KR20040088732A - Broadcasting service method via forward packet data channel in wireless telecommunication system - Google Patents

Abstract

PURPOSE: A broadcasting service method using a forward packet data channel in a wireless communication system is provided to control the frequency of retransmission of broadcasting packet data in a base station by feeding back a receiving performance of a terminal, and to transmit Walsh mask information to the terminal as an overhead message, thereby preventing a service from being temporarily disconnected. CONSTITUTION: An MS(Mobile Station) sets a PPP(Point-to-Point Protocol) connection for a data service with a BS(Base Station) by using an SO 33(Service Option 33) function(200). The MS receives a BSPM(Broadcast Service Parameter Message), and obtains information on a forward traffic channel(210). The MS transmits a registration message to the BS through an access channel at the request of a user(220). The MS starts to receive broadcasting traffic and control information from the BS according to channel information of an FBPDCH included in the BSPM through an F-PDCCH(Forward packet Data Control Channel) and an F-PDCH(Forward Packet Data Channel)(230,240).

Description

Broadcasting service method using forward packet data channel in wireless communication system {BROADCASTING SERVICE METHOD VIA FORWARD PACKET DATA CHANNEL IN WIRELESS TELECOMMUNICATION SYSTEM}

The present invention relates to a wireless data communication system, and more particularly, to a method for providing a broadcast service to a mobile terminal through a forward packet data channel.

The future communication environment is changing rapidly as it transcends the distinction between wired and wireless domains, and regional and national distinctions. In particular, the future communication environment such as IMT-2000 (International Mobile Telecommunication 2000) is a trend that is built as an environment that provides a variety of information in real time and comprehensive as well as video and audio. In addition, the development of a mobile communication system is not only a voice communication in a cellular phone (PCS) or a personal communication system (PCS), but also wirelessly using a mobile station (MS) as well as transmitting text information. It has reached the point where it can watch broadcasting service.

Currently, 3GPP2 (3rd Generation Partnership Project 2) considers various service media and efficient resource use for broadcasting service in mobile communication system. This broadcast service is achieved by unidirectional transmission of high speed forward packet data without backward return information from the mobile terminal. This is conceptually similar to the general television broadcasting service.

When the existing common channel is designed to guarantee the same broadcast service performance up to the cell boundary, excessive cell capacity is consumed. Therefore, in the CDMA2000 system, which is a third generation mobile communication system, broadcasting is performed through a supplemental channel, which is a dedicated channel proposed for packet data service, in order to guarantee a certain performance and to reduce power consumption of a cell. Provide service.

The additional channel is used for a broadcast service using a common long code mask instead of a long code mask dedicated to a user. In addition, by performing autonomous handoff and additional coding that do not require the feedback information of the mobile terminal during the broadcast service, performance over the existing common channel is guaranteed. In addition, by eliminating the transmission of the power control information and the reverse feedback information by the mobile terminal, the cell capacity is not consumed by the dedicated reverse channel, and conceptually, infinite terminals can be accommodated in one cell.

In the case of the existing common channel, when designed to ensure the same performance to the cell boundary, excessive cell capacity is consumed. Thus, by performing the soft handoff and the outer coding that do not require the feedback information of the terminal to ensure a certain performance while reducing the power consumption in the above manner to ensure the performance over the existing common channel It was.

In addition, the terminal eliminates the dedicated reverse channel by eliminating the power control information and the feedback information in the reverse direction, thereby eliminating the consumption of the reverse cell capacity, thereby conceptually accommodating the terminal in the cell infinitely.

In a scheme of supporting a broadcast service using a forward broadcast supplemental channel (F-BSCH) in the cdma2000 1x, the terminal may receive broadcast traffic by monitoring the F-BSCH in an idle state. In this case, the base station transmits the broadcast traffic at a constant data rate and transmission power regardless of the reception status of the terminals. In this case, if the transmission rate is lowered and the transmission power is increased, broadcasting can be received in most areas of the cell. However, transmission is higher than the actual transmission rate or transmission power, which leads to waste of unnecessary radio resources. Lowering) decreases cell performance.

On the other hand, when the transmission rate is increased and the transmission power is decreased, the existing data service yield can be increased, but the reception performance of broadcast traffic is deteriorated in the terminal located in a region where reception performance is poor.

In addition, as described above, the present cdma2000 1x uses a F-BSCH to support a broadcast service, and when applied to a 1xEVDV (Release C) system as described above as it is to provide a broadcast service, the terminal performs handoff. The service delay occurs until the terminal reports the location to the base station and receives the actual broadcast and multicast service. Therefore, if a service delay occurs, the terminal cannot temporarily receive broadcast traffic, which causes a problem that the reception performance of the traffic and the overall system performance are degraded.

Accordingly, an object of the present invention is to provide a method for performing a broadcast service through a forward packet data channel in a wireless communication system.

Another object of the present invention is to provide a broadcast service method for improving the reception performance and system performance of broadcast traffic for other terminals to support a broadcast service in a 1xEVDV system among CDMA mobile communication systems.

Another object of the present invention is to provide a broadcast service method for controlling the number of retransmissions of packet data of broadcast traffic in order to improve broadcast traffic reception performance and system performance in a 1xEVDV system among CDMA mobile communication systems.

It is still another object of the present invention to provide a broadcast service method for transmitting Walsh mask information as an overhead message for a broadcast service in order to prevent initial service delay and service interruption during handoff of a terminal in a 1xEVDV system among CDMA mobile communication systems. Is in.

The method for achieving the object of the present invention is a method in which the terminal is provided with a broadcast service in a wireless communication system that provides a broadcast service from the base station to the terminal using a forward packet data channel,

Collecting reception status information so as to monitor a forward packet data channel received from the base station for a preset time so that the base station can control the number of retransmissions of the broadcast packet data; and receiving the collected reception status information. A process of receiving broadcast type packet data by combining and decoding data transmitted in a status report message to the base station through a reverse channel and data repeatedly transmitted from the base station through the forward packet data channel for the number of retransmissions; Characterized in that it comprises a.

Another method for achieving the objects of the present invention is a method for providing a broadcast service by the base station in a wireless communication system for providing a broadcast service from a base station to a terminal by using a forward packet data channel, the preset from the terminal Receiving a reception status report message including reception status information collected for a time, adjusting a number of retransmissions of broadcast type packet data to be transmitted to the terminal according to the reception status information, and through the forward packet data channel And repeatedly transmitting the broadcast packet data by the adjusted number of retransmissions.

In addition, another method for achieving the object of the present invention is to broadcast by handing off a terminal receiving a broadcast service from a first base station to a second base station adjacent to the first base station using a forward packet data channel in a wireless communication system A method for receiving a service, the method comprising: receiving a broadcast service parameter message including broadcast service information related to the first base station and the second base station and Walsh mask information for the forward packet data channel from the first base station; And handing off to the second base station by using the information included in the received broadcast service parameter message; and broadcasting type packet data through a forward packet data channel from the second base station by using the Walsh mask information. Characterized in that it comprises a process of receiving It is done.

In addition, another method for achieving the object of the present invention is a method for receiving a broadcast service from a base station using a forward packet data channel in a wireless communication system, the broadcast service information associated with the base station and the forward packet data Receiving a broadcast service parameter message including Walsh mask information on a channel from the base station, and receiving broadcast type packet data from the base station through a forward packet data channel using the Walsh mask information. It features.

In addition, another method for achieving the object of the present invention is a method for providing a broadcast service by the base station in a wireless communication system for providing a broadcast service from a base station to a terminal using a forward packet data channel, the base station and the adjacent Transmitting a broadcast service parameter message including broadcast service information related to a base station and Walsh mask information to the terminal, and transmitting broadcast type packet data to the terminal using the Walsh mask information through the forward packet data channel; Characterized in that it comprises a process.

1 is a block diagram showing a configuration for providing a broadcast service in a 1xEVDV system;

2A to 2C are diagrams illustrating the structure of a BSPM message of a 1xEVDV broadcast service according to an embodiment of the present invention;

3 is a flowchart illustrating a broadcast service procedure of a terminal and a base station control period according to an embodiment of the present invention;

4 is a flowchart illustrating a procedure for controlling the number of retransmissions according to an embodiment of the present invention;

5a to 5c are diagrams illustrating the structure of a BSPM message of a 1xEVDV broadcast service according to an embodiment of the present invention;

6 is a flowchart illustrating a receiving procedure of a terminal for a handoff operation according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if 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.

The present invention described below is broadcasted through a forward packet data channel (hereinafter referred to as F-PDCH) for fast data transmission in a 1xEVDV (Evolutionin Data and Voice) system, which is a CDMA fast packet data communication system. Support the service. In particular, it supports the simultaneous service of broadcast service and dedicated service. In this case, the dedicated service means a packet data service that is performed through unicast.

1 is a block diagram illustrating a configuration for providing a broadcast service in a 1xEVDV system.

Referring to FIG. 1, a broadcasting service server (CS) 14 compresses broadcast data including a video and a sound for a broadcast service. It is generated in the form of a packet and is transmitted to base stations (BS) 12a, 12b, 12c through packet data service nodes (PDSN) 13a, 13b through a packet communication network such as the Internet. The base stations 12a, 12b, and 12c are base station transceivers (BTSs) and base station controllers (BSCs) which are well known in the field of mobile communication, and a packet control unit (PCF) is added to the BS. / PCF.

Here, in order to deliver the broadcast data generated by the broadcast server 14 to the packet data service nodes 13a and 13b, IP multicast or IP unicast is used, and the packet data service nodes 13a and 13b are used. In order to deliver to the base stations 12a, 12b, 12c in the conventional CDMA2000 access network technology is used. When IP multicast is used, the packet data service nodes 13a and 13b form a multicast group that receives IP multicast data from the broadcast server 14. Membership information of the multicast group is maintained by a multicast router (MR) (not shown) connected to each of the packet data service nodes 13a and 13b.

The IP data including the image and the sound generated by the broadcast server 14 is broadcast to the plurality of data service nodes 13a and 13b forming the multicast group or unicast to the respective data service nodes 13a and 13b. Service nodes 13a and 13b deliver IP data to the base stations using conventional CDMA2000 access network technology, and the base stations 12a, 12b and 12c transmit the IP data in the form of a radio frequency (RF) signal. Convert to and send from the service area. The flow of the IP data is as indicated by the dashed line in FIG. 1.

Referring to the data transmission through the forward packet data channel in the system, 1xEVDV is a system capable of simultaneously supporting the existing CDMA2000 1x service and the high speed forward packet data service in the frequency band of 1.25MHz. PDCH) transmits a large amount of packet data at high speed. The packet data channel is a traffic channel commonly accessed by terminals receiving high-speed data services, and uses a time division multiplex (TDM) and a code division multiplex (CDM).

When the terminal requests the high speed packet data service to the base station or when the base station connects the high speed packet data service to the terminal, the terminal and the base station negotiate and configure information necessary for the high speed packet data service. At this time, the base station gives the terminal a dedicated user identifier along with the channel information related to the packet data channel. In the 1xEV-DV system, the user identifier is called a Media Access Control (MAC) Identifier (ID) and hereinafter referred to as a MAC ID.

The MAC ID is known to the UE by being included in a message related to channel configuration, that is, an Extended Channel Assignment Message (ECAM) or a Universal Handoff Direction Message (UHDM). Here, ECAM is developed from the known Channel Assignment Message in the existing CDMA cellular system, and is used to set up the radio channels when the call is set up, and UHDM is developed from the known Handoff Direction Message. It is used to set up wireless channels for the incoming call.

According to the present invention which performs a broadcast service using the F-PDCH, in the broadcast system, the MAC ID is included in a broadcast system parameter message (BSPM) together with information for the broadcast service, and thus, a forward broadcast channel (F). -BSCH) to the terminal. This will be described below with reference to FIGS. 2A to 2C. In addition, information represented by "FBPDCH" in FIGS. 2A to 2C are information related to an F-PDCH for a broadcast service.

If the BCS_REG_USED field is set to 1, the BCS_REG_USED field is information for periodically performing registration. The BCS_REG_TIMER field is information indicating a registration period and is included only when the BCS_REG_USED is 1. If the BCS_REPORT_USED field is 1, the BCS Status Report is reported. If the BCS_REPORT_USED field is 0, the BCS_REPORT_USED field is not reported. The BCS_REPORT_TIMER field is included when the BCS_REPORT_USED is 1 and is not included when the BCS reception status is reported. The NUM_FBPDCH field is information indicating configuration information of an F-PDCH for a broadcast service, and the NUM_BCS_SESSION field is information indicating the number of broadcast service sessions.

The FBPDCH_FREQ field is information for designating a frequency for a broadcast service, and through the FBPDCH_FREQ, the terminal transitions to a corresponding frequency by looking at a frequency separately designated for each service. It is included only when FBPDCH_FREQ_INCL is 1. The FBPDCH_MUX_OPTION field is information indicating a multiplex option number used for broadcast service to the F-PDCH. The FBPDCH_RC field is information indicating radio configuration information used for broadcast service through FPDCH, and the FBPDCH_OUTER_CODE_INDEX field is information indicating index of an additional code used for broadcast service through F-PDCH.

The FBPDCH_WALSH_TABLE_ID field is information indicating an index of a Walsh table used for a broadcast service to the F-PDCH.

The NUM_FPDCCH field is information indicating the number of channels of the F-PDCCH. The FBPDCH_RECORD_RESERVED field is used for byte sorting and information to be included for future scalability.

The BCS_ID field is information indicating an ID of a broadcast service, and the NUM_LPM_ENTRIES field is information indicating the number of mappings used for one broadcast service session.

The FBPDCH_ID field is an ID of a channel configuration of an F-PDCH used for transmitting traffic of a broadcast service to a BCS_ID, and a BSR_ID field is information indicating a service reference ID for a broadcast service in a BSPM.

The NGHBR information informs the code and transmission rate of the FBPDCH related to the handoff, so that the terminal can combine signals from various base stations by the handoff.

The present invention relates to the radio area between the terminal and the base station in particular in the broadcast service system, Figure 3 is a message flow diagram illustrating a broadcast type service procedure between the terminal and the base station according to an embodiment of the present invention.

Referring to FIG. 3, in step 200, the terminal establishes a Point-to-Point Protocol (PPP) connection for a data service with a base station using a service option 33 (SO 33) to obtain information about a broadcast service. . The terminal connects to a BCS controller (not shown) through a packet communication network and receives information on broadcast service content that can be provided by the broadcast server 14. The terminal receives information on the service number BCS_ID assigned to the corresponding broadcast service content.

When all the information on the broadcast service is received, the terminal terminates the data session and becomes idle. Then, in step 210, the terminal receives a broadcast service parameter message (BSPM or less, referred to as BSPM) to obtain information of a forward traffic channel for receiving broadcast traffic according to each broadcast service content. Here, the BSPM is an overhead message that can be received by all terminals, and is periodically or aperiodically transmitted on a forward broadcast control channel (F-BCCH).

In step 220, the terminal performs a registration procedure of transmitting a registration message to the base station through an access channel according to a user's request to receive a broadcast service. Here, the registration message can be transmitted aperiodically in the case of periodic or cell change, and thus a detailed description of the message format will be omitted. Particularly, in the registration service in the broadcast service, registration is used to designate a paging zone in the same manner as a general registration. In addition, the type of broadcast service is added to the base station to inform the service server (Contents Server), etc. that they are receiving or want to receive the service. Here, there is a requirement that a terminal receiving a broadcast service should be able to receive a call signal for a voice call service. In the broadcast service, registration may be performed at a fixed time and used as billing information or for other purposes. The BCS_REG_TIMER field in the BSPM records the registration timer value. The timer value used here is currently set to 1 to 10 minutes and can be adjusted as needed. In addition, the broadcast service does not define an end procedure and terminates only when there is no regular registration of the terminal, or by adding an end field to the registration message and setting it to '1', the terminal terminates the broadcast service to the base station. You can also inform.

In step 230, the terminal transmits the broadcast traffic from the base station according to the channel information of the FBPDCH included in the BSPM through the F-PDCH and the packet data control channel (F-PDCCH, hereinafter referred to as F-PDCCH). Start receiving control information.

In the broadcast service procedure, when the terminal receives forward traffic channel information from the base station, the base station transmits broadcast traffic (broadcast packet data) to the terminal through the F-PDCH and control information of the packet data through the F-PDCCH. Send it. The control information includes the size of the packet data, an encoding scheme, a modulation scheme, and the like. An operation for controlling the number of retransmissions of encoded packet data (EP) (hereinafter referred to as EP) transmitted to the terminal for decoding to improve the reception performance and system performance of the broadcast traffic of the broadcast service will be described. As follows.

In 1xEVDV, in order to increase the reception rate of packet data, the receiver retransmits the packet data until the packet data is normally received according to the Automatic Repeat Request (ARQ) protocol. To this end, the control information includes an ARQ Identifier Sequence Number (AISN), which toggles the value of the AISN each time a new packet is transmitted so that the UE knows the transmission of the new packet.

In the case of a broadcast service, when receiving an ACK or NACK for every packet data and determining whether to retransmit it, the load of the wireless channel may be increased and the service may be delayed. Therefore, the present invention increases the system efficiency by controlling the number of retransmissions of packet data.

4 illustrates a signaling procedure for controlling broadcast traffic between a terminal and a base station while receiving a broadcast service according to an embodiment of the present invention. 4 includes only the contents related to the present invention, and in actual implementation, a signal procedure other than the signal procedure illustrated in FIG. 4 may be included. As the number of retransmissions increases, the probability that the terminal successfully decodes the packet increases, but uses more radio resources. Accordingly, the base station controller controls the number of retransmissions for one broadcast packet according to the reception state information.

Referring to FIG. 4, in step 400, the base station transmits packet data generated by the base station controller three times to the terminal according to a preset number of retransmissions (ReTx). At this time, the base station transmits the broadcast packet data three times regardless of the response (ACK or NACK) of the terminal.

In more detail, when the first packet data is received from the base station controller, the base station initially transmits the first packet data EP1 (SPID = 00) to the terminal, and then the first packet data EP1 is transmitted to the terminal. It retransmits once, and generally transmits a subpacket different from the initial transmission (SPID = 01, SPID = 10). At this time, in order to distinguish between EP1, EP2, and EP3, the base station toggles the AISN included in the F-PDCCH, sets the AISN to '0' for EP1 transmission, and sets the AISN to '1' for EP2 transmission. At the time of EP3 transmission, AISN is set to '0' again.

At the same time as transmitting the first packet data, the base station transmits control information of the broadcast packet data to the terminal through the F-PDCCH.

First, when the terminal sees the control information transmitted on the F-PDCCH and matches the MAC-ID transmitted on the F-PDCCH and the broadcast MAC-ID previously given, the terminal uses the control information transmitted on the F-PDCCH. Combine and decode the first packet data. The control information includes EP size, subpacket information, data rate information, etc. to decode EP1 received on the F-PDCH. The terminal monitors for a preset state reporting period and collects reception state information of packet data EP1, EP2, EP3 received from the base station through the F-PDCH.

Then, when the BCS_REPORT_TIMER cycle is completed in step 410, the terminal transmits reception status information such as a decoded result of the EP1 to EP3 through a reverse access channel (R-ACH) (Broadcast Status Report: BCSSR) ( Hereinafter, the BCSSR message is reported to the base station controller.

In step 420, the base station controller controls the base station to adjust the number of retransmissions using the reception status information or other traffic (eg, data service, voice service, etc.) load of the cell. At this time, the broadcast traffic performance of the terminals is guaranteed to a certain level or more. If the reception performance of the terminal is good, the number of retransmissions is reduced or maintained, and if there is a terminal with poor reception performance, the number of retransmissions is increased.

In more detail, the base station controller confirms the BCSSR message. In the case of step 400, since the decoding of the EP1 to EP3 is all completed successfully, the base station controller determines that the reception performance is good and then controls to perform retransmission only once in the base station.

The reception performance information included in the BCSSR message may be calculated using all broadcasting traffic received by the cell in which the terminal is currently located, or may use broadcasting traffic received during a window size time of a predetermined size. The reception state information may include information such as Equation 1 below.

Number of EPs that were successfully decoded / Total number of EPs received

Amount of broadcast traffic received with successful decoding / Total amount of broadcast traffic received

Received Signal Strength (Carrier) / Interference Signal Strength (Interference)

Table 1 below shows an example of a BCSSR message.

In the <Table 1>, the BCSSR message includes "REPORT_INFO_TYPE", "REPORT_INFO_LEN" and "Type-specific fields" information. The terminal quantifies the reception performance directly according to the REPORT_INFO_TYPE field and informs the base station and requests the base station to increase, decrease or maintain the number of retransmissions. And you can add reports to improve future performance.

Here, an example of reporting reception status information using a separate BCSSR message has been described. However, in the modified embodiment of the present invention, the reception status information is transmitted to an existing signal message, such as a status response message (SRM) or an extended SRM (ESRM). It is also possible to transmit by adding a field to carry. In this case, the complexity is reduced by not using new messages.

Referring back to FIG. 4, in step 430, the base station transmits the packet data EP4 to EP6 received from the base station controller and retransmits it once. Accordingly, the terminal combines and decodes the received EP4 to EP6 in the same manner as in step 400 and monitors the reception performance during the BCS_REG_TIMER period to collect reception performance information such as the decoded result.

Then, when the BCS_REG_TIMER cycle is completed in step 440, the terminal completes the monitoring and transmits the collected reception performance information to the base station controller through the BCSSR message. In this case, the terminal transmits the EP4 and the BCSSR message with information on the number of times that the EP6 failed to be decoded. Then, in step 450, the base station controller controls the number of retransmissions of EPs to be received during the next BCS_REG_TIMER period by combining the information included in the BCSSR message. In the case of step 430, since the decoding failure rate is high and the reception performance is not good, the base station controller controls the base station to increase the number of retransmissions to two.

Then, in step 460, the base station transmits the next EPs according to the adjusted number of retransmissions (2 times). Accordingly, the terminal combines and decodes the received EPs and simultaneously monitors the reception state during the BCS_REPORT_TIMER period.

Meanwhile, in order for the terminal to decode the F-PDCH, Walsh table information and Walsh mask information are required. In a typical packet data service, Walsh table information is transmitted through a broadcast service control channel (BCCH) and Walsh mask information is transmitted through an F-PDCCH. In the 1xEVDV system, when the base station knows that the terminal moves through the location registration message of the terminal during handoff of the terminal, the Walsh mask information is transmitted through the F-PDCCH. In other cases, when the Walsh mask information changes, the base station transmits reception state information through the F-PDCCH.

Even if a user first transmits a registration message to receive a broadcast service or transmits a registration message during handoff, broadcast traffic is temporarily not received until the user receives the Walsh mask information through the F-PDCCH. Accordingly, in order to prevent such a delay, the broadcast service according to the present invention includes Walsh mask information indicating Walsh codes allocated to the PDCH in the BSPM. When the broadcast service starts, the base station spreads and transmits the broadcast packet data with Walsh codes corresponding to the Walsh mask. Accordingly, the terminal despreads the received signal of the PDCH through the Walsh mask with a Walsh code obtained using the Walsh mask to obtain broadcast type packet data.

The BSPM format including the Walsh mask information is described below with reference to FIGS. 5A to 5C. In addition, information represented by "FBPDCH" in FIGS. 5A to 5C are information related to the F-PDCH.

If the BCS_REG_USED field is set to 1, the BCS_REG_USED field is information for periodically performing registration. The BCS_REG_TIMER field is information indicating a registration period and is included only when the BCS_REG_USED is 1. The NUM_FBPDCH field is information indicating configuration information of an F-PDCH for a broadcast service, and the NUM_BCS_SESSION field is information indicating the number of broadcast service sessions.

The FBPDCH_FREQ field is information for designating a frequency for a broadcast service, and through the FBPDCH_FREQ, the terminal transitions to a corresponding frequency by looking at a frequency separately designated for each service. It is included only when FBPDCH_FREQ_INCL is 1. The FBPDCH_MUX_OPTION field is information indicating a multiplex option number used for broadcast service to the FPDCH. The FBPDCH_RC field is information indicating radio configuration information used for broadcast service through the F-PDCH, and the FBPDCH_OUTER_CODE_INDEX field is information indicating an index of an additional code used for broadcast service through the F-PDCH.

The FBPDCH_WALSH_TABLE_ID field is information indicating an index of a Walsh table used for a broadcast service to the F-PDCH. The FBPDCH_WALSH_MASK field is information indicating a Walsh mask used for broadcast service to the F-PDCH.

The FPDCCH_WALSH field is information indicating a Walsh code for receiving an F-PDCCH used for a broadcast service through the F-PDCH. The FBPDCH_RECORD_RESERVED field is used for byte sorting and information to be included for future scalability.

The BCS_ID field is information indicating an ID of a broadcast service, and the NUM_LPM_ENTRIES field is information indicating the number of mappings (Logical-to-Physical mapping) used for one broadcast service session.

The FBPDCH_ID field is an ID of a channel configuration of an F-PDCH used for transmitting traffic of a broadcast service to a BCS_ID, and the BSR_ID field is information indicating a service reference ID for a broadcast service in a BSPM.

The NGHBR information informs the code and transmission rate of the F-BSCH related to the handoff, so that the UE can combine signals from various base stations by the handoff. In particular, the BSPM includes an NGHBR_FBPDCH_WALSH_MASK field as NGHBR information. The NGHBR_FBPDCH_WALSH_MASK field is information indicating a Walsh mask of a neighbor base station.

6 is a flowchart illustrating a receiving procedure of a terminal for a handoff operation according to an embodiment of the present invention. Herein, an operation when the terminal moves handoff from the first base station (Source BTS) to the second base station (Target BTS) will be described.

Referring to FIG. 6, in step 500, the terminal receives a BSPM including Walsh mask information from the first base station while receiving a broadcast service from the first base station in a cell of the first base station to perform a broadcast service. . On the other hand, the terminal acquires the possibility of handoff, code and transmission rate to other nearby base stations through the NGHBR fields of the BSPM. This NGHBR information includes Walsh mask information of the second base station.

In step 510, if the strength of the pilot received from the second base station is greater than the strength of the pilot received from the first base station, the terminal performs handoff from the first base station to the second base station. That is, in the handoff process, the terminal transitions to the designated frequency of the second base station by looking at a frequency separately designated for each service in the NGHBR field. Then, the terminal acquires the F-PDCH and the F-PDCCH to receive a broadcast service from the second base station by monitoring the corresponding second base station at the transitioned frequency. Then, in step 530, the terminal receives the broadcast service through the F-PDCH and the F-PDCCH of the second base station. In addition, the terminal transitions to receive a channel such as F-PCH, F-BCCH, F-CCCH, etc. for receiving an overhead message or a paging message from the second base station. Since the terminal already has all the information for receiving broadcast traffic, it can start receiving broadcast traffic immediately after the handoff. Accordingly, in step 540, a registration message is transmitted to the second base station through the reverse access channel to register its location. Then, the terminal receives the BSPM transmitted periodically or aperiodically from the second base station and updates broadcast service related information.

As described above, the present invention can improve the system performance and the reception performance by feeding back the reception performance of the terminal to control the number of retransmissions of the broadcast packet data in the base station. In addition, since the Walsh mask information is transmitted to the terminal as an overhead message for the broadcast service, the service initial delay does not occur when the handoff is performed, thereby preventing the service temporary disconnection.

Claims (12)

A method of receiving a broadcast service by a terminal in a wireless communication system providing a broadcast service from a base station to a terminal using a forward packet data channel, Collecting reception state information to monitor a forward packet data channel received from the base station for a preset time so that the base station can control the number of retransmissions of the broadcast packet data; Including the received reception status information in a reception status report message and transmitting it to the base station through a reverse channel; And receiving broadcast type packet data by combining and decoding data repeatedly transmitted by the retransmission number from the base station through the forward packet data channel. The method of claim 1, The reception state information includes the ratio of the number of broadcast type packet data that has been successfully decoded during the predetermined time to the total number of received broadcast type packet data. The method of claim 1, The reception state information includes the ratio of the amount of broadcast traffic successfully received in decoding to the total amount of broadcast traffic received during the preset time period. The method of claim 1, The reception state information includes the ratio of the received signal strength to the interference signal strength of the broadcast time providing method. A method of providing a broadcast service by a base station in a wireless communication system providing a broadcast service from a base station to a terminal using a forward packet data channel, Receiving a reception status report message including reception status information collected for a preset time from the terminal; Adjusting a number of retransmissions of broadcast packet data to be transmitted to the terminal according to the reception state information; And repeatedly transmitting the broadcast packet data by the adjusted number of retransmissions through the forward packet data channel. A method for receiving a broadcast service by handing off a terminal receiving a broadcast service from a first base station using a forward packet data channel to a second base station adjacent to the first base station in a wireless communication system, Receiving, from the first base station, a broadcast service parameter message including broadcast service information related to the first base station and the second base station and Walsh mask information for the forward packet data channel; Handing off to the second base station by using the information included in the received broadcast service parameter message; And receiving broadcast type packet data from the second base station through a forward packet data channel using the Walsh mask information. The method of claim 6, The Walsh mask information is information on a Walsh code used for spreading the broadcast packet data in the base station, and is used to despread the broadcast packet data. A method for receiving a broadcast service from a base station using a forward packet data channel in a wireless communication system, Receiving a broadcast service parameter message from the base station, the broadcast service parameter message including broadcast service information related to the base station and Walsh mask information for the forward packet data channel; And receiving broadcast type packet data through a forward packet data channel from the base station using the Walsh mask information. The method of claim 8, The Walsh mask information is information on a Walsh code used for spreading the broadcast packet data in the base station, and is used to despread the broadcast packet data. The method of claim 8, The broadcast service parameter message further includes information on neighboring base stations and information on a forward packet data channel. A method of providing a broadcast service by a base station in a wireless communication system providing a broadcast service from a base station to a terminal using a forward packet data channel, Transmitting a broadcast service parameter message including broadcast service information and Walsh mask information related to the base station and an adjacent base station to the terminal; And transmitting broadcast packet data to the terminal through the forward packet data channel using the Walsh mask information. The method of claim 11, The Walsh mask information is information on a Walsh code used to spread the broadcast packet data and is used to despread the broadcast packet data in the terminal.