KR20090032184A - Apparatus and method for mbms over a single frequency network in mobile communication system - Google Patents

Abstract

An apparatus for performing a single frequency network broadcast service of the mobile communication system and a method therefor are provided to perform the synchronizing process by using a system information block of a broadcast channel including the time difference between a WCDMA frame boundary for a single frequency network broadcast service cluster(MBSFN cluster) and a frame boundary for an MBSFN. A portable terminal comprises an SIB(System Information Block) confirming unit(402) and a controller(400). The SIB confirming unit checks a system information block including information about the frame boundary time difference between an MBMS over a single frequency network cluster and an adjacent cell. The controller obtains the frame synchronization by using the time difference related to the frame boundary of the system information.

Description

Apparatus and method for performing single frequency network broadcasting service of mobile communication system {APPARATUS AND METHOD FOR MBMS OVER A SINGLE FREQUENCY NETWORK IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a synchronization channel for searching for cell synchronization of a system in a single frequency network broadcast service. Relates to a device.

Due to the development of communication technology, the services provided by the mobile communication system using the wideband code division multiple access (CDMA) scheme are not only conventional voice services but also large capacity such as packet data and circuit data. It is evolving into packet service communication for transmitting data and multimedia broadcasting / communication for transmitting multimedia service. Accordingly, in order to support the multimedia broadcasting / communication, a multicast multimedia broadcasting service (MBMS) providing a service from one or multiple multimedia data sources to a plurality of user equipments (UE) is discussed. It is becoming.

1 is a diagram illustrating a multimedia broadcast / multicast service (MBMS) of a general mobile communication system.

Referring to FIG. 1, the portable terminals 131, 132, 133, 134, and 135 refer to portable terminals capable of receiving MBMS services, and cell 1 121 and cell 2 122 refer to cell 3 ( 133 is controlled by a base station, Node B, which wirelessly transmits MBMS-related data to the portable terminals 131, 132, 133, 134, and 135. A radio network controller (RNC) 110 controls the plurality of cells 121, 122, and 123, selectively transmits multimedia data to a specific cell, and sets a radio channel configured to provide an MBMS service. To control. The connection between the RNC 110 and the portable terminals 131, 132, 133, 134, and 135 is connected to a Radio Resource Control (RRC) interface.

 In general, the MBMS service supports multimedia transmission forms such as real-time video, audio, still images, text, etc., and can provide voice data and video data simultaneously according to the multimedia transmission format. In the case of the MBMS service, since the same data must be transmitted to a plurality of cells in which users are located, one-to-one or point-to-multiple access is made according to the number of users located in each cell.

Because the MBMS service needs to send the same information to several people due to the characteristics of a broadcast, a specific mobile terminal can maintain a good channel state by using S-CCPCH, which is a common channel, instead of using a dedicated channel allocated to each user. In case of a mobile terminal located in a radius, there is a problem in that a relatively good channel cannot be received. Accordingly, although techniques such as soft combining or selective combining have been used, a problem arises in that the configuration of the portable terminal is complicated by the above technique.

The above problem is solved by using a single frequency network broadcasting service (MBSFN; MBMS over a Single Frequency Network).

2 illustrates a structure of a single frequency network broadcast service. In the following description, FIG. 3 is a diagram illustrating a structure of a synchronization channel used in the single frequency network broadcast service.

Referring to FIG. 2, there are MBSFN clusters 210, 211, and 212 controlled by the RNC-A 230, the RNC-B 231, and the RNC-C 232, respectively. The MBSFN cluster includes multimedia data. Selectively transmits to a specific cluster, and controls the radio channel configured to provide MBSFN service. In addition, the MBSFN cluster is composed of a number of cells are bundled into one cluster, and all cells belonging to the MBSFN cluster are controlled by one RNC to transmit data using a primary scrambling code such as the same frequency. In addition, the single frequency network service includes a total of five primary synchronization channels (P-SCH), secondary synchonization channels (S-SCH), common pilot channels (CPICH), primary common control physical channels (P-CCPCH), and S-CCPCH. There are no channels associated with Dedicated Physical Channel (DPCH) and High Speed Dedicated Packet Access (HSDPA), which are used in conventional WCDMA using only two channels. Therefore, since the interference is eliminated, the channel environment is improved, and a high modulation technique (16 QAM) can be used. Among the channels, P-SCH and S-SCH, which are synchronous channels, have a structure as shown in FIG. As shown in FIG. 3, one frame of the synchronization channel includes 15 slots including slots # 0 to # 14. One slot includes 2560 chips and one frame includes 38400 chips.

The P-SCH 310 and the S-SCH 311 are transmitted by N (= 256) chip lengths at the beginning of every slot, and the first synchronization code Cp 320 used for the P-SCH 310 is used. ) Is the same for each slot, and all cells are used identically, and only one chip slot, which is 1 / 10th of a slot, is repeatedly transmitted in every slot. The portable terminal uses the P-SCH 310 to find the slot timing of the received signal.

The second synchronization code of the base station, that is, code group designation codes (Csi, 0 to Csi, 14) (331, 332, ..., 344) is mapped and transmitted to the S-SCH 311, and the P-SCH The portable terminal which acquires the synchronization of the time slot by using the S-SCH detects the code group designation code and the frame synchronization.

The P-SCH 310 and the S-SCH 311, which are the synchronization channels, are channels necessary for slot synchronization and frame synchronization acquisition. Using the Golay sequence, each channel is affected by the interference of each Ec / Ior. Due to the nature of the SCH repeated 256 chips per slot, there is a problem that other channels generate interference by 1/10 in each slot. In addition, there is a problem in that a synchronization channel for informing its own synchronization to the portable terminal is arranged in MBSFN and WCDMA networks.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus and method for reducing channel interference according to a single frequency network broadcast service in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for providing time difference information on a frame boundary in a system information block in order to reduce channel interference caused by a single frequency network broadcast service in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for performing a synchronization process by using a time difference on a frame boundary of a system information block through a broadcast channel when using a single frequency network broadcast service in a mobile communication system.

According to a first aspect of the present invention for achieving the above object, a portable terminal for a MBSFN (MBSFN over a Single Frequency Network) is a mobile terminal of a single frequency network broadcast service cluster (MBSFN cluster) and the adjacent cell A system information block checking unit for identifying a system information block (SIB) including frame boundary time difference information, and a control unit for obtaining frame synchronization using a time difference with respect to a frame boundary of the system information block; Characterized in that.

According to a second aspect of the present invention for achieving the above objects, a mobile communication system for providing a MBMS over a Single Frequency Network (MBSFN) and a single frequency network broadcast service cluster (MBSFN cluster) And a base station providing a system information block (SIB) including frame boundary time difference information of an adjacent cell, and a portable terminal performing a frame synchronization acquisition process using the frame boundary time difference information. It is done.

According to a third aspect of the present invention for achieving the above objects, a method for performing a MBMS over a Single Frequency Network (MBSFN) in a portable terminal includes a system information block (SIB) through a broadcast channel; Confirming a system information block, acquiring frame boundary time difference information between a single frequency network broadcast service cluster (MBSFN cluster) included in the service information block and an adjacent cell, and time for the obtained frame boundary. And obtaining a frame sync using the difference.

According to a fourth aspect of the present invention for achieving the above object, a method for providing a MBMS over a Single Frequency Network (MBSFN) in a mobile communication system is a single frequency network broadcast service cluster (MBSFN cluster) And a method for providing a single frequency network broadcast service of a base station providing a system information block (SIB) including frame boundary time difference information of an adjacent cell and a frame synchronization acquiring process using the frame boundary time difference information. It characterized in that it comprises a method for providing a single frequency network broadcast service of a portable terminal for performing the.

As described above, the present invention provides the time difference information on the WCDMA frame boundary for the single frequency network broadcast service cluster (MBSFN cluster) and the frame boundary for the MBSFN when performing a synchronization process in a portable terminal using a single frequency network broadcast service. By performing a synchronization process using a system information block of a broadcasting channel, the inter-channel interference of each Ec / Ior due to P-SCH and S-SCH, which are sync channels, can be solved. Surplus information for arranging synchronization channels can be solved. In addition, in TSTS.211-720 for MBSFN, S-CCPCH data is not transmitted in 256 chip sections of every slot in which synchronization channels are transmitted in slot formats 21 to 23 to remove interference on the synchronization channel. In other words, in this interval, the timing condition that the TFCI and the data field do not enter and the pilot field only is constrained. I can solve it.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the present invention, in order to reduce channel interference according to a single frequency network broadcasting service in a mobile communication system, an apparatus for performing a synchronization process by using a time difference on a frame boundary of a system information block through a broadcast channel when using a single frequency network broadcasting service. And the method will be described. In this case, the mobile communication system calculates a time difference between a cluster boundary of a single frequency network broadcast service and a frame boundary of an adjacent cell and adds it to the system information block and transmits it to the portable terminal through a broadcast channel.

4 is a block diagram illustrating a configuration of a portable terminal for performing a single frequency network broadcast service according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the portable terminal includes a controller 400, a system information block (SIB) checking unit 402, a memory unit 404, an input unit 406, a display unit 408, and a communication unit ( 410 may be configured to be included.

First, the controller 400 controls the overall operation of the portable terminal. For example, processing and control for voice call and data communication, and in addition to the usual function, according to the present invention, the system information block check unit 402 is a broadcast channel (BCH) which is a transmission channel Through checking the system information block (SIB) for the cell through the instruction to obtain the time difference information of the WCDMA frame boundary for the single frequency network broadcast service cluster (MBSFN cluster). Thereafter, the controller changes the frequency to a single frequency network broadcast service using the time difference information and performs the single frequency network broadcast service.

The system information block checking unit 402 checks a system information block for a cell through a broadcast channel and obtains time difference information on a frame boundary. In other words, the system information block checking unit obtains a time difference between a WCDMA frame boundary for a single frequency network broadcast service cluster (MBSFN cluster) and a frame boundary for an MBSFN, and the system information block type includes an existing System Information Block type. 11 includes a time difference for a frame boundary according to the present invention.

The memory unit 404 is composed of a read only memory (ROM), a random access memory (RAM), and a flash ROM. The ROM stores a microcode and various reference data of a program for processing and controlling the control unit 400 and the system information block check unit 402.

The RAM is a working memory of the controller 400, and stores temporary data generated while executing various programs. In addition, the flash ROM stores various updatable storage data such as a phone book, an outgoing message, and an incoming message.

The input unit 406 is a numeric key buttons of 0-9, menu button (menu), cancel button (clear), confirmation button, call button (TALK), end button (END), Internet access button, navigation key ( Or a plurality of function keys such as arrow keys) buttons and character input keys, and provides key input data corresponding to a key pressed by the user to the controller 400.

The display unit 408 displays status information generated during the operation of the portable terminal, a limited number of characters, a large amount of video and still images, and the like. The display unit 408 may use a color liquid crystal display (LCD).

The communication unit 410 transmits and receives a radio signal of data input / output through an antenna (not shown). For example, in the case of transmission, after performing channel coding and spreading on the data to be transmitted, RF processing is performed to transmit the data. In the case of reception, the received RF signal is converted into a baseband signal. The baseband signal is de-spreaded and channel decoded to restore data.

The role of the system information block check unit 402 may be performed by the controller 400 of the portable terminal. However, in the present invention, the system information block check unit 402 is an exemplary configuration for convenience of description. It is not intended to limit the scope, and one of ordinary skill in the art will recognize that various modifications are possible within the scope of the invention. For example, the controller 100 may be configured to process all of them.

5 is a diagram illustrating a time difference with respect to a frame boundary according to an exemplary embodiment of the present invention. In the following description, FIG. 6 is a diagram illustrating a timing difference between an existing WCDMA cell and an MBSFN cluster according to an embodiment of the present invention.

Referring to FIG. 5, the portable terminal 530 receiving a service from an existing WCDMA cell is present in a single frequency network broadcast service cluster (MBSFN cluster) 610.

First, assuming that the portable terminal 530 is located in the WCDMA cell A 520 before receiving the MBSFN service, the portable terminal is a WCDMA cell A (520), B (521), C for cell management A cell search process is performed with respect to 522 to receive system information about each cell.

In addition, when the WCDMA cells A 520, B 521, and C 522 are all present in one MBSFN cluster 510, as shown in FIG. 6, each cell has its own MBSFN. Since the frame boundary 620 is known, the time difference between the serving WCDMA frame boundaries 630, 631, and 632 and the frame boundary for the MBSFN can be calculated. In other words, each cell calculates the time difference of the WCDMA frame boundary for the MBSFN frame (time difference Diff A 610 for cell A, time difference Diff B 611 for cell B, and time difference for cell C). Diff C 612).

7 is a flowchart illustrating a process of performing a single frequency network broadcast service of a portable terminal according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the portable terminal performs an initial cell search through a WCDMA network in step 701. Thereafter, the portable terminal proceeds to step 703 and prepares to perform the cell search step 3. That is, in step 703, the portable terminal receives a P-SCH, which is a synchronization channel for performing slot synchronization, among slot acquisition, frame synchronization, and scrambling code acquisition, and proceeds to step 705. A synchronization of a base station slot time is obtained using a first synchronization code Cp included in the P-SCH.

In step 707, the portable terminal performs a frame synchronization acquisition process. That is, the portable terminal detects the code group designation code and the frame sync using the second synchronization code included in the S-SCH, that is, the code group designation codes Csi, 0 to Csi, 14, to acquire frame synchronization. Perform the process. Here, the code group designation code is information for determining a code group to which the base station belongs, and the synchronization acquisition process is the same as the process performed in the existing mobile communication system.

In step 709, the portable terminal performing the time slot synchronization acquisition process and the frame synchronization acquisition process acquires a scrambling code to be used.

In step 711, the portable terminal checks whether the mobile station enters into a MBMS (MBMS over a Single Frequency Network) mode. If the mobile station determines to enter the single frequency network broadcast service mode, the portable terminal proceeds to step 713 in which a system information block (SIB) for a cell is transmitted through a broadcast channel (BCH) which is a transport channel. ). Here, the system information block includes time difference information on a WCDMA frame boundary for a single frequency network broadcast service cluster (MBSFN cluster) and a frame boundary for MBSFN according to the present invention as shown in Table 1 below.

In step 715, the portable terminal checks the time difference on the frame boundary. In step 717, the portable terminal changes the frequency to the single frequency network broadcasting service using the time difference on the frame boundary.

In step 719, the portable terminal acquires cluster synchronization through multi-path discovery of the CPICH. In step 721, the portable terminal performs a multi-frequency network broadcasting service.

The portable terminal then terminates this algorithm.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible 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 the equivalents of the claims.

1 is a diagram illustrating a multicast multimedia broadcasting service of a general mobile communication system;

2 is a diagram illustrating a structure of a single frequency network broadcast service;

3 is a diagram illustrating a structure of a synchronization channel used in the single frequency network broadcast service;

4 is a block diagram illustrating a configuration of a portable terminal for performing a single frequency network broadcast service according to an embodiment of the present invention;

5 is a diagram illustrating a time difference with respect to a frame boundary according to one embodiment of the present invention;

6 illustrates a timing difference between an existing WCDMA cell and an MBSFN cluster according to an embodiment of the present invention;

7 is a flowchart illustrating a process of performing a single frequency network broadcast service of a portable terminal according to an exemplary embodiment of the present invention.

Claims (12)

In a portable terminal for a single frequency network broadcasting service (MBSFN; MBMS over a Single Frequency Network), A system information block identification unit for identifying a system information block (SIB) including frame boundary time difference information of a neighboring cell and a MBSFN cluster; And a controller for acquiring frame synchronization using a time difference with respect to a frame boundary of the system information block. The method of claim 1, The control unit, And processing the frequency change to the MBSFN by acquiring the frame synchronization. The method of claim 2, The control unit, Estimating the MBSFN frame boundary using the time difference with respect to the frame boundary, and performing a multipath search using a common pilot channel (CPICH) near the estimated frame boundary to obtain frame synchronization A portable terminal characterized by the above. In a mobile communication system for providing a single frequency network broadcasting service (MBSFN; MBMS over a Single Frequency Network), A base station providing a system information block (SIB) including a frame frequency time difference information of a neighboring cell and a single frequency network broadcast service cluster (MBSFN cluster); And a portable terminal performing a frame synchronization acquiring process using the frame boundary time difference information. The method of claim 4, wherein The portable terminal, And processing the frequency change to the MBSFN by acquiring the frame synchronization. The method of claim 5, The portable terminal, Estimating the MBSFN frame boundary using the time difference with respect to the frame boundary, and performing a multipath search using a common pilot channel (CPICH) near the estimated frame boundary to obtain frame synchronization Characterized in a mobile communication system. In a method for performing a MBSFN (MBMSN over a Single Frequency Network) in a portable terminal, Identifying a system information block (SIB) through a broadcast channel; Obtaining frame boundary time difference information between a single frequency network broadcast service cluster (MBSFN cluster) included in the service information block and an adjacent cell; And obtaining frame synchronization using the time difference with respect to the obtained frame boundary. The method of claim 7, wherein Method for performing a single frequency network broadcast service in the portable terminal, After acquiring the frame synchronization, changing the frequency to the MBSFN. The method of claim 7, wherein The process of obtaining the frame synchronization, Estimating the MBSFN frame boundary using the time difference with respect to the frame boundary; And performing a multipath search using a common pilot channel (CPICH) near the estimated frame boundary. In the method for providing a MBSFN (MBMSN over a Single Frequency Network) in a mobile communication system, A method for providing a single frequency network broadcast service of a base station providing a system information block (SIB) including frame boundary time difference information of a neighboring cell and a single frequency network broadcast service cluster (MBSFN cluster); And a method for providing a single frequency network broadcast service of a portable terminal performing a frame synchronization acquisition process using the frame boundary time difference information. The method of claim 10, Method for providing a single frequency network broadcast service of the portable terminal, And changing the frequency to the MBSFN by acquiring the frame synchronization. The method of claim 10, The process of acquiring frame synchronization, Estimating the MBSFN frame boundary using the time difference with respect to the frame boundary; And performing a multipath search using a common pilot channel (CPICH) near the estimated frame boundary.

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