WO2008098497A1 - System of multimedia broadcast multicast service and session start method, stop method - Google Patents

Abstract

A system of multimedia broadcast multicast service and a session start method, a stop method, in which the MBMS bearer service and the MBMS traffic bearer are separated, one of MBMS bear service can use multiple traffic bearers to send, the common information of the multiple MBMS bearer service can be sent by the use of the shared traffic bearer. The MBMS traffic bearer context includes the relative identifies of the various MBMS bearer services which are sent by the traffic bearer. When the MBMS bearer service session starts, if one or more of the traffic bearer to which the session relates exist, the existed traffic bearer can be used directly. When the session of the MBMS bearer service stops, the MBMS traffic bearer can not be released until all the corresponding MBMS bearer services of the various MBMS traffic bearer to which the session relates have stopped.

Description

 The present invention claims to be submitted to the Chinese Patent Office on February 13, 2007, the application number is 200710084649.6, and the invention name is "Multimedia Broadcast Multicast Service System and Session Start and Stop" The priority of the Chinese Patent Application, the entire disclosure of which is hereby incorporated by reference.

Technical field

 The present invention relates to the field of wireless communications, and in particular, to a Multimedia Broadcast Multicast Service (MBMS) technology.

Background technique

 With the development of third generation mobile communication technologies, third generation mobile communication can provide higher data rate services than second generation mobile communication, thereby supporting multiple service forms. Such as video calls, picture downloads, high-speed browsing Internet and other services. One of the characteristics of the service is that the service can be simultaneously sent to the user terminal that subscribes to the service in the wireless network. For example, weather forecasts, news clips, sports highlights, and more. Taking advantage of the simultaneous transmission of these services, the third generation of mobile communications introduced the concept of multicast/broadcast.

 The networking structure of the multicast/broadcast service is shown in Figure 1. In this structure, for intermediate nodes

11, 12, 13, in terms of how many nodes that are expected to receive data downstream, the upstream node always sends a piece of data to the intermediate node; after receiving the data, the intermediate node expects to receive data according to its downstream node. The data is copied by the quantity, and the data is distributed to the nodes that are expected to receive the data downstream, so that each branch of the multicast/broadcast service data transmission tree has only one piece of data for transmission, occupying one transmission resource, and the root node The same is true for the data transmission of 10 and its downstream node 11.

The MBMS architecture proposed by the 3rd Generation Partnership Project ("3GPP") is shown in Figure 2. The Broadcast Multicast Service Center ("BM-SC") 20 is a new mobile network function entity for supporting MBMS services. It is an entry point for content providers for authorization and on the mobile network. Initiate the MBMS bearer service and deliver the MBMS content according to the scheduled schedule. The BM-SC is connected to the Traffic Plane Function (TPF) Gateway GPRS Support Node (GGSN) 21 through the Gmb interface or the Gi interface; the TPF GGSN21 uses the Gn/Gp interface and service. The GPRS support node (Serving GPRS Support Node, referred to as "SGSN") 22 is connected; the SGSN 22 can communicate with the universal mobile communication system via the Iu interface. The UMTS Terrestrial Radio Access Network ("UTRAN") 23 is connected; the UTRAN 23 is connected to a User Equipment ("UE") 24 through a Uu interface, and the SGSN 22 can also communicate with the Global System for Mobile Communications via the Iu/Gb interface. The evolved enhanced data radio access network (GSM EDGE Radio Access Network, referred to as "GERAN") 25 is connected; the GERAN 25 is connected to the UE 26 through the Um interface. Among them, GGSN21 and SGSN22 belong to nodes in the core network (Core Net, referred to as "CN") in the wireless network.

 MBMS includes multicast mode and broadcast mode. The multicast service has a registration requirement for the UE, and the broadcast service does not require the UE to register. The UE is usually registered in the network through the activation process of the MBMS multicast service, so that the UE can receive data of the specific multicast MBMS bearer service. Activation is a signaling procedure between the UE and the network. The procedure is for each user that activates the multicast MBMS bearer service in the UE, SGSN, GGSN, BM-SC, and Base Station Controller ("BSC"). / Radio Network Controller ("RNC") establishes the MBMS UE context for carrying out MBMS services.

 The UE leaves the MBMS multicast service through the deactivation process of the MBMS multicast service. After the UE leaves the MBMS multicast service, the MBMS UE context of the UE is deleted.

In the MBMS service, the MBMS bearer context is used to store MBMS bearer information, and includes all information descriptions that define an MBMS service bearer. All the nodes carrying the MBMS data in the network need to create the MBMS bearer context. As shown in Table 1, the MBMS bearer context includes: an IP multicast address, an Access Point Name (APN, for short), a Temporary Mobile Group Identity (TMGI), a status, Required MBMS bearer capability, Quality of Service (QoS), MBMS service area, downlink node list, number of UEs, etc. The IP multicast address identifies the MBMS bearer described by the MBMS bearer context; The access point name that has been defined for the IP multicast address; TMGI is the temporary mobility group identity assigned to the MBMS bearer; the state is the activity state of the MBMS bearer, including: Standby state or activation state, whether the identity is required to be established for The bearer area resource of the MBMS data transmission; the QoS is the quality of service required for the MBMS bearer; the MBMS service area is the area that the MBMS service needs to send; the downstream node list is the list of the downstream nodes to which the MBMS bearer is requested and the MBMS data must be delivered. The multicast/broadcast mode indicates whether the MBMS bearer is in multicast or broadcast mode. The "X" in the table indicates the corresponding network. This information is stored on the entity. Parameter Description RAN SGSN GGSN BM-SC Multicast/Broadcast Mode MBMS Bearer Service in Broadcast or Group XXXX Broadcast Mode

 IP multicast address (IP multicast address only by the MBMS X X X X to multicast mode) MBMS bearer carrying context description

 APN (only for multicast IP X multicast address has been defined X X X X mode) In point name

 Temporary Mobile X X X X Group ID assigned by TMGI to MBMS 7

 Status The activity status carried by MBMS ('To X X X X or 'Activate')

 Service Shield QoS The amount of service shield required for this MBMS bearer X X X X

MBMS service area The area to be sent by the MBMS service X X X X The list of downstream nodes The MBMS bearer is requested, and the number of MBMS X X data must be sent to the downstream node list.

 Table 1

 For the network structure shown in FIG. 2, for the MBMS service, the user joins the MBMS service through the MBMS activation process, so that the network knows which users want to receive a specific MBMS service. The network node establishes a distribution tree from the BM-SC, via the GGSN, SGSN to the RNC through the MBMS registration process, thereby allowing transmission of MBMS session attributes and data. The MBMS bearer context in the BM-SC is pre-statically configured; on the SGSN and the GGSN, when the first MBMS UE context is created or when the downstream node requests the MBMS service, the corresponding MBMS bearer context is created; in the RNC, When the first MBMS UE context is created, the corresponding MBMS bearer context is created. Alternatively, when there is no corresponding MBMS bearer context in the RNC, the MBMS session start process (Session Start) may also cause the MBMS bearer context to be created.

After the UE joins a specific MBMS bearer service, UE specific information associated with the MBMS bearer service is saved in the MBMS UE context. Figure 3 shows the MBMS bearer context Relationship with the MBMS UE context.

 The following briefly describes the start and stop process of the MBMS session in the prior art.

 When the BM-SC is ready to send MBMS data, it will initiate the MBMS session start process, as shown in Figure 4. Through this process, on the one hand, the network activates the bearer resources necessary for transmitting data (for the broadcast mode, it also includes creating a corresponding MBMS bearer context), and on the other hand, notifies all relevant

The UE is about to start transmitting data. In addition, through the process, the attributes related to the MBMS session (such as: quality of service, service area, etc.) are also provided to the relevant network nodes.

 In step 410, the BM-SC sends a session start request message indicating the upcoming transmission, and provides session attributes, including temporary mobility group identification, QoS, to all GGSNs saved in the "downstream node list" parameter in the MBMS bearer context. MBMS service area, broadcast/multicast mode, etc. For the broadcast mode, the GGSN downstream node list parameter is also included, and the BM-SC sets the status attribute of the MBMS bearer context to "active".

 In step 420, after receiving the session start request message, each GGSN performs the following operations: For the MBMS bearer service in the broadcast mode, since there is no corresponding MBMS bearer context in the GGSN, the GGSN needs to create an MBMS bearer context, and The session attribute and the downstream node list are saved in this context, the status attribute of the MBMS bearer context is set to "active", and a session start response message is sent to the BM-SC.

 For the MBMS bearer service in the multicast mode, the corresponding MBMS bearer service context in the GGSN is created in the MBMS registration process. The GGSN directly saves the session attribute in the MBMS bearer context, sets the status attribute of the MBMS bearer context to "active", and sends A session starts responding to the message to the BM-SC.

 In step 430, the GGSN sends an MBMS Session Start Request message to the SGSN stored in the corresponding Downstream Node List parameter of the MBMS Bearer Context, and provides session attributes (including Temporary Mobile Group Identity, QoS, MBMS Service Area, Broadcast/Multicast). Mode, etc.).

 In step 440, after receiving the session start request message, each SGSN performs the following operations: For the MBMS bearer service in the broadcast mode, the SGSN creates a corresponding MBMS bearer context. For the MBMS bearer service in the broadcast mode and the multicast mode, the SGSN saves the session attribute in the MBMS bearer context, and sets the state attribute of the MBMS bearer context to "active".

The GGSN returns an MBMS Session Start Response message, which is provided in the message for the bearer plane. A Tunnel Endpoint Identifier (TEID) is used to send MBMS data to the GGSN.

 In step 450, the SGSN sends an MBMS Session Start Request message to the RNC to which it is connected, and the message includes the session attribute (temporary mobile group identity, QoS, MBMS service area, broadcast/multicast mode, and route area (Route Area, referred to as "RA") list, etc.).

 In step 460, after receiving the session start request message, each RNC performs the following operations: If it is the MBMS bearer service in the broadcast mode, the RNC creates a corresponding MBMS bearer context.

 For the MBMS bearer service in broadcast mode and multicast mode, the RNC returns an MBMS session start response message to the SGSN. If the RNC is in the MBMS service domain, the RNC saves the session attribute in the MBMS service context, sets the status attribute of the MBMS service context to "active", responds to an MBMS session start response message, and the RNC includes the TEID in the MBMS session to start responding. In the message, it is used when the SGSN sends MBMS data.

 In step 470, the RNC establishes the necessary radio resources for transmitting the MBMS data to the interested UE.

 The prior art MBMS session stop process is shown in FIG.

 In step 510, the BM-SC sends a session stop request message to all GGSNs in the "downstream node list" parameter in the corresponding MBMS bearer context, indicating that the MBMS session ends, and the bearer plane resource can be released. The BM-SC sets the status attribute of the MBMS bearer context to "standby".

 In step 520, after receiving the session stop request message, each GGSN returns a session stop response message to the BM-SC.

 In step 530, each GGSN sends an MBMS session stop request message to all SGSNs in the parameter in the "downstream node list" in the corresponding MBMS bearer context, and releases the bearer plane resources corresponding to the SGSNs, and sets the state attribute of the MBMS bearer context. For "standby."

 In step 540, after receiving the session stop request message, each SGSN returns a session stop response message to the corresponding GGSN.

In step 550, each SGSN releases the TEID, releases the bearer plane resource of the MBMS data of the corresponding MBMS bearer service from the GGSN, and sends an MBMS session stop request message to all RNCs that establish a bearer plane with the SGSN. In step 560, after receiving the session stop request message, each RNC returns a session stop response message to the corresponding SGSN.

 In step 570, the RNC releases the corresponding wireless and Iu resources.

 As can be seen from the above MBMS service start and stop procedures, for any MBMS bearer service, each network node can only use the bearer resources corresponding to a single quality of service and service area to transmit data.

 In order to solve the problem, the prior art 2 binds multiple traffic bearers to one MBMS bearer service, which means that the original MBMS bearer context is divided into two logical entities: MBMS Bearer Service Context, And MBMS Traffic Bearer Context.

 The MBMS bearer service context is determined by the IP multicast address and APN, or by TMGI. Some information is stored in the MBMS bearer service context, such as: the number of UEs, the list of downstream nodes, and so on.

 The MBMS Traffic Bearer Context is determined by TMGI. The information stored in the MBMS traffic bearer context includes: QoS, Service Area, and the like.

 After the UE activates an MBMS bearer service, it will trigger the establishment of the corresponding UE context. For a certain node, when the first UE context for the bearer service is established, or a service request from a downstream node is received, a corresponding MBMS bearer context is created.

 The traffic bearer context is created at the beginning of the session. There may be multiple different traffic bearer contexts corresponding to the same bearer service. As shown in Figure 6, these traffic bearer contexts each contain a set of mutually disjointed port numbers. In the request message of the start of the session, a port number set may be carried, and one or more traffic bearers are identified by the port in the port number set.

 Each traffic carries its own corresponding Quality of Service (QoS) distribution tree and a General Packet Tunneling Protocol ("GTP") tunnel. When the GGSN receives the packet whose destination address is the IP multicast address, the GGSN matches the destination port number in the packet with the port number set in the traffic bearer. According to this, the port number set of the port number can be determined. Then determine the traffic bearer to use.

On the radio link, the RNC must multiplex those traffic bearers belonging to the same bearer service so that the UE can receive these traffic bearers in parallel. Typically, these traffic bearers can be placed in the same frequency band. There may be a priority between multiple traffic bearers corresponding to the same bearer service. Department.

 Usually the session starts to trigger the paging and counting process. When a bearer service has multiple traffic bearers, only the first traffic bearer session will start the paging and counting process.

 The prior art 2 solves the problem of the prior art one. By separating the bearer service context and the traffic bearer context, multiple sets of traffic corresponding to different service qualities and service areas can be used for any MBMS bearer service. Host resources to transfer data.

 However, the inventors of the present invention have found that in the prior art 2, when different bearer resources can be used between different MBMS bearer services, the bearer resources cannot be shared, for example, different MBMS bearer services need to transmit the same. When the service data is transmitted, the same content is separately transmitted through the respective traffic bearers, thereby causing waste of resources.

Summary of the invention

 The main technical problem to be solved by the embodiments of the present invention is to provide a multimedia broadcast multicast service system and a session start and stop method, so that the bearer resources of the MBMS service can be saved.

 To solve the above technical problem, an embodiment of the present invention provides an MBMS system, including: at least one bearer device, configured to provide an MBMS traffic bearer;

 At least one service device is configured to provide an MBMS bearer service, and each MBMS bearer service is delivered by using at least one MBMS traffic bearer;

 The service device delivers the data shared by the at least two MBMS bearer services through the shared MBMS traffic bearer provided by the bearer device.

 An embodiment of the present invention further provides an MBMS session starting method, including:

 When the MBMS bearer service is started, if the MBMS traffic bearer involved in the session is established, the corresponding relationship between the MBMS bearer service and the established traffic bearer is updated. Otherwise, the MBMS traffic bearer is newly created, and the MBMS bearer service is updated. Correspondence of newly created traffic bearers.

 An embodiment of the present invention further provides an MBMS session stopping method, including:

 When the session of the MBMS bearer service is stopped, if the session of all other MBMS bearer services corresponding to each MBMS traffic bearer in the session is stopped, the MBMS traffic bearer is released, otherwise, the MBMS bearer service and each MBMS traffic bearer are updated. Correspondence.

The embodiment of the present invention separates the MBMS bearer service from the MBMS traffic bearer, and one MBMS bearer service can be delivered by using multiple traffic bearers, and multiple MBMS bearer services are shared. The information can be delivered through the same traffic bearer. By sharing the traffic bearer to multiple MBMS bearer services, the bearer resources of the MBMS service are saved.

 When the session of the MBMS bearer service starts, it is first determined whether the MBMS traffic bearer involved in the session has been established. If yes, only the correspondence between the MBMS bearer service and the established traffic bearer is updated. If not, the MBMS traffic bearer is created. And updating the correspondence between the MBMS bearer service and the newly created traffic bearer. Therefore, while sharing bearer resources, it is avoided to repeatedly establish a traffic bearer.

 When the session of the MBMS bearer service is stopped, if all the other MBMS bearer service sessions corresponding to the MBMS traffic bearers in the session are stopped, the MBMS traffic bearer is released, otherwise, the MBMS bearer service and each MBMS traffic bearer are updated. Correspondence relationship. Therefore, the other MBMS bearer services cannot be normally transmitted after the session of the MBMS bearer service is stopped, and the MBMS bearer services can be performed normally while the bearer services share resources.

DRAWINGS

 1 is a schematic diagram of a networking structure of a multicast/broadcast service in the prior art;

 2 is a schematic structural diagram of an MBMS network proposed by the 3GPP in the prior art;

 3 is a schematic diagram of a relationship between an MBMS bearer context and an MBMS UE context in the prior art; FIG. 4 is a schematic diagram of a MBMS session start process in the prior art;

 FIG. 5 is a schematic diagram of a MBMS session stop process in the prior art; FIG.

 6 is a schematic diagram of a relationship between an MBMS bearer service context and an MBMS traffic bearer context in the prior art;

 7 is a schematic diagram of a relationship between a traffic bearer and a bearer service in an MBMS system according to a first embodiment of the present invention;

 8 is a schematic diagram of a relationship between a traffic bearer context and a bearer service context in an MBMS system according to a first embodiment of the present invention;

9 is a flowchart of an MBMS session start method according to a second embodiment of the present invention; FIG. 10 is a first schematic diagram of an MBMS session start method according to a third embodiment of the present invention; FIG. 11 is an MBMS according to a third embodiment of the present invention. FIG. 12 is a first schematic diagram of an MBMS session stop method according to a fourth embodiment of the present invention; FIG. 13 is a first schematic diagram of an MBMS session stop method according to a sixth embodiment of the present invention; FIG. 14 is a second schematic diagram of an MBMS session stop method according to a sixth embodiment of the present invention. detailed description

 In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings.

 The first embodiment of the present invention relates to an MBMS system, including at least one bearer device, configured to provide an MBMS traffic bearer, and at least one service device, configured to provide an MBMS bearer service, where each MBMS bearer service is carried by at least one MBMS traffic bearer. hair. The service device delivers the data shared by the at least two MBMS bearer services through the shared MBMS traffic provided by the bearer device. By sharing traffic bearers to multiple MBMS bearer services, the bearer resources of the MBMS service are saved.

 In the second technology, a bearer service can be associated with multiple traffic bearers, forming a "one-to-many" binding relationship. As shown in (a) of FIG. 7, each traffic bearer belongs to only one designated bearer service. It can only be used by the bearer service, and the utilization of the bearer resources is low. Different from the prior art, in this embodiment, one traffic bearer can be used by multiple bearer services, and one bearer service can use multiple traffic bearers, and the bearer service and the traffic bearer are in a many-to-many relationship, as shown in the figure. 7 (b) is shown.

 In the prior art 2, when the traffic bearer and the bearer service are in a one-to-many relationship, since the same traffic bearer does not belong to multiple bearer services at the same time, the traffic bearer needs to be determined according to the valid identifier in the bearer service scope. Yes, there is no need to globally identify the traffic bearers. In this embodiment, the traffic bearer can belong to multiple bearer services at the same time, that is, different bearer services can use the same traffic bearer. Therefore, the traffic bearer needs to be globally independent in the preset range. In this embodiment, each MBMS traffic bearer corresponds to one traffic bearer identifier, and the traffic bearer identifier is unique within a preset range. For the 3GPP MBMS network architecture, the preset range is at least one scope of the GGSN; for the System Architecture Evolution ("SAE") network architecture, the preset range is at least one gateway jurisdiction. range. Through the traffic bearer identifier, all network nodes within the preset range can directly determine the traffic bearer and the traffic bearer context.

The traffic bearer identifier may be configured by one of the following methods or any combination thereof: using a part of a flow label (Flow Id ) in an IPv6 packet structure, an entire flow label, or a stream label set as a traffic bearer. Part of the identity or traffic bearer identity; use the access point name (APN) as part of the traffic bearer identity or traffic 7-mark; use the BM-SC's identity as part of the traffic 7-load identity or traffic-loaded identity.

 In addition, as shown in FIG. 8 , in this embodiment, the bearer device provides a context of MBMS traffic bearer, and each MBMS traffic bearer context includes part or all identifiers of each MBMS bearer service delivered by the traffic bearer; A context of the MBMS bearer service is provided, and each MBMS bearer service context includes part or all of the traffic bearer identifiers of the MBMS traffic bearers that deliver the bearer services. The bearer service identifier and the traffic bearer identifier included in the traffic bearer or bearer service context are not necessarily complete identifiers, and may be only a part of the identifier or an alternative identifier, as long as the bearer service or traffic bearer can be uniquely determined on the network node. can.

 The bearer device and the service device in this embodiment are one or any combination of the following: BM-SC, GGSN, SGSN, RNC in the MBMS network architecture of 3GPP; Gateway, mobility management in the SAE network architecture Entity (Mobility Management Entity, referred to as "MME"), evolved base station (eNodeB).

 From the perspective of IP packet forwarding: When a bearer device (such as a GGSN) receives an IP packet whose destination address is multicast, it can determine the IP packet according to the traffic bearer identifier (such as the flow label) in the packet. The associated "traffic bearer context" and the traffic bearer to be used. Moreover, the service device can determine the associated service context according to the "bearer service identifier" part (such as the IP multicast destination address) in the IP packet, so as to determine which 7-carrier service the IP address belongs to. Through the cooperation between the bearer device and the service device, the necessary information (such as the flow node list, service quality, service area, etc.) can be obtained from the "bearing service context," and "traffic bearer context" respectively, so as to perform corresponding processing. Finally, the IP ·^艮 text is sent downstream.

 A second embodiment of the present invention relates to an MBMS session start method.

 In this embodiment, when the BM-SC is ready to send MBMS service data, the MBMS session start procedure is initiated. Through this process, on the one hand, the network activates the bearer resources necessary for transmitting data, and on the other hand, notifies all relevant UEs that data transmission is about to start. In addition, through this process, MBMS session related attributes (including parameters such as quality of service, service area, etc.) are provided to the relevant network nodes.

Among them, activating the necessary bearer resources includes establishing the necessary context to save relevant information. For the multicast mode, one or more MBMS flows corresponding to the MBMS bearer service context are established. For the broadcast mode, one or more MBMS traffic bearer contexts are established. When there is no corresponding MBMS bearer service context, the bearer service context is established and corresponds to the MBMS traffic bearer.

 Since one MBMS bearer service (session) may correspond to multiple MBMS traffic bearers, and the session starts for traffic bearers, a session start process may be for one or more traffic bearers, and corresponding one or more traffic bearer contexts may be established. And its carrying resources. The above applies to both broadcast and multicast modes.

 On the other hand, since one MBMS traffic bearer may be used by multiple MBMS bearer services, the MBMS traffic bearer context may correspond to multiple MBMS bearer service contexts.

 As the starting point of the session start process, the relationship between the MBMS bearer service (session) and the MBMS traffic bearer is existing in the BM-SC (such as by pre-configuration), and includes both the MBMS bearer service and several MBMS traffic bearers. The correspondence between the MBMS traffic bearers and several MBMS bearer services is also included.

 BM-SC and GGSN, GGSN and SGSN, SGSN and RNC are the relationship between the upstream network node and the downstream network node. At the beginning of the session of the MBMS bearer service, the upstream network node sends a session start request message to all the downstream network nodes related to the MBMS bearer service, and the session start request message may correspond to one or more MBMS traffic belonging to the MBMS bearer service. Hosted. Which downstream network nodes send the session start request message to the upstream network node, depending on the relevant information in the MBMS bearer service (eg, the downstream node list). Regardless of whether the relevant MBMS traffic bearer context already exists on the downstream network node, or whether the relevant bearer resource between the upstream network node and the downstream network node has been activated, as long as the downstream network node is in the downstream node list, A session start request message needs to be sent to the downstream network node.

For the multicast mode, the MBMS bearer service context exists on the downstream network node that receives the session start request message, so only the corresponding MBMS traffic bearer context needs to be established. For the broadcast mode, when there is no corresponding MBMS bearer service context, You need to create an MBMS bearer service context and a corresponding MBMS traffic bearer context. Since the MBMS traffic bearer can be used by multiple MBMS bearer services, the MBMS traffic bearer involved in the session of the MBMS bearer service may have established a corresponding MBMS traffic bearer context on some downstream network nodes, and the upstream network node Related bearer resources may have been activated between them, then The new MBMS bearer service context is no longer created and the new bearer resource is no longer activated. Therefore, while sharing bearer resources, avoid repeatedly establishing traffic bearers. The downstream network node acknowledges and activates the associated bearer resource by returning a session start response message.

 In the extreme case, all the MBMS traffic bearers involved in the beginning of the session are already existing, that is, the traffic bearers are being used by other bearer services, and the corresponding traffic bearer context has been established, and the relevant bearer resources are activated. At this point, the upstream network node still needs to initiate a session start procedure to all downstream network nodes indicated by the bearer service context. The session start process at this time is to notify the downstream network node that the MBMS bearer service session has started, and the information is transmitted, and the association relationship between the bearer service and the traffic bearer is established. For the broadcast mode, it is also possible for the downstream network node to establish a corresponding MBMS bearer service context. At the same time, it can trigger a process to start a session further to a more downstream network node.

 Specifically, as shown in FIG. 9, in step 910, the BM-SC sends a session start request message to all the GGSNs stored in the parameter according to the MBMS bearer service context of the MBMS service, indicating that the GGSN is the MBMS. The service is about to start data transmission and provides the session attribute of the MBMS. The session attributes of the MBMS include "MBMS bearer service related session attributes" and corresponding one or more sets of "MBMS traffic bearer related session attributes". "MBMS bearer The service-related session attribute may include a bearer service identifier, a broadcast/multicast mode, and the like, and if it is a broadcast mode, it also carries a GGSN downstream node list parameter; "MBMS traffic bearer-related session attribute, which may include a traffic bearer identifier. , service quality, service area, etc.

 If the status attribute of the MBMS bearer service context in the BM-SC is "standby", it is set to "activate" in this step, and it is identified that the MBMS bearer service is using at least one traffic bearer. Unlike the prior art, In the prior art, an MBMS bearer service has only one MBMS traffic bearer. Therefore, when the service uses all traffic bearers, the MBMS bearer service corresponds to multiple MBMS traffic bearers, and only one of the traffic flows is used. The bearer is activated.

In step 920, after the GGSN receives the session start request message, it first searches the GGSN according to the “traffic bearer identifier” included in the request message, so as to avoid the repeated establishment of the traffic bearer while sharing the bearer resource. For the traffic bearer indicated by each "traffic bearer identifier", if the MBMS traffic bearer context corresponding to the traffic bearer has not been established on the GGSN, the corresponding MBMS traffic 7-load context is established for the traffic, and the traffic is 7 Related conversation The attribute is saved in the corresponding MBMS traffic bearer context; if the MBMS traffic bearer has established the corresponding MBMS traffic bearer context on the GGSN, the context is not re-created for the MBMS traffic, if the MBMS traffic carried in the session start request message The related session attribute of the bearer is different from the information stored in the MBMS traffic bearer context corresponding to the traffic bearer on the GGSN, and the corresponding MBMS traffic bearer context is performed according to the relevant session attribute of the MBMS traffic bearer carried in the session start request message. Updated to ensure that the new MBMS bearer service can use the existing traffic bearer to achieve resource sharing. This change may be due to the update of the attribute information. For example, when the bearer service change carried by the traffic is used, the service area may be changed, and the service area parameter in the corresponding traffic bearer context may be changed.

 For the MBMS bearer service in the broadcast mode, if there is currently no corresponding in the GGSN

The MBMS bears the service context, and in this step, the GGSN creates an MBMS bearer service context, and associates the bearer service-related session attribute with the bearer service and the traffic bearer (that is, the traffic bearer included in the session start request message). The identifier "or part of the traffic bearer identifier" and the list of downstream nodes are stored in this context. In addition, the identifier of the MBMS bearer service needs to be saved in the newly created MBMS traffic bearer context. If the corresponding MBMS bearer service context has been created in the GGSN, the association between the MBMS bearer service and the MBMS traffic bearer is updated, including: adding the identifier of the MBMS bearer service in the created MBMS traffic bearer context; And, adding an identifier (or a part of the identifier) of the created MBMS traffic bearers to the MBMS bearer service context. After that, if the status attribute of the MBMS-loaded business context is "standby," then change to "active".

 For the MBMS bearer service in the multicast mode, the corresponding MBMS bearer service context in the GGSN is created in the MBMS registration process. The GGSN directly updates the association between the MBMS bearer service and the MBMS traffic bearer in the MBMS bearer service context, including An identifier of the MBMS bearer service added to the newly created or created MBMS traffic bearer context corresponding to the MBMS bearer service; and an identifier (or identifier) of the newly created or created MBMS traffic corresponding to the MBMS bearer service Part of it is added to the MBMS 7-loaded service context; in addition, if the status attribute of the MBMS-bearing service context is "standby", it is changed to "active".

After that, the GGSN sends a session start response message to the BM-SC. In step 930, the GGSN sends an MBMS Session Start Request message to the SGSN stored in the corresponding Downstream Node List parameter of the MBMS Bearer Service Context, the information contained in the message is similar to that sent by the BM-SC.

 In step 940, after the SGSN receives the MBMS session start request message, the SGSN performs the same operations as the GGSN in step 920, and details are not described herein. After that, the SGSN returns an MBMS Session Start Response message to the GGSN, which is included in the response message. The TEID of the plane is used by the GGSN to send MBMS data.

 In step 950, the SGSN sends an MBMS Session Start Request message to the RNC to which it is connected, and the information contained in the message is similar to that sent by the GGSN.

 In step 960, the operation after the RNC receives the MBMS Session Start Request message is similar to the operation of the GGSN in step 920 and the SGSN in step 940. Afterwards, the RNC returns an MBMS Session Start Response message to the SGSN, where the response message includes a TEID for the bearer plane, which is used when the SGSN sends the MBMS data.

 In step 970, the RNC establishes the necessary radio resources for the UE interested in the MBMS for transmitting MBMS data.

 The third embodiment of the present invention also relates to an MBMS session start method, which is substantially the same as the second embodiment, except that the second embodiment describes a method for starting an MBMS session under the MBMS network architecture currently defined by 3GPP; The present embodiment mainly describes an MBMS session start method under the SAE network architecture.

 As in the second embodiment, as the starting point of the session start process, the MBMS bears the same service.

The relationship between the MBMS traffic bearers is existing in the BM-SC, and is usually pre-configured in the BM-SC, including the correspondence between the MBMS bearer service and each MBMS traffic bearer, and the MBMS traffic bearer and each MBMS. The correspondence between bearer services.

 Since the operations between the network nodes are very similar in the process of starting the session, in order to make the description clear and concise, in the present embodiment, the operation of each network node is collectively described using the upstream network node and the downstream network node. The network nodes referred to by the upstream network node and the downstream network node are described below.

As shown in FIG. 10, between the BM-SC and the Gateway and/or the MME, the BM-SC is an upstream network node, the Gateway and/or the MME are downstream network nodes; and the MME and the eNodeB (evolutionary base) Between the stations, the MME is the upstream network node and the eNodeB is the downstream network node.

 As shown in Figure 11, between the BM-SC and the Gateway, the BM-SC is the upstream network node, the Gateway is the downstream network node; between the Gateway and the MME, the Gateway is the upstream network node, the MME is the downstream network node; MME and eNodeB Between the MME is the upstream network node and the eNodeB is the downstream network node.

 The upstream network node initiates a session start procedure to its corresponding downstream network node, indicating that the MBMS service is about to begin data transmission, and provides session attributes to the downstream network node. The "session attribute" includes "MBMS bearer service-related session attributes" (including bearer service identifiers, broadcast/multicast mode, etc.) and corresponding one or more sets of "MBMS traffic bearer-related session attributes" (including traffic bearer identifiers). , service quality, service area, etc.).

 The downstream network node first searches on the local node according to the "traffic bearer identifier" provided by the upstream network node. For the traffic bearer indicated by each "traffic bearer identifier", if the traffic of the traffic is not established on the local node, the corresponding MBMS traffic is not established. 7 If the context is loaded, the corresponding MBMS traffic bearer context is established for the traffic, and the session attributes related to the traffic bearer are saved in the corresponding MBMS traffic carrying context; if the MBMS traffic is carried on the node, a corresponding correspondence has been established. The MBMS traffic bearer context, no longer re-creates the context for it, so as to avoid the repeated establishment of the traffic bearer while sharing the bearer resources; if the relevant session attribute of the MBMS traffic bearer provided by the upstream network node and the traffic bearer on the local node If the information stored in the corresponding MBMS traffic bearer context is different, the corresponding MBMS traffic bearer context is updated according to the relevant session attribute of the MBMS traffic bearer provided by the upstream network node to ensure that the new MBMS bearer service can use the existing one. Traffic carrying, Realize resource sharing. This change may be due to the update of the attribute information. For example, when the bearer service change carried by the traffic is used, the service area may be changed, and the service area parameter in the corresponding traffic bearer context may be changed.

For the MBMS bearer service in the broadcast mode, if the corresponding MBMS bearer service context has not been established, the downstream network node creates the MBMS bearer service context, and associates the service-related session attribute and the bearer service with the traffic bearer ( That is, the "traffic bearer ID" or "part of the traffic bearer ID" provided by the upstream network node and the list of downstream nodes are stored in this context. In addition, the MBMS bearer service needs to be saved in the newly created MBMS traffic bearer context. ID; if the corresponding MBMS bearer service context has been created, it is directly The association between the new MBMS bearer service and the MBMS traffic bearer includes: adding the identifier of the MBMS bearer service in the created MBMS traffic bearer context; and marking the created MBMS traffic 7 (or Part of the identity) is added to the MBMS 7-load business context. After that, if the status attribute of the MBMS bearer service context is "standby", it is changed to "active".

 For the MBMS bearer service in the multicast mode, the corresponding MBMS bearer service context in the downstream network node already exists, and the downstream network node directly updates the association relationship between the MBMS bearer service and the MBMS traffic bearer in the MBMS bearer service context, including Adding the identifier of the MBMS bearer service to the newly created or created MBMS traffic bearer context corresponding to the MBMS bearer service; and identifying the newly created or created MBMS traffic bearer context corresponding to the MBMS bearer service (or part of the identifier) ) is added to the MBMS bearer service context; in addition, if the status attribute of the MBMS bearer service context is "standby", it is changed to "active".

 In Figure 10 and Figure 11, after each of the downstream network nodes (except the eNodeB) completes the above operation, it further initiates an MBMS session start procedure to its downstream network node, repeats the above operations, and implements all correlations from the BM-SC to the eNodeB. The activation of resources is carried between the network nodes, and the relevant session attributes are provided to the network nodes to ensure that the MBMS service data can be transmitted normally.

 A fourth embodiment of the present invention relates to an MBMS session stop method. In this embodiment, the end of the session is indicated by the session stop process, including releasing the related bearer resources. Since a session of an MBMS bearer service may correspond to multiple MBMS traffic bearers, and the session stop is for a traffic bearer, a session stop process may be for one or more traffic bearers, and corresponding one may cause release of one or more traffic bearer contexts. And its carrying resources. On the other hand, since one MBMS traffic bearer may be used by multiple MBMS bearer services, that is, one MBMS traffic bearer context may correspond to multiple MBMS bearer service contexts. As a result, any MBMS traffic bearer context and its resources are only released when it is not used by any MBMS bearer service.

 In this embodiment, whether to release the MBMS traffic bearer is controlled by each network node.

The BM-SC does not consider such a one-to-many relationship between the traffic bearer and the bearer service, and directly initiates the session stop procedure at the end of the MBMS session. In this case, each network node (including GGSN, SGSN, RNC) needs to save the traffic in the context of each MBMS traffic bearer it establishes. The identifier or part of the identity of the bearer MBMS bearer service. When the session stop process is used to learn that an MBMS bearer service is stopped, the bearer service identifier is marked or deleted in all traffic bearer contexts corresponding to the session. When all bearer service identifiers in a traffic bearer context are marked or deleted After that, it indicates that the bearer service carried by the traffic has not been used. At this time, the related resources can be released, and the traffic bearer context is deleted. This approach is more flexible to implement and reduces the pressure on upstream network nodes (mainly BM-SC).

 Specifically, as shown in FIG. 12, in step 1210, the BM-SC sends a session stop request message to all GGSNs in the MBMS bearer service context "downstream node list" parameter, indicating that the MBMS session ends, and its bearer resources can be released. . The session stop request message may be for one or more MBMS traffic bearers involved in the session, that is, the message carries the MBMS bearer service identifier and the corresponding one or more MBMS traffic carrying identifiers.

 In step 1220, the GGSN searches for the MBMS traffic bearer identifier according to the MBMS traffic bearer identifier in the message, and determines the corresponding MBMS traffic bearer context, and labels or deletes the identifier of the MBMS bearer service in the MBMS traffic bearer context, indicating that the MBMS bearer service is not Then use this MBMS traffic bearer. If all the bearer service identifiers in the traffic bearer context are marked or deleted after the labeling or deletion process, it indicates that no MBMS bearer service uses the MBMS traffic bearer, and the related bearer resources are released, and the The context of the MBMS traffic bearer. In this step, the GGSN also returns a session stop response message to the BM-SC.

 In step 1230, the GGSN sends a session stop request message to all SGSNs in the MBMS bearer service context "downstream node list" parameter, indicating that the MBMS session is over, and its bearer resources can be released.

 In step 1240, the operation after the SGSN receives the session stop request message is similar to that of the GGSN, and details are not described herein. The SGSN also needs to return a session stop response message to the GGSN.

 In step 1250, the SGSN sends an MBMS Session Stop Request message to all RNCs that establish a bearer plane with the SGSN, indicating that the MBMS session ends and its bearer resources can be released.

 In step 1260, the operation after the RNC receives the session stop request message is similar to the operation of the GGSN and the SGSN, and details are not described herein again. The RNC also needs to return a session stop response message to the SGSN.

In step 1270, the RNC releases the corresponding wireless and Iu resources. The fifth embodiment of the present invention also relates to an MBMS session stop method. Unlike the fourth embodiment, in the present embodiment, the deletion of the MBMS bearer service is completely controlled by the BM-SC. Because of the many-to-many relationship between the MBMS bearer service and the MBMS traffic bearer, it is originally embodied by the BM-SC, and is also released by the BM-SC (through the session start process). Thus, for a given MBMS traffic bearer, the BM-SC can select the appropriate time to terminate it through the session stop procedure without relying on the corresponding MBMS bearer service. When the session of the MBMS bearer service needs to be stopped, the BM-SC judges each MBMS traffic bearer involved in the session. If the other MBMS bearer service is still using the MBMS traffic bearer, the BM-SC does not initiate a session stop process for the traffic bearer, or only those that are no longer involved in the traffic bearer (ie, other devices that do not involve using the traffic bearer) The downstream network node that carries the service initiates a session stop process, notifying the downstream network nodes to delete the traffic bearer and the corresponding traffic bearer context; if the BM-SC determines that the MBMS traffic bearer is no longer used, then all relevant downstream The network node initiates a session stop process, and notifies the downstream network nodes to delete the traffic bearer and the corresponding traffic bearer context. This method does not require each network node to save the corresponding MBMS bearer service identifier in its MBMS traffic bearer context, which simplifies the operation of the downstream network node. When the corresponding downstream network node (such as the GGSN) receives the session stop request, it can directly release and delete the corresponding traffic bearer and traffic bearer context according to the traffic bearer identifier in the request, and further trigger the relationship between the downstream network nodes. The session stop process between the GGSN and the SGSN and between the SGSN and the RNC deletes the corresponding traffic bearer from the RNC to the BM-SC.

 The sixth embodiment of the present invention also relates to a method for stopping an MBMS service, which is similar to the fourth embodiment, except that the fourth embodiment describes a method for stopping an MBMS session under the MBMS network architecture currently defined by 3GPP; The present embodiment mainly describes an MBMS session end method under the S AE network architecture.

 Since the operations between the network nodes are very similar in the session stop process, in order to make the description clear and concise, in the present embodiment, the operation of each network node is collectively described using the upstream network node and the downstream network node. The following describes the network nodes referred to by the upstream network node and the downstream network node.

As shown in FIG. 13, between the BM-SC and the Gateway and/or the MME, the BM-SC is an upstream network node, and the Gateway and/or the MME are downstream network nodes; between the MME and the eNodeB, the MME is an upstream network node. The eNodeB is a downstream network node. As shown in FIG. 14, between the BM-SC and the Gateway, the BM-SC is an upstream network node, the Gateway is a downstream network node; between the Gateway and the MME, the Gateway is an upstream network node, and the MME is a downstream network node; the MME and the eNodeB Between the MME is the upstream network node and the eNodeB is the downstream network node. The session stop process sends a session stop request message to indicate that the MBMS session ends, and the bearer resource can be released. Different from the prior art, in this embodiment, the session stop request message may be related to one or more MBMS traffic bearers involved in the session, that is, the message carries the MBMS bearer service identifier and the corresponding one or more MBMS traffic carrying identifiers. .

 In order to enable the downstream network node to determine whether the corresponding MBMS traffic bearer is still used by the MBMS bearer service, it is necessary to save the identifier or part of the identifier of all MBMS bearer services carried by the traffic in the MBMS traffic bearer context of each downstream network node.

 When receiving the request message, the downstream network node performs a search according to the MBMS traffic bearer identifier in the message, determines a corresponding MBMS traffic bearer context, and then labels or deletes the MBMS bearer service identifier in the determined MBMS traffic bearer context. Indicates that the MBMS bearer service no longer uses this MBMS traffic bearer. When all bearer service identifiers in a traffic bearer context are marked or deleted, indicating that the bearer service carried by the traffic bearer has not been used, the related bearer resources are released, and the corresponding MBMS traffic bearer context can be deleted. In addition, the downstream network node needs to send a session stop request message to the re-downstream network node (for example, the gateway needs to send to the MME, and the MME needs to send to the eNodeB), and triggers the corresponding downstream network node (such as the MME, eNodeB) to perform the foregoing operation.

 The seventh embodiment of the present invention also relates to a method for stopping an MBMS service, which is similar to the fifth embodiment, and the difference is that the fifth embodiment describes a method for stopping an MBMS session under the MBMS network architecture currently defined by 3GPP; The present embodiment mainly describes an MBMS session end method under the S AE network architecture.

In the present embodiment, the deletion of the MBMS bearer service is also controlled by the BM-SC. Because of the many-to-many relationship between the MBMS bearer service and the MBMS traffic bearer, it is originally embodied by the BM-SC, and is also released by the BM-SC (through the session start process). Thus, for a given MBMS traffic bearer, the BM-SC can choose the appropriate time to stop the flow through the session. To terminate it, without relying on the corresponding MBMS bearer service. When the session of the MBMS bearer service needs to be stopped, the BM-SC judges each MBMS traffic bearer involved in the session. If the other MBMS bearer service is still using the MBMS traffic bearer, the BM-SC does not initiate a session stop process for the traffic bearer, or only those that are no longer involved in the traffic bearer (ie, other devices that do not involve using the traffic bearer) The downstream network node (Gateway and/or MME) of the bearer service initiates a session stop procedure, notifying the downstream network nodes to delete the traffic bearer and the corresponding traffic bearer context; if the BM-SC determines that the MBMS traffic bearer is no longer used Then, a session stop procedure is initiated to all relevant downstream network nodes (Gateway and/or MME), and these downstream network nodes are notified to delete the traffic bearer and the corresponding traffic bearer context. This method does not require each network node to save the corresponding MBMS bearer service identifier in its MBMS traffic bearer context, which simplifies the operation of the downstream network node. When receiving the session stop request, the corresponding downstream network node (such as the Gateway) can directly release the corresponding traffic bearer and delete the corresponding traffic bearer context according to the traffic bearer identifier in the request, and further trigger the relationship between the downstream network nodes (Gateway) The flow between the MME and the eNodeB stops the corresponding traffic bearer from the eNodeB to the BM-SC.

 It should be noted that, in the foregoing method implementation manners, when using a certain MBMS traffic bearer

When the bearer service of the MBMS changes, such as adding or reducing a bearer service to use the traffic bearer, the attribute of the traffic bearer may change (such as the service area changes). In this case, the process may be modified by using a session update process or the like. The attributes of the MBMS traffic bearer. In addition, if the attributes of an MBMS traffic bearer need to be changed for other reasons, you can also modify the attributes of the MBMS traffic bearer by using a process such as session update.

 In summary, in the embodiments of the present invention, the MBMS bearer service is separated from the MBMS traffic bearer, and one MBMS bearer service may be delivered by using multiple traffic bearers, and the common information of multiple MBMS bearer services may be the same. The traffic is delivered. By sharing the traffic bearer to multiple MBMS bearer services, the bearer resources of the MBMS service are saved.

 Each MBMS traffic bearer corresponds to a traffic bearer identifier, and the traffic bearer identifier is unique within a preset range, so that the network node within the preset range can uniquely determine the traffic bearer to be used by the identifier. The preset range contains at least one GGSN or gateway.

The MBMS traffic bearer context includes part or all of the identifiers of the MBMS bearer services delivered by the traffic bearer; Part or all of the traffic bearer identifier carried by the MBMS traffic. Therefore, in the process of implementing the MBMS bearer service, the bearer service can be delivered according to the corresponding relationship, and the establishment and release of the traffic bearer can be managed according to the corresponding relationship.

 When the session of the MBMS bearer service starts, it is first determined whether the MBMS traffic bearer involved in the session has been established. If yes, only the correspondence between the MBMS bearer service and the established traffic bearer is updated. If not, the MBMS traffic bearer is created. And updating the correspondence between the MBMS bearer service and the newly established traffic bearer. Therefore, while sharing bearer resources, it is avoided to repeatedly establish traffic bearers.

 If the MBMS traffic bearer involved in the session has been established, it is also required to determine whether the information in the context of the MBMS traffic bearer that has been established is consistent with the information carried by the current upstream network node, and if it is different, according to the upstream network. The information sent by the node updates the MBMS traffic bearer context, so as to ensure that the MBMS traffic bearer can be shared by the corresponding bearer service.

 When the session of the MBMS bearer service is stopped, if the session of all other MBMS bearer services corresponding to each MBMS traffic bearer in the session is stopped, the MBMS traffic bearer is released, otherwise, the MBMS bearer service and each MBMS traffic bearer are updated. Correspondence. Therefore, the other MBMS bearer services cannot be normally transmitted after the session of the MBMS bearer service is stopped, and the MBMS bearer services can be performed normally while the bearer services share resources.

 When the MBMS bearer service session is stopped, the upstream network node determines whether the traffic bearer involved in the session can be released, and notifies the downstream network node when the network node can be released, and the downstream network node only needs to release the resource according to the notification of the upstream network node. Or, the upstream network node only informs the downstream network node that the MBMS bearer service session is stopped, and the downstream network node determines whether the traffic bearer involved in the session can be released, and if not, releases the corresponding traffic bearer. The former method is uniformly controlled by the upstream network node, and the downstream network node does not need to separately store the correspondence between each MBMS traffic bearer and the MBMS bearer service, which simplifies the operation of the downstream network node; the latter method is more flexible and reduces The pressure of the upstream network node.

 While the invention has been illustrated and described with reference to the preferred embodiments embodiments The spirit and scope of the invention.

Claims

Rights request  A multimedia broadcast multicast service system, comprising:  At least one bearer device is configured to provide a MBMS traffic bearer for the multimedia broadcast multicast service; at least one service device is configured to provide the MBMS bearer service, and each MBMS bearer service is delivered by using at least one MBMS traffic bearer;  The service device delivers the data shared by the at least two MBMS bearer services through the shared MBMS traffic bearer provided by the bearer device.  The MBMS system according to claim 1, wherein each of the MBMS traffic bearers corresponds to a traffic bearer identifier, and the traffic bearer identifier is unique within a preset range, and the preset range includes at least one gateway universal The packet radio service supports the node GGSN or gateway.  The MBMS system according to claim 2, wherein the bearer device stores a context of the provided MBMS traffic bearer, where the MBMS traffic bearer context includes each MBMS bearer delivered by the traffic bearer. Part or all of the identification of the business;  The service device stores a context of the provided MBMS bearer service, where the MBMS bearer service context includes part or all of the traffic bearer identifiers of each MBMS traffic bearer that delivers the bearer service.  The MBMS system according to any one of claims 1 to 3, wherein the bearer device and the service device are one of the following or any combination thereof:  Broadcast Multicast Service Center, Gateway General Packet Radio Service Support Node GGSN, Service Generic Packet Radio Service Support Node SGSN, Radio Network Controller, Gateway, Mobility Management Entity MME, Evolved Base Station.  A method for starting a multimedia broadcast multicast service session, comprising: a multimedia broadcast multicast service, when a session of the MBMS bearer service starts,  If the MBMS traffic bearer involved in the session has been established, update the correspondence between the MBMS bearer service and the established traffic bearer;  If the MBMS traffic bearer involved in the session is not established, the MBMS traffic bearer is newly created, and the corresponding relationship between the MBMS 7-loaded service and the newly-created traffic is updated. The MBMS session starting method according to claim 5, wherein the newly created MBMS traffic bearer comprises: Establishing a context of the MBMS traffic bearer, where the MBMS traffic bearer context includes a traffic bearer identifier, where the traffic bearer identifier is unique within a preset range.  The MBMS session starting method according to claim 6, wherein the preset range includes at least one gateway general packet radio service support node GGSN or a gateway.  The MBMS session starting method according to claim 5, wherein the updating the correspondence between the MBMS bearer service and the established or newly created traffic bearer comprises:  Setting, in the context of the MBMS bearer service, part or all of the traffic carried by the built or newly created traffic bearer; and/or  All or part of the identifier of the MBMS bearer service is set in the context of the established or newly created traffic bearer.  The MBMS session start method according to claim 5, wherein, before updating the correspondence between the MBMS bearer service and the established or newly created traffic bearer, if the context of the MBMS bearer service has not been established, Then, the MBMS bearer service context is established first.  The method for starting an MBMS session according to any one of claims 5 to 9, further comprising:  The upstream network node sends the information about the MBMS traffic bearer involved in the session, where the session involves at least one MBMS traffic bearer; the information of the MBMS traffic bearer delivered by the upstream network node includes one or any combination of the following: Identification, service area, quality of service.  The method for starting an MBMS session according to claim 10, wherein the method further comprises:  The downstream network node saves the information carried by the MBMS traffic delivered by the upstream network node to the established context of the MBMS traffic bearer.  The MBMS session starting method according to claim 5, wherein after updating the correspondence between the MBMS bearer service and the established or newly created traffic bearer, if the context state of the MBMS bearer service is " Standby", update its status to "Activate".  The method for starting an MBMS session according to claim 5, wherein the MBMS traffic bearer involved in the session is pre-configured by the broadcast multicast service center. A method for stopping a session of a multimedia broadcast multicast service, comprising: when a session of the MBMS bearer service of the multimedia broadcast multicast service is stopped, If the session of all other MBMS bearer services corresponding to each MBMS traffic bearer in the session has been stopped, the MBMS traffic bearer is released;  If the sessions of all other MBMS bearer services corresponding to each MBMS traffic bearer in the session are not stopped, the corresponding relationship between the MBMS bearer service and the MBMS traffic bearers is updated.  The MBMS session stop method according to claim 14, further comprising: the upstream network node storing a correspondence between each MBMS traffic bearer and all MBMS bearer services that are carried by the traffic;  When the session of the MBMS bearer service is stopped, the upstream network node determines, according to the corresponding relationship, whether all other MBMS bearer service sessions corresponding to the MBMS traffic bearer involved in the session have been stopped, if they have been stopped, or not If all the non-stop MBMS bearer services in the downstream network node of the MBMS bearer service session are not used, the all the downstream network nodes participating in the MBMS bearer service session are notified to release the MBMS traffic bearer; Otherwise, the corresponding relationship between the MBMS bearer service and the MBMS traffic bearers is updated; the downstream network node releases the corresponding MBMS traffic bearer according to the notification of the upstream network node.  The MBMS session stop method according to claim 14, further comprising: each network node storing a correspondence between each MBMS traffic bearer and all MBMS bearer services that are carried by the traffic;  When the session of the MBMS bearer service is stopped, the network node determines, according to the corresponding relationship, whether all other MBMS bearer service sessions corresponding to the MBMS traffic bearers involved in the session have been stopped, if all have been stopped. The MBMS traffic bearer is released. Otherwise, the correspondence between the MBMS bearer service and each MBMS traffic bearer is deleted.  The MBMS session stop method according to any one of claims 14 to 16, wherein the method further comprises:  If the session of the MBMS bearer service is stopped, if the sessions of all the MBMS bearer services corresponding to the MBMS traffic bearers involved in the session are not all stopped, and the attributes of the MBMS traffic bearers involved in the session are changed, Update the context of the MBMS traffic bearer.