WO2004043025A1

WO2004043025A1 - Method for mbms radio access bearer establishment

Info

Publication number: WO2004043025A1
Application number: PCT/KR2003/002359
Authority: WO
Inventors: Kook-Heui Lee; Detao Li; Shanpeng Xiao; Chang Duan; Lixiang Xu; Sung-Ho Choi; Chunying Sun
Original assignee: Samsung Electronics Co., Ltd.; Beijing Samsung Telecom R & D Center
Priority date: 2002-11-05
Filing date: 2003-11-05
Publication date: 2004-05-21
Also published as: CN1499762A

Abstract

A method for RAB establishment for MBMS service includes the steps of: SGSN receives data or notification from BM-SC and GGSN, or SGSN receives MBMS service information request from CRNC; SGSN initiates a RAB establishment request to CRNC; after receiving the request from SGSN, RNC starts to page for UE; RNC decides whether it is necessary to establish CRNC context for this MBMS service according to the number of UEs using this MBMS service and network demand. RNC reports the RAB establishment result to SGSN. The RAB establishment method for MBMS service is a RAB establishment method based on MBMS service, and a kind of service only needs one group of signalling to accomplish RAB process. During the MBMS RAB establishment process, Iu paging function and CRNC context creation function are finished at the same time.

Description

METHOD FOR MBMS RADIO ACCESS BEARER ESTABLISHMENT

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a Wide-band Code Division Multiple Access mobile communication system, particularly to a method for Radio Access Bearer (RAB) and Paging establishment for MBMS service.

2. Description of the Related Art

Multimedia Broadcast and Multicast Service (hereinafter referred to as MBMS) is a new service under standardization by 3^rd Generation Partnership Project (hereinafter referred to as 3 GPP). MBMS service is an unidirectional point-to-multipoint (p-t-m) service, its most remarkable characteristic is that it can make use of radio resources and network resources efficiently.

MBMS network structure is based on the core network of General Packet Radio Service (hereinafter referred to as GPRS), and some new network elements are added therein. Broadcast and multicast service center 101 (hereinafter referred to as BM-SC) is a service control center of MBMS system. Gateway GPRS Supporting Node 102

(hereinafter referred to as GGSN) and Service GPRS Supporting Node 103 (hereinafter referred to as SGSN) form the transmission network of MBMS service and provide routes for data transfer. Home Location Register 106 (hereinafter referred to as HLR) saves the data related to user and can provide services like user's authentication. UMTS Terrestrial Radio Access Network 104 (hereinafter referred to as UTRAN) provides radio resources for MBMS service over the air-interface. 107 lu indicates the interface between a Radio Access Network and a Core Network. User Equipment 105 (hereinafter referred to as UE) is the terminal device used to receive data. Radio resources used by MBMS service are not dedicated for one user, but are shared by all users using this service.

The Existing Radio Access Bearer allocation process is used to establish new RAB, or modify and release RAB having been established based on one user. Figure 2 describes the existing RAB allocation process.

201 Radio Access Bearer Allocation Request indicates that Core Network (hereinafter referred to as CN) request RNC to configure corresponding RAB according to parameters in the message. The parameters in this message include: a new RAB that needs be established, a RAB Identifier (ID) that needs to be modified as well as relevant parameters, a RAB ID that needs to be released, etc.

202 Radio Access Bearer Allocation Response indicates that RNC responds to CN after finishing RAB configuration according to requests of CN. hi this message, RNC will report configuration results to CN.

The paging process on the existing lu interface is independent from the RAB establishment process, as shown in Figure 3.

When CN needs to page certain UE, it sends 301 paging message to RNC, and then RNC pages for the UE on air interface according to parameters in the message. Parameters in the paging message includes a CN domain ID, a UE ID, a paging area, a paging reason, etc.

The Existing RAB establishment process and paging process all aim at a single UE, but MBMS service is point-to-multipoint service, which can effectively save resources. Thus, it is necessary to propose a new RAB establishment process and paging process, which should be based on service but not for a single UE, and should integrate more functions together during these processes to effectively save system resources. In addition, according to the characteristics of MBMS service, we can consider to create CRNC Context during the process of RAB establishment.

SUMMARY OF THE INVENTION

The object of this invention is to provide a method for RAB establishment for MBMS seivice. h order to realize above object, a method for RAB establishment for MBMS service comprises the steps of: a) SGSN receives data or notification from BM-SC and GGSN, or SGSN receives MBMS service information request from CRNC. b) SGSN initiates a RAB establishment request to CRNC according to notification or MBMS context saved by itself; c) after receiving the request from SGSN, RNC starts to page for UE; d) RNC decides whether it is necessary to establish CRNC context for this MBMS service according to the number of UEs using this MBMS service and network demand. e) RNC reports the RAB establishment result to SGSN. The RAB establishment method for MBMS service proposed in this invention is a RAB establishment method based on MBMS service, and a kind of service only needs one group of signaling to accomplish RAB process. During the MBMS RAB establishment process, lu paging function and CRNC context creation function are finished at the same time, which reduces signaling transmission on lu interface and saves system resources to improve the efficiency ofthe system to provide MBMS service. And during paging process, processing on service area feature is added.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawing in which:

Figure 1 is a diagram showing the MBMS system structures; Figure 2 is a diagram showing a RAB allocation process for existing technology;

Figure 3 is a diagram showing a RAB allocation process for existing technology;

Figure 4 is a diagram showing a MBMS RAB allocation process for this invention.

DETAILED DESCRIPTION OFTHE PREFERRED EMBODIEMENT

This invention emphasizes on the research for the method of establishing or allocating RAB for MBMS service on 107 lu interface. The feature of this method exists m that during the RAB allocation process, paging and creation of control RNC MBMS service context (hereinafter referred to as CRNC context) can be performed at the same time, and corresponding processing can be performed on air interface according to the attribute of service area.

This invention provides a method for MBMS RAB establishment comprising the steps of: a) SGSN receives data or notification from BM-SC and GGSN, or SGSN receives a request from CRNC. If the attribute of service area defined by BM-SC is tracing area or non-tracing area, the notification that BM-SC sends to GGSN or GGSN sends to SGSN shall include the indication for service area. b) SGSN initiates a RAB establishment request to CRNC according to notification or MBMS context saved by itself. The request message to RNC shall include following parameters, i.e. a Temporary MBMS Group Identifier (hereinafter referred to as TMGI), an IP address, an Access Point Name (hereinafter referred to as APN), a Quality of Service, an information on the UE in connection mode, etc. c) After RNC receives the request from SGSN, it starts to page for the UE.

The paging message for UE can include relevant parameters for MBMS service and indicates whether the service area is tracing area or non-tracing area. If UE wants to receive MBMS message in tracing area, Radio Resource Control (hereinafter referred to as RRC) coimection must be established; UE receiving MBMS message in non-tracing area doesn't need to establish RRC connection. d) UE responds to RNC according to parameters in the paging message and the state it stays in. e) RNC confirms to UE according to the response from UE as well as attributes of the service area, and decides if it, is necessary to establish CRNC context for the MBMS service. f) RNC reports the RAB establishment results to SGSN, and indicates whether the establishment succeeds or fails; if it fails, it can indicate the reason for failure, such as there is no user in the service area that is willing to receive this service.

In the following, we will describe the flow of MBMS RAB establishment, referring to Figure 4:

The initiation of MBMS RAB establishment process has two choices, i.e. 4011 CRNC sends a "MBMS Service Information Request" message to SGSN, or 4012 SGSN receives data or notification from BM-SC and GGSN.

402 SGSN sends MBMS RAB Establishment Request to RNC. 403 RNC analyzes the request from SGSN and pages for UE.

404 After UE receiving the paging from RNC, it sends RRC Connection Establishment Request to RNC if it is in idle mode, or sends RAB Establishment Response to RNC if it is in connection mode. According to network requirement, certain UE can also not to respond to RNC. 405 If RNC receives the RRC Connection Establishment Request from UE, it performs accordingly according to the attribute of service area that UE belongs to. If the service area is a tracing area, establish RRC connection for the UE and send "RRC Coimection Established" as a response; if the service area is a non-tracing area, don't establish RRC connection for the UE and send "RRC Connection Rejected" as a response. The reject reason is "non-tracing area". RNC determines the CRNC context for this MBMS service according to parameters in the request message received from SGSN as well as the number of UEs.

406 If UE receives a "RRC Connection Established" message from RNC, it indicates that RRC connection needs to be established between UE and RNC. UE shall send a "RRC Connection Established Response" to RNC as a response.

407 RNC sends a response to SGSN to report the result of RAB establishment. SGSN can establish the bearer of user plane on lu interface according to this result.

408 SGSN sends a response message to GGSN and BM-SC according to network requirement. While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope ofthe invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for RAB establishment for MBMS service, comprising the steps of: a) SGSN receives data or notification from BM-SC and GGSN, or SGSN receives MBMS service information request from CRNC; b) SGSN initiates a RAB establishment request to CRNC according to notification or MBMS context saved by itself; c) after receiving the request from SGSN, RNC starts to page for UE; d) RNC decides whether it is necessary to establish CRNC context for this MBMS service according to the number of UEs using this MBMS service and network demand; and e) RNC reports the RAB establishment result to SGSN.

2. The method as claimed in claim 1, wherein the notification message sent from BM-SC to GGSN and then from GGSN to SGSN includes the attribute indication of seivice area.

3. The method as claimed in claim 1, wherein a "MBMS RAB Establishment Request" message is used on lu interface, which includes following parameters: a RAB parameter, a MBMS context information, a service area, a Quality of Service, a TMGI, an information on the UE in connection mode.

4. The method as claimed in claim 1, wherein the SGSN initiates a RAB establishment request to CRNC according to notification or MBMS context saved by itself, the request includes following parameter: a Temporary MBMS Group Identifier, an IP address, an Access Point Name, service area, a Quality of Service, an information on the UE in connection mode.

5. The method as claimed in claim 1, wherein the MBMS RAB Establishment Request message includes paging information based on MBMS service, which includes a TMGI, a service area, a Quality of Service, an information on the UE in connection mode.

6. The method as claimed in claim 1, wherein the paging message for UE is added with indications for the attribute of service area, which is used to indicate whether the service area is tracing area or non-tracing area.

7. The method as claimed in claim 1, wherein the RNC processes RRC Connection

Request from UE according to the attribute of service area.

8. The method as claimed in claim 1, wherein RNC establish CRNC context for MBMS service according to requirements, after receiving MBMS RAB establishment request.

9. The method as claimed in claim 1, wherein a reason for rejection is added to the message of "RRC Connection Establishment Reject", non-tracing area.

10. The method as claimed in claim 1, wherein the RAB Establishment Response message sent from RNC to SGSN includes the result for RAB establishment, if the establishment fails, give the reason for failure.

11. A method for processing tracing area and non-tracing area during MBMS RAB establishment process and paging process, comprising the steps of: a) SGSN adds an indication for service area attribute to the RAB Establishment

Request message sent to RNC to indicate whether the service area is a tracing area or non-tracing area; b) RNC adds an attribute indication for the cell where UE belongs to the paging or notification message sent to UE to indicate whether the cell belongs to a tracing area or a non-tracing area; c) UE processes accordingly according to the state it stays in and the attributes of the cell, after receiving the paging or notification message from RNC.

12. The method as claimed in claim 11, wherein UE initiates a RRC Connection Establishment process, if it is in idle mode and the cell belongs to a tracing area; only after RRC Connection Establishment succeeds, UE starts to receive MBMS message;

UE configures radio resources according to network requirements and it is unnecessary to establish a RRC connection separately for MBMS service receiving, if UE is in idle mode or connection mode and the cell belongs to a non-tracing area, UE also send response information to RNC according to network requirements.

13. The method as claimed in claim 11, wherein UE decides whether it is necessary to establish a RRC connection in order to receive MBMS service according to the state it stays in and the service attributes ofthe cell that it belongs to.

14. The method as claimed in claim 11, wherein UE initiates a RRC Connection Establishment Request with the reason of "MBMS Service Request".