A method and an apparatus for adding a new member to an active group call in a group communication network

DESCRIPTION

METHOD AND APPARATUS FOR ADDING A NEW MEMBER IN AN ACTIVE GROUP CALL IN A GROUP COMMUNICATIONS NETWORK

FIELD

The present invention relates to a point to multipoint communication system. More specifically, the present invention relates to a method and apparatus for adding new members to an active group call in a group communications network.

BACKGROUND

For many years there has been in many forms a class of wireless services designed for fast, efficient, one-to-one or one-to-many (group) communication. In general, these services have been of the half duplex type where a user presses a push-to-talk (PTT) button on their telephone / radio to initiate the conversation. 0 pressing the button triggers in some implementations your radio or in a moderated system, where communications occur via a server of any kind, indicates the user's request to have the floor. If given the floor, or speaker permission, the user then usually speaks for a few seconds, after which he

ΡΕ1474938 releases its push-to-talk button and other speakers may ask for the word. Communication usually occurs from one speaker to a group of listeners, but can be one-to-one. This service has traditionally been used in applications where a person, a dispatcher, needs to communicate with a group of people, such as field service personnel or taxi drivers, which is where the name dispatching for this service comes from.

Similar services have been offered on the Internet and these are generally known as voice chats. These services are typically implemented in the form of personal computer applications that send Internet Protocol (IP) packet vocoder frames, that is, voice-over-IP (VoIP) service, to a central group chat server. or possibly from client to client on a peer-to-peer service.

A key feature of these services is that communication is fast and spontaneous, usually initiated at the push of a push-to-talk button, without having to go through a typical dialing and ringing sequence. Communication in this type of service is generally very short, occurring in the form of individual conversational spurts usually lasting on the order of several seconds and conversations possibly lasting a minute or less.

741474938 Delay time between the moment the user requests the word and the moment he receives from the server a positive or negative confirmation that he has the word and can start speaking, which is known as the hold latency. to speak, is a critical parameter of half-duplex type group communication systems. As described above, dispatching systems prioritize short and fast conversations, which makes service less effective if push-to-talk latency becomes long.

Existing group communications infrastructures provide limited opportunities for significantly reducing push-to-talk latency, that is, effective push-to-talk latency may not be possible to reduce below the time required to restore traffic channels within dormant packet data sessions. In addition, the speaker's and listener's traffic channels are awakened in series, because the only mechanism available to initiate waking of a dormant group is to wait for the speaker traffic channel to be re-established to signal to the server. At present, there is no mechanism that sends user signaling data originating from a mobile unit to anything other than a traffic channel limitation that requires traffic channels to be re-established before any communication can take place between them. clients and the server.

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Consequently, there is a need for mechanisms to reduce the apparent push-to-talk latency felt by the speaker and the total time required to re-establish the participating mobile units' traffic channels without negatively affecting system capacity and battery life. customer, or other resources.

In a dispatching system model, communication between endpoints occurs within virtual groups where a speaker's voice is emitted to one or more listeners. A single instance of this type of communication is commonly known as a dispatching call or simply a call. A call is an instantiation of a group that defines the characteristics of the call and is essentially a list of members with some associated information, such as the name or identification of a group. A member list is a list containing one or more users who are invited to join the call.

There is a need for a dispatching model that supports both the chat room model and the ad hoc group call service model. In the chat room model the groups are predefined and can be stored on the dispatching system server. However, in the ad hoc model, groups can be defined and / or modified in real time. International patent application WO95 / 23475 discloses a method and system for

Controlling a call in a telecommunications system comprising a telecommunications network and a first subscriber station and one or more other subscriber stations, with which a subscriber station, for example, a dispatcher participating in a telecommunications connection, may reduce the group of subscriber stations, for example members, who are participating in the call without disturbing the ongoing call.

SUMMARY OF THE INVENTION The method and apparatus of the invention are defined in the independent claims.

The described embodiments show a method in a communications device for adding a member to an active group call in a group communication network that includes receiving a member list from a user and sending a request to a server. to add the member list to the active group call and further includes the steps set forth in the characterizing part of claims 1.

In another aspect, a computer readable medium in a communication device incorporates a method for adding a member to an active group call in a group communication network, the method including the above mentioned steps.

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In another aspect, an apparatus for adding a member to an active group call in a group communication network includes means for receiving a list of members from a user and means for sending a request to a server to add the member list to the active group call and further includes the means set forth in the characterizing part of claim 13.

apparatus for adding a member to an active group call in a group communication network may include a receiver, a transmitter and a coupled processor in communication with the receiver and the transmitter. The processor is able to receive a member list from a user and send a request to a server to add the member list to the active group call. In one aspect, the communications device is a push-to-talk (PTT) device.

The described embodiments also provide a method on a server for adding a member to an active group call in a group communication network that includes the steps of receiving a request to add a member list from a group call and adding the member list from the active group call. In one aspect, the method further includes disclosing to each member in the member list that they are being added to the group call.

In another respect, a computer readable medium

741474938 on a server incorporates a method for adding

<td>a member in a</td><td>call</td><td>in</td><td>group</td><td>active</td><td>in a network</td><td>in</td>

<td>communications in</td><td>group the</td><td colspan="3">method including</td><td colspan="2">the steps above</td>

<td>mentioned.</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>In another</td><td>aspect,</td><td>one</td><td colspan="2">server for</td><td>the addition of</td><td>one</td>

<td colspan="4">member in a group call</td><td>active</td><td>in a network</td><td>in</td>

<td>communications in</td><td colspan="2">group includes</td><td>means</td><td>to the</td><td>reception of</td><td>one</td>

request to add a member list to an active group call and means to add the member list to the active group call. In one aspect, the server further includes means for disclosing to each member in the member list that they are being added to the group call.

In another aspect of the invention, a server for adding a member to an active group call in a group communications network includes a receiver, a transmitter and a coupled processor in communication with the receiver and the transmitter. The processor being able to receive a request to add a member to an active group call and to add the member list to the active group call. In one aspect, the processor is further able to disclose to each member in the member list that it is being added in the group call.

BRIEF DESCRIPTION OF DRAWINGS

The features and advantages of this

The invention will become more apparent from the detailed description described below when taken in conjunction with the drawings in which there is a correspondence between reference numbers which are common in the various drawings and in which:

Fig. 1 illustrates a group communication system; Fig. 2 illustrates how various applications interact with each other;

Fig. 3 illustrates an exemplary user registration process according to one embodiment;

Fig. 4 illustrates an exemplary process of establishing a local and intraregional call according to one embodiment;

Fig. 5 illustrates an exemplary process of establishing a remote and intraregional call in accordance with one embodiment;

Fig. 6 illustrates an exemplary process of establishing a local and interregional call according to one embodiment;

Fig. 7 illustrates an exemplary process of establishing a remote interregional call according to one embodiment;

Fig. 8 illustrates an exemplary process of leaving a group call according to one embodiment;

Fig. 9 illustrates an exemplary group call termination process according to one embodiment;

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Fig. 10 illustrates an exemplary process of sending an alert for a group call according to one embodiment;

Fig. 11 illustrates an exemplary process of late joining a group call according to one embodiment;

Fig. 12 illustrates an exemplary process of prioritizing a speaker according to one embodiment;

Fig. 13 illustrates an exemplary process of adding new members to an active group call according to one embodiment;

Fig. 14 illustrates an exemplary process of removing participants in a group call according to one embodiment;

Fig. 15 illustrates an exemplary process of unsubscribing a user according to one embodiment;

Fig. 16 illustrates how various communication devices interact with a communications manager according to one embodiment;

Fig. 17 illustrates the buffering of media by the side of a communications manager according to one embodiment; and Fig. 18 illustrates a client side buffering of media according to one embodiment.

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DETAILED DESCRIPTION

Before an embodiment of the invention is described in detail, it should be understood that the invention is not limited in its application by the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The invention may be implemented in other embodiments and may be embodied in various ways. In addition, it should be understood that the phrases and terminology used herein are intended to be descriptive only and should not be construed as limiting.

Fig. 1 illustrates an exemplary functional block diagram of a group communication system 100. Group communication system 100 is also known as push-to-talk (PTT), network broadcast (NBS), dispatching, or point-to-multipoint communications. In one embodiment, the group communication system 100 includes application server components such as dispatchers, location servers, media control unit (MCU) complexes, usage logging servers, and Internet Protocol clients ( IP) (wireless and / or fixed line devices with IP connectivity). Application server components can be used in either centralized or regional use based on the functionality of the components. Centralized use may include a

ΡΕ1474938 main traffic (HD) dispatcher 102, a main location server (HLS) 104, and a user / group database 106. These components may be centrally located in the service provider's network and may be accessible to regional uses. Centralized components can be used to locate roaming users and initiate interregional group calls. A regionalized use 108, 110 may include a regional location server (RLS) 112, a regional dispatcher 114 (RD), a regional media control unit (MCU) complex 116, and a usage record server (ULS) 118 regional.

Regional uses may be distributed across the service provider's network to ensure that network delays associated with making a call are kept to a minimum to meet the instant response requirement. Distributing call load across the various regionalized systems also ensures that suitable growth potential schemes can be developed to support large numbers of users. The regionalized application server components provide user enrollment, establishment and management of an intraregional call, and initialization and provision of alerts to users who are subscribed to the region.

Devices 120, 122 (clients) of

Comunicações1474938 group communications that can, for example, be implemented on cdma2000 handheld devices, request a packet data session using a standard data service option and use this session to register your IP address with the application server and to perform group call initializations. In one embodiment, the application server components 108, 110 are connected to the service provider's packet data service nodes (PDSNs). Clients 120 and 122, when requesting a packet data session from the wireless infrastructure, have IP connectivity to server components 108, 110

<td>of applications through</td><td>from the knots of</td><td>service of</td><td>data in</td>

<td>package.</td><td></td><td></td><td></td>

<td>At the time of</td><td>call from</td><td>current</td><td>customers</td>

<td>120, 122 can ask</td><td>a session</td><td colspan="2">packet data</td>

<td>using the option to</td><td>service of</td><td>Dice. How</td><td>part of</td>

establishment of the packet data session, the client is assigned an IP address. At this time, the client also receives the address of a DNS server 124. Client 120, 122 queries domain name service server 124, for example, using a service registry search (SRV) to find the address of regionally located server 112. After locating the regional location server 112, client 120, 122 can register by notifying the application server of its location information, for example, the IP address. Registration can be

ΡΕ1474938 is performed using an IP protocol, such as session initiation protocol (SIP) over user datagram protocol (UDP). Client IP address 120, 122 may be used to contact the client when the user is invited for a group call.

In one embodiment, after enrollment is complete, the customer may perform another domain name service registration search to find the regional dispatcher address 114. The customer contacts the regional dispatcher whenever the user requests to initiate a call. or send an alert. The interface between regional dispatcher 114 and client 120, 122 may be signaling protocol over user datagram protocol (UDP).

Once a group communication is established, the client 120, 114 and the media control unit complex 116 exchange media and signaling messages. In one embodiment the media may be sent between the call participants and the media control unit complex 116 using real time protocol (RTP) over the user datagram protocol. Signaling messages may also be via the signaling protocol over the user datagram protocol. These protocols and the functionality they provide are described below.

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Group communication system components 100 may include the IP endpoints that contain the client software and the regionalized and centralized server components that are required to provide the group communications service. Group communications clients and application server components are described in more detail in the following sections.

Customers

The group communications client 120, 122 can operate at any IP endpoint that has access to the appropriate vocoder (voice coder / decoder). IP endpoints can include applications running on a wireless system, for example cdma2000, an application development platform, for example, a binary wireless uptime (BREW), and personal computers.

The customer may include a software application that can be developed using the binary wireless uptime environment and interfaces with incoming mobile modem (MSM) software.

<td>by the customer</td><td>what</td><td>have the environment</td><td>binary</td><td>in</td><td>time</td><td>in</td>

<td>operation</td><td>without</td><td>wires. 0 environment</td><td>binary</td><td>in</td><td>time</td><td>in</td>

<td>operation</td><td>without</td><td colspan="2">wires is a platform that</td><td colspan="2">allows</td><td>to</td>

programmers create applications that can work on

741474938 Customer communication devices. The binary wireless operating environment provides the application programmer with an insulating layer, enabling application development without direct contact with modern mobile station software or original equipment manufacturer (OEM) software. This allows applications to be developed rapidly and to evolve independently of modern mobile station software and / or the original equipment manufacturer. It also allows applications to be received on any device that has the binary wireless operating environment. As shown in Fig. 2, client group communications application software 202 may run in parallel with other applications 204, 206, 208, 210. While these services can be delivered directly through the interfaces of the original equipment manufacturer 212 and the mobile station modern software 214, the binary wireless operating environment provides isolation from the modifications made by applying these layers. This allows the original equipment manufacturer 212 and mobile station modern software 214 to evolve separately from data applications 202, 204, 206, 208, 210.

For the customer to be able to operate effectively on a personal computer, the personal computer may include access to a compatible vocoder, access to sound drivers, and IP connectivity to application servers.

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Location Server

In one embodiment, the location server (LS) may accept and / or maintain the user's location information, for example, the network-level IP address, the user's physical location, such as their longitude and latitude, and / or the packet zone identification, that is, a system identifier that is broadcast hertzian on outgoing common channels identifying the scope of the packet data service node providing the packet data service for that sector. In one embodiment, the location server may include a component that handles client sign-ups and provides user location information to other applications, such as instant messaging, using a session initiation protocol interface.

The location server may include two functional elements, the regional location server (RLS) 112 and the primary location server (HLS) 104. Regional location server 112 may be used on a region-by-region basis and primary location server 104 may be centralized. Details of these elements and their functions are described below.

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Regional Location Server 112 regional location server can process and maintain customer registrations located within your region. In one embodiment, regional location server 112 is a standard session-based protocol-based location server having associated memory for storing user location information. As part of maintaining subscriptions, regional location server 112 can check the expiration date, expired fields for each subscription. The regional location server ensures that expired entries are removed and that both the regional dispatcher and the primary location server are notified of removed subscriptions.

As described above, clients can perform an IP enrollment to notify the application server of their location. Customers can keep their subscriptions for as long as they are available to the group communications service. Customers can resubscribe when the customer's IP address changes and when the subscription is about to expire.

When the customer subscribes or resubscribes, the regional location server 112 may notify their associated regional dispatcher 114. This enables the regional dispatcher 114 to pre-load user data in preparation of call setup requests, thereby reducing call setup time. 0 regional dispatcher 114 can cache user location information, thereby eliminating the need for regional dispatcher 114 to contact the regional location server for user location information during a call establishment.

regional location server 112 may notify regional dispatcher 114 in the event that user location information is updated or removed from regional location server 112. This ensures that regional location server 112 and regional dispatcher 114 remain synchronized with the latest information about users enrolled in the region.

regional location server 112 may also periodically update the primary location server 104 with the location information of enrolled users. In the event that the regional location server 112 submits a subscription to the primary location server 104 for a user who already has a valid subscription in another region, the primary location server may resolve the conflict.

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Primary Location Server 104 primary location server 104 can handle queries to user location information. In one embodiment, the master location server 104 provides a session initiation protocol-based interface to enable other applications, such as an instant messaging application, to query the location information of a particular user.

If the primary location server 104 is a centralized component and the regional location servers communicate with it, the primary location server can resolve roaming users to multiple subscriptions in different regions. Primary location server 104 may receive subscription information from each of the regional location servers. If master location server 104 receives multiple subscriptions for the same user, master location server 104 can keep the most recent subscription and request removal of the old subscription (s) from the current user on regionally located servers. This may in turn initiate the removal of that user's information cached from the regional dispatcher 114 associated with the regional location server containing the old subscription.

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Dispatcher (Distributor)

The dispatcher can facilitate the establishment of a call by locating users and assigning group calls to the media control unit (MCU) complex 116. The dispatcher is the server component that is the key to meeting the instant access requirement. To ensure the lowest call setup times, the dispatcher may include two functional elements having similar structures and functionalities but having different usage strategies. These two elements, the regional dispatcher 114 (RD) and the main dispatcher 112 (HD) are described in detail below in the following sections.

Regional Dispatcher

Regional dispatcher 114 may be the initial point of contact for call setup requests and alert requests. Regional dispatcher 114 may preload user information when it receives from regional location server 112 an indication that a user has just signed up. Alongside user information, regional dispatcher 114 can cache information about group calls taking place in the system. Regional dispatcher 114 can use cached information for users and groups during call establishment to keep to a minimum

ΡΕ1474938 Establishment time, ie no database searches will be required.

In one embodiment, the group information that the regional dispatcher stores in cache includes the group member list and the media control unit complex address 116 in which the group is operating. Regional dispatcher 114 may maintain the member list and the address of the media control unit for the duration of the call. This helps regional dispatcher 114 quickly determine if an incoming call request contains a group definition that is identical to one that has an associated call already in the system, allowing the regional dispatcher to respond quickly to establishment requests. a call and confidentially assign or deny the answer the request for the word.

regional dispatcher 114 may assign or deny the word control request. Regional dispatcher 114 may decide whether it will request a media control unit complex 116 to add the user to the call as a late join participant or to initiate a new call with the associated member list.

During the processing of a call setup request, regional dispatcher 114 may use cached user information to obtain the location information of

ΡΕ1474938 users specified in the call establishment request. If a user cannot be located, regional dispatcher 114 may ask master dispatcher 112 to locate the user. In one embodiment if at least one or more target users are located the regional dispatcher 114 continues to establish a call. After the targets are located, regional dispatcher 114 can decide which media control unit to assign the call to. This determination may be based on the IP address of the users in the group, including the initiator.

regional dispatcher 114 may handle alert requests in a similar manner to call requests. In one embodiment, the alert request is assigned to local media control unit complex 116 for processing, regardless of the location of the targets.

In one embodiment, information in the regional dispatcher cache can be periodically written to a reliable storage mechanism so that it can be recovered in the event of a failure. After the regional dispatcher fails to recover, user and group information that has been written to the trusted storage engine can be reloaded into cache memory, and the regional dispatcher proceeds to validate cached information along with processing requests for establishment of a call being

741474938 received.

In one embodiment, the regional dispatcher

114 places user data in a local cache upon notification of each user's enrollment from the regional location server 112. By eliminating the need to perform multiple database searches at call establishment time, regional dispatcher 114 significantly reduces the amount of time it takes to validate and respond to call establishment requests or alert requests.

regional dispatcher 114 may access user / group database 106 during call establishment to expand default group addresses, if present on request, to individual user lists and, if necessary, to transform identifiers users or groups, for example, in phone numbers and conference IDs, in canonical address (es).

Main Dispatcher (Distributor)

Primary dispatcher 112 (HD) can track the location information of subscribed users. The master dispatcher may contain the location information of users who have subscribed to the regional location server 112.

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4

As described above, each regional location server 112 may notify its associated regional dispatcher 114 each time a user enrollment, re-enrollment, unsubscribe, or subscription expiration occurs. Regional dispatcher 114 may use this information to place or release user information in its local cache. Each regional dispatcher 114 may update master dispatcher 112 with user location information. Because master dispatcher 112 receives updates from regional dispatcher 114, master dispatcher 114 can help find users who are geographically distributed in different regions. 0 regional dispatcher 114 may request help from master dispatcher 112 when it receives a request for a user not currently enrolled in the region, that is, it is not in the cache of the regional dispatcher containing user information.

Domain Name Service Server

In one embodiment, the group communication system 100 may use the service provider's domain name service server 124 to provide clients with location information to regional location server 112 and regional dispatcher 114. This information may be configured at each regional use and periodically updated to ensure its reliability.

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In one embodiment, each client learns the domain name service server address by negotiating the IP Protocol Control Protocol (IPCP) during the establishment of the Point-to-Point Protocol (PPP) session, when it requests a packet data session. Domain name service server 124 may be disclosed in this manner on a region-by-region basis. This situation allows the client to roam from region to region and communicate with the domain name service server 124 in the same region where the client is located. Domain name service server 124 is used on a region-by-region basis in conjunction with each packet data service node. In one embodiment, the domain name service server 124 may be updated with each regional dispatcher 124 and regional location server serving the packet data service node to which the name service server 124 is associated. domain name.

In one embodiment, the mechanism used to locate the appropriate regional dispatcher 114 and regional location server 112 is based on a combination of domain name service addresses and session initiation protocol. The domain name service (SRV) service registry lookup can be performed based on the &lt;domain&gt; part of the session initiation protocol URI under which the client subscribes. 0 service registration search registration request may include the protocol or service, which the

ΡΕ1474938 requester is trying to find. For example, if trying to locate the regionally located server 112, the client may request a subscription service in search of the domain name service registration. The domain name service response may include one or more valid network or port addresses for the server offering the requested service. 0 domain name service server 124 can be used to balance the load between servers offering the same service by allowing the domain name service server 124 to roundrobin between multiple servers as it is returning responses to requests from customers.

User / Group Database

In one embodiment, user / group database 106 is the central repository of user and group information. For each user the database may include information such as the user's address, priority assignment rating, authentication information, user contact information, and legal interception marker, which indicates whether the user is being watched. The database may also include default group definitions which are, for the dispatching services chat room template, user lists and the associated group name. Each group can be uniquely identified, for example by the group address. Customer can use group address to identify group in establishment order

741474938 of a group call. Regional dispatcher 14 may use the group address to retrieve the associated member list from user / group database 106 when it receives a request to establish a group call having a predefined group therein.

Media Control Unit Complex

The media control unit (MCU) complex can include master media control computers (MCH) and a media control unit (MCU). The main media control computer may contain and manage multiple processes of the media control unit. Each media control unit can handle real-time signaling and media processing for a single call. The functions performed by the media control unit for a call may include:

Handling regional dispatcher call assignments 114;

Sending upload and status information to the main media control computer;

Sending call initiation information to clients;

In-call signaling processing from customers, such as push-to-talk requests;

Ensure that signaling messages are reliably delivered to clients;

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Replication and distribution of media for one-to-many calls;

Providing media transformation using the appropriate transcoder for mixed one-to-many vocoder calls;

Call activation monitoring and call termination initiation based on media stream inactivity;

The production of user information for usage record server 118 (ULS);

sending media and signaling information to the appropriate legal interception point when requested.

The media control unit can process alert requests from regional dispatcher 114, send the client alert notifications, and wait for the client to acknowledge them. Upon receiving acknowledgments from the targets the media control unit releases any resources allocated to the alert transaction. At this time, the media control unit may handle other call assignments or alert requests.

Usage Registration Server usage registration server 118 can exist in all regions and can be located in the same place as the media control unit complex 116. The usage log server 118 can

ΡΕ1474938 collect media control unit complex 116 usage events for each call or event processing, format them into a usage data record (UDR), and then store these usage data records in a log file sequence of usage data. Call usage data records may contain information about individual calls including the participant list and participant usage totals. 0 Usage data record for alerts may contain information indicating the alert initiator and the target users to whom the alert was sent. Usage data log files may be collected by your service provider for billing analysis and may be deleted after a fixed time period.

usage record server 118 can write a single usage data record for each call instance at the end of each call. 0 server

118 You can also write a single usage data record each time an alert request is processed. Usage data records written by usage log server 118 may contain the following information:

call instance identifier or alert instance identifier;

identifier of the media control unit which also implies the call location. At first

From a call can be chosen from an appropriate media control unit based on the recorded location of all proposed participants. The location of the media control unit may or may not be in the same region as the initiator;

The start time of the call or alert;

The end time of the call or alert;

The name and / or identifier of the initiating user;

The initiator user's IP address;

For each participant, the username, the user's address, the user's IP address, the cumulative attendance time, which can be zero for alerts, and the total number of seconds the participant had the floor, which can be zero for alerts.

In one embodiment, a single usage data record is issued for each call that can represent the total collection of speech segments during the call. If usage data log event logging is required on a per-segment basis, it can be implemented against an additional processing load, input / output file, and disk space requirements.

The group communications system 100 performs several different functions in order to operate the group services. The functions related to the experiences of the

Incluem1474938 users include enrollment, call initiation, call termination, alerting, late joining of speaker arbitration, adding users, removing members, unsubscribing, addressing and authentication. Functions related to system setup and operation include administration and provisioning, scaling up and reliability. These functions are described in detail in the following sections.

subscription

In a wireless communication system, for example, a CDMA system, enrollment is the process by which a mobile station makes its location known to the wireless system infrastructure. This location information may include the geographical area where the mobile station is located and the identification of the base station serving the mobile station that may be used to assist in the efficient use of paging and access channels.

In one embodiment, the user's location information is the customer's IP address, regardless of whether the customer is connected via wireless services or the fixed network. An exemplary IP protocol that allows IP applications to locate clients based on their IP address is the session initiation protocol (SIP). Among other functions, the

Inicialização1474938 session initialization provides methods for clients to register their IP address and other location information with a session initiation protocol server component. In addition, the session initiation protocol provides methods for IP applications interested in finding clients to query location information on the same server component as the session initiation protocol, such as the client IP address.

Enrollment may include the process of an IP client communicating with a session initiation protocol server component to notify and maintain its location information, for example, the IP address. The session initiation protocol server component that provides this functionality is the location server. 0 The method by which a client notifies its location to the location server or changes its location is the SIP REGISTER method of the session initiation protocol.

In one embodiment, clients register their location information with a regional location server. Other IP-based applications, such as instant messaging, can benefit from knowing each client's IP address available on a location server. An external service or the customer can perform the subscription. Fig. 3 illustrates a

ΡΕ1474938 exemplary call flow for performing the enrollment function.

At power on time 302 the client may request a packet data session and begin the process of enrolling his IP address with the regionally located server 112. To enroll, the client may perform a 304 search of the domain name service registry to determine the regional location server address. Once the regional location server address 306 is obtained, the client can register his location information, for example, using a session initiation protocol enrollment message 308. The regional location server may authenticate the user 310 and issue a response 312 to the client. The regional location server can notify the regional dispatcher 314 that the user is subscribed and the regional dispatcher can use this information to preload the customer's associated data record to facilitate faster response time during establishment of a call. At this time, the customer may be contacted with an invitation to participate in a group call. In one embodiment, customers may need to make a subscription in order to receive a group call, regardless of the type of data connectivity they have, ie wireless or fixed network.

Entries can have an expiration field at

ΡΕ1474938 associated with them indicating the period during which customer registration information may be considered valid. To ensure that the customer is always reachable via IP, the customer can be aware of their subscription expiration and re-enroll before this time expires. Registrations may also expire or become outdated due to other circumstances, such as when the client's IP address is changed or the data connection between the client and the location server is damaged. Customers can become aware of the state of their data connectivity and a change in their IP address.

Once the initial signup is complete, the customer may allow his packet data session to go dormant, which may free the dedicated traffic channel. The client can monitor their packet data session to ensure that it remains valid during extended dormant periods. Conditions that may affect session validity include moving to an area with a different packet zone identification, experiencing a fading or loss of service, and accepting and / or placing a call from the switched public telephone network. . The client's IP address may change and the client may be required to re-establish data connectivity with the infrastructure. When the client re-establishes its packet data session it receives a new IP address. The new IP address needs to be communicated to the location server for

ΡΕ1474938 Ensure customer location information remains accurate. This can be achieved by re-registering.

A fixed network client that is communicating with the location server through a firewall may need to maintain the open through the firewall periodically pinged (Internet Control Message Protocol) with the location server. This situation is achieved by making new registrations.

Group Call Initiation

After registration is complete, the user can make or receive calls. Prior to initializing the first call after the power is turned on, the client can perform a domain name service registry search to find the location of the regional dispatcher. This situation can be performed as part of the boot process.

A group is associated with a initiator, the user who initiated the group establishment, and a member list that contains the target user or users. The member list can contain one or more users, one or more predefined groups, or a combination of both. If the member list has only one user, the call started using that member list

ΡΕ1474938 members is usually referred to as a private call. If the member list has any default groups, the regional dispatcher can expand the default groups in a list with one or more target users, for example, by replacing the default group identifier in the original member list with the associated member list of the default group. After expanding the default groups the resulting member list can contain only the names of the target users. At this time, the regional dispatcher attempts to locate target users in the member list, for example by scanning the regional dispatcher cache for user information. If targets are located within the regional dispatcher cache memory, group members can be subscribed to the same region as the regional dispatcher. This type of group call is known as intraregional calling. If there are other users that the regional dispatcher was unable to locate, the regional dispatcher may ask the primary dispatcher for help in locating the users. A call associated with a group that contains members in two or more regions is known as an interregional call.

Once the regional dispatcher has determined whether the call is intraregional or interregional, it can begin the process of determining which media control unit (MCU) can handle the call. For intra-regional calls the regional dispatcher can assign the call to a media control unit.

741474938 located in the same region as the regional dispatcher if media control unit resources are available in that region. The resulting call that uses this type of call setup is known as a locally handled call or a local call. For interregional calls, the regional dispatcher may be free to assign the call to a media control unit within the same region or in a remote or external region. 0 A regional dispatcher can make this decision based on the user's location information to find the optimal transmission path of the IP packets containing the media and signaling. If a majority of users are located in a particular region, the call can be assigned to that region. If users are evenly dispersed across all regions, the call can be assigned to one of the regions that has the targeted users. If the interregional call is assigned to a media control unit in a different region from the region where the regional dispatcher is located, the call is known as a remotely handled or remote call. 0 A regional dispatcher may have knowledge of the network topology and / or connectivity between the media control units and the packet data service nodes they are serving, and may use this knowledge to make a better decision on the allocation of the data. calls.

741474938

Intra-Regional Calls Group 100 system communication can be used to ensure that most calls are intraregional. Intra-regional calls may eliminate the need for communication between regional dispatcher 114 and master dispatcher 112 at the time of a call establishment. The need for communication between regions can also be eliminated when targets are in the same region and the call is being handled locally, as is the case with most intraregional calls. The following sections describe call flows, time estimates, and message schemes for intraregional calls.

Initiating a Local Call

Fig. 4 illustrates an exemplary message flow for initiating a local group call. The user may select one or more target users, one or more predefined groups or a combination of both, and may press the push-to-talk (PTT) button. The customer may send a 404 request to the regional dispatcher to establish the group call, regardless of whether or not the mobile station has a dedicated traffic channel, as will be described in more detail below. After the request has been submitted, if the packet data session of the mobile station is dormant, the customer may start

It is the process of restoring dedicated traffic channels and preparing the packet data session for media activity. The client may buffer the voice inputs received from the initiator for a while.

When the regional dispatcher receives the request it can expand the predefined groups, which may be specified in the request, in target user member lists. Then the regional dispatcher can retrieve 406 location information from the targeted users. At this point, the regional dispatcher can also determine if the group is already operating in the system. Fig. 4 shows a scenario in which the group is not yet working. The late join call scenario, which is described below, illustrates the case where the group is already operating.

After the regional dispatcher finds at least one of the target users, the regional dispatcher can send a response 408 back to the client indicating that the group call is being established. At this point, the client can optimistically grant 410 the word requested by the initiator and begin buffering their media 412.

The regional dispatcher can use the target user locations to determine the region to which the call can be assigned. If

It is determined that the target users are in the same region as the regional dispatcher, as in Fig. 4, the regional dispatcher may assign the call to a regional media control unit. The media control unit may send 414 warnings to the entire group indicating that the call is being initiated. For targeted users sending warnings can trigger their packet data sessions to go out of sleep and to re-establish their traffic channels.

After the client has received the call notice from the media control unit and the mobile station's traffic channel has been re-established, the client can forward 416 media that is buffered to the media control unit. . The media control unit may buffer 418 media received from the initiator. In one embodiment, the media control unit may buffer the media until the target response threshold value is reached or exceeded. The target response threshold value is an indication of the amount of target responses that are required to proceed with media submission. The threshold value can be a configurable parameter. Once the threshold value is reached, the replicating media control unit 420 routes the media to the target users who have answered the call notice 422.

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Sending Messages via Short Bursts of Data

Instant response refers to the response time it takes the application server to respond to a push-to-talk or call establishment request. The purpose of answering any push-to-talk request, including group call establishment requests, is to consistently respond to a request over a predetermined period of time, for example, a second or less. In many cases when a user requests to establish a group call the user's packet data session is dormant and there is no dedicated traffic channel. Restoring dedicated traffic channels can take considerable time. Accordingly, communication to the application server may be by any other means.

To ensure that the group communication system is instant response level, small IP datagrams can be sent at any time and in any direction, ie originating from the mobile station or terminating at the mobile station, regardless of the state of the network. packet data session. In one embodiment, IP datagrams may be sent in the form of short data burst (SDB) messages. In situations where the packet data session is dormant the short burst data message will be sent through the information channels.

741474938 complementary. When dedicated traffic channel connectivity is present, the short burst data message is sent through the traffic channel.

Referring to Fig. 4, the request for establishing a group call may be sent via a short data burst message. The response 408 to establishing a group call from the application server may also be sent in a short burst data message. Call setup request and response messages that are sent via the short burst data messages may enable the group communication system 100 to achieve the instant response objective.

To complete the group call establishment process, the media control unit may send call notices to users in the member list, including the initiator. These call notices can be sent via dedicated traffic channels. In most cases, packet data sessions of group members are dormant, ie no dedicated traffic channels are established. This means that the media control unit may need to resend the call alert message on an aggressive reliability schedule until all members' traffic channels are re-established and members recognize the message or the message expires. reliability timer. Sending the call notice one way

Aggressive ΡΕ1474938 ensures that the media buffers on the client and the media control unit are kept to a minimum. The customer may send the media that is buffered as soon as his traffic channel is established and he receives a call notice containing the contact information of the media control unit. The media control unit may replicate and route media that are buffered as soon as the target response threshold value is reached or exceeded. This means that the faster the targets receive and respond to the call notice, the faster this threshold value can be reached and the faster the media control unit may stop buffering and start sending. the media.

Call notice sent to the initiator can also be sent via short bursts of data. This situation provides two benefits. 0 The first is that since the call notice contains contact information from the media control unit, the group call client can start sending media that has been buffered to the media control unit as soon as it is restored. mobile station traffic channel, which can reduce the random access memory (RAM) requirements on the mobile station to store media that has been buffered. 0 second is that if the initiator decides to abort

It is possible to call or release the word, which can happen before the traffic channel is reestablished, when the call notice comes in the short bursts of data, the client can notify the media control unit with that information. The impacts of sending the initiator call notice via short bursts of data are an increase in the load on common channels and the need for the media control unit to give special treatment to the initiator call warning message.

Initiating a Remote Call

Intraregional calls can be handled locally if all members are located in the same region. The regional dispatcher may assign an intraregional call to a remote region due to overload or unavailability of local resources. In such cases, media and signaling may suffer from additional latency and errors due to longer communication paths between the users packet data service nodes and the remote media control unit. Fig. 5 illustrates an exemplary call setup for a remote intraregional call.

Initiating the intraregional call on a remote host computer is similar to the call establishment scenario described in relation to Fig. 4, except that the regional dispatcher assigns the call to a media control unit.

741474938

After the regional dispatcher obtains the location of group members, it can determine which media control unit the call can be assigned to. The regional dispatcher can make this decision based on user location information, load and availability of the media control units. In an interregional call users may be located in the same region, therefore the regional dispatcher can check the load and availability of the media control unit complex in the local region. If the regional dispatcher receives an indication that the local media control unit complex is overloaded or temporarily affected by operational failures, then it can assign the call to a remote media control unit. In one embodiment, the media control units may be replicas having identical functionality with the exception of call setup; therefore, the remote media control unit may handle the call in a similar manner to the local media control unit.

Interregional Calls group communication system 100 may be designed to allow a user to communicate with any other user regardless of their physical location or proximity to each other. Group communication system 100 can be used to limit the number of calls that are interregional because

ΡΕ1474938 Interregional calls require communication between the regional dispatcher and the primary dispatcher at the time of a call establishment. The assignment of a call may be to a media control unit that is in a remote region relative to one or more participants in the call. The following sections describe exemplary call flows, time estimates, and message schemes for interregional calls.

Initiating a Local Call

Fig. 6 illustrates an exemplary message flow for initiating a locally handled group call. Establishing a call for a local interregional call is similar to establishing a local intraregional call, as described in relation to Fig. 4, except that the regional dispatcher obtains location information for the locals. target users. In one embodiment, the regional dispatcher attempts to locate target users within its cache memory. If some users are not found in cache memory, the regional dispatcher may ask the primary dispatcher for help finding users. The master dispatcher may contain user location information for users who have made IP subscriptions using the regional location server. As described above, the regional location server may notify your associated regional dispatcher whenever a subscription to a

741474938

7th user. Each regional dispatcher can notify the primary dispatcher of user registrations. This allows the master dispatcher to help regional dispatchers find users who are geographically dispersed in different regions.

Initiating a Remote Call

Fig. 7 illustrates an exemplary process of establishing a remote interregional call. Initiating an interregional call on a remote host computer is similar to a call setting scenario, as described in relation to Fig. 4, except that the regional dispatcher assigns the call to a media control unit . After the regional dispatcher 114 (RD) obtains the location of the group members it can determine which media control unit the call can be assigned to. Regional dispatcher 114 can make this decision based on user location information, load and availability of the media control units. Using group member locations the regional dispatcher attempts to find the optimal path in the service provider's network for transmitting IP packets containing media and signaling to a majority of members. If most users are located in a particular region, the call can be assigned to that region. If users are evenly distributed across

In 741474938 regions, the call can be assigned to one of the regions that has the targeted users.

Ending a Group Call

A group call can end for two reasons: either all participants have asked to leave the call or all participants have stopped talking for a predefined period of time, called the pending time. Each participant may decide to terminate the call before the planned end of the call. If all participants leave the call, the media control unit can end the call and release all resources assigned to it. If all but one participant leaves the call, the media control unit can notify this participant, who is called a lone user. The lone user has the option of leaving the call immediately or waiting for the pending time timer to expire, which may cause the media control unit to drop the call.

The media control unit may terminate the call when the pending time timer expires. The media control unit can track each speech spurt and trigger a timer upon completion of the speech spurt. This timer is known as the pending time timer and can track the duration of silence, that is, the absence of speech or media streaming activity in the call. If

If the call remains silent for the duration of the pending time, which may be configured by the service provider, the media control unit may assume that participants are no longer interested in the call and therefore end the call.

Ending a Call Initiated by a User

Fig. 8 illustrates an exemplary scenario in which a user has decided to terminate participation in a group call. The scenario displays the message flow for terminating user participation. When the user decides to terminate the group call 802, the client may send a request to the media control unit to remove the user from the call. The media control unit can remove the 806 user from the call and notify 808 the customer that the user has been removed.

810 .

Ending a Call Initiated by a Server

Fig. 9 illustrates an exemplary flow of a message that occurs when the pending time timer expires and the media control unit ends the group call. When the pending time timer 902 expires, the media control unit may send participants 904 notification that the call is ending. Each customer who receives a call termination notification can answer 906 with a

Reconhecimento1474938 recognition. Upon receiving acknowledgments, the media control unit may notify 908 the regional dispatcher that the call has been terminated and that the resources that were assigned to the call may be released.

Sending an Alert

The alert mechanism can be used to notify target users that another user, initiator of the alert, has expressed a wish to have them participate in a group call. The alerting mechanism may contain a text message allowing the initiator to specify the subject of the call, the desired time of the call or any other text messages that may be customized by the user. Fig. 10 illustrates an exemplary message flow that occurs when a user sends an alert.

The initiator may select 1002 one or more target users, one or more predefined groups, or a combination of both, and may indicate an alert that may be sent. The customer can send 1004 a request to the regional dispatcher to send alerts to the target users specified in the request. When the regional dispatcher receives the request 1006, it can extend the predefined groups specified in the request to target user member lists and the regional dispatcher can obtain the location information of the target users. After the regional dispatcher has located at least one of the

Utilizadores1474938 target users the regional dispatcher can send a 1008 response back to the customer. The regional dispatcher may assign the alert request 1010 to a media control unit to issue the alert messages to target users 1012.

As indicated in Fig. 10, the alert request can be sent via short bursts of data (SDB). Sending alerts via short data burst messages allows the parties' packet data sessions to remain dormant. Alert notification contains the information necessary to allow target users to make group calls with the initiator and other target users, for example by selecting alert notification and pressing the push-to-talk button. When this situation occurs, group call setup proceeds in a similar manner to the call setup scenario described with respect to Fig. 4.

Late Adhesion

A group call request is considered a late membership if it is determined that the member list, which can be specified in a call request, is identical to one that is associated with an ongoing call in the system. This can occur in one of two ways. Firstly, the user can create a list of

741474938 members identical to one that already has a call associated with it, for example by selecting the same user (s) and / or group (s) and pressing the push-to-talk button. Secondly, the user can select from the call history list a call that is still in the system and press the push-to-talk button. In either case, the regional dispatcher can detect that the call the user has requested to start is already taking place and it treats the user as a late join.

Fig. 11 illustrates an exemplary case of late joining where a user can select a call from the call history list. The user can select 1102 a call from the call history list and press the push-to-talk button. The customer may send an 1104 request to the regional dispatcher to initiate the group call. The regional dispatcher may determine that the call is already in progress 1106 and send a response 1108 to the customer informing that the user is being added to an ongoing call. If the call is already in progress, the word may not be assigned to the user because a current call participant may already have the word by the time the late joining user is ready to receive the media, ie the data session in package is taken from the dormant state. The regional dispatcher can request 1110 from the media handling unit handling the call to add the joining user to the group

ΡΕ1474938 late. The media control unit adds the user and sends 1112 a notice to the user who has the media control unit contact information. After the late joining user traffic channel is reestablished the media stream within the call may be transmitted to the user. At this time, the late joining user may try to request the privilege of speaking.

Late join scenario is similar to the new group call initiation scenario as described in relation to Fig. 4. The differentiating factor is that the late join user is denied the word in response to the initial call establishment request in Group.

Speaker Arbitration

In one embodiment, each group call user is assigned a speaker priority level that determines the level of rights the user has when he is requesting privileges to get the word and to start speaking. After the group call is established, the media control unit may be responsible for controlling the word and determining whether the word can be given to a participant requesting the word. The media control unit may conduct a speaker arbitration when two or more callers are competing for the call.

741474938

<td>word ownership</td><td>on one</td><td>group in</td><td>particular.</td><td></td>

<td>Fig.</td><td> 12</td><td>illustrate</td><td>exemplary events</td><td>that can</td>

<td>occur during</td><td>one</td><td>process</td><td>of arbitration. 0</td><td>scheme of</td>

The arbitration used in this scenario allows the interruption of user B when user A requests the word. User B has the floor, that is, user B is speaking, when user A requests permission to speak by pressing the push-to-talk button 1202. The customer may send 1204 a message to the media control unit requesting permission to speak. The media control unit may perform speaker arbitration 1206 and determine that user B may be interrupted and the word assigned to user A. To ensure an interruption in the media stream, that is, user B may stop talking before user A's media is transmitted, the media control unit first sends a message to client B for user B, indicating that A word has been interrupted by another user and then sends a response 1210 assigning the word to user A.

Adding Users to an Active Group Call

The group communication system 100 allows a group call participant to add new users to an ongoing group call. This is accomplished by having the caller select one or more target users, one or more

741474938 predefined groups or a combination of both, and indicating that the participant would like targets added to the group call where the participant is currently. Fig. 13 illustrates the events that occur when new targets are added in an ongoing group call. The caller may select 1302 one or more target users, one or more groups or a combination of the two to be added to the call. The client may send 1304 a message to the regional dispatcher asking that the specified target users be added to the ongoing group call, which may be specified in the request. When the regional dispatcher receives the request it can extend the predefined groups specified in the request to lists of target user members. Then the regional dispatcher can obtain 1306 location information from the targeted users. After the regional dispatcher has located at least one of the target users, the regional dispatcher can send 1308 a response back to the customer indicating that the targets are being added to the call. The regional dispatcher can send a request to the media control unit 1310 to add the specified users to the call. The media control unit can 1313 call warnings to new targets that can begin the process of taking their packet data sessions out of dormancy. Warnings can be sent on a reliability schedule to ensure that targets receive the message. After target traffic channels are reestablished, targets can send 1314

ΡΕ1474938 acknowledgments to the media control unit. Additional targets may be included 1316 in the ongoing media and signaling communication in the call.

Removing Members in an Active Group Call Group communication system 100 allows a participant in a group call to remove members of an active group. In one embodiment, this may be achieved by a call participant by selecting one or more target participants and indicating that they should be removed from the group call. Fig. 14th illustrates exemplary events that can occur when participants are removed from an ongoing group call. The participant in a group call may select 1402 one or more target participants to be removed from the call. The client may send 1404 a message to the regional dispatcher requesting that targets, which may be specified in the message, be removed from the group call. When the regional dispatcher receives the request, it can obtain 1406 target location information and can send 1408 a response back to the client indicating that the targets are being removed. The regional dispatcher may send a 1410 request to the media control unit to remove targets from the call. The media control unit may send 1412 messages to targets, which may be specified in the removal request, indicating that they are being removed from the call. Targets may send 1414 acknowledgments to the media control unit.

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Unsubscribe

When a user no longer wishes to be contacted with the application server or any other IP application that uses the user's IP address to contact the user, the unsubscribe function can be performed. The unsubscribe function removes the user's IP address and other contact information from the regional location server and frees any resources allocated on behalf of the user. Fig. 15 illustrates how user enrollment is removed from the regional location server as a result of disconnecting from the mobile station, according to one embodiment. The client may receive 1502 an indication that the mobile station on which the client resides is being turned off. As part of the shutdown process, the client may send 1504 a message to the regional location server indicating that the user's location information should be removed. The regional location server can authenticate 1506 the request to ensure that it comes from a valid source. Upon successful authentication, the regional location server may notify 1508 the client via a success indication and may notify the regional dispatcher 1510 of the user's removal. The regional dispatcher may remove user data records from its cache memory and may free resources that may have been allocated to the user. In the event of unsubscription failure, the user's location information may

ΡΕ1474938 may have already been removed from the regional location server when the time associated with the expiration field has passed.

<td>In a form</td><td>of achievement,</td><td colspan="2">the system</td><td> 100</td><td>in</td>

<td>group communications</td><td>supports both</td><td>model</td><td>in</td><td>living room</td><td>in</td>

<td>chat as the ad template</td><td>hoc In the model</td><td>room</td><td>in</td><td>chat</td><td>the</td>

groups are predefined and can be stored on the dispatcher server. The default groups can be public implying that the group has an open member list, that is, any dispatcher user is a potential participant. In the chat room model the call is initiated when the first person chooses to join the chat room and the call is still active, with server resources allocated to the call, regardless of speech activity for a predetermined period of time that can be configured by your service provider. Users specifically ask to join and leave these types of calls. During periods of speech inactivity each call is brought into a dormant state of the group as will be described below until a user requests permission to speak.

In the ad hoc model groups can be defined in real time and have a closed member list associated with them. A closed member list may specify which users are allowed to join the group, may not be available to users outside the closed member list, and may only exist as long as

741474938 last the call. Ad hoc group definitions may not be stored anywhere; they can be used to make the call and released after the call ends.

An ad hoc group can be formed when an initiating user selects one or more target users and generates a request that is sent to a server to initiate the call. Target users can receive notification that they have been added to a group and can be automatically joined to the associated call, ie no action is required from the user. When an ad hoc call becomes idle application servers can dismantle the call and free the resources assigned to it including the group definition used to initiate the call.

In operation with the chat room model in the group communication system 100, a group of communication device users, individually known as network members, communicate with each other using a communication device assigned to each network member. The term network refers to a group of communication device users authorized to communicate with each other.

In one embodiment, a central database may contain identifying information of the members of each particular network. They may be working more than

741474938 as a network in the same communications system. For example, a first network may be defined having ten members and a second network may be defined having twenty members. The ten members of the first network can communicate with each other but cannot communicate with the members of the second network. In one embodiment, members of different networks are able to monitor communications between members of more than one network, but can only transmit information to members of their own network.

A network can operate over an existing communications system without requiring substantial changes to the existing infrastructure. Thus, a controller and users on a network can operate on any system that is capable of transmitting and receiving packet information using the Internet Protocol (IP), such as Code Division Multiple Access (CDMA), time division multiple distribution (TDMA) system, a global mobile communications system (GSM), satellite communications systems such as GlobalStar ™ or Iridium ™ or a variety of other systems.

Network members may communicate with each other using an assigned communication device, shown as communication devices (CDs) 120 and 122. communication devices 120 and 122 may be fixed or wireless network communication devices such as landline cordless phones, landline telephones

ΡΕ1474938 with push-to-talk functionality, push-to-talk satellite phones, wireless camcorders, cameras, audio devices such as music recorders and players, laptops or desktops, paging devices or any combination thereof. For example, communication device 120 may comprise a cordless landline telephone having a camcorder and screen. In addition, each communication device may be capable of sending and receiving information in either a secure or an unsecured (free) mode. Throughout the present description, reference to a particular communication device infers a push-to-talk cordless telephone. However, it should be understood that a reference to a communication device is not intended to create any limitation as such and may cover other communication devices that have the ability to transmit and receive packet information in accordance with the Internet protocol ( IP).

In group communication system 100 a transmission privilege generally allows a single user to transmit information to other network members at a given time. The transmission privilege is assigned or denied to a requesting network member depending on whether or not the transmission privilege is currently assigned to another network member when the request is received. The process of assigning or refusing transmission requests is known as arbitration. The schemes of

Arbitrators can evaluate factors such as the priority levels assigned to each communication device, the number of unsuccessful attempts to obtain the transmission privilege, the length of time a network member already has the transmission privilege, and other factors to determine whether The transmission privilege is assigned to a requesting network member.

In order to be able to participate in system 100, communication devices 120 and 122 may each have the ability to request transmission privilege from a controller or a media control unit 116. The media control unit 116 can manage the real-time and administrative operation of the groups. The media control unit is any type of computer-type device having at least one processor and one memory. The media control unit 116 may operate remotely through a service provider or members of the communications system or both, assuming authorization is given by the service provider. The media control unit 116 may receive group settings via an external administration interface. Group members can request administrative actions through their service provider or network administrative functions through defined systems, such as the member-operated security manager (SM) that respects a media control unit administration interface. The media control unit 116 may authenticate the entity attempting to establish or modify a network.

Security manager can perform key management, user authentication and related tasks to support secure networks. A single group communication system can interact with one or more security managers. The security manager may not be involved in real-time control of a network including network activation or push-to-talk arbitration. 0 Security Manager may have administrative capabilities compatible with the Media Control Unit interface to automate administrative functions. The security manager may be able to act as a data endpoint for the purpose of participating in a network, issuing network keys or simply monitoring network traffic.

In one embodiment, the means for requesting the transmission privilege from a media control unit comprises a push button or push to talk (PTT) switch. When a user in system 100 wishes to transmit information to other members, the user may press the push-to-talk switch on his communication device, sending a word control request to obtain from the media control unit 116 the privilege of streaming. If no other network member is currently assigned the transmission privilege, the requesting user may be assigned the transmission privilege and the user may be notified by an audible, visual or tactile alert via the communication device. After the

ΡΕ1474938 transmission privilege being assigned to the requesting user the information may then be transmitted from that user to the other member.

In one embodiment of the present invention, each member of the wireless network establishes a one-way and one-way connection with one or more base stations 126 or, alternatively, with a satellite gateway, as appropriate. Voice and / or data may be converted into data packets using, for example, a communication device, which is suitable for a distributed network 128 through which communication with other users may occur. In one embodiment, the distributed network 128 is the Internet.

In one embodiment, an outgoing channel is provided in each communication system, that is, a terrestrial communication system and a satellite communication system, for transmitting information from each network member to the other network members. Each network member can receive communications from other network members through the dedicated channel. In another embodiment, the dedicated return link is established in each communication system for transmitting information to the media control unit 116. In one embodiment, a combination of both schemes described above may be used. For example, a scheme may involve establishing a dedicated outbound broadcast channel but requiring wireless communication devices to

741474938 transmit the information to the media control unit 116 via a dedicated back link assigned to each communication device.

When a first network member wishes to transmit information to other network members, the first network member can request the transmission privilege by pressing a push-to-talk key on his communication device, which generates a formatted request for transmission. through distributed network 128. In the case of communication devices 120 and 122, the request may be transmitted in a hertzian fashion to one or more base stations 126. A mobile switching center (MSC) 130, which may include a well-known interworking function (IWF), a packet data service node (PDSN), or a packet control function (PCF) for packet data processing may exist between base stations 126 and distributed network 128. The request may be transmitted over the public switched telephone network (PSTN) to a set of modems that may receive the request and provide it to the distributed network 128. The terminal can monitor system 100 traffic through its connection to distributed network 128.

If the broadcast privilege is not currently assigned to any other member, when the media control unit 116 receives a broadcast privilege request, the media control unit 116 may transmit a message to the requesting network member.

ΡΕ1474938 notifying you that you have been granted the transmission privilege. Sound, visual, or other information from the first network member may then be transmitted to other network members by sending the information to the media control unit 116 using one of the transmission paths described above. In one embodiment, the media control unit 116 then provides the information to the other network members by copying the information and sending a copy to the other network members. If a single transmission channel is used the information needs to be copied only once for each transmission channel in use.

In an alternative embodiment, the media control unit 116 is incorporated into the mobile switching center 130 so that packet data from the support base stations is routed directly to the media control unit 116 without being routed in network 128. distributed. In this embodiment, the media control unit 116 is still connected to the distributed network 128 so that other communication systems and devices can participate in group communication. In yet another embodiment, the media control unit 116 may be incorporated into the packet data service or packet control function node modules of the mobile switching center 130.

In one embodiment, the media control unit 116 maintains one or more databases for

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- 67 manage information regarding individual members of the network as well as each defined network. For example, for each network member the database may contain information such as the username, account number, telephone number or call number associated with the members' communication device, a mobile station identification number assigned to the communication device, the status of the current member in the network, as if 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 communication device, an IP address associated with the communication device, and an indication of the networks with which the member is authorized to communicate. Other types of related information may also be stored in the database for each member of the network.

In one embodiment, the communication device may form connections to individual communication terminals to form a talkgroup, or network. The media control unit can comprise a variety of hardware and software functional capabilities that are configurable in different ways to suit different applications. The media control unit can provide the ability to manage real-time network administrative and authentication operations, push-to-talk (PTT) requests arbitration, maintenance and distribution of membership and subscription lists, call setup

741474938 dismantling the required communication, for example, code division multiple access network and system resources, as well as general network state control.

Networks may be within a stand-alone standalone cellular system or in a multi-site configuration. In the case of a large configuration multiple media control units may be geographically installed to form a single integrated system, each operating as a pluggable module in the existing cellular infrastructure. As such, new features introduced by networks are available to mobile users without requiring modifications to the existing cellular infrastructure.

The media control unit can maintain a list of defined networks. In one embodiment, each network definition includes a network identifier, a list of members, including telephone numbers or other identifying information, user priority information, and other generic administrative information. Networks may be statically defined as free or secure, and transitions between free and secure are not allowed. A secure network typically uses media encryption to provide authentication and protection against unauthorized eavesdropping. Media encoding for secure networks is implemented on an end-to-end basis.

ΡΕ1474938 meaning that encoding and decoding may occur within the communication device. The media control unit can operate without knowledge of algorithms, keys and security policies.

Fig. 16 illustrates an exemplary group 1600 to show how communication devices 1602, 1604, and 1060 interact with a media control unit 1608. Multiple media control units may be used as desired for large scale groups. In Fig. 16, communication device 1602 is authorized to transmit media to other members of the group. In this case, communication device 1602 is known as a speaker and transmits media over a channel. When the communication device 1602 is designated as a speaker, the remaining participants, the communication device 1604 and the communication device 1606, may not be allowed to transmit media to the group. Thus, communication device 1604 and communication device 1606 are designated as listeners.

As described above, communication devices 1602, 1604, and 1060 are connected to the media control unit 1608 using at least one channel. In one embodiment, the channel is divided into separate channels comprising a session initiation protocol (SIP) channel 1610, a media signaling channel 1612, and a media traffic channel 1614. Channel 1610 of

741474938 session initiation protocol and media signaling channel 1612 may be used at any time, as long as the bandwidth allows, by any of the communication devices 1602, 1604 and 1060, regardless of whether they are designated as a speaker or as a listener. Session Initiation Protocol is an application layer protocol defined as an Internet Engineering Special Force (IETF) that describes the control mechanisms for establishing, modifying, and terminating multimedia sessions that are operating over the Internet protocol ( IP). The session initiation protocol provides a general solution to the call signaling problems of Internet telephony applications by supporting mechanisms for registering and locating users, a mechanism that defines user capabilities and describes media parameters and mechanisms for determine user availability, call establishment and call handling.

In one embodiment, session initiation protocol channel 1610 is used to initiate and terminate participation of a communication device within group 1600. A session description protocol (SDP) signal may also be used within the channel. 1610 of the session initiation protocol. When communication device membership within the group is established, for example using session initiation protocol channel 1610,

741474938 real-time call control and signaling between the communication device and the media control unit, for example, using NBS media signaling channel 1612. In one embodiment, the media signaling channel 1612 is used to handle push-to-talk requests, releases, arbitrate conflicting requests or word control, warn of the start and end of information transmission, manage network dormancy, track endpoint connectivity, request and share network status, and notify any error messages. 0 The 1612 media signaling channel protocol minimizes the length of most common messages and simplifies the task of interpreting responses and responding to requests while maintaining flexibility for future improvements. The media signaling channel 1612 protocol also allows requests to be resent without adversely affecting the state of the protocol.

In one embodiment, traffic signaling on media signaling channel 1612 includes establishing a call and controlling signaling that may consist of session invitation and acknowledgment requests, and media signaling that may consist of requests. word control and related asynchronous messages. 0 Media traffic on media traffic channel 1614 may comprise real-time point-to-multipoint voice and / or data broadcasts. Both message categories have attributes

Funcionais1474938 singular functionalities. In addition, each communication device may issue client requests for DNS services to facilitate the association of fully qualified domain name services principal computer names with the network addresses of

Internet.

In one embodiment, establishing a call and signaling call control is performed according to the session initiation protocol semantics. Although the session initiation protocol may be carried using both the well-known user datagram protocol (UDP) and the transmission control protocol (TCP), in one embodiment, each communication device performs protocol-based signaling functions. login session using the user datagram protocol. In addition, each communications manager can expect to receive session initiation protocol signaling requests via the user datagram protocol. Real-time signaling can occur via the dynamic UDP / IP interface on the communications manager and each communication device. Other signaling may occur via a fixed TCP / IP interface between the communications manager and the communication device using, for example, the session initiation protocol.

741474938

Push-To-Talk Latency

In one embodiment, when packet data service is active, resources in the infrastructure, for example, the base station transmitter / receiver subsystem (BTS), the base station controller (BSC), the interworking ( IWF) and radio link are actively assigned to the mobile station (MS). In an IP-based VoIP dispatching system, although an active conversation is taking place between group participants, the packet data connection for each user remains active. However, after a period of inactivity, that is, the time pending in group communications, the users' traffic channels may transition to the dormant state.

The sleep transition conserves system capacity, reduces service costs and battery drain, and makes you available to receive conventional voice calls sent to you. For example, when the user is on an active packet data call, he will generally be considered by voice calls sent to him to be busy. If the packet data call is in sleep state, the user may be able to receive voice calls sent to him. For these reasons, it is desirable to transition the packet data call to the sleep state after

741474938 packet data inactivity periods.

Although packet data calls are active, even if no packet data is being exchanged, radio frequency (RF) energy can still be transmitted by mobile phones, however at a low level, to maintain synchronization and control. power control with the base station. These transmissions can cause a significant drain on the phone. However, in the dormant state the telephone cannot transmit any radio frequency. To conserve phone power and extend battery life, pending time can be set to transition the phone to sleep mode after extended periods without any data transmission.

Although packet data service is active for all users, push-to-peer requests, which may be IP datagrams sent between the mobile station and the dispatcher server, may have very low latency. However, if user channels have previously transitioned to the sleep state, the push-to-talk delay may be longer. During packet data dormancy, the status information associated with the packet data session, including the IP address of the mobile station, may be maintained. However, state information associated with layers under the peer-to-peer protocol, such as layers

741474938

<td>physical</td><td>traffic</td><td>can be released</td><td>and / or</td><td>canceled</td><td>your</td>

<td colspan="2">assignment.</td><td></td><td></td><td></td><td></td>

<td></td><td>Some</td><td>infrastructures,</td><td>for</td><td>wake up</td><td>an</td>

<td>connection</td><td>numb from</td><td>data, the channel of</td><td colspan="2">traffic has to</td><td>to be</td>

If this option is enabled again, the resources must be reassigned and the radio link protocol (RLP) must be initialized again. The effect of these actions is that after a group has not spoken for a while, when a user presses their push-to-talk button to request the word, the push-to-talk latency for the first speech spurt is usually higher. than that of subsequent speech surges. Although this is relatively uncommon, it can affect the utility of the service and should be minimized.

In one embodiment, to reduce push-to-talk latency, group call signaling, such as word control requests, word control responses, and dormancy wake-up messages, may be transmitted on some channels. available without waiting for dedicated traffic channels to be re-established. Such common channels may always be available regardless of the state of mobile stations and may not need to be requested and reassigned each time a user wishes to initiate a group call. Consequently, group call signaling can be changed even when mobile stations are dormant which can

741474938

76 to provide a way for the parallel restoration of the dedicated traffic channels of the speakers 'and listeners' mobile stations.

In one embodiment, the calling mobile station may send a word control request to the wireless infrastructure through some available common backhaul channels, such as a backhaul access channel and a power boosted access channel. return. The calling mobile station may also receive a response to the word control request on some available common outgoing channels, such as the outgoing paging channel and the common outgoing control channel. In one embodiment, the sleeping listener's mobile stations may receive dormancy wake up messages on some available common outgoing channels, such as the outgoing paging channel and the common outgoing control channel.

<td>Messages from</td><td>Signaling</td><td>gives</td><td>Call</td><td>in</td><td>Short Bursts</td>

<td colspan="2">(Burst) Data</td><td></td><td></td><td></td><td></td>

<td>In</td><td>form</td><td>in</td><td colspan="2">realization,</td><td>a reduction</td>

<td>significant</td><td>of time</td><td>in</td><td>wake up</td><td colspan="2">total effective</td>

Speaker-perceivable push-to-talk dormancy and latency can be achieved through the use of short data burst (SDB) messages, as provided, for example, in TIA / EIA / IS-2000 Standards for cdma2000 Spread Spectrum Systems, hereinafter referred to as cdma2000. In a form of

In this embodiment, short burst data messages can be sent through either dedicated physical channels such as the fundamental one-way channel (FCH) or dedicated common control channel (F-DCCH) such as the common physical channels, such as the return access channel (R-ACH), the powered back access channel (R-EACH), the common outbound control channel (F-CCCH), as the paging channel (PCH). Short burst data messages may be carried by the radio surge protocol (RBP) which maps the messages to an appropriate and available physical layer channel. Because short data burst messages can carry arbitrary IP traffic and can be sent over common physical channels, short data burst messages provide a group call signal exchange mechanism when the mobile station of a calling customer does not have any dedicated traffic channels.

Call Signaling Messages Initiated on Mobile Station

In one embodiment, the signaling media messages may carry the IP datagrams via the callback or call originated by the mobile station. A customer mobile station can quickly signal to the media control unit whenever the user requests the floor and a dedicated return traffic channel is not immediately available. Assuming

ΡΕ1474938 that the client mobile station has released all dedicated traffic channels the client mobile station can immediately route the word control request through a common back channel of a wireless infrastructure which can relay the request to the unit of media control. For example, to send such messages when a dedicated return channel is not available, the return access channel or the powered back access channel may be used. In one embodiment, the client mobile station may transmit a word request message to the media control unit in the form of a short burst data message.

Referring to Fig. 4, in one embodiment, the client mobile station may send the push-to-talk word request 404 via a common return channel such as the access channel or the voice channel. enhanced access before attempting to re-establish your dedicated traffic channel. In one embodiment, the client mobile station may send the triggered word request 404 in a short burst message regardless of the channel used.

The client mobile station may then begin to re-establish its dedicated traffic channel, for example by obtaining a new source of service option 33. The client mobile station can also initiate radio link protocol (RLP) synchronization.

741474938

In one embodiment, the customer's mobile station may re-establish its dedicated traffic channel and advantageously synchronize the radio link protocol in parallel with push-to-talk word request 404 sending. .

Consequently, the use of available common return channels and / or short data burst characteristics to signal word control requests to the communications manager when a mobile station has no dedicated dedicated traffic channels reduces the total time required to communicate. wake up the participating mobile stations. Although the speaker client may not receive confirmation that his word request has been assigned to him, until the speaker's outbound traffic channel is re-established, the ability to promptly signal the communications manager to start waking the participating listeners reduces the overall latency.

Referring to Fig. 4, the wireless infrastructure may send the triggered word request 404 to the push-to-talk to the packet data service node (PDSN) and then to the media control unit. In one embodiment, upon receiving the word control request the media control unit may arbitrate the request, send the signaling wake up messages (triggers) to a group of the target participants (listeners) and / or trigger the restoration of traffic channels 414 of the

741474938 participants (listeners). If the media control unit assigns the triggered word request with push-to-talk, the media control unit may send triggered word assignment 408 with push-to-talk to the customer's mobile station. In one embodiment, the regional dispatcher may send the triggered word assignment 408 with the push-to-talk to the customer's mobile station on an available common outbound channel, such as the outgoing paging channel and the outbound common control channel. , if the customer's dedicated traffic channel is not yet restored. In one embodiment, the infrastructure may send a push-to-talk triggered assignment 408 to the customer's mobile station in the form of short bursts of data regardless of the channel used.

In one embodiment, the media control unit may wait for the dormancy response timer to expire before responding to the word control request triggered with push-to-talk. If the group dormancy response timer is set to zero, the communications manager can respond immediately to the word control request. In one embodiment, if the client mobile station has completed the re-establishment of its traffic channel and radio link protocol synchronization, the client mobile station may route 416 to the media control unit which may have been 412 buffered the customer's mobile station.

741474938

Network Initiated Call Signaling Messages

In one embodiment, upon receiving the word control request, the media control unit may surge the media signal wake-up messages to a group of target (listener) participants and trigger the re-establishment of the traffic channels. of the participants (listeners). If the group dormancy response timer is set to zero, the media control unit can respond immediately to the word control request. In one embodiment, if the speaker has already begun re-establishing his traffic channel immediately after sending the triggered push-to-talk request, the speaker's and listener's traffic channels may advantageously be re-established in parallel.

Referring to Fig. 4, after the media control unit receives the triggered word control request with the push-to-talk the media control unit can send targeted wake-up triggers 414 to the target listeners. The media control unit can determine if there is a packet data session for the target mobile station and forwards the triggering packet to the appropriate infrastructure element, for example a base station. The infrastructure can call each individual target mobile station to reestablish its dedicated traffic channel. The target mobile station can then begin to reset the

741474938 your dedicated traffic channel, for example, by obtaining a new source of service option 33. The target mobile station may also initiate radio link protocol (RLP) synchronization. In one embodiment, the target mobile stations may re-establish their dedicated traffic channels and advantageously synchronize their parallel radio link protocols with the same functions as being performed by the customer's mobile station.

In one embodiment, after a target mobile station has completed re-establishing its dedicated traffic channel and synchronizing its radio link protocol, the target mobile station may send wake-up response 422 to the media control unit, indicating that the target mobile station is ready to receive the media. The media control unit may send a speaker announcement to the customer's mobile station before forwarding 420 to the target mobile station the media that may have been buffered 418 in the media control unit.

In one embodiment, the media control unit may send the wake trigger 414 to a target listener through any available common outgoing channels, such as the outgoing paging channel and the outgoing common control channel, while traffic of target listeners are not yet restored. In one embodiment, the media control unit may be

ΡΕ1474938 send wake-up trigger 414 to the target listener in the form of short bursts of data, regardless of the channel used. If the push-to-talk word control request is sent on the speaker's common return channel in the form of a short data burst message and the target group dormancy response timer is set to zero on the unit media control, the actual push-to-talk latency on the speaker's client may be reduced by the time required to send a short data burst request message on the back link followed by a short data burst response message on the outbound link.

Network Interfaces for Call Signaling Messages

To determine which specific traffic has originated on the network, for example the short burst data load, which is sent to an idle mobile station without any dedicated traffic channels, some infrastructure policy or interface may be implemented to distinguish such specific traffic from other traffic.

In a first embodiment, IP datagrams may be filtered based on their size, since short burst data messages may carry a limited user load. IP datagrams smaller than a predetermined size limit

No. 1474938 may be sent in the form of a short data burst message if intended for a mobile station without any dedicated traffic channels. The group communication system may use such filters since the application word request response message is quite small, for example, having 34 bytes including initial IP data.

In a second embodiment, the infrastructure provider may define an IP-based service to encapsulate IP traffic destined to be delivered to a mobile station. An IP server that is aware of this service may transmit small IP datagrams, for example, the user datagram protocol, the appropriately encapsulated datagrams with initial IP data, to this service for provision to a suspected mobile station. Dedicated traffic channel. Group communication systems may use this service to indicate to the infrastructure that the word request response message is provided to the requesting client's mobile station, for example in the form of short bursts of data. Coordination of traffic in short bursts of data with pending pages or service initiation requests is also important to ensure fast and reliable delivery of user traffic.

In a third embodiment, an IP server may transmit a special IP, for example, the user datagram protocol, data datagrams.

Iniciais1474938 IP initials for provision to a mobile station suspected of not having a dedicated traffic channel. The IP server may tag IP datagrams, for example by assigning a special value to the initial IP data, to inform the infrastructure providing the IP datagrams to the client mobile station. Group communication systems may use this service to indicate to the infrastructure that the word request response message is provided to the requesting client's mobile station, for example in the form of short bursts of data. In a third embodiment, the user datagram protocol or the transmission control protocol port width may be reserved for providing specific IP datagrams, for example short burst messages.

Initiation and Paging of Mobile Station Initiated Service

In one embodiment, a client may send a word control request 404 that may be in the form of short bursts of data, followed immediately by a service initiation request, to the wireless infrastructure, for example, multiple access. by code division, for the rapid re-establishment of your traffic channels. However, if the dormancy response timer is set to a small value, the regional dispatcher can respond quickly to the word control request and transmit a response 408 back to the client. If this response reaches the infrastructure during the early stages

In the service initiation transaction ΡΕ1474938, the infrastructure detects that the speaker's mobile station has no active traffic channel and may attempt to send the response to the speaker's mobile station. However, this paging action may abort the service initiation transaction already in progress. In one embodiment, the speaker's mobile station may respond to paging by ensuring that the word control response message is provided to the speaker and to request service initiation again, but an unnecessary delay in re-establishing the speaker's traffic channel is felt. as a result of the aborted attempt of the original service initiation.

In a first embodiment, to avoid the race condition between the service initiation process and paging, the regional dispatcher may be configured not to respond immediately to the word control request 404. Similarly, the dormancy response timer may be set so that the media control unit transmits the response 408 to the speaker's mobile station after the service initiation process is complete.

In a second embodiment, the packet data service node receiving the response 408 and the switching center of the mobile stations (MSC) responding to the speaker's service initiation request are coordinated. In other words, if the packet data service node determines that a process for starting a

ΡΕ1474938 packet data service for the speaker's mobile station is already running when response 408 arrives at the infrastructure, the switching station of the mobile stations may defer the speaker's mobile station paging. The packet data service node can cache the response and send it through the speaker's mobile station outbound traffic channel after the service initiation process is complete. Alternatively, the mobile station switching center may send the response to the speaker's mobile station in the form of a short burst message if the service initiation process is still ongoing.

In a third embodiment, the speaker's mobile station may avoid the race condition by not issuing a service initiation request until the speaker's mobile station has received a response to the word control request. In one embodiment, since the speaker's mobile station has no dedicated traffic channel, the media control unit can send the response to the speaker's mobile station through some available common outbound channels, such as the paging channel. and the common one-way control channel. In one embodiment, the media control unit may send the response to the speaker's mobile station in the form of short bursts of data. The speaker's mobile station may depend on the word control response generated on the regional dispatcher to trigger reactivation of its traffic channel, just as requests from

741474938 waivers sent by the media control unit trigger reactivation of the traffic channel to listeners of mobile stations. The race condition is avoided to the extent that the potential for simultaneous service initiation initiated on a mobile station and paging of the mobile station initiated on the network is avoided.

Caching Network-Initiated Packet Data Triggers IP datagram, including wake-up trigger 414 that reaches the wireless infrastructure, for example, code division multiple access, which is intended for a mobile station A listener who does not have any dedicated traffic channels can be lost either by the network as a whole or specifically by the wireless infrastructure. In one embodiment, the wake-up trigger 414 sent to the listener's mobile station is aggressively relayed according to a set schedule until the listeners respond or the group wake-up timer expires. For example, wake-up trigger 414 can be resent every 500 ms. However, relaying wake-up triggers 414 to this rate can cause a maximum delay of up to 500 ms or an average delay of 250 ms from the time a listener's traffic channel is re-established until the next wake trigger intended for that listener arrives at the infrastructure.

741474938

In one embodiment, the infrastructure or any entity on the network may cache the wake up trigger 414 sent by the media control unit and provide it to a target mobile station as soon as the target mobile station has restored its traffic channel. This eliminates the need for the media control unit to relay the wake up request and reduces the total dormancy waking time. Placing wake-up trigger 414 in cache memory, as opposed to relaying it, for example, at a rate of 500 ms, can eliminate a delay of up to 500 ms from the total wake-up time.

Intermediate Buffering of Media

In one embodiment, the user may be allowed to initiate the conversation after the user has requested word control by buffering the media before the dedicated channels between the client and listeners are re-established. By putting the speaker's speech into buffer the system allows the speaker to start the conversation before the listeners' traffic channels are fully reestablished. This allows the speaker to start the conversation earlier by reducing their apparent push-to-talk latency. Since listeners do not feel push-to-talk latency, their experience is unaffected, that is, push-to-talk latency is shifted from the speaker to other parts of the system. The speaker

741474938 can wait the same time to receive a response from a listener to their first speech spurt, but as described above, they already expect the response to their first speech spurt to take longer than the response to subsequent speech spurts that occur. while he is busy in an active conversation. Placement of the speaker's first speech spurt in buffer can be done on the media control unit side or on the client mobile station side.

Intermediate Buffering Made on the Side of the Media Control Unit

In one embodiment, the media control unit may put the speaker's first speech spurt into buffer. After a user presses his push-to-talk button and the user's traffic channels are restored, he may be allowed to communicate with the media control unit. At this point, since the listener traffic channels are not yet established, the media control unit 418 pushes the speaker's speech into buffer for future transmission to the target listeners. Buffering by the media control unit may reduce the speaker's perceived push-to-talk latency to the approximate time it takes to establish the speaker's traffic channel. Fig. 17 shows buffering on the drive side

Media control according to one embodiment as described below:

(1) No call is in progress, initiator and target traffic channels are dormant;

(2) Users press the push-button. The server receives from the client a request to establish a group call;

(3) The word is assigned to the user after the client receives the call setup response in progress from the server or after a configurable delay (1 second) and begins buffering the user's media;

(4) The server initiates the process of restoring target packet data traffic channels;

(5) The server sends to the client via short bursts of data a group call warning message;

(6) The client successfully re-establishes the traffic channel, initiates the sending of buffered media to the server;

(7) The client forwards the media to the server;

(8) Target traffic channels have been re-established (target response threshold value is reached);

(9) The user releases the push-to-talk button. The client ceases to put the media in buffer;

(10) The client terminates the forwarding of the buffered media to the server and requests the server to provide the word;

(11) The server sends the client acknowledgment of the assignment of the word.

Client-Side Intermediate Buffering

In one embodiment, where less apparent delay is desired, the speaker may be allowed to begin speaking even before the traffic channel is reestablished. Because the client mobile station is not yet in communication with the media control unit, the signal to the speaker to start speaking is given by the client mobile station. If the speaker is allowed to speak before the speaker's traffic channel is reestablished, the client's mobile station may buffer 412 the speech. Because communication with the communications manager is not yet established, permission to speak will be given with optimism. Fig. 18 shows the client-side buffering according to one embodiment as described below:

(1) No call is in progress;

ΡΕ1474938 initiator traffic is dormant;

(2) The user presses the push-to-talk button. The client sends to the server via short bursts of data a request to establish a group call;

(3) The client initiates the process of re-establishing a packet data traffic channel;

(4) The word is assigned to the user after the client receives the call setup response in progress from the server or after a configurable delay (1 second) and begins buffering the user's media;

(5) The client receives from the server via short bursts of data a group call warning message;

(6) The client successfully re-establishes the traffic channel;

(7) The client forwards to the server the buffered media;

(8) The user releases the push-button. The client ceases to put the media in buffer;

(9) The client terminates the forwarding of the buffered media to the server, requests the transfer of the word by the server;

(10) The client receives acknowledgment of the assignment of the word from the server.

741474938

In one embodiment, both buffering 418 made by the media control unit and buffering 412 made on the client side may operate concurrently. Client-side buffering may allow for apparent push-to-talk latency. In one embodiment, the client mobile station may buffer the media to control the apparent push-to-talk latency that is experienced by the user. The combination of short bursts of data originating from the mobile station and the buffering of the media on the client side can reduce the delays associated with restoring active traffic channels.

Accordingly, the embodiments presented provide a dispatching model that supports at least two types of dispatching calls: the chat room model and the ad-hoc model. In the chat room model, groups are predefined and can be stored on the dispatcher server. However, in the ad hoc model groups can be defined and / or modified in real time.

The described embodiments also provide a significant reduction in the effective total wake-up time and push-to-talk latency by exchanging even group call signaling.

ΡΕ1474938 when mobile stations are dormant and no traffic channels are active. The method and apparatus provide for the exchange of group call signaling by using short burst data message (SDB) signaling. The method and apparatus advantageously provide for the parallel restoration of dedicated traffic channels for the speaker's mobile station and the listener's dormant mobile stations.

In another embodiment, the dormancy wake-up latency in a group communications network may be reduced by caching the network-initiated wake triggers for the target listeners and by providing a wake-up trigger to a target mobile station as soon as the target mobile station has established its traffic channel.

In another embodiment, simultaneous service initiation and paging in a mobile station operation on a group communications network is prevented by transmitting a response to a word control request after the service initiation process is completed. In one embodiment, the response to the word control request may be in the form of short bursts of data if the service initiation process is not completed. In one embodiment, the service initiation process for the source communication device is initiated after the response has been transmitted to the