CN1981464A - Method and device for allocating temporary mobile group identities in a multimedia broadcast/multicast service - Google Patents

Abstract

A multimedia broadcast/multicast service (MBMS) server (122) in a packet data communication system (100) generates and assigns a Temporary Mobile Group Identity (TMGI) to an MBMS service, thereby acting as a central repository for the TMGI. In response to receiving the request to participate in the MBMS service, the MBMS server generates a TMGI (400). The MBMS server assigns the TMGI to the MBMS service and stores the TMGI in association with information related to the MBMS service to generate a stored TMGI. The MBMS server also conveys the TMGI to the source of the received request, thereby providing distribution of the TMGI to mobile stations (102-104) subscribing to the MBMS service. The subscribed mobile stations may then use the TMGI to receive data packets associated with the MBMS service.

Description

Method and device for allocating temporary mobile group identities in a multimedia broadcast/multicast service

technical field

The present invention generally relates to packet data communication systems, and more particularly to a multimedia broadcast multicast service in a packet data communication system.

Background technique

The Universal Mobile Telecommunications Service (UMTS) standard provides a compatibility standard for cellular mobile telecommunications systems. The UMTS standard ensures that a mobile station (MS) or user equipment (UE) operating in a UMTS system can obtain communication services when operating in a system made according to the standard. To ensure compatibility, the standard specifies radio system parameters and data transfer procedures including protocols for managing digital control messages and bearer traffic exchanged over the air interface.

In 3GPP TS 25.344 (Third Generation Cooperation Project Technical Specification 25.344) vO.5.0, 3GPPTS 23.246 v1.1.0 and 3GPP TS 23.846 v6.1.0, the UMTS standard provides the services served by the UMTS communication system to the system and subscribes to the The serving MS offers provision for Multimedia Broadcast/Multicast Service (MBMS) services. When a mobile station (MS) is active in a communication system that provides MBMS services, such as broadcasting of audio, video and/or data about sporting events such as Super League or World Cup football games, the MS may The MBMS service is registered by expressing to the communication system a willingness to receive multicast data related to the MBMS service. By registering for the MBMS service, the MS joins a multicast group associated with the service. In response to receiving a registration request from an MS, a Serving 3G GPRS Support Node (SGSN) located in the system transmits to the MS via the Radio Access Network (RAN) serving the MS the temporary Mobile Group Identifier (TMGI). The TMGI is then used by the communication system to notify MSs associated with the corresponding MBMS service/multicast group when the communication system has MBMS data to transmit to the MSs.

However, the UMTS standard does not specify elements of the communication system that create TMGIs or procedures for assigning TMGIs to relevant multicast groups and corresponding MBMS services. Therefore, there is a need for a method and apparatus for creating and distributing TMGIs related to MBMS services in a wireless communication system.

Description of drawings

FIG. 1 is a block diagram of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram of the mobile station in FIG. 1 according to an embodiment of the present invention.

FIG. 3A is a logic flowchart of a method according to an embodiment of the present invention, by which the communication system of FIG. 1 generates, allocates and distributes a temporary mobile group identity related to a multimedia broadcast/multicast service.

3B is a continuation of the logic flow diagram of the method of FIG. 3A by which the communication system of FIG. 1 generates, allocates and distributes temporary mobile group identities associated with multimedia broadcast/multicast services, according to an embodiment of the present invention.

Fig. 4 is a block diagram of a temporary mobile group identity according to an embodiment of the present invention.

Detailed ways

In order to address the need for a method and apparatus for creating and distributing TMGI associated with MBMS services in a wireless communication system, a Multimedia Broadcast/Multicast Service (MBMS) server is provided in a packet data communication system, which serves MBMS Generates and distributes Temporary Mobile Group Identifiers (TMGIs), thereby acting as a central repository for TMGIs. In response to receiving a request to participate in an MBMS service, the MBMS server generates a TMGI. The MBMS server assigns the TMGI to the MBMS service, and stores the TMGI in association with information related to the MBMS service, so as to generate the stored TMGI. The MBMS server also transmits the TMGI to the source of the received request, thereby distributing the TMGI to mobile stations subscribed to the MBMS service. Subscribing mobile stations can then use this TMGI to receive data packets related to MBMS services.

In general, an embodiment of the present invention includes a method for assigning a Temporary Mobile Group Identity (TMGI) to a Multimedia Broadcast/Multicast Service (MBMS) communication session. The method includes: receiving a request to participate in the MBMS service through the MBMS server; generating a TMGI through the MBMS server in response to receiving the request; assigning the TMGI to the MBMS service through the MBMS server; storing the TMGI in association with information to generate a stored TMGI; and transmitting the TMGI to the source of the received request through the MBMS server.

Another embodiment of the present invention comprises an MBMS server comprising at least one storage device and a processor operatively coupled to said at least one storage device. The processor receives a request to participate in an MBMS service, generates a TMGI in response to receiving said request, assigns the TMGI to the MBMS service, stores the TMGI in at least one storage device in association with information related to the MBMS service to generate a stored TMGI, and the TMGI is passed to the source of the received request.

The present invention can be more fully described with reference to FIGS. 1-4. FIG. 1 is a block diagram of a wireless communication system 100 according to an embodiment of the present invention. The communication system 100 includes a plurality of mobile stations (MS) or user equipment (UE) 102-104 (three shown), such as but not limited to cellular telephones, wireless telephones, etc., in wireless communication with a radio access network (RAN) 110. , a personal digital assistant (PDA) with radio frequency (RF) capabilities, or a wireless modem that provides RF access to digital terminal equipment (DTE) such as a laptop computer. The RAN 110 includes at least one transceiver or Node B 112, which is operatively coupled to a RAN controller 114, preferably a radio network controller (RNC). The communication system 100 also includes a support node 116 coupled to the RAN 110, and a Multimedia Broadcast/Multicast Service (MBMS) server 122, preferably in communication with the RAN Controller 114 via the support node. The ground is the Broadcast Multicast Service Center (BM-SC). Support nodes 116 typically include one or more Serving 3G-GPRS Support Nodes (SGSNs), each of which is coupled to one or more Gateway 3G-GPRS Support Nodes (GGSNs). However, the precise configuration of support nodes 116 is a matter for the operator of communication system 100 and not critical to the present invention. RAN 110 , support nodes 116 and servers 122 are collectively referred to herein as infrastructure 132 .

Each of MSs 102-104 is capable of receiving and displaying audio, video and/or data associated with MBMS services provided by communication system 100 for distributing MBMS data to MSs. MBMS services in 3GPP (Third Generation Partnership Project) standards - especially in 3GPP TS (Technical Specification) 25.344 vO.5.0, 3GPP TS 23.846 v6.0.0, 3GPP TS22.146 v6.0.0, Described in detail in 3GPP TR (Technical Report) 21.905 v5.4.0 and Report R2-030063, these specifications and reports are hereby incorporated by reference, and copies thereof are available via the Internet or the 3GPP Organization Partner Publishing Office (MobileCompetence Centre650, route des Lucioles, 06921 Sophia-Antipolis Cedex, France) was obtained from 3GPP.

RAN 110 provides communication services via air interface 138 to mobile stations (eg, MSs 102-104) located in a coverage area (eg, a cell) served by the RAN. Air interface 138 includes a downlink 140 and an uplink 145, each of which includes a plurality of communication channels. Preferably, the downlink 140 includes one paging channel 141 , at least one downlink control channel 142 and at least one downlink traffic channel 143 . Preferably, the uplink link 145 comprises one uplink access channel 146 , at least one uplink control channel 147 and at least one uplink traffic channel 148 .

The communication system 100 also includes a multimedia broadcast/multicast service (MBMS) content provider 136, such as an IP multicast server, coupled to the infrastructure 132 via a data network 134, such as an IP network, and in particular to Server 122. As part of the MBMS service provided by communication system 100 and which may be subscribed by each of MS 102-104, MBMS content provider 136 sends MBMS data to MS 102-104, typically in the form of IP data packets via server 122, support node 116 and RAN 110 .

Referring now to FIGS. 1 and 2, each of support node 116, server 122, and MSs 102-104 includes a respective processor 118, 124, 206, such as one or more microprocessors, microcontrollers, digital signal processors ( DSP), combinations thereof, or such other devices known to those of ordinary skill in the art. Each of support node 116, server 122, and MSs 102-104 also includes respective one or more storage devices 120, 126, 208 associated with respective processors, such as random access memory (RAM), dynamic random access memory (DRAM), ) and/or read-only memory (ROM) or their equivalents, which store data and programs that are executable by the processor and allow the processor to operate in the communication system 100. The one or more memory devices 208 of each MS 102-104 also maintain a mobile identifier (mobile ID) associated with the MS and a service identifier (service ID) associated with the MBMS service provided by the communication system 100. The one or more memory devices 120 of the support node 116 also maintain a support node identifier uniquely associated with the support node.

The service ID is an identifier uniquely related to the MBMS service. In an embodiment of the present invention, the service ID may include a routing address, or may be a function of a routing address, such as an Internet protocol (IP) multicast address identifying the MBMS service. For example, the routing address may be an IP address associated with an MBMS data source such as MBMS content provider 136 (it serves as a source of event-related data), such as 10.10.10.10, or the server at which the MBMS data is sourced An app on 122. In another embodiment of the invention, the service ID may include or be a function of the routing address, and may also include or be an interface ID associated with a particular support node (such as support node 116) or an MBMS server (such as server 122). Function for entry point names (APNs). For example, the APN may be a Uniform Resource Locator (URL), such as "t-mobile.com", associated with a service provider, such as the operator of the communication system 100, that operates support nodes or servers. In other embodiments of the present invention, the service ID may be any identifier that distinguishes the MBMS service provided by the communication system 100 from all other MBMS services provided by the communication system, so that the communication system identifies each MBMS service separately.

Each MS 102 - 104 also includes a receiver 202 , a transmitter 204 and a user interface 212 operably coupled to the processor 206 . Receiver 202 and transmitter 204 are provided for receiving and transmitting messages by the MS, respectively. User interface 212 includes a display screen 214 and provides a user of the MS with capabilities for interacting with the MS, including entering commands into the MS. In an embodiment of the present invention, the user interface 212 may also include a keypad, which includes a plurality of keys, through which the user of the MS can input an instruction to the MS. In another embodiment of the present invention, display screen 214 may include a touch screen capable of determining the location (ie, X and Y coordinates) of a user's touch on the touch screen and communicating the location data to processor 206 . Based on the location data, the processor 206 then translates the user's touch into a command. Preferably, the touch screen may display a "keypad" screen comprising a plurality of soft keys corresponding to keys on a conventional telephone keypad.

Preferably, the communication system 100 is a Universal Mobile Telecommunications Service (UMTS) communication system operating in accordance with the 3GPP (Third Generation Partnership Project) standard, which provides a compatibility standard for the UMTS air interface and which is therefore referred to herein as Introduced as a whole. This standard specifies the operating protocols for wireless telecommunication systems including radio system parameters and call processing procedures. In the communication system 100, communication channels such as the link 134 of the downlink or the link 135 of the uplink such as an access channel, a control channel, a paging channel, and a traffic channel each include One or more of the multiple slots. However, those of ordinary skill in the art understand that the communication system 100 may operate in accordance with any wireless telecommunication system, such as but not limited to: General Packet Radio Service (GPRS) communication system, Code Division Multiple Access (CDMA) 2000 communication system, Time Division Multiple Access (TDMA) communication system or Orthogonal Frequency Division Multiple Access (OFDM) communication system.

In order for the communication system 100 to establish a subscription group related to the provision of MBMS services and to notify subscribed MSs of broadcast/multicast of related MBMS data, the communication system 100 generates Temporary Mobile Group Identities (TMGI) each Assigned to an MBMS service and distributed to MSs subscribing to the service. 3A is a logic flow diagram 300 of a method by which the communication system 100 generates, allocates and distributes a Temporary Mobile Group Identity (TMGI) associated with an MBMS service, according to an embodiment of the present invention. The logic flow diagram when the communication system 100, and in particular the server 122, transmits (304) service announcements about MBMS services, such as broadcasts of sporting events such as the Super Bowl or the World Cup of Soccer, to each of the MSs 102-104 300 start (302).

Service announcements may be sent in any over-the-air format, such as via a broadcast over the paging channel 131, via Short Message Service (SMS), or via multicast. The service announcement includes information about the event that can be used by the user of the MS to determine whether to subscribe to the event. For example, this information may include a service ID associated with the MBMS service, a routing address such as an Internet Protocol (IP) address associated with the source of the MBMS data (such as the MBMS content provider 136 from which the data related to the event originated), such as "Sports" and/or more specifically "soccer" (when the event is a football match) and the like, the title of the event and the event date and one or more of the times.

In response to receiving (306) the service announcement, MS 102-104, such as MS 102, determines (308) whether to subscribe to the MBMS service identified in the service announcement. When the MS, ie MS 102, decides to subscribe to the service, the MS transmits (310) to the infrastructure 132 (in particular the support node 116) a request to subscribe to the MBMS service. The subscription request includes an identifier associated with the service, preferably a routing address associated with the MBMS service. When MS 102 decides not to subscribe to the service, there is no response to the announcement other than perhaps acknowledging receipt of the announcement.

In one embodiment of the invention, MS 102-104, such as MS 102, may automatically respond to the announcement based on a program stored in one or more storage devices 208 or based on information programmed into the storage devices by the user of the MS . For example, the MS may be programmed to reply affirmatively to any subscription announcements with a subject category of "Sports" or "Football" and/or a subject/event that includes the phrase "World Cup". In another embodiment of the invention, at least a portion of the information included in the service bulletin may be displayed on the display screen 214 of the user interface 212, such as "World Cup Match No. 1" and the date and time of the event. The MS may also display on the display screen 214 instructions on how to subscribe, such as text or softkeys that the user may select, or a keypad key that the user may press to generate a response. The user of the MS can then subscribe to the event by selecting the indicated text, soft key or key. In response to user selection of the indicated text, softkey or key, the MS transmits a subscription request to the support node 116, indicating that the user of the MS desires to subscribe to the service, ie the event. Included in the response is a Mobile ID uniquely associated with the MS, which enables the support node 116 to determine the source of the response.

In response to receiving (312) the subscription request, support node 116 determines (314) whether the subscribed MS (ie, MS 102) is the first MS to activate this particular MBMS service on this support node. In response to determining that MS 102 is the first MS to activate the particular MBMS service on the support node, support node 116 transmits (316) a message to server 122 requesting participation in the MBMS service. In one embodiment of the invention, the request may inform the support node 116 of a desire to participate in the MBMS service. In other embodiments of the present invention, the request may inform the MS 102 of the desire to participate in the MBMS service or the support node 116 and the MS to participate in the MBMS service. The message includes an identifier associated with the MBMS service (preferably, the service ID and/or the routing address associated with the service) and a support node identifier identifying the support node that submitted the request, such as the routing of support node 116 address. The message may also include a Mobile ID associated with the subscribing MS 102 .

After receiving the message to participate in the MBMS service from the support node 116, the server 122 determines (320) whether this is the first time the server receives to subscribe to the MBMS service (i.e. join a group related to the MBMS service or event) at the time. requests. When the server 122 determines (320) that this is the first request to subscribe to the MBMS service, the server 122 generates a Temporary Mobile Group Identifier (TMGI) associated with the service. By having the TMGI generation and distribution functions in the server 122 rather than in the support nodes 116, the communication system 100 provides a centralized repository for all TMGIs and centralized control over the creation, allocation, distribution, and deallocation of TMGIs, thereby avoiding TMGI possible re-allocation of TMGI and maximize re-use of TMGI. The server 122 stores (324) the TMGI in a database 128 included in one or more storage devices 126 of the server in order to generate a stored TMGI, the TMGI and information related to the MBMS service (such as service information related to the MBMS service ID and/or routing address) are stored together in the database in association. Server 122 also creates ( 328) A subscription group associated with the event. Server 122 may also store the Mobile ID associated with the responding MS (ie, MS 102) when the Mobile ID is available to the server.

When the server 122 determines (320) that an earlier request to participate in the MBMS service has already been received, therefore a relevant TMGI has already been generated and a subscription group associated with the MBMS service has already been created, so the server retrieves (326 ) associated TMGI, and store (328) in the database 128 associated with the TMGI and corresponding subscription group the Mobile ID associated with the responding MS and a Support Node Identifier associated with the Support Node serving the MS (Support Node ID), such as the routing address of the supporting node 116.

When support node 116 determines in step 314 that MS 102 is not the first MS to activate this particular MBMS service on this support node, support node 116 transmits (318) a message to server 122 notifying the MS of the request to participate in the MBMS service. Logic flow diagram 300 then continues to step 326 where, in response to receiving the message notifying the MS of a request to participate in the MBMS service, server 122 retrieves the associated TMGI from database 128 . The server 118 also stores (328) the mobile ID associated with the responding MS in the database 128 in association with the TMGI and the support node identifier associated with the support node serving the MS.

In response to generating or retrieving a TMGI related to the MBMS service, server 122 transmits (330, 332) the TMGI to the responding MS 102-104 via the support node (ie, support node 116) serving the MS. When the support node 116 maintains the TMGI locally in one or more storage devices 120 of the support node and the support node has not stored the TMGI, then in response to receiving the TMGI from the server 122, the support node 116 communicates with the mobile ID corresponding to the MS 102 and with MBMS service-related service IDs are stored (333) in one or more storage means 120 in association with the TMGI.

Similar to service announcements, TMGIs may be communicated to MS 102 via any cell broadcast format (eg, via a paging message on a paging channel, via a Short Message Service (SMS) message, via a multicast message). In one embodiment of the invention, server 122 transmits the TMGI to support node 116 and the support node then transmits the TMGI to MS 102 in a modified form of an Activate MBMS Environment Accept message. The Activate MBMS Environment Accept message is known in the art and described in 3GPP TR 23.846. In the communication system 100, the Activate MBMS Environment Accept message is modified to include a TMGI data field, and the support node 116 embeds the TMGI received from the server 122 in the TMGI data field. Additionally, the message conveying the TMGI may also include the Mobile ID associated with the MS subscribing to the event, which allows the MS to determine that it is an intended recipient of the TMGI.

In another embodiment of the invention, the support node 116 may store a TMGI locally in one or more storage devices 120 of the support node. That is, when a first MS, such as MS 102, subscribes to MBMS service via support node 116, the support node receives a TMGI from server 122 in response to transmitting to the server a request to participate in the MBMS service as described above. The support node then stores the received TMGI in one or more storage means 120 of the support node in association with the service ID corresponding to the MBMS service and a mobile ID corresponding to the first MS 102 . When a second MS (such as MS 103) served by the support node 116 later transmits a request to the support node to participate in the MBMS service, the support node may simply retrieve (315) from one or more storage devices 120 of the support node TMGI and transmits (332) the TMGI to the MS (ie, MS 103) without having to obtain the TMGI from server 122. In such an embodiment, the support node 116 also stores (317) the Mobile ID associated with the later subscribing MS (i.e., MS 103) in one or more stores in association with the TMGI and the service ID corresponding to the MBMS service. device 120.

When a MS such as MS 102 receives (334) the TMGI, MS 102 stores (336) the TMGI in a table 210 in one or more storage devices 208 of the MS. Preferably, the TMGI is stored in the table 210 in association with the IP multicast address and the APN associated with the MBMS service. Unless otherwise noted herein, all functions described herein as being performed by the MSs 102-104 are performed by the processor 206 of the MS, and all functions described herein as being performed by the support node 116 or the server 122 are respectively performed by the supporting The node's processor 118 and the server's processor 124 execute.

FIG. 4 is a one-bit configuration 400 of a TMGI according to an embodiment of the present invention. In one embodiment of the TMGI, the TMGI includes a first group identifier (group ID) data field 402 in which is embedded a group identifier (group ID) associated with the subscription group or MBMS service. In one embodiment of the present invention, the group ID may be a derivative of other information identifying the service, such as the service ID corresponding to the MBMS service, the routing address related to the MBMS service, or the routing address and APN related to the MBMS service . The group ID may include such information, or when bit space is limited, a shortened form of such information. For example, server 122 may apply a hash function to the information to find a shortened form of such information. In another embodiment of the present invention, the group ID can be any identifier that uniquely identifies the service, such as an event name such as "World Cup Soccer 2004 Match 1" or an event name, date and time.

In another embodiment of the TMGI, the TMGI may further include a second data field 404 in addition to the first data field 402 . Embedded in the second data field 404 is an identifier associated with each of the one or more communication sessions associated with an MBMS service. That is, one MBMS service can broadcast one event via multiple communication sessions. For example, an MBMS service may involve the broadcast of a sporting event, such as a football match. Instead of providing a continuous broadcast of an event, the MBMS service broadcasts the event via multiple communication sessions, each of which relates to a separate aspect of the event, such as involving multiple goals, periodic score updates and and/or a video or text of each of the periodic game highlights. Each of the plurality of communication sessions may then be associated with a unique identifier generated by the MBMS content provider 136 or server 122, such as a session identifier (session ID) or a sequence identifier (sequence ID). For example, a first communication session such as a first goal may be associated with a session or sequence ID '1', a second communication session such as a second goal may be associated with a session or sequence ID '2', and so on.

Session IDs do not have to be consecutive, while sequence IDs are. The session or sequence ID is then embedded in a data packet associated with the communication session by the network element that generated the ID.

By including a session ID or a sequence ID in TMGI, a user of MBMS service can better detect the retransmission of MBMS data, and thus the user can judge whether to receive the retransmission. For example, before a set of one or more MBMS data packets associated with an MBMS communication session is transmitted by the MBMS content provider 136 to the RAN controller 114 via the server 122, a TMGI including a session ID or sequence ID is transmitted to the RAN control device 114. RAN Controller 114 then broadcasts the TMGI to MSs 102-104 subscribing to the service. After receiving the TMGI, an MS 102-104 parses the TMGI to obtain a session ID or sequence ID and stores the obtained ID. When the MS detects that a Session ID or a Sequence ID has been received (from its memory), the MS may reject reception of MBMS data coming for this session, or may ask the user to decide whether to receive the data.

After the event corresponding to the MBMS service starts, the server 122 receives (338) a set of data packets from the MBMS content provider 136 including information related to the event such as scores, highlights, and/or video clips. payload data. In response to receiving the set of data packets, server 122 transmits (342) the set of data packets to RAN controller 114 via support node 116, with the service ID and TMGI associated with the MBMS service embedded (340) in the data packets by the server. Along with the transmitted data packet, server 122 may also include a 'session description' associated with the payload included in the data packet. A 'session description' is a word or a phrase describing the payload included in the set of data packets, such as "Goal 1", "Goal 2" and so on. In one embodiment of the invention, a 'session description' may be embedded by the server 122 in the set of data packets. In another embodiment of the invention, the MBMS content provider 136 may embed a 'session description' in the set of data packets.

In response to receiving the set of data packets and the associated service ID and TMGI, RAN controller 114 establishes (344) a communication session with each MS 102-104 currently served by the RAN controller and subscribed to the MBMS service. The RAN controller 114 follows well-known MBMS communication session establishment techniques, except that as part of the process of establishing a communication session, the RAN controller additionally communicates to each MS assigned to the subscription group and may also communicate a session description describing the payload. Establish a communication session.

For example, in one embodiment of the invention, the step of establishing (344) a communication session may include the following steps. The RAN controller 114 broadcasts an MBMS announcement via the transceiver 112 and the downlink control channel 136 to all MSs served by the RAN. The first announcement includes the service ID associated with the MBMS service, the TMGI assigned to the subscription group and the session description associated with the received MBMS data group. Each MS subscribed to the MBMS service and in idle mode wakes up in response to receiving the MBMS announcement. In addition, each MS 102-104 subscribing to the MBMS service also checks one or more storage devices 208 of the MS in response to receiving the MBMS advertisement to determine whether the session description included in the advertisement matches the one or more storage devices 208 held in the one or more storage devices. A session description. When no match is found, each MS in the cell that subscribes to the MBMS service and receives the first announcement transmits a connection request (usually a Radio Resource Control (RRC) connection establishment request) to the RAN controller 114 via an access channel . After receiving a connection request from each subscribing MS, the RAN controller 114 establishes a communication session by establishing a PTM communication channel or an FTP communication channel (whichever one the RAN controller determines to establish) with each responding MS.

After establishing the PTM communication channel or the PTP communication channel, the RAN controller 114 then transmits (346) the set of data packets to the subscribing MS 102-104 via the established channel or channels. After receiving the set of data packets, each MS 102-104 stores the session description included in the set of data packets in one or more storage devices 208 of the MS and displays the session description and A payload, such as a score or a video slice, is included in the set of data packets. When the event ends, server 122 de-allocates the TMGI for the event (348), thereby freeing the TMGI for allocation to another event. In embodiments of the invention where the TMGI is stored locally by the support node 116, the server 122 also notifies (349) the support node of the deallocation of the TMGI and the support node deletes the stored TMGI from the support node one or more storage devices 120. Logic flow diagram 300 then ends (350).

In one embodiment of the invention, the server 122 does not deallocate the TMGI until after a first predetermined time period expiration time after the event. By waiting a predetermined time period after the end of the event before de-allocating the TMGI, the server 122 allows MSs subscribing to the event to obtain playback of MBMS data and retransmission of lost MBMS data during the predetermined time period. For example, when the event is a sports event, server 122 may not have to deallocate the TMGI until a day or two after the event has ended. However, the predetermined time period is a matter for the designer of the communication system 100 and may vary based on the type of event being broadcast (eg, sporting event, concert, speech, etc.). In another embodiment of the present invention, the first time period may be determined dynamically. For example, server 122 may periodically query support node 116 whether it has received any request replies or retransmissions of MBMS data related to the event from a subscribing MS. When the server 122 determines that no request reply or retransmission of MBMS data has been received during the second time period, then the server deallocates the TMGI associated with that event. The server 122 determines the first and second time periods by reference to a timer 130 included in the server and coupled to the processor 124, which timer is used by the server to count down the first and second time periods.

To provide replay of MBMS data and lost MBMS data in a manner that is transparent to the RAN, does not require interlayer interaction, and supports delivery of lost MBMS data to MSs that join an event after one or more communication sessions have been established The communication system 100 also provides for automatic retransmission of event-related data packets by the MBMS content provider 136. By retransmitting the data packets, each MS subscribing to the event is given an opportunity to obtain information on missing data packets or to replay earlier received data packets. The retransmission can occur at any time after the initial transmission of the data, but preferably far enough in time from the initial transmission to capture the latest joiners of the group and allow those that have temporarily left the coverage area of the communication system 100 to return to the system's coverage district.

By providing the MBMS server 122 that generates and assigns/de-assigns Temporary Mobile Group Identities (TMGIs) to MBMS services, the communication system 100 minimizes the possibility of duplicate assignments of TMGIs. That is, by centrally locating the TMGI generation and distribution functions in the MBMS server 122, the communication system 100 avoids possible repeated distribution of TMGIs and maximizes the repeated use of TMGIs. In response to receiving a request to participate in an MBMS service, MBMS server 122 generates a TMGI. The MBMS server 122 assigns the TMGI to the MBMS service and stores the TMGI in database 128 in one or more storage devices 126 of the server in association with information related to the MBMS service to generate a stored TMGI. The MBMS server 122 also communicates the TMGI to the source of the received request, thereby providing distribution of the TMGI to mobile stations subscribing to the MBMS service. In one embodiment of the present invention, when a second mobile station requests to subscribe to an MBMS service after the first mobile station has previously subscribed to the MBMS service and created and stored a TMGI earlier, the MBMS server 122 receives a request from one or more of the servers. The stored TMGI is retrieved from a storage device 126 and the stored TMGI is transmitted to the second mobile station. In another embodiment of the present invention, the support node 116 may store a TMGI generated and distributed by the MBMS server in one or more storage devices 120 of the support node. When a second mobile station requests to subscribe to an MBMS service after the first mobile station has previously subscribed to the MBMS service via the support node, the support node may retrieve the TMGI stored in one or more storage devices 120 of the support node and store the locally stored The TMGI is transmitted to the second mobile station.

While the invention has been particularly shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes and changes in the elements thereof may be made without departing from the spirit and scope of the invention as set forth in the following claims. equivalent substitution. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive, and all such changes and substitutions are intended to be included within the scope of the present invention.

Benefits, other advantages, and solutions to problems have been described above with respect to specific embodiments. However, benefits, advantages, solutions to problems and any element (group) that may make any benefit, advantage or solution appear or become more obvious should not be construed as critical, required or important to any or all claims features or components. As used herein, the term "comprising" or any variation thereof is intended to cover a non-exclusive inclusion, thus a process, method, product or apparatus comprising a list of elements does not include only those elements and may not include nothing specifically other elements listed or inherent in such process, method, product, or apparatus. Furthermore, unless otherwise indicated herein, the use of relative terms (such as first and second, up and down, etc.), if any, are used only to distinguish one entity or action from another without necessarily requiring or Any actual such relationship or order between such entities or actions is implied.

Claims (13)

1. A method for assigning a Temporary Mobile Group Identity (TMGI) to a Multimedia Broadcast/Multicast Service (MBMS) communication session, the method comprising: receiving a request to participate in the MBMS service through the MBMS server; generating a TMGI by the MBMS server in response to receiving the request; assigning the TMGI to the MBMS service through the MBMS server; storing the TMGI in association with the MBMS service-related information by the MBMS server to generate a stored TMGI; and The TMGI is transmitted by the MBMS server to the source of the received request. 2. The method of claim 1, wherein: assigning includes assigning, by the MBMS server, the TMGI uniquely to the MBMS service. 3. The method of claim 1, wherein the temporary mobile group identity includes an identifier that uniquely identifies the MBMS service within the wireless communication system. 4. The method of claim 1, wherein: storing the Temporary Mobile Group Identity (TMGI) comprises: storing the TMGI in association with at least one of an identifier associated with the mobile station and a supporting node identifier associated with the supporting node , a subscription group is created by the Multimedia Broadcast/Multicast Service (MBMS) server. 5. The method of claim 1, wherein: the request to participate in the Multimedia Broadcast/Multicast Service (MBMS) service received by the MBMS server is the first request received by the MBMS server to participate in the MBMS service, and wherein the method further comprises : receiving by the MBMS server a second request to participate in the MBMS service; Responsive to receiving the second request, retrieving the stored Temporary Mobile Group Identity (TMGI); and The retrieved TMGI is transmitted to the source of the received second request. 6. The method of claim 1, further comprising: receiving by the support node a Temporary Mobile Group Identity (TMGI) delivered by a Multimedia Broadcast/Multicast Service (MBMS) server; storing, by the supporting node, of associating the TMGI with a mobile identifier associated with the mobile station; After storing the TMGI, a request to subscribe to the MBMS service is received by the support node from the mobile station; Retrieving, by the supporting node, a Temporary Mobile Group Identity (TMGI) stored by the supporting node in response to receiving a request from the mobile station; and The TMGI retrieved by the support node is transmitted by the support node to the mobile station. 7. The method of claim 1, further comprising: establishing a communication session with the mobile station; transmitting the data packet with the TMGI embedded therein to the mobile station; De-allocation of the TMGI from the MBMS service by the MBMS server after the end of the communication session; and The stored TMGI is deleted by the MBMS server. 8. Multimedia broadcast/multicast service (MBMS) server, including: at least one storage device; a processor operatively coupled to the at least one storage device, the processor receiving a request to participate in the MBMS service, generating a Temporary Mobile Group Identity (TMGI) in response to receiving the request, assigning the TMGI to the MBMS service, at least The TMGI is stored in a storage means in association with information related to the MBMS service to generate the stored TMGI and transmit the TMGI to the source of the received request. 9. The Multimedia Broadcast/Multicast Service (MBMS) server of claim 8, wherein: The processor uniquely assigns this TMGI to the MBMS service. 10. The Multimedia Broadcast/Multicast Service (MBMS) server of claim 8, wherein the temporary mobile group identity includes an identifier that uniquely identifies the MBMS service within the wireless communication system. 11. The Multimedia Broadcast/Multicast Service (MBMS) server of claim 8, wherein: the TMGI is created by storing in association with at least one of a mobile identifier associated with the mobile station and a supporting node identifier associated with the supporting node To subscribe to a group, the processor stores a Temporary Mobile Group Identity (TMGI). 12. The multimedia broadcast/multicast service (MBMS) server of claim 8, wherein: when the request that the MBMS server receives to participate in the MBMS service is the first request that the MBMS server receives to participate in the MBMS service, the processor generates an TMGI to generate a Temporary Mobile Group Identity (TMGI). 13. The Multimedia Broadcast/Multicast Service (MBMS) server of claim 8, wherein: the processor also receives data packets comprising MBMS data relevant to the MBMS service, and embeds the Temporary Mobile Group Identity (TMGI) in the data packets , transmitting data packets with a TMGI embedded therein to a mobile station as part of a communication session, and de-allocating the TMGI from the MBMS service and deleting the stored TMGI from the at least one storage means after the communication session ends.

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