KR100762282B1 - Method and apparatus for providing multicast service - Google Patents

Abstract

A method and an apparatus for providing a multicast service are provided to supply multi users with the multicast service of high speed and high quality through efficient synchronization of data packets. A method for providing a multicast service comprises: setting a multicast service zone including one or more RASs(Radio Access Stations) for providing the multicast service(S101); enabling the RAS to set a service start time corresponding to start time information by transmitting the start time information of the multicast service to the RAS(S117); and transmitting packets including offset information for synchronization and multicast data provided by the multicast service to an RAS corresponding to the multicast service zone(S131).

Description

METHOD AND APPARATUS FOR PROVIDING MULTICAST SERVICE}

1 is a view showing a schematic structure of a broadband wireless access network providing a multicast service according to an embodiment of the present invention.

2 is a diagram illustrating a configuration of a multicast / broadcast service server according to an embodiment of the present invention.

3 is a diagram illustrating a RAS according to an embodiment of the present invention.

4 is a flowchart illustrating a multicast service providing method through a broadband wireless access network according to an embodiment of the present invention.

5 is a block diagram illustrating a frame structure of channel allocation information according to an embodiment of the present invention.

6 is a block diagram illustrating a data frame structure according to an embodiment of the present invention.

7 is a block diagram illustrating a frame structure of control information according to an embodiment of the present invention.

8 is a block diagram illustrating a frame structure of a multicast data packet according to an embodiment of the present invention.

The present invention relates to a method and apparatus for providing a multicast service. In particular, the present invention relates to a method and apparatus for providing a multicast service through efficient data packet synchronization in a broadband wireless access network to which a plurality of base stations are connected.

Multicast service is a point-to-multipoint service that transmits data from one source to multiple receivers. The multicast service uses unidirectional characteristics by using common resources for efficient use of wireless and wired resources. Have

In particular, in a broadband wireless access network, in order to use common resources, an identifier of a packet transmitted in a radio section is defined as a multicast connection identifier (hereinafter, referred to as 'mCID'), and a mobile terminal receiving a multicast service Multiple mobile terminals receive multicast data packets by sharing this service identifier.

There are two types of multicast services. One is a single base station access method that provides a multicast service only in a single base station, and a multiple base station access method that provides a multicast service to a plurality of base stations.

Meanwhile, according to the related art, in the multiple base station access method, each base station transmits a multicast data packet to the mobile terminal through a different service identifier. Therefore, when a mobile station moves to a cell of a neighbor base station, handover is performed to receive a new service identifier. As such, when a multicast service is provided, a transmission method of a multicast data packet is delayed and a packet is lost during transmission because a synchronization method between base stations is not defined.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method capable of providing a high speed, high quality multicast service to a plurality of users by efficient data packet synchronization, and an apparatus for providing such a service.

The multicast service providing method according to an embodiment of the present invention is a method in which a server provides a multicast service to a base station. The server establishes a multicast service area that includes one or more base stations to provide multicast services. The server transmits start time information of a multicast service to the base station so that the base station sets a service start time corresponding to the start time information. Subsequently, the server transmits a packet including offset information for synchronization to the base station corresponding to the multicast service area and multicast data provided by the multicast service.

In this case, the server may transmit radio resource information for the multicast service to the base station so that the base station allocates a radio channel corresponding to the radio resource information to the multicast service.

In this case, the radio resource information transmitted by the server is composed of a plurality of symbols on the time axis and a plurality of subchannels on the frequency axis, and a symbol offset that designates a starting point on the time axis of the packet in a data frame including the packet. A subchannel offset specifying a start point on a frequency axis of the packet in the data frame, a number of symbols specifying a range of the symbol in the data frame, and a number of subchannels specifying a range of the subchannel in the data frame. It may include.

Meanwhile, the offset information transmitted by the server provides a start offset for controlling the start of the multicast data by providing a start position of the multicast data, and a length of the multicast data to control the end of the multicast data. It may include an end offset to.

Meanwhile, the server may end the transmission of the multicast data to the base station corresponding to the multicast service area, terminate the multicast service by canceling the setting of the multicast service area.

The multicast service providing method according to an embodiment of the present invention is a method in which a base station provides a multicast service in association with a server. The base station receives radio resource information for the multicast service from the server and allocates a radio channel corresponding to the radio resource information to the multicast service. The multicast service start time information is received from the server to set a start time of the multicast service. Subsequently, the base station receives offset information and multicast data from the server, and determines the transmission time of the multicast data based on the start time of the multicast service and the offset information. The base station then transmits the multicast data on the radio channel at the transmission time.

In this case, the step of determining the transmission time by the base station may be determined by summing the start time and the offset information of the multicast service.

In this case, the radio resource information received by the base station is composed of a plurality of symbols on the time axis and a plurality of subchannels on the frequency axis, and a symbol offset that designates a starting point on the time axis of the packet in a data frame including the packet. A subchannel offset specifying a start point on a frequency axis of the packet in the data frame, a number of symbols specifying a range of the symbol in the data frame, and a number of subchannels specifying a range of the subchannel in the data frame. It may include.

Meanwhile, the offset information received by the base station provides a first time offset for controlling the start of the multicast data by providing a start time of the multicast data, and a transmission time of the multicast data to provide a start time of the multicast data. And a second time offset to control termination.

A server according to an embodiment of the present invention provides a multicast service to a base station, and includes a configuration information manager, a service manager, and a data controller. The configuration information management unit sets a multicast service area for providing the multicast service, and transmits radio resource information for the multicast service to the base station so that the base station multicasts a radio channel corresponding to the radio resource information. Assign it to a service. The service manager transmits start time information of the multicast service to the base station so that the base station sets a service start time corresponding to the start time information. The data controller transmits a packet including offset information for synchronization and multicast data provided by the multicast service to a base station corresponding to the multicast service area.

A base station according to an embodiment of the present invention is an apparatus for providing a multicast service in cooperation with a server, and includes a channel controller, a service controller, and a data transmitter. The channel controller receives radio resource information for the multicast service from the server and allocates a radio channel corresponding to the radio resource information to the multicast service. The service controller receives service start time information from the server and sets a start time of the multicast service. The data transmission unit receives offset information and multicast data from the server, sets a transmission time of multicast data based on the offset information and the service start time, and transmits the multicast data to the wireless channel at the transmission time. Send it through.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

An apparatus and method for providing a multicast service according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

1 is a view showing a schematic structure of a broadband wireless access network providing a multicast service according to an embodiment of the present invention.

As shown in FIG. 1, a broadband wireless access network according to an exemplary embodiment of the present invention includes a multicast broadcast service (hereinafter referred to as an MBS) server 100, an IP network 10, and an HA (Home). An agent (20), an AAA (Authentication, Authorization, Accounting) server 30, an access control router (ACR) 40, a radio access station (RAS) 200, and a data storage server 50, It communicates with a mobile subscriber station (hereinafter referred to as a 'PSS') 60 through a wireless channel.

The MBS server 100 is connected to the data storage server 50 and provides a multicast service to the RAS 200 through the IP network 10 and the ACR 40. At this time, the MBS server 100 sets up a multicast / broadcast service zone (hereinafter, referred to as an 'MBS Zone') 300 including a plurality of RASs 200.

The ACR 40 is connected to the IP network 10 to perform routing and manage the RAS 200. The RAS 200 has a unique wireless communication area called a cell so that the PSS 60 can access and receive a wireless data service. In this case, the RAS 200 may be represented by a base station, an access point (AP), or the like.

The data storage server 50 provides the multimedia data provided through the multicast service to the MBS server 100. The multimedia data provided by the data storage server 50 may include text, voice, image, video, or a combination thereof. In this case, the multimedia data may be provided in the form of a multicast IP packet including information of the PSS 60 receiving the data.

Since the IP network 10, the HA 20, and the AAA server 30 are components generally included in a broadband wireless access network, detailed descriptions thereof will be omitted.

The PSS 60 is a communication device capable of connecting to a broadband wireless access network through a wireless channel. For example, all communication devices such as mobile terminals, wireless telephones, Internet phones, computers, and the like may be included.

2 is a diagram illustrating a configuration of the MBS server 100 according to an embodiment of the present invention.

As shown in FIG. 2, the MBS server 100 according to an embodiment of the present invention includes a configuration information manager 120, a service manager 140, and a data controller 160.

The configuration information management unit 120 sets up an MBS Zone 300 to provide a multicast service, and configures RAS through the ACR 40 with configuration information for allocating a wireless communication channel between the RAS 200 and the PSS 60. 200). The service manager 140 transmits a control signal for controlling the start and end of the multicast service to the RAS 200 through the ACR 40. The data controller 160 generates a multicast data packet including the multicast IP packet and transmits the multicast data packet to the RAS 200 through the ACR 40.

3 is a diagram illustrating a RAS 200 according to an embodiment of the present invention.

As shown in FIG. 3, the RAS 200 according to an embodiment of the present invention includes a channel controller 220, a service controller 240, and a data transmitter 260.

The channel controller 220 receives and stores the configuration information transmitted from the configuration information management unit 120 of the MBS server 100 from the ACR 40, and then establishes a wireless communication channel with the PSS 60 in response to the stored configuration information. Assign and manage The service controller 240 receives a control signal transmitted from the service manager 140 of the MBS server 100 from the ACR 40 and controls the start and end of the service in response to the received control signal. The data transmission unit 260 receives a multicast data packet transmitted by the data control unit 160 of the MBS server 100 from the ACR 40, and transmits a multicast IP packet among the multicast data packets to the mobile terminal 60. send.

Next, a multicast service providing method in a broadband wireless access system according to an embodiment of the present invention will be described with reference to FIGS. 4 to 8 based on such a structure.

4 is a flowchart illustrating a multicast service providing method through a broadband wireless access network according to an embodiment of the present invention.

Referring to FIG. 4, a method for providing a multicast service is described first. When the MBS server 100 tries to provide a multicast service to a mobile terminal 60 located in a cell of a plurality of RASs 200, the MBS server ( 100 sets an MBS Zone 300 including at least one RAS 200 to provide a multicast service (S101).

Thereafter, the configuration information manager 120 of the MBS server 100 transmits configuration information including the channel allocation information P200 to the ACR 40 (S103), and the ACR 40 sends the received Chinese New Year information back to the MBS Zone. It transmits to the channel control unit 220 of the RAS 200 belonging to (S105).

Referring to FIG. 5, the channel allocation information will be described in detail. The channel allocation information includes a multicast service zone identifier (hereinafter, referred to as a multicast service zone identifier) for identifying the MBS Zone 300 when the RAS 200 and the mobile terminal 60 communicate in an OFDMA manner. P100, OFDMA symbol offset P120, OFDMA symbol number P140, subchannel offset P160, subchannel number P180, and the like. In this case, the channel allocation information may further include a frame interval P190 for setting an interval of a data frame when the multicast IP packet is divided and transmitted.

FIG. 6 is a diagram illustrating a data frame structure configured based on channel allocation information described with reference to FIG. 5.

Referring to FIG. 6, the data frame structure is described in detail. The data frame P200 is a structure in which a symbol having a certain period on a time axis and a subchannel divided at regular intervals on a frequency axis intersect each other. It includes a multicast IP packet (P700). At this time, the OFDMA symbol offset P120 designates the starting point on the time axis of the radio channel allocated for the multicast service, and the subchannel offset P160 is the start on the frequency axis of the radio channel allocated for the multicast service. Specify a point. The number of OFDMA symbols (P140) and the number of subchannels (P180) is determined on the time axis and based on the starting point of the radio channel allocated for the multicast service designated through OFDMA symbol offset (P120) and subchannel offset (P160). By specifying the range on the frequency axis, the size of the radio channel allocated for the multicast service is determined.

4 will be described again. Next, the channel controller 220 of the RAS 200 stores the received configuration information and allocates a wireless channel for the multicast service according to the channel allocation information P200 included in the configuration information as shown in FIG. 5 (S107). .

Thereafter, the channel controller 220 of the RAS 200 transmits a configuration information reception response indicating that the configuration information has been received to the ACR 40 (S109), and the ACR 40 again manages the configuration information management unit of the MBS server 100. In step S111, the configuration information reception response is transmitted. Through this, the MBS server 100 can confirm that the configuration information transmitted by the RAS 200 has been received.

Next, the service manager 140 of the MBS server 100 transmits service start information for setting the start of the multicast service to the ACR 40 (S113), and the ACR 40 sends the received service start information back to the MBS Zone. It transmits to the service control unit 240 of the RAS 200 belonging to (S115).

The service start information will be described in detail with reference to FIG. 7. The service start information includes a zone ID P100 and a control time P300 for controlling a start time of a multicast service. At this time, when there are a plurality of MBS Zone 300 may further include a multicast connection identifier (hereinafter referred to as 'mCID') (P400) for identifying the multicast service to be provided to each MBS Zone (300).

4 will be described again. At this time, the service control unit 240 of the RAS 200 sets the start time of each multicast service to the start time included in the service start information according to the service start information (S117).

Thereafter, the service control unit 240 of the RAS 200 transmits a service start information reception response indicating that the service start information has been received to the ACR 40 (S119), and the ACR 40 again services the MBS server 100. In step S121, the service reception information reception response is transmitted to the management unit 140. Through this, the MBS server 100 can confirm that the service start information transmitted by the RAS 200 has been received.

Next, the data controller 160 of the MBS server 100 requests the data storage server 50 for the multicast IP packet including the multimedia data included in the multicast data packet (S123). That is, the data storage server 50 transmits the multicast IP packet to the data controller 160 according to the request of the data controller 160 (S125).

Thereafter, the data controller 160 of the MBS server 100 generates a multicast data packet including the multicast IP packet and synchronization information received from the data storage server 50 (S127).

Referring to FIG. 8, the multicast data packet will be described in detail. The multicast data packet includes PSS (synchronization information P500) for synchronizing the RAS 200 included in the MBS Zone 300, and a multicast service. 60) to the multicast IP packet (P700) provided. Again, the synchronization information P500 includes the Zone ID P100, the frame offset P520 indicating the start position of the multicast data frame, the frame length P540 indicating the length of the multicast IP packet, and the transmission time of the multicast data. And a time offset P560 indicating the like.

In this case, when a multicast data packet is provided with mCID (P400) and a plurality of multicast IP packets in one MBS Zone 300, a data identifier for identifying each multicast IP packet (hereinafter referred to as a 'Data ID'). It may further include (P600).

4 will be described again. Next, the data control unit 160 of the MBS server 100 transmits the multicast data packet to the ACR 40 (S129), and the ACR 40 sends the received multicast data packet back to the RAS 200 belonging to the MBS Zone. Is transmitted to the data transmission unit 260 (S131).

Thereafter, the data transmission unit 260 of the RAS 200 receives the multicast data packet, and transmits the multicast IP packet among the multicast data packets through the wireless channel allocated by the channel controller 220 as shown in FIG. 6. 60) (S133). At this time, the data transmission unit 260 determines the transmission time of the multicast IP packet by reflecting the service start time set by the service control unit 240 and the time offset P560 included in the multicast data packet, and determining the transmission time. Send a multicast IP packet to Through this, the plurality of RAS 200 may synchronize the transmission time of the multicast IP packet. In addition, the data transmitter 260 may determine the transmission time of the multicast IP packet P700 by determining the transmission time by summing the service start time and the time offset P560. In addition, the RAS 200 divides the multicast IP packet P700 corresponding to the data frame when the multicast IP packet P700 is larger than the data frame configured based on the channel assignment information, and divides the multicast IP packet P700 ( A data frame including P700 is transmitted for each frame interval P190.

That is, the mobile terminal 60 receives multimedia data through the multicast IP packet P700 received from the data transmitter 260 of the RAS 200.

Next, the service management unit 140 of the MBS server 100 transmits the service termination information including the service termination time to the ACR 40 when the transmission of the multicast data packet is terminated or if it is desired to terminate the multicast service (S135). ), The ACR 40 transmits the received Chinese New Year information back to the service control unit 240 of the RAS 200 belonging to the MBS Zone (S137). At this time, the service end information has the same structure as the service start information shown in FIG. 7 and includes only the service end time in the control time P300.

At this time, the data transmission unit 260 of the RAS 200 stops communication with the mobile terminal 60 according to the service termination information (S139).

Thereafter, the service control unit 240 of the RAS 200 transmits a service termination information reception response indicating that the service termination information has been received to the ACR 40 (S141), and the ACR 40 again services the MBS server 100. The service end information reception response is transmitted to the management unit 140 (S143). Through this, the MBS server 100 can confirm that the service termination information transmitted by the RAS 200 has been received.

Next, the configuration information management unit 120 of the MBS server 100 transmits a configuration information deletion request message to the ACR 40 in order to delete the configuration information stored in the channel control unit 220 of the RAS 200 as the service ends. The ACR 40 transmits the received configuration information deletion request message to the channel controller 220 of the RAS 200 belonging to the MBS Zone (S147).

At this time, the channel controller 220 of the RAS 200 deletes the stored configuration information according to the configuration information deletion request message of the configuration information manager 120 of the MBS server 100 (S149).

Thereafter, the channel controller 220 of the RAS 200 transmits a configuration information deletion response message indicating that the configuration information has been deleted to the ACR 40 (S151), and the ACR 40 again configures the multicast server 100. The configuration information delete response message is transmitted to the information manager 120 (S153). Through this, the MBS server 100 confirms that the component is deleted, and at this time, the MBS server 100 terminates the multicast service by releasing the set MBS Zone 300 (S155).

The embodiments of the present invention described above are not implemented only through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Implementation may be easily implemented by those skilled in the art from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

According to an embodiment of the present invention, the MBS server transmits a multicast data packet including synchronization information for a multicast IP packet to a plurality of RASs corresponding to the MBS Zone, thereby handoff process between the PSS and the RAS in the MBS Zone. By omitting this, a high quality multicast service is provided while the user is moving. In particular, RASs included in the MBS Zone transmit a multicast IP packet to each cell at the same time so that the mobile station can obtain a macro diversity effect to increase packet reliability.

In addition, the RAS and the mobile terminal communicate by the OFDMA scheme so that the user of the terminal can be provided with a large capacity multicast service at high speed.

Claims (12)

In the method for providing a multicast service to a base station, Establishing a multicast service area that includes one or more base stations to provide the multicast service; Transmitting start time information of the multicast service to the base station so that the base station sets a service start time corresponding to the start time information; And Transmitting a packet including offset information for synchronization to the base station corresponding to the multicast service area and multicast data provided by the multicast service; How to include. The method of claim 1, Transmitting radio resource information for the multicast service to the base station such that the base station assigns a radio channel corresponding to the radio resource information to the multicast service. The method of claim 2, The radio resource information is A symbol offset specifying a starting point on the time axis in a data frame consisting of a plurality of symbols on a time axis and a plurality of subchannels on a frequency axis; A subchannel offset specifying a starting point on the frequency axis in the data frame; A number of symbols specifying a range on the time axis in the data frame; And The number of subchannels specifying a range on the frequency axis in the data frame How to include. The method according to any one of claims 1 to 3, The offset information is A start offset for providing a start position of the multicast data to control the start of the multicast data; And An end offset controlling the end of the multicast data by providing a length of the multicast data How to include. The method according to any one of claims 1 to 3, Terminating transmission of the multicast data to the base station corresponding to the multicast service area; And Terminating the multicast service by releasing the setting of the multicast service area; How to include more. In the method of providing a multicast service in conjunction with the server, Receiving radio resource information for the multicast service from the server and assigning a radio channel corresponding to the radio resource information to the multicast service; Receiving a multicast service start time information from the server, and setting a start time of the multicast service; Receiving offset information and multicast data from the server; Determining a transmission time of the multicast data based on a start time of the multicast service and the offset information; And Transmitting the multicast data on the wireless channel at the transmission time How to include. The method of claim 6, And determining the transmission time includes summing a start time of the multicast service and the offset information. The method of claim 6, The radio resource information is A symbol offset specifying a starting point on the time axis in a data frame consisting of a plurality of symbols on a time axis and a plurality of subchannels on a frequency axis; A subchannel offset specifying a starting point on the frequency axis in the data frame; A number of symbols specifying a range on the time axis in the data frame; And A number of subchannels specifying a range on the frequency axis in the data frame; How to include. The method of claim 8, The radio resource information further includes a frame interval for setting a transmission interval between a plurality of data frames when the data frame is a plurality, And when the multicast data is transmitted over the plurality of data frames, transmitting the multicast data over the wireless channel causes the plurality of data frames to be transmitted corresponding to the frame interval. The method according to any one of claims 6 to 9, The offset information is A first time offset for providing a start time of the multicast data to control the start of the multicast data; And A second time offset for controlling the termination of the multicast data by providing a transmission time of the multicast data How to include. In the server for providing a multicast service to the base station, Setting a multicast service area for providing the multicast service, and transmitting radio resource information for the multicast service to the base station so that the base station allocates a radio channel corresponding to the radio resource information to the multicast service. Configuration information management unit; A service manager which transmits start time information of the multicast service to the base station so that the base station sets a service start time corresponding to the start time information; And Data control unit for transmitting a packet including offset information for synchronization to the base station corresponding to the multicast service area and multicast data provided by the multicast service Server comprising. An apparatus for providing a multicast service in association with a server, A channel controller configured to receive radio resource information for the multicast service from the server and to allocate a radio channel corresponding to the radio resource information to the multicast service; A service controller configured to receive service start time information from the server and set a start time of the multicast service; And Receiving offset information and multicast data from the server, setting a transmission time of multicast data based on the offset information and the service start time, and transmitting the multicast data through the wireless channel at the transmission time; Data transmission Device comprising a.

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