KR100981497B1 - Method and system generating for plcm of bcmcs in communication system - Google Patents

Abstract

The present invention provides a mobile communication system for providing a broadcast service from a base station in a cell to at least one mobile terminal in the cell, wherein the mobile terminal generates a public long code mask for improving reception performance of the broadcast service. Selecting a broadcast information identifier value of one of broadcast information identifiers of flows received from the base station through an arbitrary channel; And generating a public code mask.

Public Long Code Mask (PLCM), PLCM_KEY, BCMC_FLOW_ID, BSR_ID, BCMC_FLOW_ID and BSR_ID pairs.

Description

Method and system for generating open long code mask for broadcasting service in mobile communication system {METHOD AND SYSTEM GENERATING FOR PLCM OF BCMCS IN COMMUNICATION SYSTEM}

1 is a diagram illustrating the structure of a mobile communication system for constructing a general open long code mask (PLCM);

2 is a diagram illustrating a structure of a mobile communication system for constructing a public long code mask (PLCM) according to a first embodiment of the present invention;

3 is a diagram illustrating a structure of a broadcast service parameter message (BSPM) according to embodiments of the present invention;

4 is a diagram illustrating a structure of a public long code mask (PLCM) according to embodiments of the present invention;

5 illustrates generation of a 42 bit public long code mask (PLCM) in accordance with embodiments of the present invention;

6A and 6B illustrate the configuration of flow information and channel information in a BSPM according to embodiments of the present invention;

7 is a diagram illustrating an operation of simultaneously receiving and soft combining a channel for transmitting the same broadcast information according to the second embodiment of the present invention.

The present invention relates to a broadcast service method and system in a mobile communication system, and more particularly, to a method and system for generating channel information for a broadcast service.

Currently, the mobile communication system is proceeding standardization to support broadcast services beyond voice and data services. In order to receive a broadcast service, a mobile terminal must first know which broadcast is being transmitted on which channel. Such broadcast related information is transmitted through a broadcast service message (BCPMS Service Parameter Message (BSPM) or In-Traffic Service Parameter Message), and these messages receive a broadcast flow (hereinafter referred to as a flow) that is currently being broadcast in a cell. Channel information, flow information, channel information of neighboring cells, and the like. It is determined whether broadcast reception is possible according to the broadcast program information identifier (hereinafter referred to as BCMC_FLOW_ID) of the broadcast service, and a broadcast registration message is transmitted. The reason why the reception of the BCMCS Flow_ID is performed is because there is no method for notifying the mobile station whether the broadcast is possible in addition to the broadcast overhead message.

In the conventional CDMA mobile communication system, a long code is used to distinguish users from forward traffic of a unicast service and to obtain a data scrambling effect. Using such a long code could provide a limited level of security for the user and scramble the user's data to distribute the mutual interference generated when multiple users exist. Commonly used public long codes (Public Long Code) is made through a public long code mask (hereinafter referred to as PLCM). Since the PLCM is made unique based on mobile terminal-specific information such as an electronic serial number (ESN), correlation between the PLCMs can be prevented. Therefore, only the user who knows the PLCM can restore the data transmitted from the base station to the specific mobile terminal through the reverse scrambling operation.

However, if a dedicated channel assigned to only a specific user is used in a broadcasting system under discussion, a resource waste occurs due to the characteristics of a broadcast service that simultaneously transmits the same program through many channels. Therefore, the broadcast program is transmitted using a shared channel, and users descramble it with the same PLCM. That is, the mobile terminal receiving the broadcast must know the PLCM of the channel in order to descramble the desired broadcast channel in addition to the mobile terminal's own PLCM.

The broadcast service currently being discussed in the CDMA2000 1x system may be provided to the mobile station in an idle state or a traffic state. In the traffic state, the base station transmits an Extended Channel Assignment Message (ECAM), an Extended Supplemental Channel Assignment Message (ESCAM), a Universal Handoff Direction Message (UHDM), or the like. It explicitly requires the mobile terminal to assign a PLCM. At this time, the base station informs the mobile station of 39 bits necessary for PLCM generation through the ADD_PLCM_FOR_FCH_39 field or the ADD_PLCM_FOR_SCH_39 field in the messages.

On the other hand, in the broadcast service under discussion, two methods of explicitly describing PLCM-related information in a BSPM and informing the mobile terminal or automatically generating a PLCM based on broadcast information already received have been discussed.

In the method of notifying the PLCM information, the ADD_PLCM_FOR_FCH_39 or ADD_PLCM_FOR_SCH_39 field is included in the broadcast service parameter message (BSPM) as in the traffic state to generate the PLCM.

However, for PLCM, the BSPM must include an ADD_PLCM_FOR_FCH_39 or ADD_PLCM_FOR_SCH_39 field for each broadcast physical channel, and the ADD_PLCM_FOR_SCH_39 field has a length of 39 bits. However, considering that the maximum number of channels supported by BSPM is 127 (2 ^ 7-1), the maximum number is increased by (127 * 39) bits. If you do so, the BSPM will be too large.

Among the above methods, a method for generating a required PLCM using broadcast information not directly related to the PLCM is discussed to generate a PLCM using BCMC_FLOW_ID. The BSPM contains the currently transmittable BCMCS_Flow ID list, physical channel information, and neighbor base station information required by the mobile station to receive a broadcast. Current Flow ID can be allocated up to 32 bits, and an example of making a PLCM using this value will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a structure of a mobile communication system for constructing a general open long code mask (PLCM).

Referring to FIG. 1, flow 1, 2, 3 (61, 62, 63) are multiplexed and transmitted through channel 1 (31) in base station 20 of cell A, and channel 2 (32) of the same cell. In this example, Flow 1 64 is transmitted. In fact, the flows in one channel are divided into broadcast information identifiers (hereinafter, referred to as BSR_IDs), and the mobile terminal 10 performs demultiplexing with the separated values and is mapped with the flow IDs to be transferred to the upper level.

The PLCMs 41 and 42 of the channels 31 and 32 may put a Flow ID up to 32 bits in the BCMC_FLOW_ID part, and the remaining bits may be arbitrarily set according to the purpose of the PLCM. The end of the channel is where the long code is multiplied.

As shown in FIG. 1, if the PLCM is created using the minimum flow number supported by each channel 31 and 32, since both channels 31 and 32 generate the PLCM using Flow 1, The two PLCMs 41 and 42 become equal.

As such, when one flow is transmitted through two or more channels, two or more channels may select the same PLCM. However, if two different channels use the same PLCM, the interference dispersion effect between the channels is degraded and the reception performance is degraded.

Also, this method is simple when creating a PLCM using only BCMC_FLOW_ID, and there is no need to manage the PLCM separately. However, in general, the BCMCS system is a packet-based system. Instead of broadcasting only one flow on one channel, multiple flows can be multiplexed and thus cannot be applied in a situation in which multiple flows are transmitted on one channel.

Accordingly, an object of the present invention is to provide a method for automatically generating a different open long code mask for each channel by a mobile station and a base station using additional information without loading a broadcast long code mask (PLCM) for each broadcast channel in a broadcast service parameter message; In providing a system.

Another object of the present invention is to provide a method and system in which a UE can soft handoff by automatically generating a public long code mask for a channel transmitting the same flows in different cells.

The method for achieving the above object of the present invention is a mobile communication system for providing a broadcast service from a base station in a cell to at least one mobile terminal in the cell, the mobile terminal for improving the reception performance of the broadcast service A method of generating a public long code mask, the method comprising: selecting one broadcast information identifier value of broadcast information identifiers of flows received from a base station through an arbitrary channel, the selected broadcast information identifier and broadcast information corresponding thereto; And generating a unique public code mask in the cell using a pair of delimiters.

 And another method for achieving the object of the present invention, in a mobile communication system for providing a broadcast service from a base station in a different cell to at least one mobile terminal in the different cell, the mobile terminal receives the broadcast service A method of generating a public long code mask for improving performance, comprising: soft combining each channel from a base station in the different cell, and one of broadcast information identifier values of flows received through the soft combined channel. And selecting a broadcast information identifier value and generating a unique public long code mask in the cell by using a pair of the selected broadcast information identifier and a broadcast information identifier corresponding thereto.

In addition, the system for achieving the object of the present invention, a mobile communication system for generating a public long code mask for improving the reception performance of the broadcast service, including broadcast information identifiers and broadcast information identifiers over any channel; A broadcast information identifier described first or last in each channel according to a base station transmitting a broadcast service parameter message and a largest value, the smallest value, or a structure of a broadcast service parameter message received from the broadcast service parameter message received from the base station. And a mobile terminal generating a unique public code mask in the cell by using a pair of the selected broadcast information identifier and a broadcast information identifier corresponding thereto.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

An embodiment of the present invention to be described below uses the information of a broadcast service parameter message (BCMCS Service Parameter Message or less, BSPM) by the mobile station itself to improve broadcast reception performance of the mobile station. Extract PLCM). In the embodiment of the present invention, a broadcast program information identifier (hereinafter referred to as BCMC_FLOW_ID) and a broadcast information identifier (hereinafter referred to as BSR_ID) transmitted to the BSPM are simultaneously used to generate a PLCM using only additional information. The BSR_ID is an identifier for distinguishing a plurality of flows transmitted through one channel. Here, the base station can apply the method for allocating an index for generating a PLCM for all broadcast channels using the BSPM, a method for generating a PLCM using BSCMS_FLOW_ID and BSR_ID, or the above-described two methods for each channel separately. One of the methods may be selected to instruct the mobile terminal. That is, the method for the UE to use the PLCM is determined according to the FCSCH_PLCM_SCHEME_ID field value. First, the structure of the system for generating the PLCM and the BSPM and PLCM structure will be described with reference to the accompanying drawings.

2 is a diagram illustrating a structure of a mobile communication system for constructing a public long code mask (PLCM) according to a first embodiment of the present invention.                     

In the current CDMA2000 1x BCMCS system, BSR_ID is used to distinguish multiple flows in one channel.

In the mobile communication system for generating a PLCM, the base station 120 transmits the multiplexing BCMC_FLOW_ID to each channel (131, 132) to the mobile terminal (110).

The mobile terminal 110 uses the pair of BCMC_FLOW_ID and BSR_ID to prevent the PLCM from overlapping between channels in cell A. The mobile terminal 110 multiplexes the received flows multiplexed into the respective channels 131 and 132 into BSR_IDs, maps them to BCMC_FLOW_IDs, and transfers the received flows to higher layers. The mapping information of BCMC_FLOW_ID and BSR_ID is received from the base station 120 through the BSPM. That is, data received through the channel can be distinguished only by the BSR_ID. Therefore, even though one flow is transmitted through several channels, the BCMC_FLOW_ID and BSR_ID pairs can be unique values because the BSR_ID can be allocated differently. The fact that the BCMC_FLOW_ID and BSR_ID pairs are unique in one cell means that the PLCM is also unique in that cell, so it is very unlikely that the same PLCM is allocated to different channels in one cell.

3 is a diagram illustrating a structure of a broadcast service parameter message (BSPM) according to an embodiment of the present invention. Here, {} indicates that the record is repeated as many times as the number of parameters in parentheses.

Referring to FIG. 3, the "NUM_FSCH" field of the first record included in the BSPM indicates the number of forward broadcast auxiliary channels (FSCH), and "FSCH_PLCM_SCHEME_IND" indicates a forward broadcast auxiliary channel open long code mask (PLCM) method indicator. Indicates. Here, the indication bits according to each PLCM method are shown in Table 1 below.

FSCH PLCM SCHEME IND (binary)
LCM scheme used PLCM method used
00 A method of allocating an index through FSCH_PLCM_INDEX and generating a PLCM using the index value. Applies to all channels (F-SCH). 01
How to create PLCM of corresponding channel with BCMC_FLOW_ID and BSR_ID value. Applies to all channels (F-SCH). 10
How to specify whether to use the index allocation method or the generation method using BCMC_FLOW_ID and BSR_ID for each channel (F-SCH).  11 Reserved value

In Table 1, the indication value "00" of "FSCH_PLCM_SCHEME_IND" is a value indicating a method of allocating an index through "FSCH_PLCM_INDEX" and generating a PLCM with the index value, and applies to all channels (F-SCH). do.

"01" is a value indicating the method of generating the PLCM of the corresponding channel using BCMC_FLOW_ID and BSR_ID, and is applied to all the F-SCHs.

"10" indicates a method of designating each channel (F-SCH) whether to use an index allocation method or a method of generating using BCMC_FLOW_ID and BSR_ID, and "11" indicates a reserved value.

Referring to FIG. 3 again, "FSCH PLCM IND" included in the second record is a forward broadcast auxiliary channel PLCM method indicator, which is included when the FSCH PLCM SCHEME IND is set to '10', and has a length of 0 or 1 bit. Have Here, if the PLCM is determined by the index allocation method, the F-SCH channel is set to '1', and if the PLCM is generated using BCMC_FLOW_ID and BSR_ID, it is set to '0'. And "FSCH_PLCM_INDEX" included in the second record indicates the F-SCH PLCM generation index, and has a length of 0 or 8 bits. Here, if FSCH_PLCM-SCHEME_IND is '00' or FSCH_PLCM_IND is included and set to '1', the base station includes this field and omits it if it is set to another value. The base station sets an index to generate a PLCM used for the F-SCH.

The second record is a variable length record and is repeated NUM_FSCH times.

"BCMC_FLOW_ID", included in the third record, is an identifier of broadcast service FLOW and has a length of 16, 24, or 32 bits, and "NUM_LPM_ENTRIES" is a number of logical and physical parameter mapping entries, and has a length of 3 bits.

"BSR_ID" included in the fourth record has a length of 3 or 16 bits as a broadcast information identifier, and "NUM_NGHBR" is a number of neighbor base station broadcast related parameters and has a length of 0 or 6 bits.

"NGHBR_FSCH_PLCM) IND" included in the fifth record is an indicator of a forward broadcast auxiliary channel PLCM method of a neighbor base station and has a length of 0 or 1 bit. If "NGHBER_FSCH_PARMS_INCL" is not included or is included and is set to '0', the "NGHBR_FSCH_PLCM) IND" is not included. Otherwise, if the F-SCHDP index allocation method is used, the "NGHBR_FSCH_PLCM) IND" field is set to '1'. If the PLCM is generated using the BSR_ID corresponding to BCMC_FLOW_ID, the "NGHBR_FSCH_PLCM) IND" field is set to '0'.

"NGHBR_FSCH_PLCM_INDEX" included in the fifth record is an index for generating an F-SCH PLCM and has a length of 0 or 8 bits. Here, if NGHBER_FSCH_PLCM_IND is not included or is included and is set to '0', the base station omits the field. On the other hand, if not, the base station sets the index value including the field and can generate the PLCM used for the F-SCH.

After the third record, the variable length record is repeated as many as "NUM_BCMC_FLOWS times," and after the fourth record, as the variable length record, the number is repeated as many as NUM_LPM_ENTRIES. The fifth record is repeated as many as "NUM_NGHBR".

4 is a diagram illustrating a structure of a public long code mask (PLCM) according to embodiments of the present invention.

The PLCM has a length of 42 bits, and as shown in FIG. 4, the BSR_ID is placed near the Least Significant Bit (LSB), and then filled with BCMC_FLOW_ID, and the portion of the Most Significant Bit (MSB). The remaining bits are filled with '1' as an example. Here, as shown in FIG. 2, the remaining bits are filled with '1', but it should be noted that this may be set arbitrarily and filled. Here, if the length of BCMC_FLOW_ID and the length of BSR_ID do not exceed 40 bits, the PLCM can be configured as described above. When BCMC_FLOW_ID is 32 bits and BSR_ID is 3 bits, seven '1's are inserted into the MSB side of the PLCM. On the other hand, if the sum of the two values is more than 40 bits, another method must be used. The generation of PLCM in this case will be described with reference to the accompanying drawings.

5 illustrates generation of a 42 bit open long code mask (PLCM) in accordance with embodiments of the present invention.

Referring to FIG. 5, since the sum of the lengths of BCMC_FLOW_ID and BSR_ID is 40 bits or more, the MS makes a 42-bit PLCM by XOR 180 of the BSR_ID upper bits and the BCMC_FLOW_ID lower bits, respectively. Here, MSB 3bit may be set to '1' as an example, and the value may be filled with any other value.

A method for generating a PLCM by uniquely allocating a pair of BCMC_FLOW_ID and BSR_ID in such a mobile communication system will be described with reference to the accompanying drawings. First, when the mobile terminal 110 configures the BCMC_FLOW_ID when configuring the PLCM will be described.

There are several ways to select BCMC_FLOW_ID depending on how the flow is configured in the channel. If only one flow is transmitted on one channel, BCMC_FLOW_ID is not a problem because there is only one per channel. Even when one flow is transmitted over several channels, it does not matter because each channel has only one BCMC_FLOW_ID. However, when one channel transmits multiple flows, one BCMC_FLOW_ID must be selected. Any algorithm that can select one BCMC_FLOW_ID or BCMC_FLOW_ID and BSR_ID pairs when receiving a plurality of BCMC_FLOW_ID or BCMC_FLOW_ID and BSR_ID pairs as arguments is possible, and BSR_ID selects a value corresponding to the selected BCMC_FLOW_ID.

As an example of the selection algorithm described above, when a plurality of flows are transmitted to a channel through which a flow desired to be received by a user is transmitted, there may be a method of selecting a flow having a minimum BCMC_FLOW_ID value or a maximum BCMC_FLOW_ID value among the flows. Can be. When the lengths of the BCMC_FLOW_ID are different from each other, the lengths of BCMC_FLOW_ID are compared after padding the upper bits of the short BCMC_FLOW_ID based on the length of the longest BCMC_FLOW_ID with '0'. .

As another example of the above-described selection algorithm, a specific flow may be selected based on the BSPM structure. At present, there is mapping information on which flow is transmitted to which channel in BSPM. Referring to the accompanying drawings, how the flow information and the channel information are configured in the BSPM will be described below.

As shown in FIG. 6A, the list of channels through which a flow is transmitted to the BSPM may represent, for example, that Flow (A) is composed of a list of channels a, ..., m. In addition, if the list of channels through which a flow is transmitted to the BSPM as shown in FIG. 6A is expressed in reverse, as shown in FIG. 6B, it is possible to express which flows are transmitted to a specific channel. Here, one BCMC_FLOW_ID must be selected in order to generate a PLCM in a specific channel. At this time, the BCMC_FLOW_ID of the specific second described Flow is selected. As one of the BCMC_FLOW_ID selections, a flow ID appearing at the top or bottom may be selected. In FIG. 8, when the flow described above is selected as an example, BCMC_FLOW_ID of Flow A is selected.

The PLCM generation method described above is applied to FIG. 1 and flows 2, 3, and 4 (161, 162, respectively) in two different channels 131 and 132 shared by all mobile terminals 110 in a cell in cell A. Referring to operation 163 and the flow 4, 1 (164, 165) is transmitted as follows.

When transmitting flows, each flow 161, 162, 163 and 164, 165 in each channel 131, 132 is multiplexed with BSR_ID and transmitted. Then, the mobile terminal 110 generates a PLCM by connecting the " 1111 " of the upper bit part to the PLCM key value selected for each channel 131 and 132 according to the PLCM selection method. Thereafter, the mobile terminal 110 maps the BSR_IDs 151, 152, and 153 and the flows 161, 162, and 163 to respective channels 131 and 132 to obtain a flow corresponding to the corresponding BCMC_FLOW_ID. To send.

As shown in FIG. 2, in case of Flow 4 (163, 164), transmission is performed over two channels, but BSR_ID is set differently to 1 (151) and 4 (154) in each channel (BCMC_FLOW_ID, BSR_ID). ) Pairs have different values. That is, as shown in FIG. 2, the table below shows that the PLCMs 141 and 142 are different from each other. BCMC_FLOW_ID and channel 2 (for channel 1 in cell A) 131 are different from each other. BCMC_FLOW_ID for Channel 2 in cell A) 132 are all equal to FLOW_ID 4 (0 ... 0100). However, it can be seen that BSR_ID is different from BSR_ID 1 (001) for channel 1 131 and BSR_ID 4 (100) for channel 2 132.

If the flow with the maximum value is selected in the channel, if the corresponding (FLOW_ID, BSR_ID) is used to create the PLCM, the PLCMs of the two channels do not overlap each other because the FLOW_ID is the same but the BSR_ID is different.

Meanwhile, in the first embodiment of the present invention as described above, an operation of generating PLCM by receiving flows through different channels in a base station in one cell A has been described. In the second embodiment of the present invention, cells A and B are described. The operation of generating a PLCM in the case of transmitting the same flows and receiving a channel having the same PLCM value will be described.

Even in different cells, the same PLCM can be automatically generated for a channel transmitting the same flows, so that soft combining is possible for the mobile terminal. An operation for such soft combining will be described with reference to the accompanying drawings.

7 is a diagram illustrating an operation of simultaneously receiving and soft combining a channel for transmitting the same broadcast information according to the second embodiment of the present invention.

The base stations 120a and 120b each transmit the same flows in the cells A and B and simultaneously transmit a channel having the same PLCM value to the mobile terminal 110. Accordingly, the mobile terminal 110 receiving the BCMC_FLOW_ID 4 263 from the base station 120 receives the signals of the channels 231 and 232 of the cells A and B in the soft handover region and performs soft combining. In other words, after receiving the signals of the channels 231 and 232, the energy of the two signals is summed.

Then, the mobile terminal 110 descrambles the combined signal into a long code at a channel end part, and then demultiplexes the BSR_ID into a flow ID to transfer the mapped signal to a higher layer.

In this soft combining operation, the mobile terminal 110 in the soft handover area receives signals from both base stations 120a and 120b. However, in order to descramble after receiving signals from two channels 231 and 232 transmitting the same information and combining them, the two channels must be scrambled with the same PLCM. In addition, if the (BCMC_FLOW_ID, BSR_ID) values of the channels 231 and 232 carrying the same information are the same in all cells belonging to the soft handover group, the channels 231 and 232 of each cell are all the same. It will have a PLCM value. That is, as shown in FIG. 6, the lower table is an embodiment in which the channels 231 and 232 represent the same PLCM. The BCMC_FLOW_ID and the channel 2 (Channel 1) for the channel 1 (Channel 1 in cell A) 231 are shown. Notice that both BCMC_FLOW_ID for 2 in cell A) 232 are the same as BCMC_FLOW_ID 4 (0 ... 0100), and that the BSR_IDs for channel 1 231 and channel 2 232 are also equal to BSR_ID 1 (001). have.

In this case, the mobile terminal 110 may receive a soft signal from the different base stations 120a and 120b in the soft handover region from the different base stations 120a and 120b. This operation eventually helps to improve the reception performance, which enables soft handover. In this case, for the soft combining, signals of two base stations that are first received by a mobile terminal should be the same, but the same means that the information after the despreading by the Walsh code is the same. After backspreading with the Walsh code, the energy of the two signals is combined to descramble one long code so that both channels must be scrambled using the same PLCM.

Therefore, in the embodiment of the present invention, since flows are allocated to the BSR_IDs according to a predetermined rule without involvement of the base station, even though the cells are different, the same PLCM can be used to soft combine. Can be.

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 defined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, in the present invention, when one flow is transmitted through multiple channels in one cell, the BCMC_FLOW_ID and BSR_ID pairs transmitted in each channel are artificially assigned to be unique in the cell so that the PLCM does not overlap between channels. Therefore, the interference between channels can be distributed, which can help to improve performance.

In addition, since the base station does not allocate the PLCM to the mobile terminal, the base station and the mobile terminal generate the PLCM from the information that they already have according to a predetermined method, thereby saving radio resources.

Claims (22)

A method of providing a broadcast service in a communication system providing a broadcast service from at least one base station to at least one mobile terminal, Transmitting a broadcast service parameter message (BSPM) including information related to a channel for transmitting a broadcast program, a broadcast program information identifier (BCMC_Flow_ID) and a broadcast information identifier (BSR_ID) indicating the broadcast program; , Generating a code mask using the broadcast program information identifier and the broadcast information separator; And transmitting the broadcast program through the channel using the code mask. The method of claim 1, wherein the generating of the code mask comprises: Disposing the broadcast information separator in a portion including the least significant bit of the code mask; And disposing the broadcast program information identifier in a next portion of the broadcast information separator. The method of claim 2, And disposing a predetermined bit sequence in the remaining part of the code mask. The method of claim 1, The broadcast service parameter message further includes a plurality of broadcast program information identifiers and a plurality of broadcast information identifiers. The method of claim 4, wherein Selecting one broadcast program information identifier based on values of the plurality of broadcast program information identifiers in the broadcast service parameter message; And using the one selected broadcast program information identifier in the process of generating the code mask. The method of claim 4, wherein Selecting one broadcast program information identifier based on a sequence number of the plurality of broadcast program information identifiers in the broadcast service parameter message; And using the one selected broadcast program information identifier in the process of generating the code mask. A method of receiving a broadcast service in a communication system providing a broadcast service from at least one base station to at least one mobile terminal, Receiving a broadcast service parameter message (BSPM) including information related to a channel for transmitting a broadcast program, a broadcast program information identifier (BCMC_Flow_ID) and a broadcast information identifier (BSR_ID) indicating the broadcast program; , Generating a code mask using the broadcast program information identifier and the broadcast information separator; And receiving the broadcast program through the channel using the code mask. The method of claim 7, wherein the generating of the code mask comprises: Disposing the broadcast information separator in a portion including the least significant bit of the code mask; And disposing the broadcast program information identifier in a next portion of the broadcast information separator. The method of claim 8, And disposing a predetermined bit sequence in the remaining part of the code mask. The method of claim 7, wherein The broadcast service parameter message further includes a plurality of broadcast program information identifiers and a plurality of broadcast information identifiers. The method of claim 10, Selecting one broadcast program information identifier based on values of the plurality of broadcast program information identifiers in the broadcast service parameter message; And using the one selected broadcast program information identifier in the process of generating the code mask. The method of claim 10, Selecting one broadcast program information identifier based on a sequence number of the plurality of broadcast program information identifiers in the broadcast service parameter message; And using the one selected broadcast program information identifier in the process of generating the code mask. In a cellular communication system that provides a BroadcastCast MultiCast (BCMC) service from at least one base station to at least one mobile station, a mobile terminal receiving the broadcast multicast service is provided with a public long code mask (PLCM). In the method for generating) Receiving a broadcast service parameter message (BSPM) including at least one broadcast program information identifier (BCMC_Flow_ID) and a broadcast information identifier (BSR_ID); Selecting one broadcast program information identifier and a broadcast information separator; And generating a public long code mask using the broadcast program information identifier and the broadcast information separator. The method of claim 13, wherein the broadcast program information identifier, The method of claim 1, wherein the broadcast service parameter message is selected based on a sequence of a plurality of broadcast program information identifiers. The method of claim 14, wherein the broadcast program information identifier, And a first broadcast program information identifier is selected from the broadcast service parameter message. The method of claim 13, wherein the broadcast program information identifier, The method of claim 1, wherein the broadcast service parameter message is selected based on values of a plurality of broadcast program information identifiers. The method of claim 13, wherein generating the public long code mask comprises: Disposing the broadcast information separator in a portion including the least significant bit of the public long code mask; And disposing the broadcast program information identifier in a next portion of the broadcast information separator. The method of claim 17, And disposing a predetermined bit sequence in the remaining part of the open long code mask. In a mobile communication system including a base station and at least one mobile terminal located in a cell occupied by the base station and providing a BroadcastCast MultiCast (BCMC) service from the base station to the mobile terminal, the mobile terminal broadcasts. In a system for generating a public long code mask (PLCM) to receive a multicast service, Broadcast program information identifiers (BCMC_Flow_IDs) representing broadcast program identifiers for identifying broadcast programs transmitted from respective broadcast stations, and information on broadcast information identifiers (BSR_IDs) respectively matched to the broadcast program information identifiers. A base station for transmitting a broadcast service parameter message (BSPM) to the mobile terminal through at least one channel; Receiving the broadcast service parameter message from the base station, selecting one broadcast information identifier matched with one of the broadcast program information identifiers from the broadcast service parameter message, and selecting the broadcast program information identifier and the broadcast matched thereto. And a mobile terminal for generating a unique public long code mask in the cell using an information delimiter. The method of claim 19, wherein the one program information identifier, And having the largest value or the smallest value and being selected from among the broadcast program information identifiers received from the base station. The method of claim 19, wherein selecting one of the broadcast program information identifiers comprises: And a highest or lowest broadcast program information identifier included in the broadcast service parameter message is selected. The method of claim 19, wherein the broadcast service parameter message, And a public long code mask, which is transmitted to the mobile terminal at a predetermined period through a paging channel.

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