KR20100071665A - Apparatus and method for transmitting/receiving multimedia broadcast and multicast service in a wireless communication system - Google Patents

Abstract

PURPOSE: An apparatus and a method for transmitting/receiving multimedia broadcast and multicast service(MBMS) in a wireless communication system are provided to minimize the unnecessary reception of an MBMS control channel(MCCH). CONSTITUTION: An MCCH configuration unit generates a sub-header by receiving control information related to MBMS traffic. The MCCH configuration unit generates medium access control(MAC) packet using the sub-header. The MCCH configuration unit maps the MAC packet with a logical MCCH. A scheduler(321) schedules the transmission timing and priority of the MBMS traffic channel(MTCH) and the MCCH. A transmission unit(341) maps either of the MTCH or MCCH with a physical downlink shared channel(PDSCH). The transmission unit provides identification information for transmitting the MBMS to the PDSCH a physical downlink control channel.

Description

Transmission and reception apparatus and method for MMS in wireless communication system {APPARATUS AND METHOD FOR TRANSMITTING / RECEIVING MULTIMEDIA BROADCAST AND MULTICAST SERVICE IN A WIRELESS COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for transmitting / receiving control information in a wireless communication system, and more particularly, to transmit / receive control information of a multimedia broadcast and multicast service (hereinafter referred to as "MBMS"). An apparatus and method are provided.

"The present invention is derived from the research conducted as part of the IT growth engine business of the Ministry of Knowledge Economy [Task No. 2006-S-003-03, Task name: Development of next generation mobile communication service platform]."

In general, a wireless communication system is a system developed to provide a communication service while securing mobility to a user. In such a wireless communication system, a user terminal needs to transmit / receive various control information for smooth communication with a base station of a wireless communication system. For example, when a communication service is provided between a base station and a user, various control messages such as types of traffic transmitted / received, traffic load rate information, power control information, handover information, and scheduling information should be transmitted and received.

On the other hand, such a wireless communication system has evolved from the form of providing only the service between users due to the rapid development of technology to provide the same multimedia service to multiple users. One type of such a service is an MBMS service, and was developed to efficiently transmit the same data in one direction to multiple terminals in a 3GPP UMTS system.

Next, a channel structure related to the MBMS service in the UMTS mobile communication system will be described with reference to the accompanying drawings.

1 is a diagram of MBMS related channel structure in UMTS mobile communication system.

In the UMTS system, MBMS-related channels are divided into physical channels, transport channels, and logical channels. First, there are MBMS Traffic Channels (MTCHs 111, ..., 11n) to which MBMS services are transmitted in logical channels, and MBMS Control Channel (MCCH) for transmitting control information of MTCHs 111, ..., 11n and scheduling MSCH (MBMS Scheduling Channel) is defined for. All three kinds of channels present in the logical channels are transmitted through a forward access channel (FACH) of transport channels. The FACH 131 transmits information of each channel received from the logical channel through the S-CCPCH 141 among the physical channels.

The MTCHs 111, ..., 11n are channels for transmitting MBMS data traffic and exist one by one for each MBMS service. MCCH 101, which is one of the logical channels, is an MBMS control channel. The MBMS service list currently being serviced in a cell, traffic channel (MTCH) configuration information for receiving each MBMS service, and traffic channel release upon termination of MBMS service It contains instructions. In addition, MSCH 121, which is one of the logical channels, is a channel that delivers scheduling information about MBMS data traffic and indicates when traffic is transmitted through each MTCH. Accordingly, the UE can reduce power consumption by reading a physical channel only at the time when MBMS service traffic activated by itself is transmitted based on the MTCH scheduling information through the MSCH 121.

In addition, the MCCH 101 is transmitted according to a modification period and a repetition period, and a plurality of repetition periods exist in one modification period. The MCCH 101 can be changed only in units of modification cycles, and the same MCCH data is transmitted for each repetition cycle within the same modification cycle. Based on the periodic MCCH 101 transmission, the UE can read the MCCH 101 only when MBMS control information for the service activated by the UE is needed instead of continuously receiving the MCCH 101. Since the change of the MBMS control information is possible for each modification cycle, the UE may acquire the changed MBMS control information by reading the MCCH 101 at the start of every modification cycle. However, even when a new modification cycle starts, the terminal does not need to read the MCCH 101 unless the control information for the service activated by the terminal is changed. To this end, UMTS defines the MMS (MBMS Indicator Channel) 151 physical channel. The base station delivers the MBMS service list in which the control information is modified to the terminal through the MICH 151 at every MCCH modification cycle, and the terminal only receives notification that the MBMS control information for the service activated by the base station is modified through the MICH. The MCCH 101 is read at the start of the MCCH modification cycle. In this way, the UE can minimize unnecessary MCCH reception time.

On the other hand, the LTE-Long-Term Evolution (LTE) system, which is currently undergoing standards work in 3GPP, and its enhanced LTE-Advanced system are optimized for packet transmission based on shared channels, unlike the UMTS system based on circuit transmission. As a result, much larger data transmission is possible in MBMS. MBMS in LTE system has been discussed to provide two transmission schemes, single-cell transmission and multi-cell transmission, and the channel structure of each scheme is defined. However, specific detailed procedures are not yet defined.

In more detail, in the LTE mobile communication system, MCCH and MTCH are currently defined as logical channels for MBMS. However, since the MAC standard does not yet consider MBMS, there is a problem in that the MCCH and MTCH logical channels cannot be accommodated. In addition, since the MSCH and MICH used in the conventional UMTS are not considered in the LTE mobile communication system, a problem arises in that the UE reads the MCCH information every modification period regardless of whether or not the control information of the MBMS service activated by the UE is changed. .

Accordingly, the present invention provides an apparatus and method for providing an MBMS service in a 3GPP LTE mobile communication system.

The present invention also provides an apparatus and method for efficiently transmitting and receiving MBMS control information between a base station and a terminal in a 3GPP LTE-based mobile communication system.

A transmitting device according to an embodiment of the present invention is a device for providing an MBMS in a wireless communication system. The transmitting device generates a header corresponding to each MBMS traffic for each MBMS service data and maps them to logical MBMS traffic channels. MBMS configuration unit for generating a packet, MCCH configuration unit for receiving the control information for the MBMS traffic to generate a header and using them to generate a MAC packet to map the logical MBMS control channel (MCCH), A scheduler that determines and schedules transmission time and priority of the MTCH and the MCCH, maps at least one of the MTCH and the MCCH to a physical downlink shared channel, and controls and identification information of traffic provided through the physical downlink shared channel And a transmitter for providing a physical downlink control channel.

A transmission method according to an embodiment of the present invention is a method for providing an MBMS in a wireless communication system, and generates a header corresponding to each MBMS traffic for each MBMS service data to be transmitted and maps them to logical MBMS traffic channels. (MAC) packet generation, and at the time when the control information for the MBMS traffic should be transmitted, generating a header corresponding to the control information for the MBMS traffic and using them to generate a MAC packet to control the logical MBMS Generating a MAC packet by mapping to a channel (MCCH), mapping and transmitting at least one of the MTCH and MCCH to a physical downlink shared channel, and controlling and identifying information of traffic provided through the physical downlink shared channel It provides a process to the physical down control channel.

The receiving apparatus according to an embodiment of the present invention provides at least one of an MTCH for providing MBMS service data and an MCCH for providing control information of the MTCH to a physical downlink shared channel, and provides traffic to the physical downlink shared channel. A terminal device for receiving an MBMS in a wireless communication system providing control information and identification information to a physical downlink control channel, comprising: a wireless receiver configured to receive the physical downlink control channel and the physical downlink shared channel and convert the baseband signal into a baseband signal; A demodulation / decoding unit for demodulating and decoding the baseband signal, a demultiplexer for demultiplexing the demodulated and decoded signal by separating information of the MTCH, the MCCH, and the physical downlink control channel; A data processor that separates data among MTCHs provided from a multiplexer and provides the upper layer to the upper layer; Receives the information of the direction control channel and controls to receive the MCCH and the MTCH in the physical downlink shared channel, using the change indicator of the information of the MCCH to detect whether or not to change the MCCH information, and provides this to the upper layer It includes a control unit.

The reception method according to an embodiment of the present invention provides at least one of an MTCH for providing MBMS service data and an MCCH for providing control information of the MTCH to a physical downlink shared channel, and provides traffic to the physical downlink shared channel. A method for receiving an MBMS in a wireless communication system that provides control information and identification information in a physical downlink control channel, when receiving the MCCH for the first time when the MTCH is first received, the MCCH is received at the earliest time point. Receiving an MTCH, and when a modification period of the MCCH received upon receiving a specific MTCH arrives, inspecting whether the MCCH is modified by checking a modification indicator of the MCCH, and when the MCCH is modified. And providing the MCCH to a higher level so as to continuously receive the MTCH.

According to the configuration of the present invention, in the 3GPP LTE and LTE-Advanced mobile communication system based on the common channel can provide the MBMS service between the base station and the terminal, and minimize the unnecessary MCCH reception at the terminal by efficiently providing the MBMS control information And it can reduce the power consumption of the terminal.

Hereinafter, the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, a part obvious to those skilled in the art will be omitted so as not to disturb the gist of the present invention. In addition, it is to be noted that each of the terms described below are only used to help the understanding of the present invention, and may be used in different terms despite the same purpose in each manufacturing company or research group.

In the present invention described below, the MBMS is provided by a single-cell transmission or a multi-cell transmission scheme in a 3GPP LTE-based system. Physical downlink shared channel (PDSCH) physical channel is used in single-cell transmission that does not require synchronized data transmission between neighboring cells, and physical transmission is required in multi-cell transmission that requires synchronized data transmission between adjacent cells. Physical Multicast Channel (PMCH) physical channel is used. The present invention will be described in the case of MBMS of single-cell transmission. However, the same concept may be applied to the multi-cell transmission scheme.

FIG. 2 is a diagram illustrating a configuration of an MBMS related channel according to a single-cell transmission scheme in a 3GPP LTE mobile communication system to which the present invention is applied.

The 3GPP LTE mobile communication system also has a hierarchical structure divided into logical channels, transport channels, and physical channels. In the logical channels shown in FIG. 2, only channels for MBMS are shown, and in the 3GPP LTE mobile communication system, an MBMS control channel (MCCH) 201 for MBMS service and MBMS traffic channels for transmitting a plurality of MBMS traffics ( MTCHs) 211, ..., 21m are defined. The logical channels for the MBMS service are mapped to the MBMS service among the logical channels through a downlink-shared channel (DL-SCH) 221 in the transport channels. This is again mapped to a physical downlink shared channel (PDSCH) 231, which is one of the physical channels, and provided to the terminal. In addition, the physical channels include a physical downlink control channel (PDCCH) that provides control information of the PDSCH 231.

Each channel described above will be described in more detail. In the single-cell transmission scheme, the DL-SCH 221 transport channel is mapped to the PDSCH 231 physical channel, and the MCCH 201 and the MTCHs 211, ..., 21m are mapped to the DL-SCH 221 transport channel. Logical channels correspond. Logic of MCCH 201 and MTCHs 211, ..., 21m in a transport block (TB), that is, a data unit transmitted through a DL-SCH 221 transport channel between a MAC layer and a physical layer. Channel data may be included. Scheduling for MAC PDUs is managed by the MAC scheduler of the base station. In general, one MCCH 201 and one or more MTCHs are provided in one cell. Each MTCH corresponds to each MBMS service currently provided in the cell.

Next, the configuration for providing the MBMS service according to the channel configuration will be described. 3 is a functional block diagram of a transmitter for providing an MBMS service according to the present invention.

Each MBMS service data 301, 302,..., 30m is input to MBMS components 311, 312,..., 31m corresponding to the respective service data. Each of these MBMS components 311, 312,..., 31m is configured to transmit the received service data in a predetermined manner and provided to the transport channel mapping unit 331. In this case, the MBMS components 311, 312,..., 31m may generate a MAC PDU using the input data and may generate a sub-header corresponding to the input MBMS traffic data. Then, the transmission channel mapping unit 311 maps the transmission channel and the physical channel as described in FIG. 2 and outputs the mapping to the transmission unit 341. Accordingly, the transmitter 341 provides the MBMS service according to the method required by the 3GPP LTE system. In addition, the scheduler 321 receives the information of the MBMS service data and other logical channel information and performs scheduling according to the transmission time, the size and retransmission of the transmission data. This scheduling result is provided to the data components of the respective MBMS components 311, 312, ..., 31m and other logical channels. In FIG. 3, most of the connection in which the scheduler 321 provides scheduling information is omitted, and only the configuration of the transport channel mapping unit 331 is illustrated.

In addition, the configuration for the MCCH is not shown in FIG. The MCCH processor may be further configured to receive control information for the MCCH, and the MCCH processor may configure the input MCCH control information as a MAC PDU and generate a MAC sub-header thereof. This MAC sub-header will be described in more detail with reference to the accompanying drawings.

Meanwhile, what data is transmitted through the PDSCH 231 physical channel at a specific time-to-transmit (TTI) can be known through control information included in a physical downlink control channel (PDCCH) 241 physical channel. And a logical channel type transmitted through the PDSCH 231 using a Radio Network Temporary Identity (RNTI). Taking an example of a channel other than the MBMS service, SI-RNTI is used for BCCH, P-RNTI is used for PCCH, and C-RNTI is used for DCCH and DTCH. Among them, the SI-RNTI and the P-RNTI corresponding to the BCCH and the PCCH having common channel characteristics are assigned one fixed value. On the other hand, the C-RNTI allocated to each terminal unit is uniquely allocated to each terminal in the cell. Similarly, since MCCH and MTCH, which are channels for MBMS, are channels commonly used in a cell, fixed assignment of values in a cell is required, such as SI-RNTI and P-RNTI.

Therefore, in the present invention, two RNTIs are defined to provide MBMS, that is, MBMS Control-RNTI (MC-RNTI) and MBMS Traffic-RNTI (MT-RNTI). The MC-RNTI is an identifier corresponding to the MCCH 201 which is an MBMS control channel, and the MT-RNTI is an identifier corresponding to all the MTCHs 211, ..., 21m which are channels for MBMS traffic. MC-RNTI and MT-RNTI allow to operate in two modes. In the first mode, different values are assigned to the MC-RNTI and the MT-RNTI, and in the second mode, the same values are assigned to the MC-RNTI and the MT-RNTI. When MC-RNTI and MT-RNTI have the same value, MCCH and MTCH may be included in the same MAC PDU and transmitted. When MC-RNTI and MT-RNTI have different values, MCCH and MTCH are different. It is delivered in the MAC PDU.

Next, the method according to the values of MC-RNTI and MT-RNTI will be described with reference to FIG. 4. 4 is a timing diagram illustrating a change cycle and a repeat cycle of an MCCH among logical channels.

In FIG. 4, the hatched portion shows the occupancy time at which the MCCH 201 is transmitted, and there are a plurality of repetition periods 420 within the modification period 410. In FIG. 4, an example in which the MCCH 201 is repeatedly transmitted four times in one change period 410 is illustrated. That is, four MCCHs 201 are transmitted within the change period 410 as shown by reference numerals 431, 432, 433, and 434. However, it should be noted that the number of iterations may change depending on the standard of the system.

Data included in the MAC PUD transmitted in the modification period and the repetition period may be different. First, when MC-RNTI and MT-MRTI are different and in a modification period, the MAC-PDU may be configured as shown in Equation 1 below. It may be configured in the form.

MAC PDU_ _{modification period} = MCCH modification indicator sub-header + MCCH sub-header + MCCH modification indicator + MCCH information (payload)

MAC PDU_ _{repetition period} = MCCH subheader + MCCH information (payload)

Next, when MC-RNTI and MT-MRTI are the same, the MCCH and MTCH may be included in one MAC PDU, so the MAC PDU transmitted in the modification period may be configured as shown in Equation 3 below. The transmitted MAC PDU may be configured as shown in Equation 4 below.

MAC PDU_ _{modification period} = MCCH modification indicator sub-header + MCCH sub-header + MTCH-1 sub-header + MTCH-2 sub-header +. + MCCH modification indicator + MCCH information (payload) + MTCH-1 information (payload) + MTCH-2 information (payload) +.

MAC PDU_ _{repetition period} = MCCH sub-header + MTCH-1 sub-header + MTCH-2 sub-header +. + MCCH information (payload) + MTCH-1 information (payload) + MTCH-2 information (payload)

As described above, the MCCH modification indicator transmitted in the modification period may be transmitted by configuring a separate logical channel. Therefore, when the MCCH modification indicator is configured as a MAC PDU, a sub-header for the MCCH modification indicator is required. This configuration can be implemented in the same form as the MTCH configuration shown in FIG.

FIG. 5 illustrates a general structure of a MAC PDU delivered through a DL-SCH transport channel in an LTE mobile communication system.

The MAC PDU consists of a MAC header and a MAC payload. The MAC payload includes MAC control elements 511 and 512, which are control information transferred between MAC layers, MAC SDUs 513, ..., 514, which are upper layer data, and padding for octet alignment. 515). In addition, the MAC header 500 is composed of a plurality of MAC sub-headers 501, 502, 503, 504,..., 505, 506, and each of the MAC sub-headers 501, 502,..., 506 is a MAC. It corresponds to each element constituting the payload and represents information (identifier, length) about it.

An internal configuration of the MAC sub headers 501, 502, ..., 506 shown in FIG. 5 will be described with reference to FIGS. 6A through 6C.

6A through 6C are diagrams illustrating structures of a MAC PDU sub-header in an LTE mobile communication system.

FIG. 6A is a diagram illustrating a structure of a MAC PDU sub-header having a 7-bit L field, and FIG. 6B is a diagram illustrating a structure of a MAC PDU sub-header having a 15-bit L field. 6c is a diagram illustrating the structure of a MAC PDU sub-header used for a fixed length MAC control element. In the MAC sub-header shown in FIGS. 6A to 6C, a logical channel identifier (LCID) indicates a logical channel identifier when the MAC SDU is DCCH or DTCH, and a control element type when the MAC control element is a MAC control element. type). However, in the current 3GPP LTE-Advanced mobile communication system, the MAC sub-header structure does not yet support MCCH and MTCH for MBMS.

Accordingly, the present invention proposes a structure of the MAC PDU sub-header of the type shown in FIGS. 7A to 7C. 7A to 7C are diagrams illustrating the structure of a MAC PDU sub-header for use in a 3GPP LTE mobile communication system according to the present invention.

7A is a diagram illustrating a structure of a MAC PDU sub-header having a 7-bit L field according to the present invention, and FIG. 7B is a diagram of a MAC PDU sub-header having a 15-bit L field according to the present invention. 7 is a diagram illustrating a structure of a MAC PDU sub-header used for a fixed length MAC control element according to the present invention. In the sub-header proposed in FIGS. 7A to 7C, one bit R which is not used in the conventional MAC PDU sub-header is additionally used for MBMS. That is, in the MAC PDU sub-headers proposed in FIGS. 7A to 7C, the M field 701 composed of 1 bit is used, and when the M field 701 is set to '1', MBMS-related data is stored in the MAC PDU. If included, and set to '0' to serve as the same sub-header as in the prior art. When the M field is set to '1', the MCCH Modification Indicators control element, MCCH and MTCH data may be included in the MAC PDU, and each is identified by an LCID. That is, when the LCID defined by 5 bits is '00000', it indicates an MCCH modification indicator. The MCCH has an LCID of '00001' and the MTCH has a value of '00002' to '11111'.

9A and 9B are diagrams illustrating a structure of a MAC PDU payload including MCCH data (PDU) and MCCH modification indicator for MBMS control information transmission according to the present invention in an LTE mobile communication system. FIG. 9A illustrates a MAC PDU payload structure transmitted every modification period 410. FIG. 9B illustrates a MAC PDU payload structure transmitted every repetition period.

9A and 9B, the MCCH data (PDU) is delivered every MCCH repetition period, and the MCCH data indicator is included in addition to the MCCH data at the modification period. The MCCH modification indicator consists of 8 * N bits, and one MBMS Service Identifier (Temporary MBMS Group Identity, TMGI) corresponds to one bit of 8 * N bits through a hash function. Therefore, if the MCCH information for a specific MBMS service is changed in this modification period, the corresponding bit of the MCCH modification indicator is set to '1'.

7A to 7C and 9A and 9B, in terms of the entire MAC PDU, the MAC sub-header indicating the MCCH is included in the MAC header and the MCCH PDU is included in the MAC payload in every MCCH repetition period. In each MCCH modification period, a sub-header indicating the MCCH modification indicator is included in the MAC header, and the MCCH modification indicator control element is included in the MAC PDU payload.

The operation of this process will be described with reference to the control flowcharts of FIGS. 8A and 8B.

8A is a control flow diagram for generation and transmission of MCCH in accordance with the present invention. 8A is a control flowchart described only in view of transmission of MCCH. Therefore, the control flow will be described only in relation to the transmission of the MCCH.

The scheduler 321 checks whether a modification period is started in step 800. The MCCH has only two periods, a modification period and a repetition period. That is, the transmitted MCCH is generated in the modification period, and the generation is not performed in the repetition period. Therefore, whether the correction cycle is started in step 800 is a process for checking the repetition cycle and the correction cycle.

If it is determined in step 800 that the modification period, the scheduler 321 proceeds to step 802 and controls to generate a MAC sub-header of the type shown in Figure 9a. In operation 804, the scheduler 321 generates an MCCH PDU and stores the generated MCCH PDU in a predetermined memory. The reason for storing the MCCH PDU generated in this manner is to transmit the MCCH PDU stored in the repetition period. Thereafter, the scheduler 321 combines the header generated in step 806 and the MCCH PDU and transmits the data according to the transmission time in step 808.

On the other hand, if the modification period is not a modification period in step 800, the scheduler 321 transmits only the MCCH PDU in step 810. That is, it is transmitted in the form as shown in Figure 9b. In this case, the scheduler 321 may control to read and transmit the MCCH PDU generated and stored in step 804 without generating the MCCH PDU. In the description of FIG. 8, MTCH, MC-RNTI, and MT-RNTI are not mentioned. This is because it can be transmitted in the same manner as described above, it should be noted that in FIG. 8A is only described in terms of the MCCH.

8B is a control flow diagram for generation and transmission of an MTCH in accordance with the present invention. 8B is a control flowchart described only in terms of transmission of MTCH. Therefore, the control flow will be described only in relation to the transmission of the MTCH.

When the scheduler 321 receives MBMS service data to be transmitted, the scheduler 321 controls to generate a header corresponding to each MTCH in step 820. The scheduler 321 then controls to combine the header generated in step 822 with the MTCH. This combination may not be made by the control of the scheduler 321, but it will be described here as being by the control of the scheduler 321. After generating the header and the like of the MTCH, the scheduler 321 maps to the transport channel in step 824. That is, the MTCH is mapped to the DL-SCH 221 shown in FIG. In operation 826, the scheduler 321 transmits the data through the physical layer.

In addition, in preparation for the process for transmitting the MTCH and MCCH, the generation and transmission process of the MCCH may be generated through the same process as the process for generating and transmitting the MTCH. The only difference is that the generated information is different from the header information, and that MCCH has priority in scheduling than MTCH.

In the above, the operation for providing the MBMS service from the viewpoint of the base station has been described. Next, an operation for receiving an MBMS service from the perspective of the terminal will be described.

10 is an internal block diagram of a terminal for receiving an MBMS service in a terminal of a 3GPP LTE mobile communication system according to the present invention.

The signal transmitted on the air is received through an antenna (not shown in FIG. 10) and input to the wireless receiver 1001. The wireless receiving unit 1001 converts the received signal into a baseband signal, converts an analog signal into a digital signal, and provides the demodulation / decoding unit 1002. The demodulation / decoding unit 1002 then demodulates and decodes the digital signal and provides the demultiplexer 1003. The demultiplexer 1003 is a part functionally included in the actual terminal. In other words, each block may be processed in a plurality of blocks instead of one. The demultiplexer 1003 distinguishes and outputs each logical channel. That is, the PDSCH 231 demultiplexes and outputs the MBMS service data (MTCH) according to the case of receiving the MCCH or the MCCH. In this case, the demultiplexer 1003 outputs a signal transmitted to the MCCH 201 among logical channels to the controller 1011, and provides signals of the MTCHs to the data processor 1004. In addition, information provided to the PDCCH 241 which is another physical channel is provided to the controller 1011.

11 is a control flowchart for receiving an MBMS service from a terminal using a method according to the present invention.

The controller 1011 checks whether the MCCH 201 is first received in step 1100. The first case of receiving the MCCH 201 may be a case of newly entering a specific cell or attempting to receive an MBMS service for the first time in a single cell method. On the other hand, in the multi-cell method, it may be a case of moving out of the multi-cell region to another multi-cell region or in case of receiving a service for the first time. When the MCCH 201 is first received, the controller 1011 proceeds to step 1102 to receive the MCCH 201 at the closest time. That is, the MCCH 201 is received in the closest period of the modification period or the repetition period. After that, the controller 1011 proceeds to step 1104 to transfer the received MCCH 201 to a higher level so as to receive the MBMS service in a short time.

If the check result of step 1100 does not receive the MCCH 201 for the first time, the controller 1011 proceeds to step 1110. In other words, if the first reception is not received, the MBMS service is continuously provided, and the MBMS service is not out of range for updating the MBMS service. In this case, the controller 1011 checks whether a modification period has arrived in step 1110. When the modification period arrives, the control unit 1011 proceeds to step 1112 to check the modification indicators generated according to the present invention in the MCCH 201, and proceeds to step 1114 and the control unit 1011 controls the activated MBMS service. Check that the information value is one. This is to check whether the changed information is provided to the MCCH 201 for the activated MBMS service. If the control result value of the activated MBMS service is 1, the controller 1011 proceeds to step 1116 and transfers the information provided to the received MCCH 201 to a higher level. Through this, modified information can be obtained quickly.

On the other hand, if the control information value for all the activated MBMS service in step 1114 is not 1, the controller 1011 proceeds to step 1120 and discards the received MCCH, and proceeds to step 1122 to the MC-RNTI and MT. -Check whether the RNTI is the same If the two values are the same as the result of the check in step 1122, decoding by the MC-RNTI is stopped during the modification period. However, if the MC-RNTI and the MT-RNTI are not the same, the process proceeds to step 1126 and discards the MCCH received during one modification period without transmitting to the upper layer.

Therefore, after the decoding or the MCCH reception of the PDSCH is stopped during one modification period, the MCCH 201 is received again in the next modification period, and the control information for the MBMS service is provided using this value.

In the above, the operation from the viewpoint of the base station and the terminal has been described. The operation of the MBMS service will be briefly reviewed.

The base station broadcasts the MCCH modification indicator and MCCH data in the MAC PDU in the cell at the start of every MCCH modification cycle. Then, the UE can check whether the MBMS control information for the service activated by itself is changed by reading the MCCH modification indicator at the start of every modification cycle. The terminal immediately receives the MCCH data at the earliest time or at the start of the MCCH modification cycle in which the changed control information is delivered, depending on whether or not the control information for the MBMS service activated by the UE is acquired. In this case, when the MCCH data is immediately received at the earliest point, the basic MBMS control information has not been obtained yet. In the case where the changed control information is received at the start of the MCCH modification cycle in which the changed control information is transmitted, it is a case where the necessary MBMS control information has already been obtained and whether there is changed control information.

When the UE needs to receive MBMS control information at the earliest time point, the MAC layer of the UE delivers the received MCCH data to a higher layer regardless of the presence of a modification indicator control element. However, when the UE needs to check the MBMS control information only in every modification cycle, the UE transmits the received MCCH data to the upper layer only when at least one modification indicator bit corresponding to the MBMS service activated by the UE is set to one. If all of the modification indicator bits for the MBMS service activated by the UE are set to 0, the received MCCH data is discarded without being delivered to the upper layer, and the physical layer decodes the PDSCH by the MC-RNTI for one MCCH modification period. Stop and resume PDSCH decoding by MC-RNTI in the next MCCH modification period.

1 is a diagram illustrating a structure of a channel related to MBMS in a UMTS mobile communication system;

2 is a diagram illustrating a configuration of an MBMS related channel according to a single-cell transmission scheme in a 3GPP LTE mobile communication system to which the present invention is applied;

3 is a functional block diagram of a transmitter for providing an MBMS service according to the present invention.

4 is a timing diagram illustrating a change cycle and a repeat cycle of an MCCH among logical channels;

FIG. 5 illustrates a general structure of a MAC PDU delivered through a DL-SCH transport channel in an LTE mobile communication system.

6A through 6C are diagrams illustrating structures of a MAC PDU sub-header in an LTE mobile communication system.

7A to 7C are diagrams illustrating the structure of a MAC PDU sub-header for use in a 3GPP LTE-Advanced mobile communication system according to the present invention;

8A is a control flow diagram for generation and transmission of MCCH in accordance with the present invention;

8b is a control flow diagram for generation and transmission of an MTCH in accordance with the present invention;

9A and 9B are diagrams of a structure of a MAC PDU payload including MCCH data (PDU) and MCCH modification indicator for MBMS control information transmission according to the present invention in an LTE mobile communication system;

10 is an internal block diagram of a terminal for receiving an MBMS service according to the present invention in a terminal of a 3GPP LTE mobile communication system;

11 is a control flowchart for receiving an MBMS service from a terminal using a scheme according to the present invention.

Claims (14)

An apparatus for providing MBMS in a wireless communication system, An MBMS component for generating a MAC packet by generating a sub-header corresponding to each MBMS traffic for each MBMS service data and mapping them to a logical MBMS traffic channel; An MCCH configuration unit for receiving the control information on the MBMS traffic, generating a sub-header, and generating MAC packets using them to map the logical MBMS control channel (MCCH); A scheduler for determining and scheduling transmission time and priority of the MTCH and MCCH; And a transmitter for mapping at least one of the MTCH and the MCCH into a physical downlink shared channel (PDSCH) and providing identification information indicating transmission of an MBMS to the PDSCH through a physical downlink control channel. . The method of claim 1, wherein the identification information, And an identifier (MC-RNTI) for indicating the MCCH or an identifier (MT-RNTI) for indicating the MTCH. The method of claim 2, And transmitting the MCCH and the MTCH together in the MAC packet when the MC-RNTI and the MT-RNTI have the same value. The method of claim 1, wherein the MTCH or sub-header of the MCCH, And a field indicating the MBMS traffic. The method of claim 1, Receiving modification indication information for indicating a change of the MBMS service information, generating a sub-header and generating a MAC packet using them, wherein the sub-header of the modification indicator includes a field indicating the MBMS traffic; And a MCCH modification indication constructing unit that sets the identifier of the sub-header to a modification indicator identifier. The method of claim 5, wherein the scheduler, Provide control information for updated MBMS traffic to the MCCH at each predetermined modification period, have at least one repetition period within the modification period, and provide control information for the updated MBMS traffic to the MCCH in the repetition period. Transmission apparatus for MBMS in a wireless communication system to enable. The method of claim 6, wherein the scheduler, In the modification period, at least the output of the MCCH modification indication configuration unit and the output of the MCCH configuration unit configured to transmit as a single MAC packet, The transmitting apparatus for MBMS in the wireless communication system to transmit in the repetition period to exclude the output of the MCCH modification indication configuration unit transmitted in the modification period. In the method for providing MBMS in a wireless communication system, Generating a MAC packet by generating a sub-header corresponding to each MBMS traffic for each MBMS service data to be transmitted and mapping them to logical MBMS traffic channels; At the time when the control information for the MBMS traffic should be transmitted, a sub-header corresponding to the control information for the MBMS traffic is generated, and MAC packets are generated using these to map to the logical MBMS control channel (MCCH). Generating the packet, Mapping at least one of the MTCH and MCCH to a physical downlink shared channel and transmitting the same; And providing identification information for notifying when the MBMS is transmitted through the physical downlink shared channel (PDSCH) to a physical downlink control channel (PDCCH). The method of claim 8, wherein the identification information, And an identifier (MC-RNTI) for indicating the MCCH or an identifier (MT-RNTI) for indicating the MTCH. 10. The method of claim 9, wherein when the MC-RNTI and the MT-RNTI have the same value, the MCCH and the MTCH are transmitted together in the MAC packet. The method of claim 8, Generating a modification indication information and a sub-header for instructing a change of the MBMS service information and transmitting the modified indication information and a sub-header in a MAC packet by using the same; The sub-header of the modification indicator includes a field indicating the MBMS traffic, and sets the identifier of the sub-header as a modification indicator identifier. The method of claim 11, wherein the MCCH, A modification period for transmitting the MCCH control information and the sub-header for at least the MCCH modification indication information and its sub-header and updated MBMS service information; And a repetition period of transmitting the MCCH control information and its sub-header for updated MBMS traffic transmitted in at least one modification period within a modification period. At least one of an MTCH providing MBMS service data and an MCCH providing control information of the MTCH is provided to a physical downlink shared channel (PDSCH), and the physical downlink control channel (PDSCH) provides identification information indicating the transmission of the MBMS to the PDSCH. In the wireless communication system provided by the method for receiving the MBMS, Receiving the MCCH at the earliest time when the MCCH should be first received when the MTCH is first received, and receiving the MTCH; When the modification period of the received MCCH arrives upon receiving a specific MTCH, checking whether the MCCH is modified by checking a modification indicator; And if the MCCH is modified, providing the received MCCH to a higher level so as to continuously receive the received MTCH. The method of claim 13, When the modification indicator indicates that the UE is not modified for all services currently activated, the MCCH is discarded, and the identifier of the MCCH (MC-RNTI) and the MTCH (MT-RNTI) of the MCCH in the identification information. To check if it is the same, Stopping decoding of the MCCH received through the PDSCH until the MCCH updated by the next modification period when the MC-RNTI and the MT-RNTI are different from each other; If the MC-RNTI and the MT-RNTI are identical to each other, discarding the received MCCH until receiving the MCCH updated by a next modification period.

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