KR20040088113A - Method for coding and decoding of the target channel type field in multimedia broadcast multicast service - Google Patents

Abstract

PURPOSE: A method for coding and decoding a TCTF(Target Channel Type Field) of a control message for an MBMS(Multimedia Broadcast/Multicast Service) is provided to effectively allocate a value for discriminating a channel defined for an MBMS control message in a TCTF. CONSTITUTION: An MAC layer receives an RLC(Radio Link Control) PDU(Packet Data Unit) from an upper layer(631). The MAC layer checks an MBMS ID of the RLC PDU(633). The MAC layer checks whether MBMS_ID_6_LSB(Least Significant Bit) is '000000'(635). If the MBMS_ID_6_LSB is not '000000', the MAC layer adds the MBMS_ID_6_LSB in a value of a TCTF(637). The MAC layer transfers a constructed TB(Transport Block) to a physical layer(639). The physical layer transmits the received TB through a common channel(641).

Description

METHODO FOR CODING AND DECODING OF THE TARGET CHANNEL TYPE FIELD IN MULTIMEDIA BROADCAST MULTICAST SERVICE}

The present invention relates to a Multicast Multimedia Broadcast Service (hereinafter referred to as MBMS), and more particularly to a method of coding and decoding a channel signal for the service.

The MBMS refers to a service for transmitting the same multimedia data to a plurality of receivers through a wireless network. In this case, by allowing multiple receivers to share one radio channel, it is possible to save radio transmission resources.

1 schematically illustrates devices participating in providing an MBMS service. User equipment (hereinafter referred to as 'UE') (161, 162, 163, 171, 172) refers to a terminal device or a subscriber that can receive the MBMS service, and the cell 1 (Cell 1; 160) Cell 2 (Cell 2) 170 refers to a base station apparatus for transmitting MBMS-related data to subscribers. RNC 140 refers to a wireless network controller that controls the plurality of cells 160 and 170, and selectively transmits multimedia data to a specific cell. And control a radio channel set to provide the MBMS service.

In addition, the Serving GPRS Support Node (hereinafter referred to as 'SGSN') 130 controls the MBMS-related services of the respective subscribers. Representative examples include a role of managing data related to service billing of each subscriber and a role of selectively transmitting multimedia data to a specific RNC 140. The Transit N / W 120 serves to provide a communication path between the BM-SC 110 and the SGSN 130 and may be connected to an external network through a Gateway GPRS Support Node (GGSN). The BM-SC 110 indicates the source of MBMS data and is responsible for scheduling each data. Although not shown in FIG. 1, a Home Location Register (HLR) may be connected to the SGSN 130 to authenticate a subscriber.

As shown in FIG. 1, MBMS data streams are transmitted through UEs 161, 162, 163 via the Transit N / W 120, SGSN 130, RNC 140, Node B and cells 160, 170. , 171 and 172. Although not shown in FIG. 1, there may be a plurality of SGSNs 130 for one MBMS service and a plurality of RNCs 140 for each SGSN 130. In addition, the SGSN 130 is an RNC 140, and the RNC 140 must perform selective data transmission to each of a plurality of cells, and for this purpose, a list of nodes (ie, SGSN) to which a stream should be delivered. Is the list of RNCs, and the RNC is a list of cells) to later selectively transmit MBMS data only to the stored nodes.

2 schematically illustrates operations that must be performed between the subscriber station and the network in order to perform a predetermined MBMS service.

First, the SUBSCRIPTION step 201 is a process in which a user who wants to receive a certain MBMS service registers with a service provider. The registration process is a process in which a service provider and a user exchange basic information related to charging or service reception.

The ANNOUNCEMENT step 202 is a step in which service notification for any MBMS service is made. Through the ANNOUNCEMENT step 202, UEs wishing to receive any MBMS service may recognize basic information about the corresponding service, for example, an MBMS SERVICE ID, a service start time, and a duration of the MBMS service. Can be. For example, the identifier of the MBMS service may consist of a multicast address and an Access Point Name (APN). The BM-SC 110 may broadcast a SERVICE ANNOUNCEMENT message or the like using a CBS (Cell Broadcasting Service) to deliver basic information related to the service to the UEs 161 to 172. Since it is irrelevant matter, detailed description will be omitted.

The UEs 161 to 172, which have acquired basic information about a specific service through the ANNOUNCEMENT step 202, perform a JOINING step 203 if they want to receive the corresponding MBMS service data. In the JOINING step 203, the UE transfers the identifier for the corresponding MBMS service to be received through the ANNOUNCEMENT step 202 to the BM-SC 110 in an arbitrary message. Through the above process, a context for MBMS for managing an MBMS service is generated in the UEs 161 to 172 and the BM-SC 110. In addition, the devices located between the BM-SC 110 and the UEs 161 to 172, that is, the SGSN 130, the Transit N / W 120, and the like, may receive a UE (MS) that wants to receive an MBMS service ( 161 to 172 and a device in which the UEs 161 to 172 are located. For example, the SGSN 130 may grasp a list of UEs 161 to 172 and a list of RNCs 140 where the UEs 161 to 172 are located, and where the UEs 161 to 172 are located later. It will send MBMS data only to RNC 140.

In the MULTICAST MODE BEARER SETUP step 204, a transport bearer for providing the MBMS service on the SGSN 140 and the Transit N / W 120 may be preset. For example, a GTP-U / UDP / IP / L2 / L1 bearer (see 3GPP TS 23.060) for the MBMS service may be preset between the SGSN 130 and the GGSN (not shown).

The NOTIFICATION step 205 is a step of notifying that the MBMS service will start soon, and calling UEs 161 to 172 that want to receive the MBMS service. In the NOTIFICATION step 205, an existing calling method may be used or an calling method optimized for MBMS service may be used.

RADIO RESOURCE ALLOCATION step 206 is the step of actually allocating a radio resource to provide the MBMS service and announcing the information to related devices. In the RADIO RESOURCE ALLOCATION step 206, the RNC 140 transmits radio bearer information for transmitting the MBMS service to UEs 161 to 172 located in arbitrary cells 160 and 170. Notifying Step (hereinafter, Radio Bearer Setup process) alc Transport Bearer information and Radio Bearer information to be configured on an Iub interface to cells where UEs to receive MBMS service are located by the RNC 150. It can be divided into the step of notifying (hereinafter referred to as Radio Link Setup process). When the RADIO RESOURCE ALLOCATION step 206 is completed, all UEs wishing to receive a specific MBMS service are aware of radio link related information to be provided with the service and higher layer information to be processed by the cells, and cells are connected to the radio link. The Iub interface setup is complete. That is, the MBMS service is ready to be delivered to the UE.

After proceeding to the RADIO RESOURCE ALLOCATION step 206, the actual MBMS data stream is transmitted to the UEs 161-172 in a DATA TRANSFER step 207. In addition, control information related to the MBMS may be transmitted while the DATA TRANSFER step 207 is in progress. For example, when radio bearer information is changed, the RNC transfers the changed information to UEs receiving the MBMS service.

After the MBMS service is terminated, the radio resources set in the RADIO RESOURCE ALLOCATION step 206 are released in a RADIO RESOURCE RELEASE step 208, and a message such as MBMS RB RELEASE is received. And send to (161 to 172). Alternatively, the UE 161 to 172 may voluntarily stop receiving the MBMS service while receiving a service.

In order for the UEs 161 to 172 to access a network and receive any service, a context, which is a set of information required to provide a corresponding service to the UEs 161 to 172 and network devices, must be generated. According to the related art, when the UEs 161 to 172 connect to the RNC 140 to set up an RRC connection setup, the RNC 140 sets a UE context for the corresponding UEs 161 to 172. Create The UE context is composed of basic information such as information on the UE identifier, location information of the UE, RRC status information of the UE, radio resource information allocated to the UE, and the RNC 140 while the RRC connection is active. Managed by

As another example, there is a mobility management (MM) context for managing location information of UEs 161 to 172 in a core network. In order for the UEs 161 to 172 to receive a PS (Packet Switched) service, the MM context is provided to network devices providing corresponding services such as the SGSN 130 and the GGSN (not shown) through a GPRS attach procedure. You need to create The MM context of the SGSN 130 may include UE identifier information such as an International Mobile Subscriber Identity (IMSI), a Temporary Mobile Subscriber Identity (P-TMSI), an International Mobile Equipment Identity (IMEI), and a Mobile Subscriber ISDN Number (MSSIS). Routing Area), location information such as Service Area Code (SAC), Authentication Vectors, authentication such as CK, IK, KSI, encryption related information, billing information and DRX parameters (Discontinuous Reception Parameters).

Meanwhile, new contexts for MBMS are defined in network devices for the MBMS service. To this end, the existing contexts as described above may be extended or newly defined. When defining a context for a newly defined MBMS, since the MBMS service receives the same information simultaneously by a plurality of UEs, the context is not created separately for each of the UEs 161 to 172, but for each service or one session in the service. It can be generated by star.

In order for the MBMS service to be made, first, a context for MBMS should be created in the UEs 161 to 172 and the BM-SC 110 which are endpoints of the MBMS service. In addition, the context for MBMS should also be generated in RNC 140, SGSN 130, and GGSN (not shown), which are network devices used to transmit MBMS.

Meanwhile, the context for MBMS is generated in each of the network devices through the JOININIG step 203 of the UEs 161 to 172, and information stored in the context for MBMS is transmitted at the time when actual MBMS data is transmitted. MBMS data can be efficiently transmitted. On the other hand, when the context for MBMS is created and how it is managed depends on the role of each network device.

Hereinafter, a process of providing an MBMS service to a certain UE will be described in more detail with reference to FIG. 3. The CN illustrated in FIG. 2 includes all of SGSN 130, Transit N / W 120, and BM-SC 110. However, since the present invention mainly relates to the operation of a radio access network (RAN), FIG. Considered only SGSN among the CN nodes.

First, the UE, upon recognizing basic information about an MBMS service, that is, an MBMS service identifier, through the ANNOUNCEMENT step 202, transmits an ACTIVATE MBMS PDP CONTEXT REQUEST to the SGSN (301).

Upon receiving the message, the SGSN configures an MBMS PDP CONTEXT, stores an identifier of the UE, etc. in the CONTEXT, and performs a necessary operation with the GGSN, if the UE is the first UE requesting the corresponding service. The necessary operation may be a GTP tunnel setup process, and the SGSN may notify the GGSN of the service related information and exchange a logical identifier for use with each other.

The MBMS PDP CONTEXT is a set of variables in which relevant information about an arbitrary MBMS service is stored, and a list of UEs transmitting the ACTIVATE MBMS PDP CONTEXT REQUEST message, a location, and information related to a transport bearer for transmitting the corresponding MBMS service data. It may be storing. The SGSN sends 302 an ACTIVATE MBMS PDP CONTEXT ACCEPT message to the UE, notifying that the JOINING process 203 is completed.

After the SGSN is about to begin the MBMS service or after receiving the first MBMS service data, the SGSN performs a NOTIFICATION process (205, 303, and 304) for UEs that want to receive the service, that is, UEs that transmit ACTIVATE MBMS PDP CONTEXT REQUEST. Wakes through. PAGING may be used in the NOTIFICATION process. Since the above process is not directly related to the present invention, a detailed description thereof will be omitted.

The purpose of the NOTIFICATION process is to instruct UEs associated with a particular MBMS service to take necessary actions since the MBMS service is about to begin. In the NOTIFICATION process, the SGSN sends a NOTIFICATION message to the RNC (303). ), The RNC again transmits a NOTIFICATION message to the UEs (304).

The UEs may send 305 NOTIFICATION RESPONSE messages to the SGSN to confirm receipt of the MBMS service or to indicate that the NOTIFICATION message has been received. Although one message is shown in the figure, it is apparent that several messages can be transmitted at the same time.

The SGSN collects the NOTIFICATION RESPONSE messages sent by several UEs and updates the MBMS PDP CONTEXT. That is, the list of UEs transmitting the NOTIFICATION RESPONSE message may be updated for each RNC.

Meanwhile, the SGSN transmits an MBMS RAB ASSIGNMENT REQUEST message to the RNC (306). The MBMS RAB ASSIGNMENT REQUEST message may include QoS information required for providing an MBMS service and a list of UEs for establishing an MBMS RAB.

The RAB (Radio Access Bearer) means a set of transmission resources configured in the RAN to provide any service, specifically, a transport bearer between the SGSN and the RNC (Iu interface) and between the RNC and the Node B ( Transport bearer and radio channel).

The RNC determines MBMS RB (Radio Bearer) information for each cell based on QoS information received through the MBMS RAB ASSIGNMENT REQUEST message. Likewise, cells to configure the MBMS RB can be determined using the UE list and the like. The MBMS RB information includes layer 2 (Layer 2; hereinafter referred to as 'L2') information and layer 1 (Layer 1; hereinafter referred to as 'L1') information. The L2 information includes RLC / PDCP related information. The L1 information may include TFS information, TFCS (Transport format combination set) information, channelization code information, transmission output related information, and the like.

The RNC transmits the determined MBMS RB information to the UEs through an MBMS RB SETUP message (307). When the process is completed, the MBMS data transmission preparation is ready for any UE, after which the RNC informs the SGSN that the MBMS RAB configuration is completed through the MBMS RAB ASSIGNMENT RESPONSE message (309), the SGSN is the UE Initiate data transfer into the network (207).

FIG. 4 is a diagram illustrating a flow of data transmitted through a media access control (MAC) layer according to a type of a signal transmitted through each channel in a mobile communication system.

Referring to FIG. 4, Paging Control CHannel (PCCH), Broadcast Control CHannel (BCCH), Common Control CHannel (CCCH), Common Traffic CHannel (CTCH), Dedicated Control CHannel (DCCH), and DTCH (DCH) are processed by the MAC layer. Logical channels such as Dedicated Traffic CHannel) are mapped to physical channels such as Paging CHannel (PCH), FACH, DSCH, and DCH.

In the DCCH and the DTCH, which are dedicated channels, multiple logical channels are configured to use the same transport channel, and thus multiplexing information is inserted in the MAC-d block 423. That is, a C / T (Control / Traffic) field, which is information on the multiplexing process, is inserted.

On the other hand, the BCCH, CCCH and CTCH are input to the target control type field (TCTF) inserter without performing the multiplexing process as described above.

Blocks shown on the right side of FIG. 4 show the progress of a MAC PDU (Packet Data Unit) in which packets received from the DCCH or DTCH logical channel are processed by the MAC function shown on the left side of FIG. In FIG. 4, it is a MAC PDU transmitted on the FACH delivery channel. The MAC PDU is called a transport block (hereinafter, referred to as TB).

Data corresponding to DCCH or DTCH, which is a logical channel, are transmitted from the upper layer to the MAC layer in the form of MAC SDU, and are added to the C / T field indicating a logical channel where data occurs as described above. For a common transport channel such as the FACH, the C / T field is always needed. That is, the field is necessary only when several logical channels are configured to use the same transport channel for the dedicated channel (DCH). In general, the C / T field is 4 bits and up to 15 logical channels per transmission channel can be allowed at the same time.

When scheduling data on the transport channel, the priority tag for the FACH and DSCH is set to MAC-d 423 and used by MAC-c / sh 425. The priority for the FACH may be set for each UE, and the priority for the DSCH may be set for each PDU. Flow control block 427 is needed to limit buffering between the MAC-d 423 and MAC-c / sh 425. After receiving data from the MAC-d 423, the MAC-c / sh 425 entity first inserts a UE authentication bit (UE ID; 2 bits).

Thereafter, the logical channel type for the delivery channel (FACH) is a logical channel type using the BCCH, CCCH, CTCH or DCCH / DTCH, i.e., 16-bit if C-RNTI, for U-RNTI 32 bits) and TCTF are required to separate.

Once the MAC PDU is configured, the exact timing is determined by the task dealing with scheduling / priority when the PDU is transmitted to the physical layer on the FACH delivery channel.

In summary, packet data of the DCCH and DTCH, which are dedicated logical channels, are multiplexed through the MAC-d 423, and a C / T field is inserted. Thereafter, UE authentication type information 429 inserts UE authentication type information and actual UE identifier information.

In addition, the TCTF insertion unit 431 inserts the TCTF field into BCCH, CCCH, and CTCH data including the DCCH and DTCH. As described above, the TCTF field is a field indicating channel type information for identifying logical channels.

As shown in FIG. 3, among the MBMS-related control messages, there is a forward control message (ie, group control message) transmitted to a plurality of UEs such as the MBMS RB SETUP.

However, although the logical channel through which the MBMS related control message is transmitted is discussed, there is no value assigned to distinguish the logical channel for the MBMS control signal on the TCTF field described above with reference to FIG. 4.

Therefore, when a group control message for a specific MBMS service is transmitted, an inefficient process is performed because the terminal receiving the group control message cannot determine whether or not it is a signal for the MBMS service that it has applied for. There is a problem.

Accordingly, an object of the present invention is to provide a method for efficiently allocating a value for distinguishing a channel defined for an MBMS control message on a TCTF to solve the above problem.

Another object of the present invention is to provide a coding and decoding method of a TCTF for an MBMS control message in a MAC layer processor.

In addition, another object of the present invention is to provide a method of setting a TCTF value so that messages not related to a specific MBMS service are not transmitted to a higher layer in setting a TCTF value allocated to the MBMS control message.

The present invention for achieving the above object comprises a base station and a plurality of user terminals capable of communicating with the base station in a cell occupied by the base station, the plurality of user terminals of the plurality of user terminals from the base station In a mobile communication system providing Multimedia Broadcast / Multicast Service (MBMS) data, a method for coding a target channel type field (TCTF) of a medium access control (Medium Access Control) layer, comprising: Receiving a packet data unit (PDU) constituting a control signal for the MBMS service from a Radio Link Control layer, and including the information related to the MBMS service identifier corresponding to the control channel signal, the target channel type field; And configuring the configured target channel type field in the packet. And inserting the data unit into the data layer to transmit it to the physical layer.

The present invention also provides a base station and a plurality of user terminals capable of communicating with the base station in a cell occupied by the base station, the plurality of user terminals of the plurality of user terminals; A method for decoding a target channel type field (TCTF) of a medium access control layer in a mobile communication system providing multicast multimedia broadcast service (MBMS) data from a base station Receiving the transport block from a layer, determining a target channel type field (TCTF) of the transport block to determine whether the transport block is data for an MBMS service, and the transport block is an MBMS service MBMS service identifier through the target channel type field when the data is for Process to determine information related to, and the transport block, characterized in that it comprises the step of transmitting a radio link control layer to process a control signal for the MBMS service.

In a first aspect for achieving the above object, a value allocated to a TCTF for the MBMS control message is composed of 2-bit data of '01' and LSB 6 bits of the MBMS service identifier corresponding to the MBMS control message. It is done.

In a second aspect for achieving the above object, the value assigned to the TCTF for the MBMS control message is composed of two bits of '10' data and LSB 6 bits of the MBMS service identifier corresponding to the MBMS control message. It is done.

1 is a diagram schematically illustrating a network structure for providing an MBMS service in a mobile communication system.

2 is a signal flow diagram illustrating a process for initiating an MBMS service in a mobile communication system.

FIG. 3 is a signal flowchart illustrating the process of FIG. 2 in detail. FIG.

4 is a diagram illustrating a data flow through a MAC layer for each channel signal in a mobile communication system.

5 is a diagram illustrating a TCTF processing procedure for an MBMS service related control channel according to the present invention.

6A is a flowchart illustrating a TCTF coding process for an MBMS control channel according to the first embodiment of the present invention.

6B is a flowchart illustrating a TCTF coding process for an MBMS control channel according to the second embodiment of the present invention.

7A is a flowchart illustrating a TCTF decoding process for an MBMS control channel according to the first embodiment of the present invention.

7B is a flowchart illustrating a TCTF decoding process for an MBMS control channel according to a second embodiment of the present invention.

8 is a block diagram showing the structure of a wireless network controller according to the present invention.

9 is a block diagram showing the structure of a mobile communication terminal according to the present invention;

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, two representative embodiments of the present invention are set forth in order to achieve the above-described technical problem. And other embodiments that can be presented with the present invention are replaced by the description in the configuration of the present invention.

The present invention proposes a method of setting a TCTF value in an MBMS Control Channel (hereinafter referred to as MCCH), which is considered as a logical channel through which the MBMS Control message is transmitted. That is, the present invention proposes a method of efficiently configuring a TCTF value for distinguishing the MCCH used for MBMS control message exchange in a UTRAN (UMTS Terrestrial Radio Access Network).

First, a protocol structure of a transmitter and a receiver configured between a UE and a UTRAN in a UMTS communication system will be described with reference to FIG. 5.

Referring to FIG. 5, it can be seen that the MCCH channel has been added in the structure described above with reference to FIG. 4.

The UE 550 and the UTRAN 500 may configure CCCH, DCCH, DTCH, etc. through the RRC CONNNECTION SETUP procedure after the UE 550 is first powered on.

The CCCH and DCCH are channels for transmitting and receiving RRC messages by the sender and receiver, and the DTCH is channels for transmitting and receiving user data. As described above, one CCCH may be configured, and a plurality of DCCHs and DTCHs may be configured. The DCCH, DTCH, and CCCH are logical channels, and the types of the logical channels are identified through the TCTF field of the MAC header as described above, and the correspondence between the currently defined types of logical channels and TCTF values is shown in Table 1 below. Same as>

That is, the TCTF insertion unit 533 of FIG. 5 adds a TCTF field to the value of Table 1 according to the channel type of the input signal.

Hereinafter, the role of each protocol entity transferred from the top to the bottom of FIG. 5 will be described.

One or two RLCs may be configured in the logical channel. In FIG. 5, only one RCL is configured per logical channel for convenience. The transmitting RLCs 521 to 524 divide data transmitted from the connected higher layers 511 to 514 into an appropriate size, and add additional information such as a serial number to the divided data.

On the other hand, the receiving side RLC (581 to 584) is divided by referring to the serial number and the like of the data transmitted from the MAC layer and serves to assemble the transmitted data to the connected upper layers (591 to 594). The characteristics of the RLC layers, for example, the size of the data to be exchanged with the MAC layer or the range of the serial number, are defined according to the type of logical channel to which they belong.

As described above with reference to FIG. 4, the transmitting MAC layer 530 plays three roles such as multiplexing information insertion, UE identifier information insertion, and TCTF information insertion.

The transmitter-side multiplexing information inserting unit 531 inserts an identifier of the logical channel into data transmitted through DTCH or DCCH. The logical channel identifier is required when there are a plurality of logical channels per logical channel type. Therefore, multiplexing information is not inserted into CCCH, BCCH, and CTCH in which only one logical channel exists for each type of logical channel.

The receiving-side multiplexed information reading unit 571 transfers the received data to the appropriate RLC layer using the logical channel identifier.

The UE identifier inserter 532 inserts a receiver's identifier into data transmitted from the multiplexed information inserter 531. The UE identifier inserter 532 is also applied only to the DCCH and DTCH, and does not apply to the remaining logical channels.

On the other hand, the UE identifier reading unit 571 on the receiving side checks whether the UE identifier of the data transmitted by the physical layer 560 or the TCTF reading unit 573 matches the UE identifier, and if so, the multiplexing information reading unit. 570 serves as a delivery.

The TCTF inserter 533 on the transmitting side inserts a TCTF into data transmitted from the RLC layers 521 and 522 or the UE identifier inserter 532. As described above, the TCTF serves to indicate the type of the logical channel. However, in the case of BCCH, CCCH, and CTCH, only one logical channel exists per channel type, and thus, the TCTF serves to indicate the logical channel itself.

On the other hand, the data transmitted through the BCCH, CCCH, and CTCH is transferred directly from the RLC layer 521 to the TCTF insertion unit 533 without passing through the multiplexing information insertion unit 531 and the UE identifier insertion unit 532. do. The TCTF insertion unit 533 inserts an appropriate TCTF value according to the type of the logical channel. In addition, the data transmitted through the DCCH or DTCH is transferred to the TCTF insertion unit 533 through the multiplexing information insertion unit 531 and the UE identifier insertion unit 532, the TCTF insertion unit 533 is the DCCH Alternatively, a TCTF field having a value of "11" is inserted into data transmitted through the DTCH.

The TCTF reading section 573 on the receiving side transfers the data to BCCH, CCCH, CTCH or the UE identifier reading section 572 using the TCTF field of the received data.

Meanwhile, when the MCCH message, which is a logical channel for transmitting the aforementioned MBMS control message, is received from the RLC layer according to the present invention, the values of the TCTFs are separately allocated to distinguish the logical channels. You must assign a new field value.

The data transmitted through the MCCH message is inserted into a TCTF field including a specific value by a method which will be described later by the TCTF insertion unit 533.

In addition, the data transmitted by allocating a specific field value for the MCCH message may check the TCTF field value at a receiver to confirm that the transmitted data is a control signal for a specific MBMS service.

As described above, after data is divided into appropriate sizes in the RLC layer and additional information is inserted, data transmitted from the MAC layer to the physical layer is called TB. For example, if 500 bits of data delivered from the upper layer are divided into five 100 bits of data in the RLC layer, and then 16 bits of RLC side information and 8 bits of MAC side information are inserted in each, the MAC layer is transferred to the physical layer. It carries five data blocks of 124 bits and is called TB.

As described above, the TCTF field indicates a type of a specific logical channel. In some cases (ie, when only one logical channel is configured per channel type), the TCTF field may indicate the logical channel itself. When the MCCH message is newly defined as a logical channel for transmitting a control message related to the MBMS service, the TCTF value should also be newly defined. That is, one of the parts marked as Reserved in Table 1 may be used.

In the present invention, a specific value is not designated as a TCTF indicating an MCCH message as described above, and the TCTF value for the MCCH message is set by a method described below.

Looking at the above-described TCTF values in Table 1, it can be seen that there are two reserved portions which are not allocated to a specific channel and are reserved. Namely, values '01000001' through '01111111' except for '01000000' allocated for CCCH among values starting with '01', and values except '10000000' allocated for CTCH among values starting with '10'. 10000001 'to' 10111111 'values are reserved areas.

Hereinafter, a method of allocating values for the MCCH control message using the spare area of the TCTF field will be described in two embodiments.

<First Embodiment>

First, a method of allocating values starting with '01' of the two spare areas for the MCCH control message may be proposed. When the TCTF is reconfigured by the above method, it is as shown in Table 2.

As shown in Table 2, the present invention uses values belonging to a certain range rather than a specific single value as a TCTF field value for defining an MCCH control message. The reason for this is that the TCTF reader of the receiving side that receives the specific MBMS service blocks the MBMS service message that is not related to the MBMS service that it receives, and does not transmit it to the higher layer. For example, when a control message for an MBMS service called A and an MBMS service called B is transmitted in a specific cell, if the UE receives the MBMS service called A, it is not necessary to receive a control message related to the MBMS service B. If the MBMS services A and B can be distinguished using the TCTF field, the operation of the UE will be more efficient.

Hereinafter, an efficient TCTF setting method for an MCCH message according to the first embodiment of the present invention will be described.

The transmitter sets the TCTF to '01 +6 LSB of MBMS ID '. Meanwhile, for the MBMS service in which LSB 6 bits of the MBMS ID is '000000', the last 6 bits of the TCTF field are set to a predetermined value instead of '000000'. As described above, when the LSB 6 bit of the MBMS ID is '000000', the TCTF becomes '01000000' to be an identification value of the CCCH. Therefore, in order to prevent it from being recognized as the CCCH, it is assigned to another value.

In this case, a case may occur in which a duplicate of another MBMS ID corresponding to the 6-bit value assigned to the other value is duplicated. However, this is not a problem because it is less likely to occur and can be normally processed in a higher layer. .

When the first 2 bits of the 8-bit data of the TCTF field is '01' and the following 6 bits are '000000', the receiving side recognizes a logical channel of the received message as a CCCH and receives the RLC layer connected to the CCCH. The message that was sent. However, when the first 2 bits of the 8-bit data of the TCTF field is '01' and the following 6 bits are not '000000', the 6 bits are determined as the last 6 bits of the MBMS ID of the specific MBMS service. If the UE has an MBMS ID for an MBMS service, compares the last 6 bits of the MBMS ID with the LSB 6 ratio of the TCTF field, and if it matches, delivers an MCCH message to a higher layer and does not match. Discard if not.

On the other hand, if the last 6 bits of the MBMS ID of the MBMS service that the receiver wants to receive is '000000' and the last 6 bits of the TCTF field of the received TB is a predetermined value, the received TB is a control signal for the MBMS service. Determining that, and delivers to the upper layer through the MCCH as described above.

The MBMS ID means an identifier used by the RNC and the UE to refer to a specific MBMS service. The identifier for the specific MBMS service is an identifier assigned by BM-SC, a Temporary Mobile Croup ID (TMGI) assigned by SCSN, and an MMS-Radio Network Temporary ID (M-RNTI) assigned by RNC. And the like. The plurality of identifiers are different from each other when used. For example, in the above-described ANNOUNCEMENT step, only the BM-SC identifier may be used. However, when the RNC and the UEs agree, the shorter M-RNTI may be used. The MBMS ID means an identifier that the RNC and the UE agree to use in the TCTF field.

Hereinafter, a procedure of transmitting / receiving an MCCH control message by TCTC values assigned according to the first embodiment of the present invention described above will be described with reference to FIGS. 6A and 7A.

6A is a flowchart illustrating a TCTF coding process for an MBMS control channel according to the first embodiment of the present invention.

The RLC PDU is data delivered to the MAC layer after the necessary work is completed in the RLC layer, or data transmitted from the MAC layer to the RLC layer.

Meanwhile, MBMS_ID_6_LSB shown in FIG. 6A means the last 6 bits of the MBMS ID of a specific MBMS service, and PREDEFINED_6 is a 6-bit value previously agreed upon by the RNC and the UE for use when MBMS_ID_6_LSB is '000000'. For example, if PREDEFINED_6 is '000001', the TCTF value for the MBMS service whose MBMS ID is '11000000' is not '01000000', but '01000001' is used.

Referring to FIG. 6A, first, when the MAC layer receives an RLC PDU (611), operation of the present invention is started.

The MAC layer checks 613 the MBMS ID of the RLC PDU and extracts the last 6 bits. That is, when the RLC PDU is a control message associated with a specific MBMS service, the last 6 bits of the MBMS ID of the specific MBMS service become MBMS_ID_6_LSB.

The MAC layer checks whether the checked MBMS_ID_6_LSB is '000000' (615). If the MBMS_ID_6_LSB is not '000000', the MBMS_ID_6_LSB is included in the value of the TCTF. That is, the TCTF is configured 617 by attaching '01' and the MBMS_ID_6_LSB value as described above.

The MAC layer transfers the TB configured through the above process to the physical layer (619), and the physical layer transmits the received TB through a common channel such as a secondary-common control channel (S-CCPCH) (621). )do.

If MBMS_ID_6_LSB is '000000', the TCTF is configured by '01' and PREDEFINED_6 (623) to be distinguished from the CCCH channel as described above, and is transmitted by the same procedure as described above.

7A is a flowchart illustrating a TCTF decoding process of an arbitrary UE X for an MBMS control channel transmitted in FIG. 6A according to the first embodiment of the present invention.

In FIG. 7A, TCTF_2_MSB means two bits of the MSB of the TCTF value of the MAC header of the received TB. In addition, TCTF_6_LSB means 6 bits of the back (LSB) of the TCTF value of the MAC header of the received TB. MBMS_ID_6_LSB_X means MBMS_ID_6_LSB of an MBMS service that is being provided or desired to be provided by any UE X. If UE X receives or wishes to receive multiple MBMS services, MBMS_ID_6_LSB_X is a collection of MBMS_ID_6_LSBs of each service. In addition, if the LSB 6 bits of the MBMS service that UE X is being provided or intended to receive are '000000', MBMS_ID_6_LSB_X becomes the predefined PREDEFINED_6.

Referring to FIG. 7A, first, data received through the common channel in the physical layer 711 is processed into TB, and then transmitted to the MAC layer.

The TCTF_2_MSB of the TB received above is checked (713), and if the TCTF_2_MSB is not '01', it is processed (725) according to the corresponding channel signal. That is, if the TCTF_2_MSB is '00', it is processed as BCCH data, if the TCTF_2_MSB is '10', it is processed as CTCH data, and if the TCTF_2_MSB is '11', it is processed as DCCH or DTCH data.

On the other hand, if the TCTF_2_MSB is '01', it is checked whether the TCTF_6_LSB is '000000' (715). If the TCTF_6_LSB is '000000', since the data is for CCCH, the TB is transmitted to the RLC layer connected to the CCCH (727).

If the TCTF_6_LSB is not '000000', the TB determines the MCCH control message 717 and considers the TCTF_6_LSB as MBMS_ID_6_LSB.

In addition, if the TCTF_6_LSB is PREDEFIND_6 determined at the time of transmission (719), the MBMS_ID_6_LSB meant by the TCTF_6_LSB was originally '000000', so that the MBMS_ID_6_LSB is replaced with '000000' (729).

The UE X compares the determined MBMS_ID_6_LSB value and MBMS_ID_6_LSB_X values to determine 721 whether the received MCCH data is a control message for an MBMS service valid to the UE. If the MBMS_ID_6_LSB matches one of the MBMS_ID_6_LSB_X, it is regarded as a valid MBMS control message to the UE X, and the data is transmitted to the upper layer (723). That is, the MAC makes the received TB in the form of an RLC PDU, that is, removes the MAC header, and then transfers the received TB to an upper layer (723).

As a result of the comparison, when the MBMS_ID_6_LSB does not have any match among the MBMS_ID_6_LSB_X values, the received TB is a message not related to the MBMS service provided by UE X. Therefore, the MAC does not transmit the TB to a higher layer. Discard (731).

Hereinafter, an operation according to an efficient TCTF setting method for an MCCH message according to the first embodiment of the present invention will be described.

Specific MBMS service A is provided in any cell. Assume that the MBMS ID of the service is '10000111', for example. In the example, the size of the identifier may be about 16 bits if the identifier is M-RNTI. However, the above example assumes an 8-bit MBMS ID for convenience.

At any point in time, the RNC wants to send an MCCH message for the MBMS service. For example, the MBMS RB SETUP message including the radio bearer information to provide the MBMS service A is transmitted. At this time, the RRC layer of the RNC or another upper layer 512 controlling the MBMS transfers the MBMS RB SETUP message to the RLC layer 522. The RLC layer performs a predetermined operation and then transfers data to the TCTF inserter 533. The TCTF insertion unit 533 inserts a TCTF field into the received data. At this time, the method of setting the TCTF for the above-described MCCH is applied.

Meanwhile, since 6 bits of LSB (Least Significant Bit) of the MBMS ID '10000111' are '000111', the TCTF field will be 8-bit data of '01000111' in which '01' and '000111' are combined.

Thereafter, the data is transmitted to the UE through the physical layer 540, and the UE processes the signal received through the physical layer 560, makes a TB, and delivers the signal to the TCTF reading unit 573 of the MAC layer 570. do.

Since the UE wants to receive a service having an MBMS ID of '10000111', TBs having a TCTF field value of '01000111' are delivered to a higher layer, and the first two bits of the TCTF field value are '01', and the LSB 6 bits are ' TBs other than 000111 'are discarded.

Second Embodiment

As a second embodiment according to the present invention, a method for allocating values for the MCCH control message starting with '10' among two spare areas not allocated to a specific channel in the TCTF may be proposed. When the TCTF is reconfigured by the above method, it is as shown in Table 3 below.

As shown in Table 3, the present invention uses values belonging to a certain range rather than a specific single value as a TCTF field value for defining an MCCH message. As described above, in the first embodiment, as described above, the TCTF reader of the receiving side that receives the specific MBMS service blocks the MBMS service message that is not related to the MBMS service that it receives, as much as possible. This is not to be conveyed.

Hereinafter, an efficient TCTF setting method for an MCCH message according to the second embodiment of the present invention will be described. The second embodiment operates in the same manner, with only a difference in TCTF values from the first embodiment.

The transmitter sets the TCTF to '10 +6 LSB of MBMS ID '. Meanwhile, for the MBMS service in which LSB 6 bits of the MBMS ID is '000000', the last 6 bits of the TCTF field are set to a predetermined value instead of '000000'. As described above, when the LSB 6 bit of the MBMS ID is '000000', the TCTF becomes '10000000' and becomes an identification value of the CTCH. Therefore, in order to prevent it from being recognized as the CTCH, it is assigned to another value.

In this case, a case may occur in which a duplicate of another MBMS ID corresponding to the 6-bit value assigned to the other value is duplicated. However, this is not a problem because it is less likely to occur and can be normally processed in a higher layer. .

When the first 2 bits of the 8-bit data of the TCTF field is '10' and the following 6 bits are '000000', the receiving side recognizes the logical channel of the received message as the CTCH and receives the received data through the RLC layer connected to the CTCH. The message that was sent. However, when the first 2 bits of the 8-bit data of the TCTF field is '10' and the following 6 bits are not '000000', the 6 bits are determined as the last 6 bits of the MBMS ID of the specific MBMS service. If the UE has the MBMS ID for the MBMS service, compares the last 6 bits of the MBMS ID with the LSB 6 ratio of the TCTF field, if it matches, delivers it to the higher layer, and if it does not match, discards do.

On the other hand, if the last 6 bits of the MBMS ID of the MBMS service that the receiver wants to receive is '000000' and the last 6 bits of the TCTF field of the received TB is a predetermined value, the received TB is a control signal for the MBMS service. Determined as, and delivers to the upper layer as described above.

The MBMS ID means an identifier used by the RNC and the UE to refer to a specific MBMS service as described above in the first embodiment. The identifier for the specific MBMS service is an identifier assigned by BM-SC, a Temporary Mobile Croup ID (TMGI) assigned by SCSN, and an MMS-Radio Network Temporary ID (M-RNTI) assigned by RNC. And the like. The plurality of identifiers are different from each other when used. For example, in the above-described ANNOUNCEMENT step, only the BM-SC identifier may be used. However, when the RNC and the UEs agree, the shorter M-RNTI may be used. The MBMS ID means an identifier that the RNC and the UE agree to use in the TCTF field.

Hereinafter, a procedure of transmitting / receiving an MCCH control message by TCTC values allocated according to the first embodiment of the present invention described above will be described with reference to FIGS. 6B and 7B.

6B is a flowchart illustrating a TCTF coding process for an MBMS control channel according to the second embodiment of the present invention.

As described above in the first embodiment, the MBMS_ID_6_LSB shown in FIG. 6B means the last 6 bits of the MBMS ID of a specific MBMS service, and PREDEFINED_6 is used by the RNC and the UE for use when the MBMS_ID_6_LSB is '000000'. It is a value of 6 bits agreed in advance.

Referring to FIG. 6B, when the MAC layer first receives 631 an RLC PDU, the operation of the present invention is started.

The MAC layer checks the MBMS ID of the RLC PDU (633) and extracts the last 6 bits. That is, when the RLC PDU is a control message associated with a specific MBMS service, the last 6 bits of the MBMS ID of the specific MBMS service become MBMS_ID_6_LSB.

The MAC layer checks whether the checked MBMS_ID_6_LSB is '000000' (635). If the MBMS_ID_6_LSB is not '000000', the MBMS_ID_6_LSB is included in the value of the TCTF. That is, the TCTF is configured by attaching '10' and the MBMS_ID_6_LSB value as described above (637).

The MAC layer transfers the TB configured through the above process to the physical layer (639), and the physical layer transmits the received TB through a common channel such as a secondary-common control channel (S-CCPCH) (641). )do.

If MBMS_ID_6_LSB is '000000', the TCTF is configured with '10' and PREDEFINED_6 to distinguish it from the CTCH channel as described above, and is transmitted by the same procedure as described above.

7B is a flowchart illustrating a TCTF decoding process of an arbitrary UE X for an MBMS control channel transmitted in FIG. 6B according to the second embodiment of the present invention.

As defined in the first embodiment, TCTF_2_MSB in FIG. 7B means two bits of the MSB of the TCTF value of the MAC header of the received TB. In addition, TCTF_6_LSB means 6 bits of the back (LSB) of the TCTF value of the MAC header of the received TB. MBMS_ID_6_LSB_X means MBMS_ID_6_LSB of an MBMS service that is being provided or desired to be provided by any UE X. If UE X receives or wishes to receive multiple MBMS services, MBMS_ID_6_LSB_X is a collection of MBMS_ID_6_LSBs of each service. In addition, if the LSB 6 bits of the MBMS service that UE X is being provided or intended to receive are '000000', MBMS_ID_6_LSB_X becomes the predefined PREDEFINED_6.

Referring to FIG. 7B, first, the physical layer processes the data received through the common channel 741 to make a TB, and then transfers the data to the MAC layer.

The TCTF_2_MSB of the TB received above is examined (743), and if the TCTF_2_MSB is not '10', it is processed (745) according to the corresponding channel signal. That is, if the TCTF_2_MSB is '00', it is processed as BCCH data, and if the TCTF_2_MSB is '01', it is processed as CCCH data, and if the TCTF_2_MSB is '11', it is processed as DCCH or DTCH data.

On the other hand, if the TCTF_2_MSB is '10', it is checked whether the TCTF_6_LSB is '000000' (745). If the TCTF_6_LSB is '000000', since the data is for the CTCH, the TB is transmitted to the RLC layer connected to the CTCH (757).

If the test result indicates that the TCTF_6_LSB is not '000000', the TB is determined as data for the MCCH control message (747), and the TCTF_6_LSB is regarded as MBMS_ID_6_LSB.

If the TCTF_6_LSB is PREDEFIND_6 determined at the time of transmission (749), the MBMS_ID_6_LSB meant by the TCTF_6_LSB was originally '000000', thereby replacing the MBMS_ID_6_LSB with '000000' (759).

The UE X compares the determined MBMS_ID_6_LSB value and MBMS_ID_6_LSB_X values to determine (751) whether the received MCCH data is a control message for MBMS service valid to the UE. If the MBMS_ID_6_LSB matches one of the MBMS_ID_6_LSB_X, it is regarded as a valid MBMS control message to the UE X, and is delivered to the upper layer (753). That is, the MAC makes the received TB in the form of an RLC PDU, that is, removes the MAC header, and then transfers it to the upper layer (753).

As a result of the comparison, when the MBMS_ID_6_LSB does not have any match among the MBMS_ID_6_LSB_X values, the received TB is a message not related to the MBMS service provided by UE X. Therefore, the MAC does not transmit the TB to a higher layer. Dispose of (761).

Hereinafter, an operation according to an efficient TCTF setting method for an MCCH control message according to the second embodiment of the present invention will be described.

Specific MBMS service A is provided in any cell. Assume that the MBMS ID of the service is '11100101', for example. In the example, the size of the identifier may be about 16 bits if the identifier is M-RNTI. However, the above example assumes an 8-bit MBMS ID for convenience.

Since the LSB (Least Significant Bit) 6 bits of the MBMS ID '11100101' is '100101', the TCTF field will be 8-bit data of '10100101' in which '10' and '100101' are combined.

Thereafter, the data is transmitted to the UE through the physical layer 540, and the UE processes the signal received through the physical layer 560, makes a TB, and delivers the signal to the TCTF reading unit 573 of the MAC layer 570. do.

Since the UE wants to receive a service having an MBMS ID of '11100101', TBs having a TCTF field value of '10100101' are delivered to a higher layer, and the first two bits of the TCTF field value are '10', and the LSB 6 bits are ' TBs other than 100101 'are discarded.

Hereinafter, structures of an RNC and a UE for performing functions in embodiments of the present invention will be described with reference to FIGS. 8 and 9. The structures of the RNC and the UE differ in the functions of the TCTF reader and the TCTF inserter in the conventional architecture. In addition, MCCH control data determined and transmitted from the TCTF reader and the TCTF inserter are processed separately from other logical channels in the upper layer.

8 is a diagram illustrating a structure of a universal terrestrial radio access network (UTRAN) for performing a function in an embodiment of the present invention. Here, the UTRAN is a term that collectively refers to Node B and RNC.

Referring to FIG. 8, first of all, the RNC receiving the MCCH control message from the upper layers 850a to 850n passes through the multiplexer 840 and the TCTF is inserted by the TCTF insertion unit 820. The inserted TCTF field is configured by converting the MBMS ID information in the spare area as described above (in the embodiment of the present invention, extracting LSB 6 bits). On the other hand, since the MCCH channel is not a dedicated channel, the MCCH control message does not go through the UE identifier inserter 830.

Although not shown in FIG. 8, the data output from the upper layers 850a to 850n is segmented between the upper layers 850a to 850n and the multiplexer 840 to a predetermined predetermined size, and the segmentation is performed. It is of course possible to configure separate elements for data processing, such as assigning serial numbers to the data. The multiplexer 840 multiplexes data output from the upper layers 850a to 850n with multiplexed information, and transmits the multiplexed signal to the transmitter 810 when the multiplexed signal is transmitted through a DCH. If it is transmitted through the transfer to the UE identifier inserter 830. The UE identifier inserter 830 inserts the identifier into the signal received from the multiplexer 840 and outputs the identifier to the transmitter 810 of the Node B.

In this case, the UE identifier inserter 830 inserts in the multiplexer 840 which identifier to insert into the signal output from the multiplexer 840, that is, which of RNC service identifiers and UE identifiers to insert. It is determined according to the multiplexing information or the control of the upper layers 850a to 850n. For example, when the multiplexing information is 0 or 1, the RNC service identifier may be inserted, and in other cases, the RNC service identifier may be inserted. Alternatively, when data that needs to insert the RNC service identifier is transmitted to the UE identifier inserter 830, the upper layers 850a to 850n may control to insert the RNC service identifier. Data output from the UE identifier inserter 830 or the multiplexer 840 is converted into a radio frequency (RF) signal by the transmitter 810 and transmitted through the antenna 800.

In summary, the plurality of logical channels (PCCH, BCCH, CCCH, CTCH, DCCH, DTCH) transmitted from the upper layers 850a to 850n are configured in the form of packets in TB units in the multiplexer. Depending on the characteristics of the channel is transmitted directly to the transmitter 810, or via the TCTF inserter 820 to the transmitter 810, or via the UE identifier inserter 830 and TCTF inserter 820 The transmitter 810 is transmitted.

According to the present invention, the MCCH signal is data for an MBMS control message, and is transmitted to the transmitter 810 via the TCTF inserter 820.

9 is a diagram illustrating a structure of a UE for performing a function in an embodiment of the present invention corresponding to FIG. 8.

First, a radio frequency (RF) signal received through an antenna 900 is transmitted to the receiver 910. The receiver 910 recognizes a channelization code to be applied to a signal received through the antenna 900 according to control of a higher layer, for example, radio resource control (RRC) layers 950a to 950n. The receiver 910 de-spreads a signal received through the antenna 900 with the recognized channelization code, and then performs segmentation and cyclic redundancy check (CRC) operations at a predetermined size. The process is output to the UE identifier reading unit 930 and the demultiplexer (DEMUX) 940 through the process. The RRC layers 950a to 950n control the receiver 910 to receive the FACH signal when the UE is in the Cell_FACH state and control the receiver 910 to receive the DCH signal when the UE is in the Cell_DCH state. . That is, when the UE is in the Cell_FACH state, the receiving unit 910 delivers the received message to the UE identifier reading unit 930, and when the UE is in the Cell_DCH state, the receiving unit 910 receives the receiving process. One message is passed to the demultiplexer 940.

Meanwhile, the UE identifier reading unit 930 knows the UE identifier indicating the UE in advance, and compares the UE identifier included in the UE identifier information of the message transmitted by the receiving unit 910 with the UE identifier in advance. .

MBMS control messages according to the present invention examine the TCTF field of the TB received by the TCTF reader 920 as described above, and determine that the TB is a control message for a specific MBMS service.

As a result of the determination, when the TB is a TB for a control message (ie, an MCCH control message) for a valid MBMS service applied for by the UE, the TB performs processing on an MCCH channel through a demultiplexer 940. Passed to upper layer

As described above, in the detailed description of the present invention, specific embodiments have been described. However, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

According to the present invention, when transmitting and receiving a control message for the MBMS service, the receiver determines the information on the control message in the MAC layer, messages not related to a specific MBMS service is not delivered to the upper layer efficiency of message processing There is an advantage that can be further increased.

Claims (20)

A base station and a plurality of user terminals capable of communicating with the base station in a cell occupied by the base station, and to a plurality of user terminals of the plurality of user terminals from the base station to a multicast multimedia broadcasting service (MBMS: Multimedia Broadcast / A method of coding a target channel type field (TCTF) of a medium access control layer in a mobile communication system providing multicast service data, Receiving a packet data unit (PDU) constituting a control signal for the MBMS service from a radio link control layer; Configuring the target channel type field including information associated with an MBMS service identifier corresponding to the control channel signal; And inserting the configured target channel type field into the packet data unit to transmit to the physical layer. The method of claim 1, The configured target channel type field is configured using a spare area of the field. The method of claim 1, And the control signal for the MBMS service forms an MBMS Control Channel (MCCH). The method of claim 1, Wherein the MBMS service identifier is a wireless network temporary identifier (M-RNTI) for MBMS. The method of claim 1, The MBMS service identifier is any one selected from an identifier assigned by the BM-SC, TMGI assigned by SGSN and RNTI assigned by the RNC. The method of claim 4, wherein And the information related to the MBMS service identifier included in the target channel type field configuration is some bits selected from the MBMS service identifier. The method of claim 6, And a bit selected from the MBMS service identifier is 6 bits of Least Significant Bit (LSB) of the MBMS service identifier. The method of claim 7, wherein The target channel type field is composed of 2 bits of '01' and 6 bits of the MBMS service identifier. The method of claim 7, wherein The target channel type field is composed of 2 bits of '10' and 6 bits of the MBMS service identifier. The method of claim 7, wherein And if all 6 bits of the LSB are '0', replace the bits with predetermined bits. A base station and a plurality of user terminals capable of communicating with the base station in a cell occupied by the base station, and to a plurality of user terminals of the plurality of user terminals from the base station to a multicast multimedia broadcasting service (MBMS: Multimedia Broadcast / A method for decoding a target channel type field (TCTF) of a medium access control layer in a mobile communication system providing multicast service data, Receiving the transport block from a physical layer, Determining whether the transport block is data for MBMS service by checking a target channel type field (TCTF) of the transport block; If the transport block is data for an MBMS service, checking information related to an MBMS service identifier through the target channel type field; And transmitting the transport block to a radio link control layer which processes a control signal for an MBMS service. The method of claim 11, The target channel type field configured for the MBMS service in the target channel type field is configured using a spare area of the field. The method of claim 11, And the control signal for the MBMS service forms an MBMS Control Channel (MCCH). The method of claim 11, Wherein the MBMS service identifier is a wireless network temporary identifier (M-RNTI) for MBMS. The method of claim 11, The MBMS service identifier is any one selected from an identifier assigned by the BM-SC, TMGI assigned by SGSN and RNTI assigned by the RNC. The method of claim 14, And the information related to the MBMS service identifier included in the target channel type field configuration is some bits selected from the MBMS service identifier. The method of claim 16, And a bit selected from the MBMS service identifier is 6 bits of Least Significant Bit (LSB) of the MBMS service identifier. The method of claim 17, The target channel type field is composed of 2 bits of '01' and 6 bits of the MBMS service identifier. The method of claim 17, The target channel type field is composed of 2 bits of '10' and 6 bits of the MBMS service identifier. The method of claim 17, And if all 6 bits of the LSB are '0', replace the bits with predetermined bits.