CN102395110B - Method for supporting MBMS service transmission in LTE system - Google Patents

Abstract

A method for supporting MBMS data transmission in an LTE system: when an MBMS session starts, the BM-SC sends an "MBMS session start request" message to the ECN (ECN(M)) that provides the MBMS service; the ECN that provides the MBMS service sends a "MBMS The ECN that provides the MBMS service sends a "MBMS Session Start Request" message to the ECN registered with the UE; the ECN that the UE registers sends a "MBMS Session Start Response" message to the ECN that provides the MBMS service; the UE registers The ECN sends the "MBMS Session Start Request" message to the ERAN; the ERAN sends the "MBMS Session Start Response" message to the ECN registered by the UE; the ERAN establishes necessary radio resources for transmitting MBMS data. The present invention proposes a new method for providing MBMS UE context to wireless resource management equipment, which simplifies the signaling process and improves efficiency.

Description

Method for supporting MBMS service transmission in LTE system

This application is a divisional application of Application No. 200610001694.6 entitled "Method for Supporting MBMS Service Transmission in LTE System" submitted to China Patent Office on January 24, 2006.

technical field

The present invention relates to a method for supporting MBMS service transmission in a mobile communication system long-term evolution (hereinafter referred to as LTE) system proposed by the Third Generation Partnership Project (hereinafter referred to as 3GPP).

Background technique

Figure 1 describes the system structure of MBMS. The MBMS network structure is based on the general packet radio service (referred to as GPRS) core network, and a new network unit is added. The following is a description of the MBMS system structure in FIG. 1 .

101 The broadcast and multicast service center (BM-SC for short) is the service control center of the MBMS system. 102 Gateway GPRS Support Node (GGSN for short) and 103 Serving GPRS Support Node (SGSN for short) constitute a transmission network for MBMS services and provide routes for data transmission. 104 The UMTS Terrestrial Radio Access Network (abbreviated as UTRAN) provides radio resources for MBMS services on the air interface. 105 User equipment (UE for short) is a terminal device for receiving data. 106 The Home Location Register (HLR for short) saves data related to the user and can provide services such as user authentication. 107Uu is a wireless interface, and 108Iu is an interface between an access network and a core network. The Iu resource used by the MBMS service is not dedicated to the user, but shared by all users of the service.

The process of an existing UE joining an MBMS service is shown in FIG. 2 .

201 UE initiates the process of establishing a PDP context. After the PDP context is successfully established, the PDP context is saved in the UE, SGSN, and GGSN. At the same time, a signaling connection in the PS domain is established between the UE and the GGSN. The intermediate device of the signaling connection is a radio access network (hereinafter referred to as RAN) and SGSN.

202 The UE sends an Internet Multicast Management Protocol (hereinafter referred to as IGMP) join message to the GGSN, and the message reaches the GGSN through the signaling connection established in step 201 . The message includes a parameter: an Internet Protocol (hereinafter referred to as IP) multicast address, which can identify a certain MBMS multicast service or a certain multicast service in the external data network.

203 The GGSN performs signaling interaction with the BM-SC to authorize the UE.

204 GGSN sends MBMS notification request message to SGSN, the message includes parameters: UE ID, IP multicast address.

205 After receiving the message in step 204, the SGSN sends a request MBMS context activation message to the UE, which contains parameters: UE ID, IP multicast address.

206 After the UE receives the message in step 205, it sends an activation MBMS context request message to the SGSN, which contains the IP multicast address, the access point name (hereinafter referred to as APN), MBMS_NSAPI (network layer service access point identifier) and UE's MBMS carrying capacity.

207 SGSN sends "MBMS Notification Response" message to GGSN. The MBMS Notification Response message includes: Cause value. The Cause value indicates whether activation of the MBMS Context was successful or unsuccessful due to SGSN or UE reasons. Upon receipt of a response message indicating a failed operation or a timeout of the activation clock in the GGSN. GGSN can fall back to IP multicast access (defined in 3GPP TS29.061).

208 If necessary, a secure encryption process is performed between the UE and the SGSN.

209 The SGSN sends an MBMS context establishment request message to the GGSN, and the message includes the IP multicast address and the APN.

210 After receiving the message in step 209, the GGSN performs signaling interaction with the BM-SC so as to authorize the MBMS service and the UE.

211 If the GGSN has not established the bearer context information of the MBMS service, the GGSN sends an "MBMS Registration Request" message to the BM-SC. The message includes the IP multicast address and the APN.

The BM-SC sends an "MBMS Registration Response" message to the GGSN, which contains MBMS bearer context information. The BM-SC adds the identifier of the GGSN to the list of downlink nodes in the bearer context of the BM-SC.

If the MBMS service has not been allocated a Temporary Mobile Group Identity (hereinafter referred to as TMGI), the BM-SC allocates a new TMGI. And send it to GGSN and SGSN through the "MBMS Registration Response" message, and further pass it to UE through the "Activate MBMS Context Accept" message (215).

If the state of the bearer context is active, the BM-SC initiates a session start procedure with the GGSN.

212 GGSN generates MBMS UE context, and sends "Generate MBMS Context Response" to SGSN.

213 If the SGSN has not established the bearer context information of the MBMS service, the SGSN sends an "MBMS Registration Request" message to the GGSN. The message includes the IP multicast address and the APN.

The GGSN sends an "MBMS Registration Response" message to the SGSN, and the message includes MBMS bearer context information. The GGSN adds the identity of the SGSN to the list of downlink nodes in the bearer context of the GGSNC.

214 If at least one PS domain RAB is established for this UE, the SGSN provides the MBMS UE context information to the RAN.

215 SGSN sends "Activate MBMS Context Accept" message to UE. SGSN does not need to wait until 212 is completed before sending this message.

The process of starting an existing MBMS session is shown in FIG. 3 .

301 The BM-SC sends a session start request message to the GGSN in the downstream node list in the MBMS bearer context to indicate that the transmission is about to start, and to provide MBMS session attributes (such as Temporary Mobile Group Identity (hereinafter referred to as TMGI), service quality (hereinafter referred to as Qos), MBMS service area, session ID, estimated session time, broadcast or multicast, etc.) and 2G (second generation mobile communication) 3G (third generation mobile communication) indication. The BM-SC sets the state of the MBMS bearer context as active. For the broadcast MBMS bearer service, the GGSN creates the MBMS bearer context. The GGSN saves the session attribute and the list of downstream nodes in the MBMS bearer context, and sets the status attribute of the bearer context to active. The GGSN sends a session start response message to the BM-SC.

302 The GGSN sends an MBMS session start request message to the SGSN in the downstream node list in the MBMS bearer context. The message contains session attributes (such as TMGI, Qos, MBMS service area, session ID, estimated session time, broadcast or multicast, etc.) and 2G 3G instructions. For the broadcast MBMS bearer service, SGSN creates MBMS bearer context. SGSN saves the session attribute and 2G 3G indication in the MBMS bearer context, and sets the status attribute of the bearer context to active. The SGSN sends the MBMS session start response message to the GGSN, and the message includes the Tunnel End Identification (hereinafter referred to as TEID), and the GGSN will use the bearer plane of this tunnel to send MBMS data. For an MBMS bearer service, if the SGSN receives multiple MBMS session start request messages, the SGSN only establishes a bearer plane with one GGSN.

303 The SGSN sends the MBMS session start request message to the BSC (base combat controller) and (or) RNC connected to the SGSN, and the SGSN uses 2G and 3G instructions to decide whether the MBMS session start request message is only sent to the BSCs, RNCs, or to the BSCs And sent to RNCs. The message contains session attributes such as TMGI, Qos, MBMS service area, session ID, estimated session time, broadcast or multicast, and so on. For the multicast service, the SGSN may include the number of UEs in packet mobility management idle mode (hereinafter referred to as PMM-IDLE) joining the MBMS service in each routing area (hereinafter referred to as RA). For broadcast MBMS bearer service, BSC or RNC creates MBMS bearer context. In the Iu mode, the BSC or RNC saves the session attributes in the MBMS service context, sets the MBMS service context as the active state, and sends the MBMS session response message to the SGSN. RNC or BSC in Iu mode contains TEID in this response message. TEID is used for the bearer plane of SGSN sending MBMS data. For an MBMS bearer service, if the BSC or RNC receives multiple MBMS session start request messages, it only establishes a bearer plane with one SGSN.

304 BSC or RNC establishes necessary radio resources for transmitting MBMS data to interested UEs.

The existing MBMS UE connection process is shown in Figure 4. The purpose of the MBMS UE connection process is to let the RNC know that the UE that has the Iu packet domain signaling connection joins or leaves one or several MBMS services. Below is a detailed description of the process.

401CN sends MBMS UE connection request message to RNC. The message includes the TMGI list that the UE has joined but has not yet connected to the UTRAN or the UE has left and has not notified the UTRAN, and a point-to-point radio access bearer (hereinafter referred to as RAB) identifier. 402 RNC receives MBMS UE connection request message. For the TMGI indicating that the MBMS service joined by the UE has not been connected to the UTRAN, the RNC adds the UE to the MBMS service context. If there is no MBMS service context, the RNC creates the corresponding MBMS service context. If the UE is in a cell controlled by the DRNC, perform the UE connection process on the Iur interface. For the TMGI indicating that the MBMS service left by the UE has not been connected to the UTRAN, the RNC deletes the UE from the MBMS service context. After processing all TMGIs, the RNC sends the MBMS UE Connection Response message to the CN, reporting the unsuccessful connection or disconnection and the reason.

The existing 3GPP system structure has many shortcomings such as poor upgradeability, long call setup time, complex system structure, etc. Therefore, the 3GPP standardization organization is working on the standardization of LTE. In response to the requirements of LTE, various companies have proposed desired LTE system structures, and one of the proposed LTE system structures is shown in FIG. 5 . For example, the functions of the original RNC and NodeB are combined into a network entity (herein called ERAN 502), and the functions of SGSN and GGSN are combined to form a network entity (herein called ECN 503). Among them, the Packet Data Compression Protocol (hereinafter referred to as PDCP) is the function of the original RNC, and it can be placed in the ECN or the ERAN in LTE. In this way, the system is simplified by reducing the number of network nodes, and the delay of the system is reduced. 504E-PDN is an external public data network that provides data sources. 501 UE is the same as 101 in FIG. 1 . Some companies propose that ERAN be divided into two network node devices, one with functions similar to the original Node B and one with functions similar to the original RNC, or a new split combination of the functions of RNC and Node B. Some companies propose to divide the ECN into user plane entities and control plane entities according to functions. In LTE, the functional entity part corresponding to the access network, that is, the functional part corresponding to the original UTRAN is called EUTRAN (enhanced UTRAN).

Based on the LTE system structure, how to transmit MBMS services is an unsolved problem in existing specifications. In the original structure, MBMS data is from BM-SC, to GGSN, to SGSN, to RNC where UE is located (see Figure 3 and its description for details). Among them, the SGSN saves the MBMS UE context and the UE context (such as the UE state, the RNC where the UE is in the PMM connection mode, the routing area (hereinafter referred to as RA) where the UE is in the PMM idle mode, etc.), so the SGSN can find the downstream RNC . If in LTE, not all ECNs provide data routing for each MBMS service. Then the ECN providing the MBMS service and the ECN registered by the UE may not be the same, so how the ECN providing the MBMS service finds the downstream node will be a problem.

Contents of the invention

In order to solve the above problems, the present invention provides a method for supporting MBMS service transmission in LTE, which solves the existing problems in transmitting MBMS services in the LTE system.

According to one aspect of the present invention, a method for supporting MBMS data transmission in an LTE system includes the steps of:

The ECN registered by the UE receives the "Activate MBMS Context Request" message from the UE;

The ECN sends a "Create MBMS UE Context Request" message to the ECN that provides the MBMS service;

Provide the authorization process between ECN initiation of MBMS service and BM-SC;

The ECN that provides the MBMS service sends a "Create MBMS UE Context Response" message to the ECN where the UE is registered;

The ECN with which the UE is registered sends an Activation MBMS Context Accept message to the UE.

According to another aspect of the present invention, a method for supporting MBMS data transmission in an LTE system includes the steps of:

The ECN where the UE is registered sends a "UE Context Update Request" message to the ECN that provides the MBMS service;

The ECN that provides the MBMS service sends a "UE Context Update Response" message to the ECN where the UE is registered.

According to another aspect of the present invention, a method for supporting MBMS data transmission in an LTE system includes the steps of:

The ECN where the UE is registered sends the "UP Establishment Request" message to ERAN, which contains the MBMS UE context information;

The ERAN sends an "UP Setup Response" message to the ECN where the UE is registered.

According to another aspect of the present invention, a method for supporting MBMS data transmission in an LTE system includes the steps of:

The UE sends an IGMP join message to the ECN;

ERAN receives UE connection request message from ECN;

If the ERAN has not registered the MBMS service, the ERAN sends an "IGMP join" message to the BM-SC;

The BM-SC adds this ERAN to the downstream node list of the MBMS bearer context.

According to another aspect of the present invention, a method for supporting MBMS data transmission in an LTE system includes the steps of:

The UE sends an IGMP join message to the ECN;

ERAN receives UE connection request message from ECN;

If the ERAN has not registered the MBMS service, the ERAN sends a "MBMS Registration Request" message to the BM-SC;

The BM-SC adds this ERAN to the downstream node list of the MBMS bearer context;

BM-SC sends "MBMS Registration Response" message to ERAN.

According to another aspect of the present invention, a method for supporting MBMS data transmission in an LTE system includes the steps of:

When the MBMS session starts, BM-SC sends "MBMS session start request"

message to ERANs in the downstream node list of the MBMS Bearer Context;

ERAN sends a "MBMS Session Start Response" message to BM-SC;

ERAN establishes necessary radio resources for UEs joining MBMS services.

The invention proposes a method for supporting MBMS data transmission in several LTE systems, so that BM-SC and ECN can find downstream nodes and make several MBMS data transmission paths possible. The invention also proposes a new method for providing MBMS UE context to radio resource management equipment, which simplifies the signaling process and improves efficiency.

Description of drawings

Fig. 1 is the logic network equipment figure of MBMS business;

Fig. 2 is the process of the existing UE joining the MBMS service;

Fig. 3 is an existing MBMS session start process;

Fig. 4 is the existing MBMS UE connection process;

Fig. 5 is a kind of proposed LTE system structure;

Figure 6 is based on the LTE system structure, a logical network device diagram of the MBMS service;

Figure 7 is the basic process of UE joining MBMS service in the MBMS network structure;

FIG. 8 is another method for UE to join the MBMS service in the MBMS network structure;

Fig. 9 is a method for starting an MBMS service session;

FIG. 10 is a process for supporting the MBMS data transmission path in FIG. 9, and the UE joins the MBMS service (method 1);

Fig. 11 is the process of the UE joining the MBMS service (method 1), the action flow of the ECN;

Fig. 12 is the process of supporting the MBMS data transmission path in Fig. 9, and the UE joins the MBMS service (method 2);

FIG. 13 is a signaling flow for supporting UE access system to select a network node without RMA;

Figure 14 is the process of UE joining the MBMS service changing from LTE idle mode to active mode;

Fig. 15 is for the embodiment Fig. 14, the action flow of ECN;

Fig. 16 is the action flow of ERAN for the embodiment Fig. 14;

Fig. 17 is the second method that the MBMS service session starts;

FIG. 18 is a process for supporting the MBMS data transmission path in FIG. 17, and the UE joins the MBMS service (method 1);

Figure 19 is the process of UE joining the MBMS service (method 1) corresponding to Figure 18, the action flow of ECN;

FIG. 20 is a process for supporting the MBMS data transmission path in FIG. 17, and the UE joins the MBMS service (method 2);

FIG. 21 is a process in which the UE is in the LTE idle mode and the ECN(R) where the UE is located changes;

Figure 22 shows the process of the UE joining the MBMS service changing from the idle mode to the active mode, and the ECN sending the MBMS UE context to the ERAN;

Fig. 23 is the action flow of ECN corresponding to Embodiment 22;

Figure 24 is the third method of MBMS service session initiation;

Fig. 25 is a method for supporting the MBMS data transmission path in Fig. 24, and the UE joins the MBMS service;

Figure 26 shows the process of transmitting MBMS bearer capability to the network when the UE enters the connected mode.

Detailed ways

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. in the description below

In , known functions or structures will not be described in detail.

Figure 6 is based on the LTE core network, adding a new network unit BM-SC MBMS network structure. 601 is the same as the description in FIG. 1, and is the service control center of the MBMS system. 602 and 603 are the same as network nodes 502 and 503 in Fig. 5, respectively. The function of the ECN is to initiate the establishment and release of the bearer, route the MBMS data to the appropriate downstream node equipment, and indicate the MBMS function support to the UE. The function of ERAN is to effectively transmit MBMS data to the designated MBMS service area, MBMS paging, and support parallel services with MBMS.

In the MBMS network structure, the basic process of UE joining the MBMS service is shown in Figure 7. The following is a detailed description of the graph.

701 If there is no user plane for sending the IGMP join message, establish the user plane. The process of establishing the user plane is not the focus of the present invention, and the detailed technical content is omitted here.

702 The UE sends an IGMP join message to the ECN(R), which reaches the ECN(R) via the existing or established user plane at 701 . The message includes a parameter: IP multicast address, which can identify a certain MBMS multicast service or a certain multicast service in the external data network.

703 The ECN(R) performs signaling interaction with the BM-SC to authorize the UE. Through the MBMS authorization response message, the BM-SC notifies the ECN(R) to provide the ECN identifier of the MBMS service, that is, the ECN(M) identifier. It can be represented by an access point name (hereinafter referred to as APN) or an ECN(M) address (such as an IP address).

704 The ECN(R) sends a request MBMS context activation message to the UE, the message includes parameters: IP multicast address, ECN(M) identifier and other information. There are two methods for the ECN(R) to send a request for MBMS context activation to the UE. One is to directly send a NAS message to request the MBMS context message to the UE, which is transparently transmitted through the ERAN. Another method is to send an Iu+ message to request MBMS context activation to ERAN. The ERAN then sends an air interface message requesting MBMS context activation to the UE.

705 UE creates MBMS UE context after receiving the message in step 704. The UE sends an Activation MBMS Context Request message to the ECN(R), which contains an IP multicast address, an ECN(M) identifier (which can be represented by an APN or an ECN(M) address (such as an IP address), MBMS_NSAPI (network layer service access point identifier) and the UE's MBMS bearer capability. The message may be a NAS message. NAS and AS can also be ignored. UE first sends this message to ERAN. The ERAN then sends an Iu+ message to activate the MBMS context request to the ECN(R).

706ECN (R) sends and establishes MBMS UE context request message to ECN (M), and this message includes IP multicast address, global mobile subscriber identity (hereinafter referred to as IMSI) and ECN (M) mark.

707 After receiving the message in step 706, the ECN(M) performs signaling interaction with the BM-SC to authorize the MBMS service and the UE. The authorization decision is sent to the ECN(M) via the MBMS Authorization Response message.

708 BM-SC creates MBMS UE context.

709 If the ECN (M) has not established the bearer context information of the MBMS service, the ECN (M) sends an "MBMS Registration Request" message to the BM-SC.

710 BM-SC sends an "MBMS Registration Response" message to the ECN(M), and the message includes MBMS bearer context information. The BM-SC adds the identifier of the ECN(M) to the list of downlink nodes in the bearer context of the BM-SC.

If the state of the bearer context is active, the BM-SC initiates a session start procedure with the ECN(M).

711 ECN(M) generates MBMS UE context, 712 and sends "create MBMS UE context response" to ECN(R).

713 ECN(R) sends Activate MBMS Context Accept to UE. There are two ways for the ECN(R) to send the Activate MBMS Context Accept to the UE. One is to directly send the NAS message to activate the MBMS Context Accept to the UE, which is transparently transmitted through the ERAN. Another method is to send Iu+ message to activate MBMS context acceptance to ERAN. The ERAN then sends the air interface message Activate MBMS Context Accept to the UE. Corresponding to the former method, if at least one user plane is established for this UE, ECN(R) provides MBMS UE context information to ERAN, which is the same as the prior art, ignoring the detailed technical content. Corresponding to the latter method, MBMS UE context information is included in the message activation MBMS context acceptance of the Iu+ interface. After ERAN receives this message, 714 saves the MBMS UE context. ERAN sends an Activation MBMS Context Accept message to UE, which does not contain MBMS UE context information.

In the MBMS network structure, another method for the UE to join the MBMS service is shown in Figure 8

Show. The following is a detailed description of the graph.

801 If there is no user plane for sending the IGMP join message, establish this user plane. The process of establishing the user plane is not the focus of the present invention, and the detailed technical content is omitted here.

802 The UE sends an IGMP Join message to the ECN(R), which reaches the ECN(R) via the existing or established user plane at 801 . The message includes a parameter: IP multicast address, which can identify a certain MBMS multicast service or a certain multicast service in the external data network.

803 The ECN(R) performs signaling interaction with the BM-SC to authorize the UE. Through the MBMS authorization response message, the BM-SC notifies the ECN(R) to provide the ECN identifier of the MBMS service, that is, the ECN(M) identifier. It can be represented by an access point name (hereinafter referred to as APN) or an ECN(M) address (such as an IP address).

804 The ECN(R) sends a request MBMS context activation message to the UE, the message includes parameters: IP multicast address, ECN(M) identifier and other information. There are two methods for the ECN(R) to send a request for MBMS context activation to the UE. One is to directly send a NAS message to request the MBMS context message to the UE, which is transparently transmitted through the ERAN. Another method is to send an Iu+ message to request MBMS context activation to ERAN. The ERAN then sends an air interface message requesting MBMS context activation to the UE.

805 UE creates MBMS UE context after receiving the message in step 804. The UE sends an activation MBMS context request message to the ECN(M), which contains the IP multicast address, the ECN(M) identifier (which can be represented by the APN or the address of the ECN(M) (such as an IP address), MBMS_NSAPI (network layer service access point identifier) and the UE's MBMS bearer capability. The message may be a NAS message. NAS and AS can also be ignored. Send this message to ERAN first. The ERAN then sends an Iu+ message to activate the MBMS context request to the ECN(M).

806 After receiving the message in step 805, the ECN(M) performs signaling interaction with the BM-SC so as to authorize the MBMS service and the UE. The authorization decision is sent to the ECN(M) via the MBMS Authorization Response message.

807BM-SC creates MBMS UE context.

808 If the ECN (M) has not established the bearer context information of the MBMS service, the ECN (M) sends an "MBMS Registration Request" message to the BM-SC. The BM-SC sends a "MBMS Registration Response" message to the ECN(M), which contains MBMS bearer context information. The BM-SC adds the identifier of the ECN(M) to the list of downlink nodes in the bearer context of the BM-SC.

If the state of the bearer context is active, the BM-SC initiates a session start procedure with the ECN(M).

809ECN(M) generates MBMS UE context.

810 The ECN(M) sends an Activate MBMS Context Accept to the UE. ECN(M) send activation

There are two ways to accept the MBMS context to the UE. One is to directly send a NAS message to activate the MBMS context to accept to the UE, which is transparently transmitted through the ERAN. Another method is to send Iu+ message to activate MBMS context acceptance to ERAN. The ERAN then sends the air interface message Activate MBMS Context Accept to the UE. Corresponding to the former method, if at least one user plane is established for this UE, the ECN(M) provides the MBMS UE context information to the ERAN, which is the same as the prior art, ignoring the detailed technical content. Corresponding to the latter method, MBMS UE context information is included in the message activation MBMS context acceptance of the Iu+ interface. After receiving this message, ERAN executes 811 to save the MBMS UE context. ERAN sends an Activation MBMS Context Accept message to UE, which does not contain MBMS UE context information.

In the MBMS network structure, a method for starting an MBMS service session is shown in FIG. 9 . The following is a detailed description of the graph.

901 The BM-SC sends a session start request message to the ECN (M) in the downstream node list in the MBMS bearer context to indicate that the transmission is about to start, and to provide MBMS session attributes such as MBMS service identifier, Qos, MBMS service area, session identifier, Estimate session time, broadcast or multicast, etc. In the above description of Fig. 7 and Fig. 8, the BM-SC has saved the registered downstream node ECN(M) in the MBMS bearer context. The BM-SC sets the state of the MBMS bearer context as active. For the broadcast MBMS bearer service, ECN(M) creates MBMS bearer context. The ECN(M) saves the session attribute and the list of downstream nodes in the MBMS bearer context, and sets the status attribute of the bearer context to active. ECN(M) sends a session start response message to BM-SC.

902 ECN(M) sends MBMS Session Start Request message to interested ERANs. The ECN(M) will save the UE context information, that is, the ERAN where the UE that has joined the MBMS service in the LTE active mode resides, and the ERANs included in the tracking area where the UE that has joined the MBMS service and is in the LTE idle mode. How the ECN (M) obtains the context information of the UE joining the MBMS service, such as the location information of the UE, will be described in conjunction with FIG. 10 , FIG. 11 , FIG. 12 and FIG. 13 . The MBMS session start request message includes session attributes such as MBMS service identifier, Qos, MBMS service area, session identifier, estimated session time, broadcast or multicast, and so on. For broadcast MBMS bearer services, ERAN creates MBMS service contexts. ERAN saves the session attribute in the MBMS service context, and sets the status attribute of the service context to active. The situation of ERAN creating the MBMS service context is the same as that of the prior art. For example, ERAN receives information from ECN to notify UE to activate MBMS service, or ERAN receives an MBMS session start message from ECN. Detailed technical descriptions are omitted here. ERAN sends an MBMS session start response message to ECN(M), which contains the user plane identifier for this MBMS service such as TEID, and ECN(M) will use this bearer plane to send MBMS data. For an MBMS bearer service, if the ERAN receives multiple MBMS session start request messages, the ERAN only establishes a user plane with one ECN(M).

903 ERAN establishes necessary radio resources for transmitting MBMS data to interested UEs.

FIG. 10 shows the process of UE joining the MBMS service supporting the MBMS data transmission path shown in FIG. 9 (method 1). Only the differences from FIG. 7 will be described in detail below.

Compared with the basic process of UE joining MBMS service in Figure 7, 1001 to 1005, 1007 to 1011 and 1013 to 1014 are the same as 701 to 705, 707 to 711 and 713 to 714 respectively, and the detailed description is omitted here. The difference is that:

1006 After the ECN (R) receives the activation MBMS context request message, the ECN (R) sends an MBMS UE context request message to the ECN (M), and the message includes an IP multicast address, a global mobile subscriber identity (hereinafter referred to as IMSI) and an ECN ( M) logo. In addition, the message also includes UE context information. The UE context information includes the ERAN identifier where the UE is located. After receiving the MBMS context activation request message, the ECN(M) saves the UE context information. Then execute step 1007.

1012 ECN(M) sends "Create MBMS UE Context Response" to ECN(R). After receiving the message, the ECN (R) saves the ECN (M) (such as APN or IP address) and then executes 1013 .

FIG. 11 shows the operation flow of ECN corresponding to the method for UE to join the MBMS service. Among them, 1102 to 1108 are the action flow when ECN is used as ECN(R). 1109 to 1114 are the operation flow when ECN is used as ECN (M). This figure will be described in detail below.

1101 The ECN receives the message. 1102 If the ECN receives the activation MBMS context request message from the UE (or ERAN), 1103 if the ECN (M) is not another ECN, execute the existing process, for example, the ECN sends the MBMS authorization request to the BM-SC and other subsequent processes , a detailed technical description is omitted here. If the ECN(M) is another ECN, 1104ECN sends a request to create an MBMS UE context to another ECN (that is, ECN(M)), and the message includes the UE context. At this time, the UE is in an active state. Corresponding to the UE in the activated state, the UE context information includes the ERAN where the UE is located, 1105 and then the ECN waits for a response.

1106 If the ECN receives an MBMS UE context response message from another ECN, 1107 the ECN stores the identifier of another ECN (i.e. ECN(M), where the ECN(M) identifier can be an APN or an IP address. 1108 The ECN sends an Activate MBMS Context Accept message to the ERAN.

1109 If the ECN receives an MBMS UE context creation request message from another ECN, 1110 the ECN sends an MBMS Authorization Request message to the BM-SC, and waits for a response.

1111 If the ECN receives the MBMS Authorization Response message from the BM-SC, according to the authorization result in the Authorization Response message, if the UE is not authorized to receive the MBMS service, the process is terminated, which is not shown in the figure. 1112 If UE is authorized, ECN creates MBMS UE context. If the UE is the first UE in the ECN(M) to join the MBMS service (the ECN(M) has not created the MBMS bearer context), the ECN(M) will also perform the process of registering with the BM-SC, which is different from the current There are the same technologies, which are not drawn in the figure, and the detailed technical content is ignored here. 1113 ECN sends create MBMS UE context response message to ECN(R).

Figure 12 shows the process of UE joining the MBMS service supporting the MBMS data transmission path shown in Figure 9

process (method 2). Only the differences from FIG. 8 will be described in detail below.

This process is compared with the basic process of UE joining the MBMS service in Figure 8, 1201 to 1204, 1206 to 1208, and 1211 to 1214 are the same as 801 to 804, 806 to 808, and 811 to 814 in Figure 8, and the detailed description is omitted here. The difference is that:

1205 The UE or the ERAN notifies the ECN (M) of the ECN registered by the UE (that is, the ECN (R)) through the Activate MBMS Context Request message. If the message is a NAS message sent by the UE to the ECN, the UE notifies the ECN(M). If there is no distinction between NAS and AS in LTE. UE first sends this message to ERAN. The ERAN then sends an Iu+ message to activate the MBMS context request to the ECN(M). Then the ERAN notifies the ECN(M) of the ECN(R) where the UE is located. Then execute 1206.

1209ECN(M) creates the MBMS UE context, and saves the ERAN where the UE is located in the MBMS UE context. Then the ECN(M) sends a UE activation success indication message to the ECN(R), and the message includes the UE identifier such as IMSI. After receiving the UE activation success indication message in 1209, the ECN(R) saves the ECN(M) in the UE context. Execute 1210.

When the location information of the UE changes, the ECN(R) will notify the ECN(M). For example, when the ERAN where the UE is located changes, or the UE changes from the LTE active state to the idle state (the location information of the UE changes from a certain ERAN to multiple ERANs under a certain tracking area (hereinafter referred to as TA), or the UE changes from the LTE The ECN(M) needs to be notified when the idle mode changes to the active state. This process is shown in Figure 13, and the process will be described in detail below.

1301 The ECN(R) sends a UE context update request message to the ECN(M), and the message includes UE identifier such as IMSI and UE context information. UE context information such as the ERAN where the UE is located, or the TA where the UE is located and the ERAN list included in the TA. After receiving this message, the ENC(M) updates the UE context information. 1302 The ECN(M) sends a UE context update response message to the ECN(R).

Fig. 14 shows the process of UE joining MBMS service changing from LTE idle mode to active mode. Below is a detailed description of the process.

1401 The UE sends an initial connection request message to the ERAN, and the message includes parameters such as the UE identifier such as IMSI and the wireless access capability of the UE. After ERAN receives this message, 1402 sends a service request message to ECN(R), and the message includes parameters such as UE identifier and service type.

Because the UE state changes, the location information of the UE in the ECN changes from multiple ERANs under one TA to one ERAN, 1403 ECN(R) sends a UE context update request message to ECN(M). The message contains UE identifier such as IMSI and UE context. In this case, the UE context information is the ERAN where the UE is located. After receiving the UE context update request message, the ECN(M) updates the UE context information. 1404 ECN (M) sends UE context update response message to ECN (R), and the message includes MBMS UE context information. The MBMS context information refers to the list of MBMS service IDs that the UE joins.

1405 The ECN(R) sends a user plane (hereinafter referred to as UP) establishment request message to the ERAN, and the message includes parameters required for the establishment of the user plane, such as user plane identification, Qos, etc., and the MBMSUE context. There is no absolute order in which the ECN sends the UP establishment request and executes 403 and 1404 .

ERAN saves the MBMS UE context after receiving the UP establishment request message. 1406 The ERAN sends an UP establishment request message to the UE.

1407 The UE configures resources according to the UP establishment request message, and then sends an UP establishment response message to the ERAN. 1408 ERAN sends UP setup response message to ECN(R).

The process 1405 of the Iu+ interface is not only applicable when supporting the MBMS data transmission path shown in Figure 9, but also applicable to other data transmission paths, regardless of the data transmission path. The UP setup procedure of the Iu+ interface can be used to send MBMS UE context information to ERAN.

Figure 14 corresponds to an embodiment of the UE context update process between the ECN(R) and the ECN(M) and the process in which the ECN sends the MBMS UE context to the ERAN through a user plane establishment request, where the action flow of the ECN is shown in Figure 15 . Below is a detailed description of the process.

1501 ECN receives a message, 1502 ECN receives a service request message from ERAN, 1503 if ECN (M) is another ECN, 1504 ECN sends a UE context update request to ECN (M), and waits for a response. For the case where ECN(M) and ECN(R) are the same ECN, the detailed description is omitted here. In fact, as described in Figure 13, when the location information of the UE changes, the ECN(R) needs to send a UE context update request message to the ECN(M). When the active state changes to the idle state (the location information of the UE changes from a certain ERAN to multiple ERANs under a certain tracking area (hereinafter referred to as TA)), or the UE changes from the LTE idle mode to the active state, it is necessary to notify the ECN (M ). Here, the action of the ECN is described by taking the UE transitioning from the LTE idle mode to the active mode as an example.

1505 If the ECN receives a UE context update response message from another ECN, 1506 the ECN sends an UP establishment request message to the ERAN. If the UE has joined the MBMS service, the message contains the MBMS UE context (including the MBMS service identification list that the UE joined), and wait for a response. As described above, the UE context update process between ECN(R) and ECN(M) occurs under various conditions. In other cases, the ECN does not necessarily execute step 1506 after receiving the UE context update response. This is only for the case when the UE transitions from the LTE idle mode to the active mode.

1507 If the ECN receives the UP setup response message from the ERAN, 1508 the ECN saves the information, such as the user plane identifier allocated by the ERAN.

1509 If the ECN receives a UE context update request from another ECN, 1510 the ECN updates the UE context information, such as the ERAN where the UE resides. 1511 The ECN sends a UE context update response to the ECN that sent the message, that is, ECN(R).

Among them, 1502 to 1508 are the action flow of ECN as ECN(R). 1509 to 1511 are the operation flow of ECN as ECN (M).

Figure 14 corresponds to an embodiment of the UE context update process between the ECN(R) and the ECN(M) and the process in which the ECN sends the MBMS UE context to the ERAN through a user plane establishment request, where the action flow of the ERAN is shown in Figure 16. Below is a detailed description of the process.

1601 ERAN receives message, 1602 ERAN receives UP establishment request message from ECN, 1603 if UP establishment request message includes MBMS UE context information, 1604 ERAN saves MBMS UE context information. Then execute other processes, for example, ERAN sends an UP establishment request message to UE, which is not the main content of the present invention, and detailed technical description is omitted here. If the message does not contain MBMS UE context information, the RAN also performs other MBMS-independent procedures.

In the MBMS network structure, the second method for starting an MBMS service session is shown in Figure 17 . The following is a detailed description of the graph.

1701 The BM-SC sends a session start request message to the ECN (M) in the downstream node list in the MBMS bearer context to indicate that the transmission is about to start, and to provide MBMS session attributes such as MBMS service identifier, Qos, MBMS service area, session identifier, Estimate session time, broadcast or multicast, etc. In the above description of Fig. 7 and Fig. 8, the BM-SC has saved the registered downstream node ECN(M) in the MBMS bearer context. The BM-SC sets the state of the MBMS bearer context as active. For the broadcast MBMS bearer service, ECN(M) creates MBMS bearer context. The ECN(M) saves the session attribute and the list of downstream nodes in the MBMS bearer context, and sets the status attribute of the bearer context to active. ECN(M) sends a session start response message to BM-SC.

1702 The ECN(M) sends an MBMS session start request message to the ECN(R) in the downstream node list in the MBMS bearer context. How the ECN (M) obtains the ECN (R) where the UE joining the MBMS service resides will be described in conjunction with FIG. 18 , FIG. 19 , FIG. 20 and FIG. 21 . The message contains session attributes such as MBMS service identifier, Qos, MBMS service area, session identifier, estimated session time, broadcast or multicast, and so on. For broadcast MBMS bearer services, ECN(R) creates MBMS bearer context. ECN(R) saves the session attribute in the MBMS bearer context, and sets the status attribute of the bearer context to active. ECN(R) sends MBMS session start response message to ECN(M), the message contains user plane identifier such as TEID, ECN(M) will use this bearer plane to send MBMS data to ECN(R). For an MBMS bearer service, if the ECN(R) receives multiple MBMS session start request messages, the ECN(R) only establishes a bearer plane with one ECN(M).

1703 ECN(R) sends MBMS session start request message to interested ERAN. ECN(R) can find the ERAN of interest through two methods. One method is that ECN(R) saves the MBMS UE context when the UE joins the MBMS service. For details, refer to the description of FIG. 18 . The MBMS UE context includes the UE ID, the list of MBMS service IDs joined by the UE, and the ECN(M) list. The ERAN where the UE joining the MBMS service is located or the ERANs nodes included in the TA where the UE joining the MBMS service is located is the ERAN of interest. The second method is that the MBMS session start request message sent by the ECN (M) to the ECN (R) includes a list of UE identifiers. ECN(R) finds interested ERANs according to the UE joining the MBMS service. The MBMS session start request message includes session attributes such as MBMS service identifier, Qos, MBMS service area, session identifier, estimated session time, broadcast or multicast, and so on. For broadcast MBMS bearer services, ERAN creates MBMS service contexts. ERAN saves the session attribute in the MBMS service context, and sets the status attribute of the service context to active. ERAN sends an MBMS session start response message to ECN(R), which contains a user plane identifier such as TEID for this MBMS service, and ECN(R) will use this bearer plane to send MBMS data to ERAN. For an MBMS bearer service, if the ERAN receives multiple MBMS session start request messages, the ERAN only establishes a user plane with one ECN(R).

1704 ERAN establishes necessary radio resources for transmitting MBMS data to interested UEs.

FIG. 18 shows the process of UE joining the MBMS service supporting the MBMS data transmission path shown in FIG. 17 (method 1). Only the differences from FIG. 7 will be described in detail below.

This process is compared with the basic process of UE joining the MBMS service in FIG. 7 , 1801 to 1810 and 1813 to 1814 are the same as 701 to 710 and 713 to 714 in FIG. 7 respectively, and the detailed description is omitted here. The difference is that:

1811 The ECN(M) creates the MBMS UE context, and the context information includes the ECN(R) where the UE is located.

1812 The ECN(M) sends a Create MBMS UE Context Response message to the ECN(R). Corresponds to the method of 1703ECN(R) to save the MBMS UE context. If this MBMS service is the first MBMS service that the UE joins, the ECN(R) creates the MBMS UE context and saves the UE ID, the MBMS service ID and the ECN(M) ID (which can be APN or IP address). If it is not the first MBMS service joined by the UE, the ECN(R) updates the MBMS UE context, and saves the MBMS service identifier and the ECN(M) identifier into the MBMS service identifier list and the ECN(M) identifier list respectively. Corresponding to the method in 1703 that the MBMS session start request message sent by the ECN(M) to the ECN(R) includes the UE ID list, the ECN(R) only needs to save the ECN(M) ID.

Corresponding to the method for the UE to join the MBMS service, the ECN action flow is shown in Figure 19, and only steps 1904, 1907 and 1912 that are different from those in Figure 11 will be described in detail below. Other steps are the same as those in Fig. 11, and the detailed description is omitted here.

1904 The ECN sends a request to create an MBMS UE context to another ECN (that is, ECN(M)). Then execute 1905ECN and wait for the response.

1907 corresponds to 1703 ECN(R) method for saving MBMS UE context. If it is the first MBMS service that UE joins, ECN(R) creates MBMS UE context, saves UE ID, MBMS service ID and ECN(M) ID (which can be APN or IP address). If it is not the first MBMS service joined by the UE, the ECN(R) updates the MBMS UE context, and saves the MBMS service identifier and the ECN(M) identifier into the MBMS service identifier list and the ECN(M) identifier list respectively. Corresponding to the method in 1703 that the MBMS session start request message sent by the ECN(M) to the ECN(R) includes the UE ID list, the ECN(R) only needs to save the ECN(M) ID.

1912 If the UE is authorized, the ECN creates an MBMS UE context, and the UE context includes the ECN registered by the UE (that is, ECN(R)). If the UE is the first UE in the ECN(M) to join the MBMS service, the ECN(M) will also perform the process of registering with the BM-SC, which is the same as the prior art, not shown in the figure, here Ignore the detailed technical content.

FIG. 20 shows the process of UE joining the MBMS service supporting the MBMS data transmission path shown in FIG. 17 (method 2). Only the differences from FIG. 8 will be described in detail below.

Compared with the basic process of UE joining the MBMS service in Figure 8, 2001 to 2004, 2006 to 2008, and 2011 to 2014 are the same as 801 to 804, 806 to 808, and 811 to 814 in Figure 8, and the detailed description is omitted here. The difference is that:

2005 The UE or the ERAN notifies the ECN (M) of the ECN registered by the UE (that is, the ECN(R)) through the Activate MBMS Context Request message. If the message is a NAS message sent by the UE to the ECN, the UE notifies the ECN(M). If there is no distinction between NAS and AS in LTE. UE first sends this message to ERAN. The ERAN then sends an Iu+ message to activate the MBMS context request to the ECN(M). Then the ERAN notifies the ECN(M) of the ECN(R) where the UE is located. Then execute 2006.

2009ECN(M) creates the MBMS UE context, and saves the ECN(R) where the UE is located in the MBMS UE context. Then the ECN(M) sends a UE activation success indication message to the ECN(R), and the message includes the UE identifier such as IMSI. The ECN(R) receives the 2009 UE activation success indication message, which corresponds to the method of 1703ECN(R) saving the MBMS UE context. If it is the first MBMS service that UE joins, ECN(R) creates MBMS UE context, saves UE ID, MBMS service ID and ECN(M) ID (which can be APN or IP address). If it is not the first MBMS service joined by the UE, the ECN(R) updates the MBMS UE context, and saves the MBMS service identifier and the ECN(M) identifier into the MBMS service identifier list and the ECN(M) identifier list respectively. Corresponding to the method in 1703 that the MBMS session start request message sent by the ECN(M) to the ECN(R) includes the UE ID list, the ECN(R) only needs to save the ECN(M) ID. Execution 2010.

To support the data transmission path in Figure 17, when the UE is in LTE idle mode and the ECN(R) where the UE is located changes, the ECN(M) needs to be notified. Figure 21 describes this process.

2101 UE is in LTE idle mode, UE moves from one tracking area to another tracking area, UE sends a tracking area update request message to the new ECN, the message contains the old tracking area ID and the new tracking area ID. After receiving this message, the ECN finds that the UE is originally in another ECN according to the old tracking area identifier. 2102 The ECN sends an ECN context update request message to the old ECN, and the message includes the old tracking area ID and the new tracking area ID. 2103 After receiving the ECN Context Request message, the old ECN sends an ECN Context Response message to the new ECN, through which the UE context information is sent to the new ECN, such as authentication information and UE capabilities. The message also includes the ECN(M) list for the UE to join the MBMS service.

Step 2104 is a process of notifying the ECN(M)UE that the registered ECN(R) has changed. There are two ways to notify ECN(M) here. (1) The new ECN(R) sends a location update request message to the ECN(M), and the message includes the UE identifier such as IMSI. After receiving the message, the ECN(M) updates the ECN(R) where the UE is located, and sends a location update response message to the new ECN(R), which contains the UE identifier such as IMSI. (2) The old ECN(R) sends a location update request message to the ECN(M), and the message includes the new ECN identifier and UE identifier such as IMSI. After receiving this message, the ECN(M) updates the ECN(R) where the UE is located, and sends an update location response message to the old ECN(R), which contains the UE identifier such as IMSI. For the second method, the update location request process can be before the ECN context request and response process between the old and new ECNs. For both methods, there may be no response message for the update location process.

2105 If necessary, perform a security procedure between the UE and the network.

2106 The new ECN sends an update location message to the Home Subscriber Server (hereinafter referred to as HSS), requesting the HSS to update the location information of the UE. 2107 After receiving this message, the HSS sends a cancel location message to the old ECN to request the old ECN to delete the relevant information of the UE. The old ECN deletes the relevant information of the UE, and sends a cancel location confirmation message to the HSS. After the HSS receives the cancellation location confirmation message from the old ECN, 2108 the HSS sends an update location confirmation to the new ECN.

After the new ECN receives the update location confirmation message, 2109 the new ECN sends a tracking area update complete message to the UE. 2110 The UE updates the information, and sends a tracking area update complete message to the new ECN.

Among them, the messages of 2101, 2109 and 2110 can be NAS messages, which are transparently transmitted by ERAN, or can not distinguish NAS and AS, and are two messages of air interface and Iu+ interface respectively.

Here I want to focus on explaining that the UE is in idle mode. During the tracking area update process between different ECNs, when UE information is transferred between two ECNs, the old ECN needs to send the ECN related to the MBMS service that the UE has joined through the context transfer response message. (M) list to the new ECN (2103 in the figure), and how to notify the ECN (M) process (2104 in the figure). It is not focused on explaining the TA update process itself between different ECNs. If the TA update process between different ECNs changes in the future, such as the process between ECN and HSS, it will not affect the main content of the present invention.

When UE changes from LTE idle mode to active mode, ECN sends MBMS UE context information to ERAN through the user plane establishment process between ECN and ERAN, as shown in Figure 22.

2201 The UE sends an initial connection request message to the ERAN, and the message includes parameters such as the UE identifier such as IMSI and the wireless access capability of the UE. After receiving this message, ERAN sends 2202 a service request message to ECN (that is, ECN(R)), and the message includes parameters such as UE identifier and service type.

2203 The ECN sends an UP establishment request message to the ERAN. The message includes parameters required for user plane establishment, such as user plane identification, Qos, etc. If the UE has joined the MBMS service, the message also includes the MBMS UE context. The MBMS UE context refers to the list of MBMS service identifiers that the UE joins.

After ERAN receives the UP establishment request message, if the message contains MBMS UE context, ERAN saves the MBMS UE context. 2204 ERAN sends UP establishment request message to UE.

2205 The UE configures resources according to the UP establishment request message, and then sends the UP establishment response message to the ERAN. 2206 ERAN sends UP setup response message to ECN(R).

The process of 2203 is not only applicable when supporting the MBMS data transmission path shown in Figure 17, but also applicable to other data transmission paths, regardless of the data transmission path. Here, taking the UE transitioning from the LTE idle mode to the active mode as an example to illustrate the process of the ECN sending the MBMS UE context information to the ERAN through the UP establishment request message. If there is any change in the process of UE switching from LTE idle mode to active mode in the future, such as a change in the number of messages, it will not affect the main content of the present invention.

Corresponding to the process of UE transitioning from idle mode to active mode, the action flow of ERAN is the same as that of FIG. 16 and its description, and will not be described in detail here. The operation flow of ECN is shown in Figure 23.

2301 ECN receives the message, 2302 ECN receives the service request message from ERAN, 2303 if user plane needs to be established for the requested service, 2304 ECN sends UP establishment request message to ERAN, the message contains user plane configuration information. If the UE has joined one or more MBMS services, the message also contains the MBMS UE context. The MBMS UE context refers to the list of MBMS service identifiers that the UE joins. ECN waits for a response. For the case where there is no need to establish a user plane for the requested service, the detailed technical content is omitted here.

2305 If the ECN receives the UP setup response message from the ERAN, 2306 the ECN saves the information, such as the user plane identifier allocated by the ERAN.

In the MBMS network structure, the third method for starting an MBMS service session is shown in Figure 24 . The following is a detailed description of the graph.

2401 The BM-SC sends a session start request message to the ERANs in the downstream node list in the MBMS bearer context, to indicate that the transmission is about to start, and to provide MBMS session attributes such as MBMS service identifier, Qos, MBMS service area, session identifier, estimated session Time, broadcast or multicast, etc. The process of how the BM-SC finds the downstream node ERANs will be described in conjunction with FIG. 25 . The BM-SC sets the state of the MBMS bearer context as active. For broadcast MBMS bearer services, ERAN creates MBMS service contexts. ERAN saves the session attribute in the MBMS service context, and sets the status attribute of the service context to active. ERAN sends a session start response message to BM-SC. ERAN creates the MBMS service context under the following conditions: ERAN receives a notification from ECN UE to join the MBMS service; ERAN receives a session start request from BM-SC. In the above case, if ERAN does not have MBMS service context, ERAN will create MBMS service context.

2404 ERAN establishes necessary radio resources for transmitting MBMS data to interested UEs.

Supporting the MBMS data transmission path shown in Figure 24, the method for the UE to join the MBMS service is shown in Figure 25. The following is a detailed description of the graph.

2501 If there is no user plane for sending the IGMP join message, establish this user plane. The process of establishing the user plane is not the focus of the present invention, and the detailed technical content is omitted here.

2502 The UE sends an IGMP join message to the ECN, and the message reaches the ECN through the existing or established user plane at 2501 . The message includes a parameter: IP multicast address, which can identify a certain MBMS multicast service or a certain multicast service in the external data network.

2503 The ECN performs signaling interaction with the BM-SC to authorize the UE. The APN is included in the MBMS Authorization Response message.

2504 If the ECN does not store the UE's MBMS capability, the ECN sends a UE MBMS Bearer Capability Request message to the UE to request the UE's MBMS bearer capability. This message can be a NAS message, or it does not need to distinguish between NAS and AS. ECN sends Iu+ message UE MBMS Bearer Capability Request to ERAN. After receiving this message, ERAN sends an air interface message UE MBMS Bearer Capability Request to UE. After receiving this message, UE sends UE MBMS Bearer Capability Response, which contains UE's MBMS Bearer Capability. Like the request message, the response message can be a NAS message, or it can be two messages on the air interface and the Iu+ interface without distinguishing between NAS and AS. After receiving the response message, the ECN saves the UE's MBMS bearer capability. According to the UE's MBMS bearer capability, if the UE does not have the capability, the ECN can reject the UE's joining and terminate the UE's joining of the MBMS service.

2505 The ECN sends the UE connection request message to the ERAN, and the message includes the MBMS service identifier, IP multicast address and APN that the UE joins.

2506 If the UE is the first UE in the ERAN to join the MBMS service, the ERAN registers with the BM-SC. There are two methods here, one is that ERAN sends an IGMP join message to BM-SC. The other is that the ERAN sends an MBMS registration request message to the BM-SC, and the message includes an IP multicast address and an APN. After receiving the IGMP join or MBMS registration request message, the BM-SC saves the ERAN in the downstream node list in the MBMS bearer context. Corresponding to the method in which the ECN sends the MBMS Registration Request message to the BM-SC, the BM-SC sends the MBMS Registration Response message to the ERAN.

During the process of the UE joining the MBMS service, if the ECN does not have the UE's MBMS bearer capability, the ECN will request the UE's MBMS bearer capability. Another method for the ECN to obtain the UE MBMS bearer capability is that when the UE enters the connected mode, the UE sends the MBMS bearer capability to the network, such as through the initial connection request message, as shown in Figure 26.

2601 The UE sends an initial connection request message to the ERAN, and the message includes parameters such as the UE identifier such as IMSI and the wireless access capability of the UE. If the UE supports the MBMS service, the message also includes the UE's MBMS bearer capability. ERAN receives this message, 2602 ERAN sends a service request message to ECN, and the message includes UE identification and service type. If the initial connection request of the air interface message includes UE's MBMS bearer capability, the service request message sent by ERAN to ECN also includes Contains the UE's MBMS bearer capability. The ECN stores the UE's MBMS bearer capability.

2603 The ECN sends an UP establishment request message to the ERAN, and the message includes parameters required for establishment of the user plane, such as user plane identification, Qos, and the like.

After the ERAN receives the UP establishment request message, 2604 the ERAN sends the UP establishment request message to the UE.

2605 The UE configures resources according to the UP establishment request message, and then sends the UP establishment response message to the ERAN. 2606 ERAN sends UP establishment response message to ECN.

Using the method that the UE sends the UE's MBMS bearer capability to the network, when the UE joins the MBMS service (as shown in FIG. 25 ), the ECN does not need to request the UE's MBMS bearer capability (step 2504).

When a UE joining a certain MBMS service moves to another ERAN, and this UE is the first UE joining a certain MBMS service in the new ERAN, the ERAN needs to register with the BM-SC, and the process of 2506 occurs.

When a UE joining a certain MBMS service moves to a new TA, and this UE is the first UE joining a certain MBMS service in the TA, the ECN sends a UE connection request message to all ERANs included in the TA. If there is no other UE joining a certain MBMS service in the ERANs included in the TA, all the ERANs need to register with the BM-SC, and the process of 2506 occurs.

When UE joining MBMS service moves to idle mode, ECN will send UE connection request to all ERANs in TA. For the ERANs that have not registered with the BM-SC, the ERANs need to register with the BM-SC, and the process of 2506 occurs.

In a word, when the ERAN receives the UE connection request message from the ECN, if the ERAN has not registered a certain MBMS service in the UE connection request message, the ERAN sends a 2506 message to the BM-SC.

When the last UE in the ERANs that joins a certain MBMS service leaves or moves away, the ERANs need to deregister with the BM-SC. The specific process is as follows: In the first method, ERAN sends an IGMP leave message to BM-SC, and after receiving the message, BM-SC deletes ERAN from the downstream node of the MBMS bearer context. In the second method, the ERAN sends an MBMS deregistration message to the BM-SC, and the BM-SC deletes the ERAN from the downstream node of the MBMS bearer context after receiving the message. The BM-SC sends an MBMS deregistration response message to the ERAN.

Claims (5)

1. A method for supporting MBMS data transmission in an LTE system, comprising steps: When the MBMS session starts, the BM-SC sends a "MBMS session start request" message to the evolved core network ECN that provides MBMS services; ECN providing MBMS service sends "MBMS Session Start Response" message to BM-SC; The ECN that provides the MBMS service sends a "MBMS session start request" message to the ECN where the UE is registered; The ECN where the UE is registered sends the "MBMS Session Start Response" message to the ECN that provides the MBMS service; The ECN registered by the UE sends the "MBMS Session Start Request" message to the evolved radio access network ERAN; The ERAN sends an "MBMS Session Start Response" message to the ECN with which the UE is registered; and ERAN establishes necessary radio resources for transmitting MBMS data. 2. The method according to claim 1, wherein the "MBMS Session Start Request" message sent by the BM-SC, the ECN providing the MBMS service, and the ECN registered with the UE all contain the MBMS service identifier. 3. The method according to claim 1, wherein the "MBMS Session Start Request" message sent by the BM-SC, the ECN providing the MBMS service, and the ECN registered with the UE includes the Qos information of the MBMS service. 4. The method according to claim 1, wherein the "MBMS session start request" messages sent by the BM-SC, the ECN providing MBMS services and the ECN registered by the UE all contain information about whether the MBMS services are broadcast or multicast. 5. The method according to claim 1, wherein the "MBMS Session Start Response" message sent by the ECN registered by the UE and the ERAN respectively include the user plane identifier.