WO2004043022A1

WO2004043022A1 - Service access method for multimedia broadcast/ multicast service

Info

Publication number: WO2004043022A1
Application number: PCT/KR2003/002356
Authority: WO
Inventors: Sung-Ho Choi; Kook-Heui Lee; Qinghai Gao; Detao Li; Lixiang Xu; Soeng-Hun Kim
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: CN1499759A

Abstract

This invention proposes a MBMS service access method a MBMS Control SAP (MC SAP) is added between non-access sub-layer and access sub-layer of both IF side and UE side, which is used to establish and release connections related to certain MBMS service and to exchange information with these connections. The inter-layer communication based on a certain MBMS service messages at IF side and UE side is realized through the new MBMS Control SAP (MC SAP), which radically solves the problem of MBMS service access in 3rd generation mobile communication system.

Description

SERVICE ACCESS METHOD FOR MULTIMEDIA BROADCAST/MULTICAST SERVICE

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a service access method for Multimedia Broadcast/Multicast Service (MBMS) in Wideband Code Division Multiple Access (hereinafter referred to as WCDMA) mobile communication system, particularly to a service access method for Multimedia Broadcast/Multicast Service when introducing Multimedia- Broadcast/Multicast Service control Service Access Point (SAP).

2. Description of the Related Art

Multimedia Broadcast and Multicast Service is a new service under standardization by 3^rd Generation Partnership Project (hereinafter referred to as

3 GPP). MBMS service is a 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.

Figure 1 is a diagram showing MBMS system structure. 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. Following is the description for MSMS system structure in Figure 1. Broadcast and multicast service center 101 (hereinafter referred to as

BM-SC) is the 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. UMTS Terrestrial Radio Access Network 104 (hereinafter referred to as UTRAN) provides radio resources for MBMS service over the air-interface. User Equipment 105 (hereinafter referred to as UE) is the terminal device used to receive data. Home Location Register 106 (hereinafter referred to as HLR) saves the data related to user and can provide services like user's authentication. Uul07 is radio interface, and Iul08 indicates the interface between an access network and a core network. In the figure, other parts except for UE compose the infrastructure field (simplified as IF). Radio resources used by MBMS service are not dedicated for one user, but are shared by all users using this service. Figure 2 is a diagram showing the existing Service Access Point (hereinafter referred to as SAP). These SAPs include General Control (hereinafter referred to as GC) SAP, Notification (hereinafter referred to as Nt) SAP and Dedicated Control (hereinafter referred to as DC) SAP. Based on these SAPs, Radio Access Network Application Protocol (hereinafter referred to as RANAP) services are divided into general control service, notification service and dedicated control service.

GC is used in Core Network (hereinafter referred to as CN) to provide information and sends some instructions that are not associated with specific user or session. A typical situation is when there is a GC SAP at access point of each Access Network/Core Network (AN/CN). And at UE side, a possible model is regarded that each Mobile Station (hereinafter referred to as MS) has a GC SAP.

Nt is used to broadcast data to certain users. It is typically used for initial paging in Access Network (AN). At each connection point of AN/CN, there is an Nt SAP typically. And at UE side, a possible model is regarded that each MS has an Nt SAP.

DC is used to establish and release connections with certain UEs, and to exchange information related to these connections. A typical situation is that there are many DC SAPs at each AN/CN connection point. These SAPs are all identified by SAP Identifiers respectively (hereinafter referred to as SAPI). And at UE side, a possible model is regarded that each MS has DC SAP.

Figure 3 is a diagram showing the existing inter-layer communication during the Establishment procedure of point-to-point Radio Access Bearer (hereinafter referred to as RAB). As this procedure aims at one UE, it is realized through DC SAP. (1) Inter-layer communication at IF side

301) IF side initiates a RAB Establishment Request. When IF non-access sub-layer decides to need RAB Establishment, it sends a RAB Establishment Request primitive to access sub-layer. After access sub-layer receives the primitive, it sends a RAB Allocation Request message to UE. 304) IF side initiates a RAB Establishment Confirmation primitive. After the successful RAB Establishment, IF access sub-layer sends a RAB Establishment Confirmation primitive to non-access sub-layer.

(2) Inter-layer communication at UE side

302) IF initiates a RAB Establishment Indication primitive. After UE receives the RAB Establishment Request, its access sub-layer sends a RAB

Establishment Indication primitive to its non-access sub-layer.

303) IF initiates RAB Establishment Response. The non-access sub-layer of UE sends a RAB Establishment Response primitive to its access sub-layer. After the access sub-layer receives the primitive, it sends a MBMS Allocation Response message to MBMS.

From above analysis, we can see that existing Service Access Point includes GC (General Control), Nt (Notification) and DC (Dedicated Control). In existing technology, the inter-layer communications during RAB Establishment procedure as well as other relevant procedurees are all implemented through these SAPs. MBMS service aims for a group of users and is service by service but not user by user, which is quite different from existing services. It is impossible to describe broadcast and multicast service with services and functions of existing protocols, and MBMS service access can't be realized yet. Messages used to provide MBMS service orient to a group of users and are connection-oriented. The existing three kinds of RANAP services are not applicable to describe this kind of messages. Thus, we need a new SAP type to explain and translate this kind of messages. For MBMS service, UE needs uplink feedback information. Thus, the new SAP provided by access sub-layer should be symmetrical, i.e. the access sub-layer of CN shall provide the same access point as that of UE.

SUMMARY OF THE INVENTION

In order to provide a reasonable access method for MBMS service, an object of the invention is to provide a MBMS services access method that adds MBMS Control Service Access Points (MBMS Control SAP) (hereinafter referred to as MC SAP). As UE needs uplink feedback information for MBMS service, the new MC SAP provided by access sub-layer should be symmetrical, i.e. the access sub-layer of CN shall provide the same access point as that of UE. Messages corresponding to MBMS service can be implemented based on this new MC SAP.

According to a MBMS service access method of the invention, a MBMS Control SAP (MC) is added between non-access sub-layer and access sub-layer of both IF side and UE side, which is used to establish and release connections related to certain MBMS service and to exchange information with these connections; the inter-layer communication based on a certain MBMS service message at IF side and UE side is realized through MC.

At IF side, if the non-access sub-layer of IF side decides to establish MBMS RAB, it sends a MBMS RAB Establishment Request primitive to the access sub-layer. This primitive is sent to the access sub-layer through MC SAP at IF side; if the access sub-layer at IF side has established MBMS RAB, it sends a MBMS RAB Establishment Confirmation primitive to the non-access sub-layer; if the non-access sub-layer at IF side decides to release MBMS RAB, it will sends a MBMS RAB Release Request primitive to the access sub-layer. Tnis primitive is sent to the access sub-layer through MC SAP at IF side.

At UE side, if the access sub-layer at UE side is requested to establish MBMS Radio Bearer (RB), it will send a MBMS RB Establishment Indication primitive to the non-access sub-layer. This primitive is sent to the non-access sub-layer through MC DAP at UE side; if the non-access sub-layer decides to establish MBMS RB, it will send a MBMS RB Establishment primitive to the access sub-layer. This primitive is sent to the access sub-layer through MC SAP at UE side; if the access sub-layer at UE side is requested to release MBMS RB, it will send a MBMS RB Release Indication primitive to the non-access sub-layer. This primitive is sent to the non-access sub-layer through MC SAP at UE side. Through MC SAP and corresponding inter-layer communication primitives in the invention, messages related to MBMS service in mobile communication system can be explained and translated by MC SAP, which radically solves the problem of inter-layer communication needed in MBMS service access and solves the MBMS service access problem in 3^rd system. In addition, the technical solution in the invention has no effect on all existing messages and keeps full compatibility. In addition, as messages for the same MBMS service are implemented through the same SAP, the procedurees of the technical solution in the invention is simple and the logical concepts are clear compared to existing method that is implemented through several DCs. 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 logical network devices of MBMS service; Figure 2 is a diagram showing the existing SAPs;

Figure 3 is a diagram showing the existing inter-layer communication during RAB Establishment procedure;

Figure 4 is a diagram showing the SAP after adding MC;

Figure 5 is a diagram showing the MBMS RAB Establishment procedure; Figure 6 is a diagram showing the inter-layer communication during MBMS

RAB Establishment procedure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIEMENT

This invention proposes a new service access method for MBMS service. MC

SAP between access sub-layer and non-access sub-layer both at IF side and UE side proposed in this invention is used to explain and translate messages for MBMS service. The SAP after adding MC is shown in Figure 4. In Figure 4, an MC SAP is added to both lu interface and Uu interface. The features of MC SAP are as follows:

MC SAP is symmetric, i.e. the access sub-layers of CN and UE provide the same MC.

MC SAP is used to establish and release connection related to certain MBMS service and to exchange information related to these connection, which makes CN be able to provide information or distribute commands to a certain group of users. Each AN/CN connection point corresponds to several MC SAPs. At UE side, the number of MC SAPs is the same as that of DC SAPs. We consider the situation when there is one MC SAP.

Based on MC SAP, RANAP provides a new kind of messages for MBMS service, which aims to a group of users and are connection-oriented. This new kind of RANAP services are "MBMS control services".

a) MBMS RAB Establishment procedure

Figure 5 is a diagram showing the MBMS RAB Establishment procedure.

501 GGSN sends data to SGSN. 502 SGSN sends "MBMS Notification" to UTRAN to indicate the coming of MBMS service. The notification includes information such as Temporary Mobility Group Identity (hereinafter referred to as TMGI) of current service.

503 If UE is in IDLE state, establish RRC connection for UE.

504 if UE is willing to receive this MBMS service, UE sends "MBMS Service Request" to Radio Network Controller (hereinafter referred to as RNC).

505 RNC sends a "MBMS Service Request" message to SGSN and establish a shared lu connection for this MBMS service. In order to transfer MBMS data, it is necessary to establish MBMS RAB.

506 SGSN sends a "MBMS RAB Establishment Request" message to RNC via the lu connection shared by this MBMS service. MC is responsible for explanation and translation of this kind of messages (including "MBMS RAB Establishment Response", "MBMS RAB Release", etc) on lu interface. This kind of messages are connection-oriented and used for a service but not for a UE.

507 RNC sends "MBMS RB Request" to UE and UE AS notifies Non-Access Sub-layer to establish MBMS RB through MC SAP in the form of indication primitive. After that, UE NAS will notify AS to establish MBMS RB through MC SAP in the form of response primitive.

508 RNC sends "MBMS RAB Establishment Response" to SGSN. At this time, SGSN AS will notify NAS through MC SAP in the form of confirmation primitive that MBMS RAB has been established and data can be transferred.

509 SGSN starts to send downlink data.

510 After data transmission finishes, SGSN NAS will notify AS to release MBMS RAB through MC SAP in the form of request primitive.

511 SGSN sends "MBMS RAB Release Request" to RNC, and RNC sends a "MBMS RB Release Request" message to UE to request to release corresponding RAB and RB.

b) Inter-layer communication through MC SAP at IF side during MBMS RAB Establishment procedure

Following is the description for inter-layer communication through MC at IF side, taking MBMS RAB Request and MBMS RAB Response as examples, as shown in Figure 6.

601 MBMS RAB Establishment Request; When NAS of SGSN decides to establish MBMS RAB, it is necessary to request AS -to establish MBMS RAB, ~ which is MBMS RAB Establishment Request primitive. This primitive is sent to AS through MC SAP at SGSN side. After SGSN AS receives this primitive, a MBMS RAB Allocation Request message is sent to RNC to request to establish MBMS RAB.

604 MBMS RAB Establishment Confirmation; After AS has established MBMS RAB, it needs to report to NAS, notifying NAS that it can transfer MBMS data service, which is MBMS RAB Establishment Confirmation primitive. This primitive is reported to NAS via MC SAP at SGSN side.

In addition, if NAS at IF side decides to release MBMS RAB, it will send MBMS RAB Release Request primitive to AS. This primitive is sent to AS via MC SAP at IF side.

c) Inter-layer communication via MC at UE side during MBMS RB

Establishment procedure

Following takes the MBMS RB Establishment procedure as an example to describe inter-layer communication via MC at UE side, as shown in Figure 6.

602 MBMS RB Establishment Indication; After AS at UE side receives RB Establishment Request sent from AS at IF side, it needs to report to NAS to prepare for MBMS RB Establishment, which is MBMS RB Establishment Indication primitive. This primitive is reported to NAS via MC SAP at UE side.

603 MBMS RB Establishment Response; After NAS receives MBMS RB Establishment Indication primitive, if it decides to establish MBMS RB, it will notify AS to establish MBMS RB, which is MBMS RB Establishment Response primitive. This primitive is notified to AS via MC SAP at UE side. After AS receives this primitive, it configures corresponding resources and establish MBMS RB.

In addition, if AS at UE side is requested to release MBMS RB, it will send MBMS RB Release Indication primitive to NAS. This primitive is sent to NAS via MC SAP at UE side.

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 of the invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A service access method for MBMS service, comprising the steps of: a) Adding a MBMS Control SAP (SAP MC) between non-access sub-layer and access sub-layer at IF side, the MBMS Control SAP is used to establish and release connections related to certain MBMS service and to exchange information with these connections; and b) Realizing an inter-layer communication based on a certain MBMS service message at IF side through MC.

2. The method as claimed in claim 1, further comprising the steps of:

Adding a MBMS Control SAP (SAP MC) at UE side, which is used to establish and release connections related to certain MBMS service and to exchange information with these connections; and

Realizing an inter-layer communication based on a certain MBMS service message at UE side through MC.

3. The method as claimed in claim 1, wherein an non-access sub-layer at IF side sends MBMS RAB Establishment Request primitive to access sub-layer, if it decides to establish MBMS RAB, this primitive is sent to access sub-layer through MC SAP at IF side.

4. The method as claimed in claim 1, wherein an access sub-layer at IF side sends a MBMS RAB Establishment Confirmation primitive to the non-access sub-layer, if it has established MBMS RAB, this primitive is sent to non-access sub-layer via MC SAP at IF side.

5. The method as claimed in claim 1, wherein an non-access sub-layer at IF side sends a MBMS RAB Release Request primitive to the access sub-layer if it decides to release MBMS RAB, this primitive is sent to the access sub-layer through MC SAP at IF side.

6. The method as claimed in claim 2, wherein the access sub-layer at UE side sends a MBMS RB Establishment Indication primitive to the non-access sub-layer, if it is requested to establish MBMS RB, this primitive is sent to the non-access sub-layer through MC SAP at UE side.

7. The method as claimed in claim 2, wherein the non-access sub-layer sends a MBMS RB Establishment primitive to the access sub-layer, if it decides to establish MBMS RB, this primitive is sent to the access sub-layer through MC SAP at UE side.

8. The method as claimed in claim 2, wherein the access sub-layer at UE side sends a MBMS RB Release Indication primitive to the non-access sub-layer, if it is requested to release MBMS RB, this primitive is sent to the non-access sub-layer through MC SAP at UE side.

9. A service access method for MBMS service, comprising the steps of:

10. The method as claimed in claim 9, wherein an access sub-layer at UE side sends a MBMS RB Establishment Indication primitive to the non-access sub-layer, if it is requested to establish MBMS RB, this primitive is sent to the non-access sub-layer through MC SAP at UE side; the non-access sub-layer sends a MBMS RB Establishment primitive to the access sub-layer, if it decides to establish MBMS RB, this primitive is sent to the access sub-layer through MC SAP at UE side; an access sub-layer at UE side will send a MBMS RB Release Indication primitive to the non-access sub-layer, if it is requested to release MBMS RB, this primitive is sent to the non-access sub-layer through MC SAP at UE side.