KR101084132B1 - Method of providing and receiving multicast service in broadband wireless access system - Google Patents

Abstract

The present invention relates to a method for providing and receiving a multicast service that can reduce data loss by shortening a service connection time during handover in a broadband wireless access system. In the multicast service providing method according to the present invention, in a multicast service providing method in a broadband wireless access system, a multicast identified by a specific connection identifier (CID) from a serving base station to a user equipment Providing a multicast service; And after the terminal performs a handover from the serving base station to the target base station, the target base station providing the multicast service identified by the same connection identifier as the connection identifier to the terminal. do.

Multimedia service, MBS, Connection identifier, Broadband, Wireless access

Description

Method of providing and receiving multicast service when performing handover in broadband wireless access system

1 illustrates a protocol hierarchy of a broadband wireless access system.

2 illustrates an example of a system configuration for providing a multicast service in a broadband wireless access system.

3 is a view for explaining a multicast service providing method according to the prior art.

4 is a flowchart illustrating a procedure before and after performing a handover in the prior art.

5 is a flowchart illustrating a procedure of resetting the service procedure.

6 is a view for explaining the basic concept of the present invention.

7 is a process flow diagram in accordance with one preferred embodiment of the present invention.

The present invention relates to a broadband wireless access system. More specifically, the present invention relates to a method of providing and receiving a multicast service that can reduce data loss by shortening a service connection time during handover in a broadband wireless access system.

The Broadband Wireless Access System (MAC) defines a protocol of a Media Access Control (MAC) layer and a Physical (PHY) layer for point-to-multipoint connection between a base station and a terminal. 1 illustrates a protocol hierarchy of a broadband wireless access system.

The physical layer of the broadband wireless access system is largely divided into a single carrier (Single Carrier) and a multi-carrier (OFDM / OFDMA). The multi-carrier method employs OFDM and introduces Orthogonal Frequency Division Multiple Access (OFDMA) as an access method for allocating resources in subchannel units in which a part of carriers is grouped.

In the OFDMA physical layer, active carriers are divided into groups and transmitted to different receivers for each group. The group of carriers transmitted to the receiver is called a sub-channel. Carriers constituting each subchannel may be adjacent to each other or spaced at equal intervals. In this way, by allowing multiple access in subchannel units, implementation complexity increases, but there is an advantage in that frequency diversity gain, power concentration gain, and forward power control can be efficiently performed.

The slot assigned to each user is defined by a data region of two-dimensional space, which is a set of consecutive subchannels allocated by bursts. In OFDMA, one data area is shown as a rectangular shape determined by time coordinates and subchannel coordinates. Such a data area may be allocated to an uplink of a specific user or a base station may transmit the data area to a specific user in downlink. To define such a data region in two-dimensional space, the number of OFDM symbols in the time domain and the number of consecutive subchannels starting at a position separated by an offset from a reference point in the frequency domain should be given.

Hereinafter, a multicast service provided in a broadband wireless access system will be described.

Multicast service is a point-to-multipoint service that transmits data from one source to multiple receivers. It transmits the same data to multiple receivers through a common radio channel for efficient use of radio resources. . In the present specification, a multicast service may be used as a term for a multicast broadcast service (MBS).

2 illustrates an example of a system configuration for providing a multicast service in a broadband wireless access system. As shown in FIG. 2, a component for a multicast service includes an MBS content server, a MBS distribution server, a base station (BS), and a terminal (MSS). The MBS content server provides the MBS data to the base stations and performs authentication and distribution of the encryption key of the terminal for the MBS content. The MBS distribution server is responsible for scheduling MBS data delivered to a plurality of base stations. Optionally, the MBS distribution server can be omitted and the MBS content server can play a role of scheduling MBS data. The base station provides the MBS data received through the backbone network to the terminal through the air interface, the terminal receives the MBS data from the base station.

In the multicast service providing method according to the prior art, the base station prepares the multicast service by a new connection with each terminal receiving the multicast service. The base station assigns a connection identifier (CID: Connection ID) to the MAC frame header to provide the multicast service to each terminal, the CID is not fixed for each multicast service, each base station uses a random traffic CID Doing. 3 is a view for explaining a multicast service providing method according to the prior art. In FIG. 3, as described above, a connection identifier for providing a multicast service is used differently for each base station. Therefore, when the terminal performs a handover (when the terminal moves from BS1 to BS4 in FIG. 3), the terminal moving to the target base station BS4 must perform registration and service procedures with the target base station.

4 is a flowchart illustrating a procedure before and after performing a handover in the prior art. 4 is largely composed of a process before handover [S100], a scanning process [S200], and a process after handover [S300]. The process before performing the handover [S100] is a process in which the UE establishes a connection with the serving base station and receives a multicast service. The scanning process [S200] refers to a process of measuring a signal quality by receiving a signal from neighbor base stations (Neighbor Base-Stations) in order to find an optimal handover target base station before the terminal performs a handover. After performing the handover [S300], the terminal establishes a connection with the target base station after performing the handover.

As described above, in order to continuously receive the multicast service provided by the serving base station from the target base station after performing the handover by the terminal, the registration process and service flows resetting to the target base station (re) -establishment) process must be performed [S301]. 5 is a flowchart illustrating the service procedure resetting process.

In FIG. 5, the terminal transmits a service generation request (DSA-REQ) message including a multicast IP address and a port number of the multicast service to the target base station [S51]. (The service request message may be transmitted by the base station to the terminal.)

The target base station transmits a DSX-RVD message indicating the reception of the service request message to the terminal [S52], and performs an authentication procedure for determining whether the terminal is a user suitable for receiving the multicast service.

After performing the authentication procedure, the target base station transmits downlink service parameter information (eg, a service identifier, a multicast connection identifier (CID), a quality of service (QoS) parameter, and a security negotiation identifier) to the terminal. Identifier (SAID), etc.) is included in the service generation response message (DSA-RSP) and transmitted [S53]. The target base station transmits a confirmation message (DSA-ACK) for the service generation response message (DSA-RSP) to the terminal [S54].

As another method of the service procedure resetting process, after a target base station receives service quality parameter information including a connection identifier associated with a multicast service of a terminal performing a handover from a serving base station, the terminal registers with the target base station. When performing the operation, the target base station can deliver the changed service quality parameter including the new multicast connection ID to the terminal without receiving the service generation request message or the service change request message from the terminal.

In the prior art, since an arbitrary connection identifier (CID) is used for each base station for one same multicast service, the terminal receives the same multicast service as the multicast service received from the same serving base station after performing the handover. For this reason, packet loss occurs because the handover time is increased by performing a procedure of receiving a new CID from the target base station.

The present invention has been made to solve the problems of the prior art as described above, and an object of the present invention is to provide a service connection when a terminal performs handover while receiving a specific multicast service from a serving base station in a broadband wireless access system. It is to provide a multicast service providing and receiving method that can reduce the time.

As an aspect of the present invention for solving the above technical problem, the multicast service providing method according to the present invention, in a multicast service providing method in a broadband wireless access system, in a serving base station (seving base station) Providing a multicast service identified by a specific connection identifier (CID) to the terminal; And after the terminal performs a handover from the serving base station to the target base station, the target base station providing the multicast service identified by the same connection identifier as the connection identifier to the terminal. do.

In another aspect of the present invention, a method for providing a multicast service according to the present invention, in a broadband wireless access system, all base stations in a specific region use the same quality of service parameter including the same connection ID (CID). It provides a multicast service.

In still another aspect of the present invention, the method for receiving a multicast service according to the present invention is a method for receiving a multicast service of a terminal in a broadband wireless access system, which is identified by a specific connection identifier (CID: Connection ID) from a serving base station. Receiving a multicast service; Performing a handover to a target base station; And receiving the multicast service identified by the same connection identifier as the connection identifier from the target base station.

The construction, operation, and other features of the present invention will be readily understood by the preferred embodiments of the present invention described below with reference to the accompanying drawings. 6 is a view for explaining the basic concept of the present invention, Figure 7 is a flow chart according to a preferred embodiment of the present invention.

6 shows that all base stations BS1, BS2, BS3, BS4 in a given area provide a specific multicast service using the same connection identifier CID1. Therefore, when the terminal receiving the multicast service from BS1 performs the handover and receives the multicast service from BS4, there is no need to perform a separate process such as resetting the service flows.

A more detailed description with reference to FIG. 7 is as follows. Before the handover is performed, the process of establishing a connection with the serving base station to receive a specific multicast service and the scanning process for handover are the same as the prior art illustrated in FIG. However, a process performed between the terminal and the target base station to receive the multicast service after the handover is simplified.

That is, in FIG. 4, the service procedure reset process may be omitted in the registration process and the service flow reset process [S301] at the target base station [S301 ']. In the related art, since a different connection identifier (CID) is used for each base station, the target base station is connected to the multicast service in order for the terminal to continuously receive the multicast service provided from the serving base station by performing a handover. Since it was necessary to confirm the connection identifier assigned to the service, a service procedure reset process as shown in FIG. 5 had to be performed. However, in the present invention, since all the base stations in a certain area provide a specific multicast service by the same connection identifier, even if a handover is performed, the procedure of reconfiguring the service procedure by checking the connection identifier of the target base station for the multicast service is performed. There is no need to perform the process.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

According to the method for providing and receiving a multicast service when performing handover in a broadband wireless access system, service connection time during handover can be shortened, thereby reducing data loss.

Claims (5)

A method of providing a multicast service in a broadband wireless access system, Performing, by the second base station, handover from the terminal and the first base station to the second base station; And The second base station provides a multicast service to the terminal, but uses the same connection identifier as the connection ID (CID) used by the first base station to identify the multicast service. Providing a cast service,  And all base stations in a specific area where the multicast service is provided use the same connection identifier as the specific connection identifier to identify the multicast service. delete In a broadband wireless access system, All base stations in a specific region where a specific multicast service is provided provide the specific multicast service to a terminal in the specific region by using the same quality of service parameter including the same connection identifier (CID). How to provide multicast service. A method for receiving a multicast service of a terminal in a broadband wireless access system, Receiving a multicast service identified by a specific connection identifier (CID) from a first base station; Performing a handover from the first base station to a second base station; And Receiving the multicast service identified by the same connection identifier as the connection identifier from the second base station, And all base stations in a specific area where the multicast service is provided use the same connection identifier as the specific connection identifier to identify the multicast service. delete

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