KR100956183B1 - Method and Apparatus for Providing Broadcasting and Muticasting Service - Google Patents

Abstract

The present invention relates to a method and apparatus for providing a multicast broadcast service, the method comprising the steps of: setting a macro diversity group; And searching for each macro diversity group for MBS, transmitting MBS content when the terminal exists in the macro diversity group, and stopping transmission of MBS content when the terminal does not exist in the macro diversity group. It is characterized by including.

According to the present invention, it is possible to provide an efficient multicast broadcast service in a wireless communication system. In particular, in providing a multicast broadcast service, a macro diversity gain can be obtained while providing a dynamic multicast broadcast service that efficiently uses radio resources. Through this, it is possible to provide a dynamic multicast broadcasting service stably maintaining the quality of service according to the change of the wireless environment.

Description

 Method and apparatus for providing multicast broadcasting service {Method and Apparatus for Providing Broadcasting and Muticasting Service}

The present invention relates to a multicast broadcast service in a wireless communication system, and more particularly, to a method and apparatus for providing a dynamic multicast broadcast service in a wireless communication system.

 Wireless communication systems are developing into multimedia communication and multimedia broadcasting / communication capable of transmitting multimedia services. In order to support the multimedia broadcasting / communication, the base station multicasts and broadcasts the same data information to a plurality of mobile stations. As such, the multicast and broadcast service for data transmission in a wireless communication system is referred to as a multicast and broadcast service (MBS).

The MBS is a multimedia broadcast multicast service in the broadcast technology as a concept similar to the (MBMS), the content on the cellular network for transmitting the same information simultaneously to many users, defined by a ^{(3 rd Generation Parternership Project) 3GPP} . The MBS supports multimedia transmission forms such as real-time video, audio, still images, and text, and is a service that can simultaneously provide audio data and video data according to a multimedia transmission format.

1 schematically illustrates an MBS system structure in a broadband wireless access communication system as an example of a general wireless communication system. Referring to FIG. 1, one or two or more cells may be included in one logical group for MBS service area classification according to its local location. The logical group is called an MBS zone. The MBS zone is divided into an identifier for identifying the MBS zone. For example, the cells 101, 103, 105, 107, 109, and 111 of FIG. 1 constitute one MBS zone, and the MBS zone The identifier for identification has a '1', and the cells 131, 133, 135, 137, 139, 141, and 143 constitute another MBS zone and have an MBS zone identifier '2'.

The base stations included in each MBS zone multicast or broadcast the same broadcast to mobile stations using the same time and frequency band, and the mobile stations in each MBS zone receive the same broadcast.

Meanwhile, a server that manages the MBS zones, that is, an MBS server (not shown) exists in each MBS zone to manage a broadcast service list. For example, in order for the mobile station 170 to receive an arbitrary broadcast service, that is, a first broadcast service for the first time in the cell 109 having the MBS zone identifier 1, the base station 109 of the cell sets the MBS connection for the first broadcast service. Should be performed. When the MBS connection is completed for the first broadcast service and the mobile station moves to other base stations in the MBS zone, the MBS connection does not need to be re-configured for the first broadcast service that has completed the connection. . This is because broadcast services provided in the same MBS zone have the same connection identifiers (hereinafter, referred to as "CIDs") and the same frame structure in the same MBS zone.

On the other hand, the MSB using a point-to-multipoint connection has the following characteristics compared to unicast in which each session has a separate connection. The first is point-to-multipoint connection, and the second is sharing radio resources to transmit the same information to multiple users. Third, macro diversity using multiple base stations is possible. Finally, there is no feedback information.

Among the above characteristics, the first, second and third characteristics are the advantages of MBS, while the last one is the disadvantage of MBS. If the wireless environment changes too quickly and is difficult to predict, the last drawback can greatly reduce overall MBS performance.

To improve this, you can support macro diversity. Macro diversity can be supported in the case of Multi-BS MBS among multicast and broadcast services (MBS).

MBS can be classified into two categories depending on whether the transmission of multicast traffic is determined dynamically or statically. The first category is Static MBS, which always transmits content over a multicast channel by the access network without considering whether there is a terminal receiving content at the base station. The second category is Dynamic MBS, which allows users to dynamically join a multicast session and leave the session. MBSC and ASN-GW (Access Service Network-GateWay) monitor whether there is a terminal receiving content and decides to transmit MBS content.

The terminal receives the synchronized MBS content from all base stations in the MBS zone, resulting in a macro diversity gain. Static MBS that supports macro diversity may be overused even if MBS content arrives farther than unicast traffic due to macro diversity gain. This is because all base stations in the MBS zone must transmit the same data at the same time regardless of the existence of the terminal receiving the MBS content.

On the other hand, dynamic MBS has the advantage of preventing the waste of radio resources of the base station by transmitting the MBS content only when there is a terminal receiving the MBS content. If the neighbor base station does not transmit the MBS content, the terminal receiving the MBS content has a disadvantage in that it can no longer obtain the macro diversity gain. This may cause fluctuations in signal quality, making it difficult to provide stable services.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the present invention provides a method and apparatus for providing a dynamic multicast broadcast service for efficiently performing a multicast broadcast service in a wireless communication system. It is.

In order to solve the above technical problem, a method of providing a broadcast service to a plurality of terminals in a wireless communication system according to the present invention, in the method for providing a multicast broadcast service in a wireless communication system, setting a macro diversity group step; And searching for the macro diversity group unit for MBS, transmitting MBS content when the terminal exists in the macro diversity group, and stopping transmission of MBS content when the terminal does not exist in the macro diversity group. Characterized by including. The macro diversity group preferably includes at least one base station and all base stations within the maximum MBS zone. In addition, the macro diversity group may be set in the MBS proxy in the ASN-GW.

In order to solve the above technical problem, a method of providing a broadcast service to a plurality of terminals in a wireless communication system according to the present invention, MBS data in a macro diversity group set in a wireless communication network supporting MBS using a plurality of base stations Determining whether there is a terminal receiving the data; And controlling the base station or sector corresponding to the macro diversity group to transmit MBS data according to the determination result. Preferably, the macro diversity group is composed of at least one of base stations and sectors of the base station. The base station or the sectors are preferably located at a distance that interferes with each other within a predetermined range. Preferably, the set number of macro diversity groups is larger than at least one and the size of the MBS zone is smaller.

In order to solve the above technical problem, the apparatus for providing a broadcast service to a plurality of terminals in a wireless communication system according to the present invention, in the apparatus for providing a multicast broadcast service in a wireless communication system, to set a macro diversity group A macro diversity group setting unit; A terminal searching unit searching for whether a terminal exists in units of the macro diversity group configured for MBS; And a MBS controller for transmitting MBS contents when the terminal exists in the macro diversity group, and stopping transmission of MBS contents when the terminal does not exist in the macro diversity group. . The macro diversity group is characterized by including a number from at least two base stations to less than all base stations in the maximum total MBS zone. The multicast broadcast service providing apparatus is preferably ASN-GW.

According to the present invention, it is possible to provide an efficient multicast broadcast service in a wireless communication system, and in particular, in providing a multicast broadcast service, while providing a dynamic multicast broadcast service that efficiently uses radio resources, the macro diversity gain can be improved. Through this, it is possible to provide a dynamic multicast broadcasting service stably maintaining the quality of service according to the change of wireless environment.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments. For reference, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted in the following description.

In Multi-BS MBS supporting macro diversity, synchronization between all base stations in the MBS zone is required in order to obtain macro diversity gain. Accordingly, the MBS scheduling of the present invention is preferably performed in an MBS controller (MBSC) or an access service network-gateway (ASN-GW).

Also in Dynamic MBS, user terminals dynamically join multicast sessions and leave the sessions. Accordingly, the MBSC and / or ASN-GW of the present invention monitors whether there is a terminal receiving content and decides to transmit MBS content.

2 is a diagram illustrating a network of a multicast broadcast service supporting dynamic MBS to which the present invention is applied. The base stations in the macro diversity group simultaneously transmit the same data to the terminals. The terminal obtains a macro diversity gain by receiving synchronized MBS content from base stations in the macro diversity group.

3 is a block diagram illustrating a configuration of a broadcast service providing apparatus to a plurality of terminals according to the present invention. In the broadband wireless access communication system, a device for providing a broadcast service to a plurality of terminals is set to a macro diversity group. The unit 310 includes a terminal search unit 320 and an MBS control unit 330.

The macro diversity group setting unit 310 sets a macro diversity group, and preferably sets the macro diversity group to a size of at least a base station unit and an MBS zone unit or less. The macro diversity group may include at least one of base stations and sectors of the base station. The base stations or sectors are located where they interfere with each other within a predetermined range. The predetermined range acts as an interference when crossing the CP (Cyclic Prefix) duration, 'the distance that a signal transmitted from another base station can enter within the CP duration'. Based on 12.8 us, it is preferable that the distance difference between each base station is about 4 km or less. In addition, the size of the macro diversity group may include the number of all base stations in at least one base station to the maximum total MBS zone, but preferably, the size of the macro diversity group is smaller than the number of all base stations in the entire MBS zone. .

The terminal search unit 320 searches whether the terminal exists in units of the macro diversity group configured for MBS.

The MBS controller 330 transmits MBS contents when the terminal exists in the macro diversity group, and stops transmitting MBS contents when the terminal does not exist in the macro diversity group. .

The apparatus for providing broadcast service to the plurality of terminals may be implemented as a proxy module in the ASN-GW.

 The MBS proxy module manages a cluster of base stations as a macro diversity group so as to not only reduce radio resource waste but also obtain macro diversity gain.

4 illustrates an example of a macro diversity group according to the present invention. In FIG. 4, gamma of BS1, alpha of BS2, and beta of BS3 belong to the same macro diversity group. Therefore, if there is no terminal in the gamma sector of BS1, but there is a terminal in the alpha sector of BS2 or the beta sector of BS3 that is receiving the multicast content, BS1 will transmit MBS content to support macro diversity. The macro diversity gain can reduce waste of radio resources if the macro diversity group (or subgroup) concept according to the present invention is applied.

FIG. 5 is a flowchart illustrating a method for providing a broadcast service to a plurality of terminals according to the present invention, and the present invention will be described with reference to FIG. 5.

First, in order to provide a broadcast service to a plurality of terminals in a broadband wireless access communication system, a macro diversity group is set (step S510). The macro diversity group is at least a base station unit and a MBS zone unit or less. Can be the size of When an MBS request is received (step S520), the UE searches for the macro diversity group and searches whether a terminal exists in the macro diversity group. (Step S530) MBS contents when the terminal exists in the macro diversity group. In step S540, if the terminal does not exist in the macro diversity group, MBS content transmission is stopped.

Figure 6 shows the internal procedure of ASN-GW for MBS and messages from or to ASN-GW. The process of FIG. 6 is briefly described as follows.

The macro diversity group is set up (step S600). The group setting may first configure the macro diversity group, and the configuration may be updated later. Then, as a first step for the terminal that wants the MBS service, it requests a subscription to the network that provides the MBS service. (Step S605) If the subscription is successful, the terminal receives the MBS group to receive the MBS traffic. Will join. The server providing the MBS service makes an MBS service announcement to the terminal (step S610). This is some service information downloaded to the terminal for the MBS service. When the service announcement is performed, dynamic service addition is performed as necessary (step S615). To start the MBS service, the terminal or the base station starts the dynamic service addition process for the multicast or broadcast connection. will be.

After the dynamic service is added, the number of terminals in the macro diversity group (MS Num) is increased (step S620), and if it is the first terminal in the macro diversity group (step S625), the MBS router or MBS Controller (MBSC) is transmitted. Request the MBS service (join request) (step S630), and start the session (step S635). If the terminal is the first terminal in the macro diversity group to start receiving MBS content, the join request is sent to the Multicast Router or MBSC. Must be communicated. If it is not the first terminal, or if the session is started, and if not the first terminal, the MBS content is delivered through the connected session (step S640). For the terminals having the multicast CID for the MBS service, the MBS content is broadcast Will be.

If the terminal stops receiving the service or no longer has MBS data to be transmitted, the dynamic service is deleted (step S645). That is, to terminate the MBS service, the terminal or the base station dynamically deletes the multicast or broadcast connection. The process of deleting the service will begin. When the dynamic service is deleted, the number of MSs in the macro diversity group is reduced (step S650). The terminal is the last terminal in the macro diversity group that has received MBS content (step S655), and the MBS service ends. If desired, a 'Leave' request is sent to a multicast router or MBSC (step S660), and a Leave is performed for the terminal (step S665).

In the above, the present invention is characterized by the MBS determination in the MBS proxy in the ASN-GW. However, in the MBS procedure according to the present invention, the MBS proxy checks whether the terminal is the first or last terminal in the macro diversity group.

The MBS proxy module in the ASN-GW manages macro diversity groups. If there is at least one terminal in the macro diversity group receiving the MBS content, transmission of the MBS content is continued. The present invention not only supports macro diversity by managing macro diversity groups, but also reduces radio resource abuse occurring in a dynamic MBS model.

As a result, the present invention provides a macro diversity group (minimum 1) in the middle of a base station unit or MBS zone unit in a hierarchy to obtain macro diversity gain and at the same time efficiently and stably use resources. MBS content may be transmitted if there is a terminal in this unit, and stops if there is no terminal. The macro diversity group may be determined from a network engineering point of view and set to the MBS proxy through EMS.

On the other hand, the present invention described above can also be embodied as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, hard disks, optical data storage devices, and also in the form of carrier waves (e.g., transmission over the Internet). It includes what is implemented. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. And functional programs, codes and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art to which the present invention pertains can implement the present invention in other specific forms without changing the technical spirit or essential features, The examples are to be understood in all respects as illustrative and not restrictive.

In addition, the scope of the present invention is specified by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. Should be interpreted as

1 schematically illustrates the MBS system structure in a general broadband wireless communication system.

2 is a diagram illustrating a network of a multicast broadcast service supporting dynamic MBS to which the present invention is applied.

3 is a block diagram illustrating a configuration of an apparatus for providing a multicast broadcast service according to the present invention.

4 illustrates an example of a macro diversity group according to the present invention.

5 is a flowchart illustrating a broadcast service providing method to a plurality of terminals according to the present invention.

Figure 6 shows the internal procedure of ASN-GW for MBS and messages from or to ASN-GW.

Claims (11)

In the method for providing a multicast broadcast service in a wireless communication system, Establishing a macro diversity group; And When the terminal is searched for in the macro diversity group for a multicast and broadcast service (MBS), the terminal transmits MBS contents when the terminal exists in the macro diversity group, and the terminal does not exist in the macro diversity group. Stopping the transmission of MBS content, And wherein the macro diversity group comprises at least two base stations and all base stations within a maximum MBS zone. delete The method of claim 1, wherein the macro diversity group Method for providing a multicast broadcast service, characterized in that the MBS proxy set in the Access Service Network-GateWay (ASN-GW). Determining whether a terminal for receiving MBS data exists in a macro diversity group established in a wireless communication network supporting MBS using a plurality of base stations; And And controlling the base station or sector corresponding to the macro diversity group to transmit MBS data according to the determination result. And wherein the macro diversity group comprises at least one of a base station and sectors of the base station. delete The method of claim 4, wherein the base stations or the sectors Method for providing a multicast broadcast service, characterized in that located in a place where mutual interference within a predetermined range. The method of claim 6, wherein the predetermined range is A method for providing a multicast broadcast service, characterized in that a signal transmitted from another base station is a distance located within a cyclic prefix period. The method of claim 4, wherein the set number of macro diversity groups is A method for providing a multicast broadcast service, characterized in that the setting is larger than at least one and smaller than the size of the MBS zone. An apparatus for providing a multicast broadcast service in a wireless communication system, A macro diversity group setting unit for setting a macro diversity group; A terminal searching unit searching for whether a terminal exists in units of the macro diversity group configured for MBS; And And a MBS controller for transmitting MBS contents when the terminal exists in the macro diversity group, and stopping transmission of MBS contents when the terminal does not exist in the macro diversity group. And the macro diversity group comprises at least two base stations and all base stations within a maximum MBS zone. delete The apparatus of claim 9, wherein the multicast broadcast service providing apparatus is A multicast broadcast service providing apparatus, characterized in that the ASN-GW.

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