX deny message, 688, to the current speaker immediately upon entering fault-recovery condition 664. CMCSTICDDR200 CM 104 transitions from ad release condition 680 to idle condition 604 and sends a PTA release announcement, 692, to all network participants immediately upon entering ad release condition 680. CMCSTICDDR201 0 CM 104 transitions from the standby condition 624 to the standby condition 616 and sends a message ZZZ, 696, announcing that the network has switched to standby condition to all network participants immediately upon entering the standby condition 616 The network condition machine remains in the 616 resting condition as long as no network participant asks for the

79/98 floor control. CMCSTICDDR202 the CM 104 transitions from the rest condition 616 to the wake condition 700, when a PTT request, 704, from a network participant is received.

CMCSTICDDR203 The CM 104 transitions from the waking condition 700 to the resting condition 616 and sends a PTX denial response, 708, to the requesting CD 352 if the arbitration algorithm denies the control of the floor to the requesting CD 352. Once the network is at rest, this can happen only if the requesting CD 352 has listening only privileges. CMCSTICDDR2 04 The CM transitions from the waking condition 700 to the waking-pending condition 712 and sends an AYT waking request, 716, to all network participants if the arbitration guarantees the control of the floor to the requesting CD 352. After sending the AYT 716 wake-up request, CM 104 considers the requesting CD 352 to be the pending speaker of the network.

The CM 104 remains in the waking condition 712 as long as no PTT 720 request message is received from a network participant, the waking timer 724 has not expired and the PTX 728 resting response timer has not expired. The CM 104 resets the wake timer 724 and the PTX 72 sleep response timer 8 when entering wake-pending condition 712. CMCSTICDDR205 The CM 104 transitions from the wake-pending condition 712 to the rest-arbitration condition 732 when the PTT 720 request message is received from a CD 352 distinct from the pending speaker of the network. CMCSTICDDR2 06 0 CM 104 transitions from the pending wake-up condition 712 to the guarantee-rest condition 736 when the network wake-up timer 724 expires. CMCSTICDDR207 0 CM 104 transitions from pending wake-up condition 712 to storage condition

80/98 intermediate-warranty 740 when the PTX 728 resting response timer expires.

CMCSTICDDR208 CM 104 applies the arbitration algorithm to the pending speaker of the network and to the interruption participant immediately upon entering the rest-arbitration condition 732. CMCSTICDDR209 0 CM 104 transitions from the rest-arbitration condition * 732 to the pending wake-up condition 712 and sends the interrupt participant a PTX denial message, 744, if the arbitration algorithm legislates in favor of the pending speaker. CMCSTICDDR210 CM 104 transits from standby-arbitration condition 732 to pending wake-up condition 712, sends the pending denial message PTX 744 to the pending speaker and considers the interrupt participant as the new pending speaker of the network if the arbitration algorithm legislates in favor of the interrupting participant.

CMCSTICDDR211 The CM 104 transitions from condition of rest guarantee 736 to condition of announcement 628 and sends a guarantee response PTX, 748, to the pending speaker of the network immediately upon entering the condition of rest guarantee 736. CMCSTICDDR212 The CM 104 transitions from the intermediate storage condition 740 to the intermediate storage condition 752 and sends a warranty response PTX, 756, to the pending speaker of the network immediately upon entering the intermediate storage condition 740. The network condition remains in intermediate storage condition 752 as long as wake timer 724 has not expired. While in the intermediate storage condition 752, the CM 104 temporarily stores any media traffic received from the pending network speaker.

CMCSTICDDR213 0 CM 104 transitions from intermediate storage condition 752 to ad condition

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628 when the 724 wake-up timer expires. CMCSTICDDR214 The CM 104 temporarily stores any media traffic received from the pending network speaker in the network media intermediate storage while it remains in the intermediate storage condition 752. CMCSTICDDR215 CM 104 responds to any media signaling request that contains invalid or reserved field values by sending an ERR response, 760, in an error condition, 764, to the CD 352 that sent the message and otherwise ignores the request .

CMCSTICDRR216 CD 352 implements the NBS 800 Media Signaling condition diagram shown in figure 16 whenever a user is participating in a network. CMCSTICDDR217 CD 352 is initialized in a start condition, 804, after CD 352 accepts the network session description by sending a SIP ACK message, 808, to CM 104. CMCSTICDDR218 CD 352 transitions from start condition 804 to start-wait condition, 812, and sends an ASK request message, 816, to CM 104 immediately upon entering start condition 812.

CD 3 52 remains in a listening condition, 820, as long as the user does not press the push-to-talk button 824, no PTA 828 messages are received from the CM 104 and no waiting ZZZ 832 messages are received from the CM 104. CMCSTICDDR219 0 CD 352 transitions from listening condition 82 0 to a floor order condition, 83 6, when the user presses the push-to-speak button 824. CMCSTICDRR220 0 CD 352 transitions from listening condition 820 to speaker announcement condition 840 when message PTA 828 is received from CM 104. CMCSTICDDR221 0 CD 352 transitions from listening condition 820 to condition of rest-inactivity 844 when message Waiting ZZZ 832 is received from CM 104. CMCSTICDDR222 0 CD 352 transits from

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floor order condition 836 to floor condition '848 and send a warranty claim PTT 852 to CM 104 immediately upon entering floor order condition 836.

CD 352 remains in the 5 848 floor wait condition as long as · no PTX 856 response messages are received from the CM 104 and the Abort PTT 860 timer has not expired. The CDt 352 resets your PTT Abort Timer 860 and a PTT Relay Timer (not shown) when entering floor 848 standby condition.

CMCSTICDDR223 CD 3 52 transitions from floor waiting condition 848 to speech condition 864 and alerts the user that the user has gained control of the network floor when a PTX 868 warranty response message is received from CM 104. CMCSTICDDR224 0 CD 352 transits from waiting condition

848 to the lost floor condition 872 when the PTX 856 denial message is received from the CM 104. CMCSTICDDR225 The CD 352 remains in the floor waiting condition 848 and retransmits an identical PTT request 876 to the CM 104 after its PTT Relay Timer expires.

CMCSTICDDR226 CD 352 transitions from floor waiting condition 848 to listening condition 820 after your PTT Abort Stopwatch 860 expires. CMCSTICDDR227 0 CD 352 transitions from speech condition 864 to floor release condition 880 if the user releases the button, press25 stop 884 while still waiting for a PTX response.

CD 352 remains in speech condition 864 as long as no PTX 888 interrupt message is received from CM 104 and the user has not released the 884 push-to-talk button.

CMCSTICDDR22 8 0 CD 352 transitions from speech condition 864 to lost floor condition 872 when interrupt response message PTX 888 is received from CM 104.

CMCSTICDDR229 0 CD 352 transits from speech condition 864

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to the floor release condition 88 0 when the user releases the push-to-talk button. CMCSTICDDR230 CD 352 remains in speech condition 864 when the warranty reply message PTX 868 is received from CM 104.

CMCSTICDDR231 O-CD 352 transitions from the lost floor condition 872 to the listening condition 820 and alerts the user with a message that indicates that the network floor control was lost immediately upon entering the lost floor condition 872.

CMCSTICDDR232 0 CD 352 transitions from floor 880 release condition to release wait condition 896 and sends a PTT release order 900 to CM 104 immediately upon entering floor order 836 condition. CD 352 remains in condition release wait 896 while no PTX 904 confirmation reply message is received from CM 104 and the Abort PTT 860 timer has not expired. 0 CD 352 resets your PTT Abort Timer 860 and a PTT retransmission timer when entering the 896 release wait condition. The PTT retransmission timer is. activated each time there is a PTT order or release.

CMCSTICDDR233 0 CD 352 transitions from release waiting condition 896 to listening condition 820 when the confirmation reply message PTX 904 is received from CM 104. CMCSTICDDR234 0 CD 352 remains in release waiting condition 896 and retransmits a request for PTT 900 release identical to CM 104 after your PTT Relay Timer expires. CMCSTICDDR235 CD 352 transitions from release wait condition 896 to wait condition 820 after its PTT Abort Timer 860 expires.

CMCSTIDDR236 0 CD 352 transitions from speaker announcement condition 840 to listening condition 820 and

84/98 announces the speaker immediately upon entering the 840 speaker announcement condition. The announcement may indicate that a new speaker has floor control, the current speaker has released the floor, or that no speaker currently has floor control.

The CD 352 remains in the idle condition 844 as long as no AYT 908 order message is received from the CM 104 and the user does not press the push-to-talk key 824. CMCSTICDDR237 0 CD 352 transitions from the idle-idle condition 844 to the condition rest-wake 912 when the order message AYT 908 is received from CM 104. CMCSTICDDR238 The CD 352 transitions from the standby condition 844 to the floor order condition 836 when the user presses the push-to-talk key 824.

CMCSTICDDR239 CD 352 discards any message

Waiting ZZZ 916 received while in sleep-inactivity condition 844. CMCSTICDDR240 CD 352 transitions from sleep-wake condition 912 to listening condition

820 and sends an IAH 916 response message to CM 104 immediately upon entering the rest-wake condition.

CMCSTICDDR241 Upon receipt of a request for AYT 920 buzz from CM 104 while in any condition other than the 844 rest-inactivity condition, the

CD 352 saves its current condition, transitions temporarily to an IAH 924 response condition, builds and sends an IAH 928 response message to CM 104 and returns to its previous condition. The CM 104 sends an ERR response 932 to CD 3 52 when it receives a media signaling error and enters error condition 936, such as, for example, a malformed request that makes use of invalid or reserved field values.

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CMCSTICDDR242 Upon receipt of the ERR 932 response received from CM 104 while in any condition, CD 352 alerts the user that an error has occurred, disables CD 352 (940) and performs an appropriate SIP signaling in order to gracefully end their participation in the network (944).

When the CD 352 has entered the idle condition (844), the CD 352 can receive calls from point-to-point voice services via another IS-107 service option, and still remain a participant in a network at rest. After the voice service call is finished, the CD 352 returns to the IS707.5 idle / idle condition, indicated by reference number 844.

However, if the network leaves the 844 idle condition while CD 352 has chosen to receive a point-to-point voice service option call, CD 352 may lose the AYT 908 wake-up request and be removed from the call list. active participants. In such cases, the CD 352 can determine its status as a participant by sending an ASK 382 request to CM 104. Once CD 352 is removed from the list of active network participants, CD 352 registers itself with the CM 104 SIP server in order to once again participate in the network.

The CD 352 allows the user to originate and receive conventional point-to-point PSTN calls, as well as participate in service discussions. group. Although the CD 352 can operate internally in one of several modes, the CD 352 avoids restricting certain functionality within the context of different operating modes in which the user needs to navigate explicitly. In this way, the total receipt and making of calls from point-to-point voice services while group services are allowed and activated.

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The CD 3 52 can be used to carry out point-to-point voice services or protected point-to-point packet voice calls at any time, whether group services are active or not, as long as CD 352 does not · is simultaneously acting as a speaker. If CD 352 has been registered as a member of a network, CD 3 52 unregisters it from the network. If the selected point-to-point call is made through a voice service option, the CD 352 terminates data services. Once the point-to-point call is completed, CD 352 can transparently allow packet data service and register itself as a member of the current selected network.

The CD 352 can be used to receive packet voice calls from point to point PSTN or protected while group service is activated, within the limitations imposed by the cellular infrastructure. If CD 352 has joined a network, and the selected network is active, CD 352 appears busy for an incoming PSTN call and the call is given the appropriate busy treatment by the cellular infrastructure. If the selected network is at rest, but the network waiting time 62 0 has not expired, the call is also given the normal busy treatment by the cellular infrastructure. However, if the selected network's wait time 620 has expired, the network has been put to sleep mode 616 and the CD 352 has released its resources over the air, the call may not be given the infrastructure busy treatment and the CD3 52 can be radio broadcast in order to start receiving the incoming call.

Although a voice service call is active, the CD 352 is unable to receive any NBS network traffic. After a service call is completed

87/98 voice, it may be necessary for the CD 352 to rejoin the network, as it may have missed one or more AYT 716 requests. Whenever the CD 352 appears busy for an incoming voice service call, the caller is redirected based on any busy treatment that has been defined for the called CD 352 (such as, for example, outgoing calls, voicemail, etc.) by the cellular infrastructure, as expected. A user can optionally configure the CD 3 52 to prevent incoming point-to-point calls while a network is selected and the CD 352 is registered as a member.

CD 3 52 also detects if your IP network address has changed or is about to be changed. If CD 352 is participating in a network when the address change occurs, CD 352 again INVITE itself to the network, as discussed with respect to figure 11.

For example, a wandering CD 352 can switch cellular systems or cellular networks and thereby negotiate a new IP network address. Or, CD 3 52 may experience a service disruption or drop the packet data service option call for any reason and, when service is reestablished, have assigned a new IP network address to it. If the CD 352 is participating in a network during a change of address and does not rejoin the selected network in due time, the CM 104 has finally expired its membership and removes the CD 352 from the list for the selected network. The CD 352 is removed from the list of active network participants if it does not finally respond to a series of media signaling AYT request messages 716.

In the absence of the IS-707.5 Packet Data Service Option, NBS can operate through the IS-707.5

88/98 Quick Connect to the Network (QNC) package commonly available. However, QNC does not currently support the resting condition. Therefore, application-level messages such as standby can be ignored by an NBS that operates the CD 352 through the QNC.

QNC does not have a protocol stack similar to that presented by IS-707.5. The CD 352 can be configured to negotiate a packet connection via QNC and not IS-707.5 and, if QNC service is available, treats the connection as a non-resting packet data service connection or , optionally, support for CRTP header compression.

According to the Mobile IP, the CD 352 is connected to the network through an external agent, who assigns the address to the mobile care. The address taken care of is a temporary but legal address, to which IP datagrams can be addressed from anywhere on the Internet. The mobile uses the care address to contact your local agent and inform you of the current care address for the mobile. After confirming the identity of the mobile, the local agent then sends packets addressed to the mobile's permanent local address (which normal Internet routing mechanisms distribute to the local agent directly or to the local agent's network) to the mobile using the address care of the furniture.

While NBS can work over Mobile IP, Mobile IP can have a potentially adverse impact on end-to-end latency and on the perceived voice quality of NBS media traffic and signaling. This can be of particular significance if CD 352 joins a network using its permanent address and the local agent is located far away, in the sense of network topology, from CM 104 and CD 352. In such a case, traffic from

89/98 media can optionally be routed via the public Internet or other variable quality of service networks, which may not have been necessary if the Mobile IP was not used. To avoid this, it is preferable that the CD 352 access services- NBS using its address in the care of and re-associate with networks when its address in the care of changing *.

Both SIP call signaling and PGP public key encryption employ a unique user id or similar unique identifier for CD 352. User database 232 defines an internal user identifier, which can be sent to and used by CD 352 in media signaling requests. The CD 3 52 user id address preferably does not contain any private data whose public disclosure could compromise existing cellular infrastructure authentication mechanisms.

The CD 352 user address is used in the headers in the SIP register and request and can be used in forming other parts of the required SIP syntax. The user address is also an entry for generating the private PGP key used to authenticate SIP requests. The CD 352 user interface allows the user to see the user's address. The CD 3 52 user interface can allow the user to change the user address, with the risk of potentially disrupting the ability to access NBS or satisfy SIP authentication requests.

In order to protect against certain denial of service attacks and to prevent CD 352 masking, the CM 104 can optionally request that CD 352 authenticate itself before registering or joining a network. Authorization is done at the application level, regardless of other authorization schemes that

90/98 may exist on the network, or at the level of cellular infrastructure. CD 352 authorization is also implemented, and works, regardless of concepts and data structures that support encrypted (protected) NBS networks.

In particular, CM 104 may request that CD 352 include an Authorization header with its SIP requests. The authorization header allows the SIP message to be signed by the CD 352 through PGP public key cryptographic signatures.

Public key cryptography generates a public and private key from a private secret, typically known only to the encoder (in this case, CD 3 52). The private key, in combination with the secret, must sign a message, but the public key alone can be used to verify the signature of a signed message. In this way, in order to support SIP authorization, each CD 352 is preferably provided with a private secret and a private key, which are never shared. Each CM 104, to which CD 352 may need to authorize himself, must know the public key of CD 3.52. Since the public key is not secret, it can be stored as part of the user part of database 232 maintained by CM 104 or accessed through generic public key servers on the Internet.

CM 104 may require authorization from CD 352 at the server, network or user level. At the server level, CM 104 requires that all clients connecting to the CM 104 SIP 236 server (see figure 3) present authorization credentials, rejecting any requests that are not authorized. When server-level authorization is allowed, only clients whose identities (ie, a client's public key) are previously known to CM 104 can effectively use

91/98 the server. Server-level authorization can protect the SIP 236 server from many relatively easy denial of service attacks.

A CM 104 can protect or more networks that it manages through authorization, but leave other networks unprotected. IF CD 352 attempts to INVITE itself to a protected network, the CM 104 SIP 236 server will reject the request, unless CD 352 can be authorized by CM 104.

In addition, CM 104 can use authorization to ensure that CD 352 (or any user-agent customer in general) does not attempt to disguise itself as another CD 352 and, consequently, or deny service to legitimate network participants , or passively monitor a network's media channels. If CM 104 requires a specific CD 352 to be authorized, CM 104 will not accept any requests from a customer connecting as CD 352, unless the customer's SIP requests include a PGP signature that can be verified by CM 104 At the user level, authentication can be configured on a per-user basis (ie, CM 104 may require certain users to be authenticated while allowing other users to remain unauthenticated).

The PGP public key can either be provided administratively within, or created by, CD 352, once the CD 352 user address is defined. The private key does not need to be stored externally, but the related public key is usually loadable on the user part of the 232 database of any server that requires authentication from the 352 CD.

In one modality, the NBS primary CD 352, or platform of network participants, is a cellular handset

92/98 based on CD 352MA. Since NBS is built using IP and IP transport protocols, any IP capable platform with connectivity to the CM 104, can potentially serve as an NBS CD 352. Therefore, manual dialing users can connect to the CM 104 through PSTN through existing IP terminal servers operated by Internet Service Providers (ISP), as shown in figure 1. The terminal server acts as a bridge between the PSTN and a LAN that supports IP. The terminal server comprises a bank of modems, which provide a connection point for high-speed PSTN modems, a server and one or more network interfaces. The server is capable of hosting several independent PPP sessions, one for a given connected modem user. 0 server also acts as a router, routing IP packets between each of the individual PPP interfaces and any active LAN interfaces. The CM 104 or includes a terminal server available in the integrated commercial stock (or to be arranged in conjunction with an external terminal server).

Manual dialing terminal server supports and includes the ability to negotiate CRTP Header Compression through its PPP sessions. Similarly, the PPP stack used by a manual dial client includes and attempts to use CRTP. However, because of the additional bandwidth available through high-speed modems, the inability, on the part of a user based on manual dialing, to negotiate CRTP Header Compression may not necessarily force a network to avoid using specification specifications. RTP-based payload.

If the terminal server is located on an internal LAN of the CD 352 MA service provider and, consequently, close, in the sense of network topology,

93/98 of the service provider's CM 104, manual dial-in users can avoid quality of service emissions that may contribute to high end-to-end latency if the path between the ISP's terminal server and the CM 104 crosses a part of the public Internet. Since PSTN-based modems typically do not support a rest concept similar to that implemented by IS-707.5, network participants

<td colspan="2">based on</td><td>dial</td><td colspan="2">manual</td><td>ignore any messages</td>

<td>wait</td><td colspan="2">received from</td><td>CM</td><td> 104</td><td>Although the database</td>

<td>user</td><td> 232</td><td>track</td><td>if</td><td>one</td><td>connected user is based</td>

<td>cell phone</td><td>or</td><td colspan="2">earth this</td><td colspan="2">feature is still presented.</td>

therefore, the CM 104 may or may not send standby messages or other media signal messages to users of manual dialing.

NBS service areas are designed to be integrated, both to allow users to roam between service areas, and to associate with equivalent networks within different service areas. Peer-to-peer communication between multiple CMs 104 takes the form of SIP server redirects, exchange of user and network database records and additional messages specific to an integrated NBS service.

In an integrated NBS service modality, it may be preferable to allow any CM 104 to take ownership of a network. Thus, the operation of a network is not specific to a CM 104 or node 2 08 of the particular MCU. The choice of the CM 104 can be determined dynamically, based on factors such as proximity to the majority of network participants and the quality of service available in an inter-systemic network of service providers. Similarly, any

94/98 SIP 236 redirect server is able to redirect any 352 CD to the MCU SIP agent user server and / or, if necessary, send the 352 CD to another SIP redirect server.

In an integrated NBS service modality, the network address of a network has meaning throughout the NBS system. Consequently, the redirection of requests originated by CD 352 provides an important and essential abstraction layer that allows multiple CM 104 installations to be integrated into a single homogeneous NBS service.

In an integrated NBS service, the system is graded by duplicating the functionality provided by the MCU's 256 node manager, its related set of 252 MCUs (roughly called the MCU Grouping), including its SIP user-agent server. A single database, 232, and the administration interface 248 are shared by all components of the system.

The process by which a CD 352 joins a network in such an integrated system is substantially identical to that used in a system consisting of a single CM 104 installation. The CD 352 initially sends all SIP requests to the top level SIP redirect server (now global) 236. The redirect server 236 redirects, via SIP mechanisms, the requesting CD 3 52 to the appropriate destination. In the case of an INVITE request to join a network, the destination is the user-agent server 252 associated with node 208 of the MCU with current responsibility for the network in question. In the case of an INVITE that requests a current list of available networks for the CD 352, the destination is any user-agent capable of responding to the request.

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Separately, the redirect server 236 can exchange additional messages with the MCU 252 by sending and receiving inter-application messages using specific implementation protocols and / or message sending and receiving conventions. As in the non-integrated case, special start action may be required to ensure that the 236 redirect server determines a destination for each of the legitimate INVITE requests it receives. One modality has the existing SIP records on the top level 236 redirection server. In addition, the top level server can query the system database and try to map each request request to a network definition contained therein.

CD 352 can offer encrypted network broadcast communications. At the option of network users, voice and data transmitted on a specific network can be encrypted on the transmission CD 352 and decoded by all other CDs on the network. Encryption is end-to-end - that is, from one CD to another. Network communications are typically encrypted by an encryption algorithm built into an NBS-capable CD. The choice of whether a 352 CD treats a network as encrypted or unencrypted is at the discretion of network users; that is, the inclusion of CM 104 is not necessary.

Users can select on a network-by-network basis if they would prefer the traffic transmitted / received on that network to be encrypted / decrypted. The user is given the ability to enter an encryption key for the network using, for example, the telephone keypad. The user is thus able to engage in encrypted communications with other users on the network who have

96/98 also selected the encryption option for that network and that are also using the same encryption key.

The user can enable or disable network traffic encryption · for any network key that the user has entered on CD 352 at any time. Media traffic can be symmetrically encrypted using a symmetric key (a traffic encryption key, or TEK) that is shared by network users. Network traffic encryption keys can be generated offline by a network user or network administrator and then securely distributed to network participants who manually enter the keys on their respective communication devices. The key is used for media traffic through a specific network, until new keys are generated and distributed to network users in replacement of the previous network TEK.

The CD 352 is notified that it is a member of a specific network through messages received from CM 104. The network administrator for a specific network can initiate an advisory signal that indicates that the network is intended to be encrypted. This indication is generally advisory, and does not necessarily indicate, in an authorized manner, that communications on the network are actually encrypted. The CD 352 user interface allows the user to designate any network as an encrypted network and allows the user to enter the network TEK of the CD 352, regardless of whether an encrypted advisory signal to the network has been received or not by the CM 104.

CD 3 52 can enforce minimum and maximum key extensions. The CD 352 can provide a means for

97/98 that a key checksum is entered together with the key and, if obtained, verify the checksum against the key entered. If the checksum is not entered, CD 352 calculates the checksum and makes it available for display to the user. CD 352 does not necessarily display the key on the CD 352 screen after the initial key entry.

Once a key is successfully introduced for a given network, media transmissions on the network are encrypted using that specific key, and all traffic received on the network is decrypted using that specific key. Encrypted traffic includes additional headers that allow CD 352 to synchronize the encryption / decryption process, to allow for later synchronization (synchronization for a transmission already in progress) and to confirm that the sender and receiver are using keys traffic encryption. If a CD 352 receives encrypted traffic (detected by the presence of encryption headers) on a network that has not been designated as encrypted, the CD 352 indicates to the user that it is receiving encrypted traffic and does not give out the traffic (muffles the sound of the audio or suppress data output). Similarly, if CD 352 receives traffic from media that is not encrypted on a network for which it is configured to encrypt, or if the traffic is not correctly decrypted (for example, if keys are incompatible), CD 352 alerts the user and drown out the sound of traffic.

The key to an encrypted network can simply be a random (binary) number. In general, the key is generated by a party on a network, or one by an administrator for that network, and distributed securely

98/98 to network participants. Since the key distribution policy is currently left to network users, it is a potential source of compromised network security. Therefore, it is recommended that the network encryption key be distributed to network participants using secure devices, such as PGP encrypted electronic mail. 0 security manager 20

Figure 1 also offers a central repository for common network keys. Other methods are also possible, such as, for example, a standard phone call or a face-to-face meeting. The keys can also be automatically distributed to CDs, using a secret PGP key embedded in a communication device for SIP authentication.

The foregoing description of preferred embodiments is presented to allow anyone skilled in the art to manufacture or use the present invention. The various changes in these modalities will be readily apparent to those who deal with the technique, and the generic principles defined here can be applied to other modalities without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the modalities shown here, but it should receive the widest range compatible with the principles and novel aspects presented here.

Other aspects and advantages of the invention are presented in the claims that follow.

Contents5

14 members in 11 offices

This recordMember, by publication datePriority claim1 more office is in the list below

Priority claims2

Priority claims
Document	Office	Kind	Date
51862200	United States of America	A	2000-03-03
0106739	United States of America	W	2001-03-02

Members14

Family members, oldest first
Document	Office	Kind
CA2401324A1	Canada	A1	2001-09-13
WO0167787A2	World Intellectual Property Organization (WIPO)	A2	2001-09-13
AU4000401A	Australia	A	2001-09-17
US2002102999A1	United States of America	A1	2002-08-01
WO0167787A3	World Intellectual Property Organization (WIPO)	A3	2003-03-06
TW526669B	Taiwan Province of China	B	2003-04-01
EP1310109A2	European Patent Office (EPO)	A2	2003-05-14
KR20030047874A	Republic of Korea	A	2003-06-18
AR030054A1	Argentina	A1	2003-08-13
JP2004500774A	Japan	A	2004-01-08
CN1504059A	China	A	2004-06-09
US6928294B2	United States of America	B2	2005-08-09
BR0108899AThis record	Brazil	A	2005-10-18
CN100448316C	China	C	2008-12-31

3 legal events, as the office reported them to INPADOC

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Events

Legal events, newest first
	Event	Code
2018-03-27	Others concerning applications: alteration of classificationB15K	B15K
2012-10-23	Patent lapsed as no evidence of payment of the annual fee has been furnished to inpi [chapter 8.11 patent gazette]LapsedREFERENTE AO DESPACHO 8.6 PUBLICADO NA RPI 2144 DE 07/02/2012.B08K	B08K
2012-02-07	Application dismissed because of non-payment of annual fees [chapter 8.6 patent gazette]REFERENTE A 11A ANUIDADE(S).B08F	B08F