Method and apparatus for delivering information to an idle mobile station in a group communication network

Cross Reference to Related Applications [0001] This application claims the benefit of US Provisional Patent Application Serial No. 60 / 291,454 filed May 15, 2001.

The present invention relates to a point-to-multipoint communication system. In particular, the present invention relates to methods and devices for delivering information to idle mobile stations within a group communication network.

Background [0003] For many years, classes of wireless services for fast, efficient one-to-one or one-to-many (group) communications have existed in various forms. In general, these services were half-duplex. In this case, the user presses the "push-to-talk" (PTT) button on his phone / radio to start speaking. Pressing a button, in some implementations, locks one's radio or, in moderate systems, where communication occurs through some kind of server, requests the user for "speaking rights". Shown. If the right to speak, or speaker, is allowed, then the user can generally speak for a few seconds, then release the PTT {XE "PTT"} button and another speaker can request the right to speak. Communication is generally one speaker and multiple listeners, but it can be one-to-one. This service has traditionally been used in applications where one person, a "communication commander," needs to communicate with a group of people, such as local service personnel or taxi drivers. This is why the service was named "Communication Directive".

[0004] In recent years, similar services have been provided on the Internet, commonly known as "voice chat". These services typically send Internet Protocol (IP) {XE IP} packets, or vocabulary frames within the Voice over IP (VoIP) service, from client to client via a central group chat server or perhaps peer-to-peer service. Implemented as a computer {XE "PC"} application.

[0005] An important feature of these services is that communication is fast and spontaneous, usually simply pressing the PTT {XE "PTT"} button without going through the typical dialing and ringing sequences. Is started by. This type of service is generally very short. Individuals speak unilaterally on the order of a few seconds, and a "conversation" probably ends in a minute or less.

[0006] The time delay between when the user requests a voice and when the user begins speaking upon receiving a positive or negative confirmation from the server with the voice, which is PTT {XE "PTT"}. Known as latency, it is an important parameter for half-duplex group communication systems. As mentioned above, communication commands prioritize short and quick conversations, but higher PTT latency can reduce service efficiency.

[0007] Existing group communications infrastructure infrastructure has limited opportunities to significantly reduce PTT latency. That is, the actual PTT latency may probably not be reduced below the time required to reestablish a traffic channel within a dormant packet data session. Furthermore, the speaker's traffic channel and the listener's traffic channel are continuously raised. This is because the only mechanism available to start awakening a dormant group is to wait for the speaker's traffic channel to be reestablished to signal the server. Currently, there is no mechanism to send signaling data to mobile users about anything other than the traffic channel-a limitation that requires the traffic channel to be reestablished before communication between the client and server occurs.

[0008] Therefore, reduce the apparent PTT latency experienced by the speaker and reestablish the traffic channel to join the mobile without affecting system capacity, client battery life, or other resources. There is a need for a mechanism to reduce the total time required to do this.

<p>[0009] The disclosed embodiments provide new and improved methods and devices for delivering information to idle mobile stations in group communication networks. In the first aspect of the present invention, in a group communication network, a method for distributing information to an idle mobile station determines whether the information is smaller than a predetermined size limit value, and the information is more than a predetermined size limit value. If it is small, it includes a step of distributing the information to the mobile station via a forward common channel. In one form, when the mobile station is idle without a traffic channel, the information is delivered, for example, in the form of a short data burst.</p><p>[0010] In a second aspect of the invention, a method for delivering information to an idle mobile station in a group communication network encapsulates the information in a frame and sends the frame to a server for delivery to the mobile station. , Includes the process of having the server extract information from the frame and distributing that information to the mobile station via a forward common channel. In one form, when the mobile station is idle without a traffic channel, the information is delivered, for example, in short data burst (SDB) format.</p><p>[0011] In a third embodiment of the present invention, in a group communication network, a method for delivering information to an idle mobile station receives information for delivery to the mobile station, and the information is on a forward common channel. It includes the process of being tagged for distribution via and delivering that information to a mobile station. In one form, when the mobile station is idle without a traffic channel, the information is delivered, for example, in short data burst (SDB) format.</p><p>[0012] In one embodiment, the device for delivering information to a mobile station in a group communication network is a memory device, a receiver, a transmitter, and a processor communicatively connected to the memory device, the receiver, and the transmitter. including. The processor can perform the steps of the method described above.</p>

[0013] The features and advantages of the present invention will become more apparent from the detailed description described below, along with the drawings with the same reference numerals.

Detailed Description [0021] Prior to elaborating an embodiment of the invention, the invention details the configuration and arrangement of components described in the following description or illustrated in the drawings in the application. It must be understood that it is not limited to. The present invention can be carried out in other embodiments and can be carried out in various ways. It is also understood that the wording and terminology used herein is for explanatory purposes and should not be considered limiting.

[0022] FIG. 1 illustrates an exemplary functional block diagram of the group communication system 100. The group communication system 100 is also known as a push-speaking system, a net broadcast service (NBS), a dispatch system, or a point-to-multipoint communication system. In the NBS100, groups of communication device users, individually known as net members, communicate with each other using communication devices assigned to each net member. The term "net" means a group of communication device users authorized to communicate with each other.

[0023] In one embodiment, the central database may include information that identifies each particular net member. One or more nets can operate in the same communication system. For example, the first net can be defined to have 10 members and the second net can be defined to have 20 members. The 10 members of the first net can communicate with each other, but not with the members of the second net. In other embodiments, members of different nets can monitor communications between members of one or more nets, but can only send information to members within their own net.

[0024] The net can operate through an existing communication system without requiring major changes to the existing infrastructure. Thus, controllers and users on the net can operate in any system that can send and receive packet information using Internet Protocol (IP). This system includes, for example, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, global systems for mobile communication systems (GSM), Globalstar® or Iridium®. There are satellite communication systems, or various other systems.

[0025] Net members can communicate with each other using the assigned communication devices, designated as communication devices (CDs) 102, 104, 106 and 108. CDs 102, 104, 106 and 108 include, for example, terrestrial radio phones, wired phones with push-speaking capabilities, satellite phones with push-speaking capabilities, wireless video cameras, still cameras, audio equipment such as music recorders or players, laptops. Alternatively, it may be a wireless or wired communication device such as a desktop computer, a paging device, or a combination thereof. For example, the CD102 can consist of a wireless terrestrial telephone with a video camera and display. In addition, each CD can send and receive information in either safe or unsafe (clear) mode. Throughout the discussion below, references to individual CDs guess radio push-speaking phones. However, it is understood that references to CDs are not intended to be limited to such and may include other communication devices capable of sending and receiving packet information according to the Internet Protocol (IP). It must be.

In the NBS system of FIG. 2, transmission rights generally allow a single user to transmit information to other net members at one time. When a request is received, the request net member is granted or denied the transmission right, depending on whether the transmission right is currently assigned to another net member. The process of allowing and rejecting submission requests is known as mediation. In deciding whether the requesting net member is granted transmission rights, the arbitration scheme may include, for example, the priority level assigned to each CD, the number of unsuccessful attempts to obtain transmission rights, and the net. Factors such as the length of time a member has held transmission rights, or other factors can be assessed.

[0027] To participate in the NBS system, CDs 102, 104, 106 and 108 can each have the ability to request transmission rights from the controller or communication manager (CM) 110. The CM110 can manage the real-time arbitration operation of the net. A CM is any type of computer-type device that has at least one processor and memory. In one embodiment, the CM is the Sun workstation Netra T1®.

[0028] Given that authority is provided by the service provider, the CM110 may operate remotely via the communication system service provider, netmembers, or both. The CM110 can receive net definitions via an external arbitration interface. Net members can request management activities through a service provider or manage net functions through a defined system such as Member Operations Security Manager (SM) 112 that conforms to the CM arbitration interface. The CM110 can authenticate parties attempting to establish or modify the net.

[0029] The SM112 can perform related tasks to support key management, user authentication, and secure nets. A single group communication system can interact with one or more SM112s. The SM112 does not have to be included in real-time control of the net, including net activation or PTT arbitration. The SM112 can have management capabilities compatible with the CM110 interface to automate management functions. The SM112 can act as a data endpoint for the purpose of joining the net, broadcasting the net key, or simply monitoring the net traffic.

[0030] In one embodiment, the means for requesting transmission rights from a CM consists of a press-speak (PTT) key or switch. When a user of NBS100 wants to send information to other net members, the user can press the press-speak switch located on the CD to send a voice control request and get the right to send from CM110. If no other net member is currently assigned a transmit right, the requesting user is granted the transmit right and can notify the user of an audible, visual, or tactile warning via the CD. .. After the requesting user has been granted the right to send, the information can then be sent from that user to other net members.

[0031] In one embodiment of the invention, each radio net member establishes forward and reverse links using one or more base stations 116 or, in some cases, satellite gateways 118. Base station 116 can be used to describe a communication channel on a CD from base station 116 or satellite gateway 118. The satellite gateway 118 can be used to describe the communication channel from the CD to the base station 116 or the satellite gateway 118. Voice and / or data can be converted, for example, into data packets using CDs, suitable for a particular distributed network capable of communicating with other users. In one embodiment, the distributed network 120 is the Internet.

[0032] In one embodiment, dedicated forward channels are established in each communication system, i.e. terrestrial and satellite communication systems, to broadcast information from each net member to another net member. Each net member can receive communications from other net members via a dedicated channel. In another embodiment, a dedicated reverse link is established in each communication system to transmit information to the CM110. In one embodiment, a combination of schemes described above may be used. For example, the scheme can include establishing a dedicated forward broadcast channel, but requires wireless CDs to transmit information to the CM110 via a dedicated reverse link assigned to each CD.

[0033] When a first net member wants to send information to other members of that net, the first net member can request the right to send by pressing the press and speak key on his CD, which is distributed. Generates a formatted request for transmission over the type network 120. For CDs 102 and 104, the request can be transmitted wirelessly to one or more base stations 116. A switchboard for mobile phone systems (MSC) 122 for processing data packets, which can include the well-known interaction function (IWF), packet data serving node (PDSN), or packet control function (PCF). It can be intervened between BS116 and distributed network 120. For CD106, the request is transmitted via satellite gateway 118. For CD108, the request can be sent to modem bank 126 via the public switched telephone network (PSTN) 124. Modem bank 126 receives the request and supplies it to the distributed network 120. The NBS terminal 128 monitors the traffic of the NBS system via the connection to the distributed network 120. Since the NBS terminal 128 is connected to the distributed network 120, geographical proximity to net participants is not required.

[0034] If no other member currently holds the send right, when the CM110 receives the send right request, the CM110 can send the message to the requesting net member and the send right is granted. Inform the requesting member. Therefore, audio information, visual information or other information from the first net member can be transmitted to other net members by transmitting the information to the CM110 using one of the transmission routes described above. it can. In one embodiment, the CM110 replicates information and supplies information to other netmembers by transmitting each replica to other netmembers. If a single broadcast channel is used, it only needs to be replicated once for each broadcast channel in use.

[0035] In an alternative embodiment, the CM110 is embedded in the MSC122 so that data packets from supporting base stations are sent directly to the CM110 rather than to the distributed network 120. In this embodiment, the CM 110 is still connected to the distributed network 120 so that other communication systems and communication devices can participate in group communication. In yet other embodiments, the CM can be incorporated into a PDSN, or MSC PCF module.

[0036] In one embodiment, the CM110 maintains one or more databases for managing information relating to individual net members as well as information relating to each defined net. For example, for each net member, the database contains the username, account number, phone number, or dial number associated with the member's CD, the mobile identification number assigned to the CD, and whether the member is actively participating in the net. The current member status on the net, the preferred code to determine how transmission rights are assigned, the phone number associated with the CD, the IP address associated with the CD, and which net the member communicates with. It consists of information such as an indication of whether you are authorized to do so. Other related types of information can also be stored in the database for each net member.

[0037] In one embodiment, the CD may form a connection of individual communication terminals to form a speaker group or net. CMs can be configured with different functional capabilities in hardware and software that can be configured differently to suit different applications. CM is (NBS) net real-time operation, management operation and reliability, mediation of push-speak (PTT) requests, retention and distribution of net membership and registries, necessary communication, such as setting calls for CDMA systems and network resources. And destroy, as well as provide the ability to manage overall control of net status.

[0038] NBS nets can reside in a stand-alone deployable cellular system, or in a large multi-site configuration. For large configurations, multiple CMs, each acting as a plug-in module to an existing cellular infrastructure infrastructure, can be geographically arranged to form a single integrated system. Therefore, new features introduced by NBS Net are available to cellular users without the need to modify the existing cellular infrastructure infrastructure.

[0039] CM can hold a list of defined NBS nets. In one embodiment, each net definition includes a list of members, including net identifiers, telephone numbers or other identifying information, user priority information, and other comprehensive management information. Nets can be statically defined as clear or safe, and no transition between clear and safe is allowed. Secure NBS generally uses media encryption to provide authentication and protect against eavesdropping. Media encryption for a secure net is performed on an end-to-end basis, which means that encryption and decryption can be performed within the communication device. CM can be done without knowledge of security algorithms, keys, or policies.

[0040] FIG. 2 illustrates an exemplary NBS net 200 to show how the communication device 202 communicates with the CM204. In the case of a large NBS net, multiple CMs can be arranged upon request. In FIG. 2, CD202 has permission to transmit the medium to other members of the net. In this case, the CD202 is known as the speaker and transmits the medium over the channel. Once CD202 is designated as the speaker, the remaining net participants CD206 and CD208 cannot have permission to send media to the net. Therefore, CD206 and CD208 are designated as listeners.

[0041] As mentioned above, CD202, 206, and 208 are connected to CM204 using at least one channel. In one embodiment, the channel is divided into separate channels consisting of Session Initiation Protocol (SIP) channel 210, NBS media signaling channel 212, and media traffic channel 214. Bandwidth is allowed by either CDs 202, 206 and 208, whether designated as speaker or listener, so SIP channel 210 and NBS media signaling channel 212 can be used at any time. .. SIP is an application layer protocol defined by the Internet Engineering Task Force (IETF) that describes the controls for establishing, modifying, and terminating multimedia sessions over the Internet Protocol (IP). SIP supports a mechanism for registering and locating users, defining user capabilities and describing media parameters, and determining user availability, call configuration, and call processing. By doing so, it provides a general solution to the problem of call signaling for internet telephone applications.

[0042] In one embodiment, the SIP channel 210 is used to initiate and terminate the participation of CDs within the NBS net 100. Session Description Protocol (SDP) signals can also be used within SIP channel 210. When CD participation is configured within the NBS net using, for example, SIP channel 210, real-time call control and signaling between the CD and CM is performed, for example, using NBS medium signaling channel 212. In one embodiment, the NBS media signaling channel 212 handles push-speak and release, mediation or voice control between conflicting requests, signals the start and end of information transmission, manages net dormancy, and manages net dormancy. Used to track endpoint connectivity, request and exchange net status, and notify of any error messages. The protocol of NBS media signaling channel 212 minimizes the most common message lengths, interprets responses, and simplifies the task of responding to requests, while maintaining flexibility for future augmentation. The protocol of NBS media signaling channel 212 also allows the request to be retransmitted without adversely affecting the protocol state.

[0043] In one embodiment, the signaling traffic on the NBS media channel 212 is from call configuration and control signaling, which can consist of session invitation requests and acknowledgements, and real-time voice control requests and associated asynchronous messages. Includes media signaling that can be configured. Media traffic Media traffic on channel 214 can consist of real-time point-to-multipoint audio and / or data broadcasts. Both messaging categories have unique functional attributes. In addition, each CD can issue Domain Name Service (DNS) client requests to facilitate mapping fully qualified DNS hostnames to Internet network addresses.

[0044] In one embodiment, NBS call configuration and call control signaling are performed according to SIP semiotics. Although SIP can be moved using the well-known User Datagram Protocol (UDP) or Transmission Control Protocol (TCP), in one embodiment, each CD uses UDP to provide SIP-based signaling functionality. Run. Also, each CM can be expected to receive a SIP signaling request via UDP. Real-time signaling can occur via the CM and the dynamic UDP / IP interface on each CD. For example, SIP can be used to generate other signaling through a fixed TCP / IP interface between CM and CD.

PTT Wait Time [0045] In one embodiment, when the packet data service is active, resources within the infrastructure infrastructure, such as the Base Station Transceiver Subsystem (BTS) {XE IWF}, Base Station Controller (BSC) {XE "BSC"}, Interaction (IWF) {XE "IWF"}, and radio links are actively assigned to mobile stations (MS). In the IP {XE IP} based VoIP dispatch service, active conversations continue between group participants, but packet data connections for each user are actively maintained. However, after a period of inactivity, i.e. a period of "hang time" in group communication, the user traffic channel can transition to a dormant state.

The transition to dormant state saves system capacity, reduces service costs and battery drain, and makes it available to the user to receive incoming common voice calls. For example, when a user is in an active packet data call, the user is considered to be "busy" for incoming voice calls. If the user's packet data call is dormant, the user may be able to receive the incoming voice call. For these reasons, it is desirable to transition packet data calls after a period of packet data inactivity.

[0047] When a packet data call is active, to maintain synchronization with the base station and power control, despite low radio frequency (RF) energy, even if no data packets have been exchanged. It can still be transmitted by mobile phone. These transmissions may result in significant power consumption of the phone. However, in the dormant state, the phone may not perform any RF transmission. To save power on the phone and extend battery life, hang times can be set to put the phone into a dormant state after an extended period of no data transmission.

[0048] While the packet data service is active for all users, a PTT {XE "PTT"} request, which is an IP {XE "IP"} datagram sent between the MS and the dispatch server. However, this requirement has a very low latency. However, the PTE {XE "PTT"} latency may be longer if the user channel had previously transitioned to a dormant state. The state information associated with the packet data session, including the period of packet data dormancy and the mobile IP address, can be maintained. However, state information related to layers below PPP, such as the physical traffic layer, can be released and / or revoked.

[0049] In some infrastructure infrastructures, traffic channels must be reassigned, resources must be reassigned, and wireless link protocol (RLP) {XE to make dormant data connections occur. The Radio Link Protocol (RLP) } layer must be reinitialized. The effect is that after a group of speakers haven't spoken for a while, when the user presses their PTT {XE PTT} button to request a say, they wait for the PTT for what they say first. The time is generally much longer than the PTT wait time for what you are talking about next. This is relatively rare, but it affects the utility of the service and should be shortened.

[0050] {XE "PTT"} In one embodiment, when the group communication device is dormant, the PTT {XE "PTT"} wait time can be caused by:

1. Speaker Channel Allocation Delay-Assigning a traffic channel for the speaker's phone in response to the user pressing the speak button and the dispatch application initiating an IP-based voice-request message. Delay in initialization.

2. Speaking Request Propagation Delay-Time for a speaking request message to propagate to the dispatch server.

3. Mediation Delay-The time it takes for the dispatch server to process potentially multiple voice requests.

4. Wake Up Message Delay-Time to propagate an IP message from a dispatch server to a cellular infrastructure that serves listeners, such as a PDSN.

5. Listener Paging Delay-Time delay due to the requirement to wait for the listener's call to wake up and receive the page within the appropriate paging channel slot.

6. Listener Channel Allocation Delay-Delay in allocating and initializing the listener's telephone traffic channel.

Some of these delays are more important than others in their contribution to the overall PTT latency. For example, speaker channel allocation latency and listener channel allocation latency and listener paging latency are often on the order of greater magnitude than other components and together drive the ultimate PTT latency performance.

[0057] To reduce PTT latency, in one embodiment, the voice control request, the voice control response, and the dormant wakeup message are several without waiting for a dedicated traffic channel to be reestablished. Can be transmitted through the available common channels of. Such common channels are always available, regardless of mobile state, and may not need to be requested or reassigned each time a user wants to initiate a group call. Therefore, group call signaling is interchangeable even when the mobile is dormant, which can provide a means for reestablishing a dedicated traffic channel for the speaker's mobile and the listener's mobile.

[0058] In one embodiment, the calling mobile has voice-control over the wireless infrastructure infrastructure through several available reverse common channels, such as reverse access channels and reverse enhanced access channels. Requests can be sent. The calling mobile can also receive responses to voice control requests via several available forward common channels, such as forward paging channels and forward common control channels. In one embodiment, the dormant listener mobile can receive dormant wakeup messages via several available forward common channels, such as forward paging channels and forward common control channels.

Burst Calls of Short Data-Signaling Messages [0059] In one embodiment, the actual total dormant wakeup time and the significant reduction in PTT {XE "PTT"} latency perceived by the speaker are, for example, "cdma2000" below. It can be achieved through the use of short data burst (SDB) messages supplied in the "TIA / EIA / IS-2000 Standard for cdma2000 Spread Spectrum Systems" called "Standard". In one embodiment, the SDB message is a (FCH) dedicated physical channel, such as a forward basic channel, or a forward dedicated common control channel (R-ACH), or a reverse access channel (R-ACH), reverse. It can be transmitted over a common physical channel such as an enhanced access channel (R-EACH), a forward common control channel (F-CCCH), or a paging channel (PCH). SDB messages can be sent using the Radio Burst Protocol (RBP), {XE "Radio Burst Protocol'RBP"}, which maps the message onto the appropriate and available physical layer channels. SDB messages can carry any IP {XE IP} traffic and can be sent over a common physical channel, so when the calling client's mobile does not have a dedicated traffic channel. , Provides a mechanism for exchanging group call signaling.

Mobile Source Call-Signaling Message [0060] In one embodiment, the medium-signaling message can carry an IP datagram via a reverse link or a mobile source link. The client mobile station can quickly signal the CM when the user requests a voice, and the dedicated reverse traffic channel is not immediately available. Assuming that the client mobile station has released all dedicated traffic channels, the client mobile station can immediately send a voice control request via the reverse common channel of the wireless infrastructure infrastructure. The wireless infrastructure infrastructure can relay the request to the CM. For example, when a reverse channel is not available, such a message can be sent using a reverse access channel or a reverse enhanced access channel. In one embodiment, the client mobile station can send a voice-request message to the CM as an SDB message.

[0061] FIG. 3 shows a voice-exemplary call-signaling for the control request process. The client mobile station (MS) can receive requests from users who want to initiate a group call. In one embodiment, the client MS can be a PTT device. In one embodiment, the client may send a PTT voice request 302 over a reverse common channel, such as an access channel or an enhanced access channel, before attempting to reestablish its dedicated traffic channel. .. In one embodiment, the client MS can send a PTT voice request 302 in an SDB message regardless of which channel is used.

[0062] The client MS can then initiate the re-establishment of its dedicated traffic channel 304, for example by executing "Service Option 33 Reconfiguration". The client MS can also initiate Radio Link Protocol (RLP) Sync 306. In one embodiment, the client MS can reestablish its dedicated traffic channel and favorably synchronize the RLP in parallel with sending the PTT voice request 302.

[0063] Therefore, when the mobile station does not have an active dedicated traffic channel, the use of available reverse common channels and / or SDB features is necessary to awaken the participating mobile. Total time is reduced. The speaker's client begins to awaken the participating listeners, although it may not receive confirmation that the speaker's forward traffic channel has been reestablished. Therefore, the ability to quickly signal the CM reduces the overall latency.

[0064] With reference to Figure 3, the wireless infrastructure infrastructure can send a PTT voice-control request 308 to the Packet Data Service Node (PDSN) and then to the CM. In one embodiment, after receiving the voice-control request 310, the CM can arbitrate the request and participate in the media signaling wakeup message (trigger) {XE "AYT wakeup request"}. It can be burst-forwarded to a group of people (listeners) and / or trigger the re-establishment of a participant (listener) traffic channel. If the CM allows the PTT voice request, the CM can send the PTT voice permission 312 to the infrastructure, and the infrastructure can send the PTT voice permission 314 to the client MS. In one embodiment, the infrastructure speaks to the client MS via available common channels such as forward paging channels and forward command control channels, unless the client's dedicated traffic channels have been reestablished. Permission 314 can be sent. In one embodiment, the infrastructure can send the PTT Speaking Grant 314 to the client in SDB format, regardless of which channel is used.

[0065] In one embodiment, the CM can wait for the dormancy response timer to expire before responding to the PTT voice-control request. If the group's dormancy response timer is set to zero, the CM can respond quickly to voice-control {XE PTT} requests. In one embodiment, once the client MS has completed reestablishment of its traffic channel and RLP synchronization, the stream medium 316 buffered by the client MS can be sent to the CM.

Network Sourced Call Signaling Message [0066] In one embodiment, after receiving a voice-control request, the CM can burst forward a media signaling wakeup message to a group of target participants (listeners). , Can trigger the re-establishment of the participant's (listener's) traffic channel. If the group's dormancy response timer is set to zero, the CM can respond quickly to voice control {XE PTT} requests. In one embodiment, if the speaker begins to quickly reestablish its traffic channel after sending a PTT {XE "PTT"} request, then the caller's traffic channel and the listener's traffic channel are reestablished in parallel favorably. Will be done.

[0067] Figure 4 shows exemplary call signaling for a network-initiated dormant wakeup process. After the CM receives the PTT Speaking Right-Control Request 310 (Figure 3), the CM can send the Wake Up Trigger 402 towards the target listener. PSDN can determine if a packet data session exists for the target mobile and sends its trigger packet to the appropriate infrastructure element, eg a base station. The infrastructure will contact each individual target MS to initiate the reestablishment of its dedicated traffic channel 406. The target MS can initiate the re-establishment of its dedicated traffic channel 408, for example, by executing "Service Option 33 Reconfiguration". The target MS can also initiate Radio Link Protocol (RLP) Synchronization 410 . In one embodiment, the target MSs can reestablish their dedicated traffic channels and synchronize their RLPs in parallel with the same functionality performed by the client MS.

[0068] In one embodiment, when the target MS completes the reestablishment of its dedicated traffic channel and the synchronization of the RLP, the CM can retransmit the wakeup trigger 412 to the target MS. The target MS can send a wake-up response to the CM indicating that the target MS is ready to receive the medium. The CM can send the speaker's announcement to the client MS before sending the medium 418 buffered in the CM to the target MS.

[0069] In one embodiment, the infrastructure infrastructure has some available common order, such as forward paging channels and forward common control channels, even though the target listener's traffic channels have not yet been reestablished. A wake-up trigger 412 can be sent to the target listener via the directional channel. In one embodiment, the infrastructure can send the Wake Up Trigger 412 in SDB form to the target listener, regardless of which channel is used. PTT Speaking-If the control request is sent as an SDB message on the speaker's reverse common channel and the dormancy response timer of the target group is set to zero in the CM, the actual PTT latency at the speaker client is a reverse link. The time required to send an SDB request message on top and then send an SDB response over a forward link can be reduced.

Network Interface for Call Signaling Messages [0070] To determine what network the source of a particular traffic, such as the SDB payload, is sent to an idle mobile station without using a dedicated traffic channel. Certain infrastructure policies or interfaces can be implemented to distinguish such particular traffic from other traffic.

[0071] In a first embodiment, SDB messages can carry a limited user payload so that IP datagrams can be filtered based on their size. IP datagrams smaller than a given size limit can be sent as SDB messages if sent to mobile without a dedicated traffic channel. Application Speaking-The request-response message is extremely small, for example 34 bytes including the IP header, so group communication systems can use such filters.

[0072] In a second embodiment, the infrastructure can define an IP-based service for encapsulating the IP traffic that is to be delivered to the mobile station. IP servers with knowledge of this service can deliver small IPs, such as UDP, datagrams properly encapsulated in IP headers, to mobiles that are presumed not to have a dedicated traffic channel. Can be sent to. The group communication system can use this service to indicate to the infrastructure that the voice-request response message should be delivered, for example, to the requesting client MS in SDB format. Matching SDB traffic with pending page or service outbreak requests is also important to ensure the prompt and reliable delivery of user traffic.

[0073] In a third embodiment, the IP server is a datagram with a special IP, such as UDP, IP header, for delivery to mobile, which is presumed not to have a dedicated traffic channel. Can be sent. To instruct the infrastructure infrastructure to deliver the IP datagram to the client MS, the IP server can tag the IP datagram, for example, by specifying a special value in the IP header. The group communication system can use this service to indicate to the infrastructure that a voice-request response message should be delivered, for example, to the requesting client MS in SDB format. In a third embodiment, a UDP or TCP port range can be reserved for delivery of specific IP datagrams, such as SDB messages.

Mobile-initiated service generation and paging [0074] In one embodiment, the speaker's mobile station (MS) sends a voice-control request 302 to the CM, as described in connection with FIG. Can be done. This can be done in SDB format, which immediately follows sending a service occurrence request 304 to the wireless, eg, CDMA infrastructure, to quickly reestablish its traffic channel. However, if the dormancy response timer is set to a small value, the CM can quickly respond to the voice-control request 310 and send the response 312 back to the speaker MS. If this response arrives at the infrastructure early in service-initiated transaction 304, the infrastructure will try to contact the speaker's MS with the response because the speaker's MS does not have any active traffic channels. Notice that you are trying. However, this paging action can abort an already ongoing service occurrence transaction. In one embodiment, the speaker's MS can respond to the page, ensure that the voice-control response message is delivered to the speaker, and request service occurrence again. However, they face unnecessary delays in reestablishing the speaker's traffic channel as a result of the original service outbreak attempt that was discontinued.

[0075] In the first embodiment, in order to avoid a race condition between the service generation process and paging, the CM can be configured not to respond quickly to the voice-control request 310. Thus, for example, the dormancy response timer in the CM can be adjusted so that the CM sends a response 312 to the speaker's MS after the service generation process 304 is complete.

[0076] In the second embodiment, the PDSN that receives the response 312 initiated by the CM and the switchboard (MSC) for the mobile phone system that responds to the speaker's service occurrence request are coordinated. That is, if the PDSN determines that the packet data service generation process for the speaker's MS is already underway when the CM-initiated response 312 arrives at the infrastructure, the MSC should page to the speaker's MS. Can be postponed. The PDSN can cache the response and send it over the speaker's mobile forward traffic channel once the service occurrence process is complete. Alternatively, if the service generation process is still in progress, the MSC can send the response as an SDB message to the speaker's MS.

[0077] In a third embodiment, the speaker MS may avoid the race condition by not issuing the service occurrence request 304 until the speaker MS receives a response to the voice-control request 302. it can. In one embodiment, the speaker's MS does not have an active dedicated traffic channel, so the CM has several available forward common channels, such as forward paging channels and forward common control channels. The response can be sent to the speaker's MS via. In one embodiment, the CM can send its response in SDB format to the speaker's MS. In the same way that the wakeup request sent by the CM triggers the reactivation of the traffic channel for the listener's mobile, the speaker's MS is generated by the CM to trigger that traffic channel reactivation. Speaking right-can rely on control response 312. Race conditions are avoided because the possibility of simultaneous mobile-initiated service outbreaks and network-initiated mobile paging is avoided.

Network-Initiated Packet Data Trigger Caching [0078] IP datagrams directed to the listener's mobile, including the wake-up trigger 402, reaching the radio, eg, the CDMA infrastructure infrastructure, without a dedicated traffic channel. It may be lost in general by the network, or especially by the wireless infrastructure infrastructure. In one embodiment, the wakeup trigger 402 transmitted to the listener's mobile is actively retransmitted according to a defined schedule until the listener responds or the group's wakeup timer expires. For example, the Wake Up Trigger 402 can be retransmitted every 500ms. However, retransmitting the Wake Up Trigger 402 at this rate is between the time the listener's traffic channel is reestablished and the time the next Wake Up Trigger directed at that listener arrives at the infrastructure. It can cause delays up to 500ms, or an average delay of 250ms.

[0079] In one embodiment, the infrastructure or other entity in the network can cache the Wake Up Trigger 402 sent by the CM, as soon as the target MS reestablishes its traffic channel. It can be delivered to the target MS. This eliminates the need for the CM to retransmit the wakeup request 412 and reduces the total dormant wakeup time. For example, storing the wakeup trigger 402 in the cache, as opposed to retransmitting the wakeup trigger 402 at a rate of 500 ms, can eliminate the delay from the total dormant wakeup time to 500 ms.

Media Buffering [0080] In one embodiment, the user speaks after the user requests voice control by buffering the media before a dedicated channel is reestablished between the client and the listener. May be allowed to start. By buffering the speaker's speech, the system allows the speaker to start speaking before the listener's traffic channel is fully established. This allows the speaker to start speaking faster and reduce the apparent PTT {XE PTT} waiting time. The listener does not experience PTT waiting time, so those experiences are unaffected. That is, the PTT wait time is shifted from the speaker to the rest of the system. The speaker may wait the same amount to receive a response from the listener to the content of the first story. However, as mentioned above, the speaker has already expected that the response to the content of the first story will take longer than the content of the next story that occurs while the speaker is engaged in the actual conversation. There is. Buffering of the content of the speaker's first talk can be done on the CM side or the client MS side.

CM Buffering [0081] In one embodiment, the CM can buffer the content of the speaker's first story. After the user presses his PTT {XE "PTT"} button and the user's traffic channel is reestablished, the user may be allowed to communicate with the CM. At this point, the listener's traffic channel has not yet been activated, so the CM buffers the speaker's speech for future transmissions to the target listener. CM buffering can reduce the apparent PTT {XE PTT} latency seen by the speaker to the approximate time it takes to establish the speaker's traffic channel. FIG. 5 shows CM buffering according to one embodiment.

Client-Side Buffering [0082] In one embodiment, when a shorter apparent latency is desired, the speaker can start talking even before his traffic channel is reestablished. Since the client MS has not yet communicated with the CM, the signal to the speaker to start talking is created by the client MS. If the speaker can speak before the speaker's traffic channel is reestablished, the client MS can buffer the speech. Permission to speak is optimistically given as communication with the CM has not yet been established. FIG. 6 shows client-side buffering according to one embodiment. In one embodiment, both CM buffering and client-side buffering can operate simultaneously. Client-side buffering can reduce the apparent PTT {XE "PTT"} latency.

[0083] As with CM buffering, the total delay cannot be changed. The user still experiences the same delay in receiving the response returned from the listener, but the apparent PTT {XE "PTT"} latency of the speaker can be reduced.

[0084] In one embodiment, the client MS can buffer the medium to control the apparent PTT latency experienced by the user. The combination of mobile-generated SDB and client-side media buffering can reduce the delay associated with reestablishing an active traffic channel.

Quick Paging Channel [0085] In one embodiment, the CM will display until the group's wakeup timer expires or until all listener clients respond to a network-initiated trigger to raise their respective traffic channels. You can delay responding to the speaker's PTT {XE PTT}. The CM can wait until all listeners are contacted before the CM allows the speaker to stream the medium in the group. The longer it takes a group of listeners to respond to the page, the longer the PTT wait time perceived by the speaker.

[0086] In one embodiment, during the dormant wakeup period, each listener client is individually sent a series of wakeup triggers by CM. For example, in a CDMA infrastructure infrastructure, upon arrival, a series of wake-up triggers will trigger one or more pages for each mobile. After receiving the page, each mobile can reestablish the traffic channel, receive the next wakeup request sent to the mobile, and use the wakeup request reply {XE IAH reply}. Can respond to commercials. A major component of the time required by the listener's handset to respond to this application-level "connection test packet" is spent on the infrastructure waiting for a reasonable amount of time to look for mobile.

[0087] To save battery life, when the mobile is idle, the mobile is defined within the paging channel {XE "forward paging channel (F-PCH"}, for example for each of the 2048 slots. Rather, the mobile may monitor the forward common control channel (F-CCCH) or forward paging channel (F-PCH), depending on the capabilities of the mobile. , Mobile can monitor paging slots according to the slot cycle index.

[0088] In one embodiment, to save battery life, the mobile can operate in "slotted paging" mode. In this mode, the mobile wakes up in short time cycles to hear the pages sent by the base station (BS). BS, which can know when the mobile listens, can send pages to a particular mobile during a particular paging slot period.

[0089] In one embodiment, the period during which the mobile wakes up to listen to the paging channel is controlled by a parameter called the slot cycle index (SCI) {XE slot cycle index (SCI)}, which has a large SCI. Then the mobile wakes up to listen to the paging channel for a longer time between slots. The phone consumes a large percentage of time sleeping, so a large slot cycle value increases the waiting time of the phone, but the BS calls Increases the amount of time the BS may have to wait before it can be called.

[0090] The amount of time a BS may need to delay its page for a phone is zero if the phone slot was just started when the BS needed to page the phone slot, When the BS needs to page the phone, if the phone slot has just finished, it is a full slot cycle and changes during this time. On average, the delay due to waiting for a phone slot to come around is half the slot cycle period. The shorter the slot cycle used by mobile, the sooner the listener can be called by the infrastructure. However, shorter slot cycles mean higher rate battery drain.

[0091] In one embodiment, the forward quick paging channel (F-QPCH) {XE Forward Quick Paging Channel (F = QPCH)} is pending when the mobile does not need to monitor the paging channel itself. It can be used to make mobile decidable in a power efficient way whether the page exists. Mobiles capable of monitoring F-QPCH can wake up all predetermined numbers of slots to extract the value of a 1-bit indicator in, for example, 80ms slots on a paging channel. If the extracted bits are not set, there are no pages pending in the paging channel and the mobile is dormant for another slot cycle. If the extracted bits are set, the page for that mobile is pending and the mobile schedules itself to wake up and monitor the paging channel at the next appropriate paging channel slot. can do.

[0092] The modulation adopted by F-QPCH allows mobile to monitor F-QPCH much more efficiently than mobile can monitor paging channels. This allows mobile to operate efficiently in a very short slot cycle in a power efficient manner. One of the advantages of using F-QPCH is that the slot cycle is faster than the slot cycle allowed at the same battery consumption rate, giving mobile a means to detect and respond to common page messages from the infrastructure. Therefore, a wakeup request message from the CM is given. This in turn translates into PTT latency and total dormancy wakeup time-the ability to minimize one of the delay components that directly contributes to the time required to reestablish the listener's traffic channel.

Slot Timer [0093] In one embodiment, the mobile can operate in a non-slot paging mode with a "slot timer". When activated, it releases the mobile's dedicated traffic channel, and when it enters idle mode for the period defined by the slot timer, the slot timer requires the mobile to monitor the paging channel in non-slot mode. The value of this timer can be set at the base station. This feature allows the infrastructure to instruct idle mode to monitor slots on the paging channel, eg, every 80 ms, when the mobile is in idle mode, and the infrastructure can be in any slot. A means for paging mobile is provided. One advantage of using non-slot mode, such as when using only the fast paging channel feature, provides a means for mobile to detect and respond to pages faster than allowed at the same battery drain. This reduces the time required to reestablish the listener's traffic channel during the dormant wakeup period.

[0094] Without the rapid paging channel feature, extended use of non-slot monitoring may be expensive in terms of battery life. However, using rapid paging channels and non-slot mode together provides a means of calling mobile almost instantly in a -1 slot or 2 slot period, eg 80-160ms.

[0095] Non-slot mode can be seen as one of the two intermediate stages of dormancy available to mobile stations. When operating in non-slot mode, the mobile does not have a dedicated physical channel and can be considered technically dormant. However, in this mode, the mobile can be called in essentially any slot, thus avoiding the paging delay associated with network-initiated reactivation.

Control-Retained Mode [0096] In one embodiment, a mobile-related PPP tier state, while one of the endpoints allows a dedicated traffic channel and other resources associated with the mobile packet data service option call. The mobile and infrastructure infrastructure can operate under packet data standards that provide additional dormancy / idle. The mobile or infrastructure infrastructure can transition the packet data call state from dormant / idle to active by reestablishing the traffic channel and renegotiating with RLP. The time required to reestablish a traffic channel can depend on whether the mobile or infrastructure infrastructure begins to reestablish. However, basically all system resources may need to be requested and allocated to mobile, so in both cases the delay can be compared to the delay required to create a new call on the system.

[0097] In one embodiment, the mobile can operate in a "control-hold" mode that acts as an interim position between active and idle modes. In control-retained mode, dedicated mobile-related traffic channels can be released and mobile reverse pilots can operate in "gate" mode. In one embodiment, a dedicated common control channel and / or RLP state may also be maintained. In essence, control-retained mode provides a semi-diapause state in which most system resources remain allocated, while average reverse link transmit power is gated to reduce the impact on system capacity. It is reduced to the pilot. FIG. 7 shows an exemplary configuration for wireless mode.

[0098] In one embodiment, the mobile can transition from active mode to control-retained mode by sending a resource release request message or a resource release request mini-message. The mobile can transition from control retention mode to active mode by sending a resource request message or a source request mini message. These messages can be carried via a dedicated control channel, and mini-messages are sent using shorter, eg, 5 ms frames, which allow fast transitions to and from control-retained mode. can do. As mentioned above, one advantage of control-retained mode over traditional idle mode or dormant / idle mode is the relatively fast transition from control-retained mode to active mode.

[0099] In one embodiment, upon receiving an indication from the CM that the enrolled group has transitioned to group dormancy, the client mobile first transitions itself to control-retained mode for further persistence of inactivity. After the period, the mode further shifts to idle mode. Therefore, when the user presses PTT or a wakeup request trigger is received in the infrastructure, control-retained mode provides a mechanism to significantly reduce the time required to reestablish a dedicated traffic channel. provide.

Stored Service Configuration [0100] In one embodiment, the infrastructure infrastructure can provide the ability to cache or store service configuration states in mobile and infrastructure infrastructure when transitioning to idle mode. Upon returning to active mode and reestablishing the traffic channel, the mobile can indicate in the inbound message or page response message that the service configuration for that call has been cached or stored. Mobile can also include Cyclic Redundancy Checks (CRCs) in outbreak or page response messages that can be calculated over the entire length of the service configuration. If the base station also caches its service configuration, the base station uses the received CRC to verify that its service configuration matches the mobile's stored service configuration, and if so. If so, the BS can indicate in the "service connection message" that the mobile can use the previously remembered service configuration.

[0101] In one embodiment, the use of the packet-data service option may not require a change in service configuration when transitioning from idle mode. Therefore, the use of stored service configurations can significantly reduce the time required to reestablish dedicated traffic channel resources. Therefore, a feature of the stored service configuration is a mechanism for significantly reducing PTT latency by reducing the time required to reestablish a traffic channel carrying both PTT signaling and associated media. By providing it provides an important enhancement to idle mode.

[0102] In one embodiment, the transition from the active mode to the idle mode can be performed for the client MS as follows.

[0103] 1. The group was active and mobile was devoted to traffic channels.

[0104] 2. After a period of inactivity beyond the group's hang time timer, the application layer group dormancy announcement is received via the mobile forward traffic channel.

[0105] 3. Mobile transitions to control retention mode and caches the state of this service configuration. Similarly, the client base station also stores the state of the service configuration in the cache.

[0106] 4. After a period of inactivity, the mobile releases its dedicated channel and transitions to idle mode. Mobile can start monitoring rapid paging channels and enter non-slot mode if ordered by the infrastructure. If the period of inactivity is relatively short, either by a local user pressing PTT or due to packet data traffic generated by the network from other group participants, the mobile will idle before transitioning to active mode and returning. The mode may not be reached. In this case, the mobile has a dedicated channel, so the transition back to active mode occurs quickly.

[0107] In one embodiment, the dormant wake-up event can be implemented as follows.

[0108] 1. The group is dormant, all mobiles are idle and do not have a dedicated physical channel. Mobile monitors rapid paging channels.

[0109] 2. In response to the user pressing and speaking button, the speaker's mobile has an application layer voice-request message in a short data burst format via one of the available reverse common channels. Send the signal to the CM. The speaker's mobile can start buffering the user medium forward from this point.

[0110] 3. The speaker's mobile sends an "occurrence message" to the infrastructure to reestablish its traffic channel. In the request, the speaker's mobile can cache the service configuration and indicate that the configuration data can include a CRC. This initiates the process of reestablishing the speaker's mobile traffic channel.

[0111] 4. The CM receives the voice request, decides whether to allow the request through the mediation process, and sends a voice request response message to the speaker. The CM also initiates a series of bursts of wakeup requests for all participants.

[0112] 5. Upon receiving each wakeup request, first determine the next appropriate slot to call the listener's mobile, and before that slot that the page is pending on the paging channel for that listener's mobile. The infrastructure calls each listener's mobile by notifying them via F-QPCH.

[0113] 6. Upon receiving an indication on the F-QPCH that the page is pending, each listener's mobile monitors the paging channel for the page.

[0114] 7. Upon receiving a page on the paging channel, each listener's mobile responds to that page, and in that page response, the mobile can cache the service configuration and include a CRC for the configuration data. Is shown. This initiates the process of reestablishing each listener's traffic channel.

[0115] 8. After establishing the speaker's traffic channel, the next voice request response from the CM is received at the speaker. The speaker begins to stream the medium to the commercial.

[0116] 9. After the establishment of each listener's traffic channel, the next wakeup request transmitted by the CM is received by the listener. The listener responds with a wake-up response message.

[0117] 10. When all listeners have responded or the group's wake-up timer has expired, the CM will begin streaming the medium to the group.

[0118] Therefore, the embodiments disclosed herein for methods and devices for reducing latency in group communication networks are group calls, even when the mobile is dormant and the traffic channel is inactive. By exchanging signaling, the actual total dormancy wakeup time and PTT {XE PTT} latency are significantly reduced. This method and device exchange group call signaling through the use of short data burst (SDB) message signaling. This method and device reestablish a dedicated traffic channel in parallel to the speaker's mobile and the dormant listener's mobile.

[0119] In another embodiment, the dormant wakeup latency in a group communication network caches a wakeup trigger initiated by the network directed to the target listener, and the target mobile station has its traffic channel. Can be reduced by delivering a wakeup trigger to the target mobile station as soon as it is reestablished.

[0120] In another embodiment, it is avoided by sending a response to the voice control request after the simultaneous service occurrence and paging, service generation process on the operating mobile is completed in the group communication network. .. In one embodiment, the response to the voice control request may be in SDB format if the service generation process is not completed. In another embodiment, the service generation process for the source communication device is initiated after sending a response to the source communication device.

<figref num="1">[0014] FIG. 1 illustrates a group communication system.</figref><figref num="2">[0015] FIG. 2 illustrates how some communication devices interact with a communication manager.</figref><figref num="3">[0016] FIG. 3 illustrates the details of call signaling for a voice control request process according to one embodiment.</figref><figref num="4">[0017] FIG. 4 illustrates the details of call signaling for a network-initiated dormant wake-up process according to one embodiment.</figref><figref num="5">FIG. 5 shows a buffering medium on the communication manager side according to one embodiment.</figref><figref num="6">[0019] FIG. 6 illustrates a client-side buffering medium according to an embodiment.</figref><figref num="7">[0020] FIG. 7 illustrates an exemplary wireless link mode according to one embodiment.</figref>