KR20060031528A - A method for transferring and receiving channel access information in broadband wireless access system - Google Patents

Abstract

The present invention transmits uplink / downlink access information messages transmitted from a base station (hereinafter referred to as BS) to a mobile terminal (hereinafter referred to as MSS) in a broadband wireless access system. And a method for receiving and interpreting uplink / downlink access information messages by the mobile terminal.

According to an embodiment of the present invention, a method for receiving channel access information in a broadband wireless access system includes a base station and a mobile terminal receiving a packet data service from the base station. In the processing method, when receiving a frame including the predetermined channel access information from the base station, the frame including the channel access information is reduced (reduced) by excluding the duplicated information from the first channel access information Determining whether a frame including access information is received, and performing initialization for access to the base station when the frame including the reduced channel access information is not received from the base station. It is done.

Broadband Wireless Access System, Uplink / Downlink Access Message

Description

A Method for Transferring and Receiving Channel Access Information in Broadband Wireless Access System             

1 is a frame structure diagram showing channel access information in a broadband wireless access system according to the present invention;

2 is a view for explaining a method for transmitting / receiving a reduced compressed map according to the present invention;

3 is a flowchart illustrating a method of transmitting and receiving channel access information in a broadband wireless access system according to an embodiment of the present invention.

The present invention relates to a method for transmitting and receiving channel access information in a communication system, and more particularly, to a method for transmitting and receiving channel access information for accessing a mobile terminal in a broadband wireless communication system.                         

In general, communication systems have been developed mainly for voice services, and are gradually developing as communication systems capable of not only voice but also data services and various multimedia services. However, since the voice-oriented communication system has a relatively small data transmission bandwidth and a high usage fee, the voice-oriented communication system cannot meet the rapidly increasing demand for users. In addition, due to the development of the communication industry and increasing user demand for Internet services, there is an increasing need for a communication system that can efficiently provide Internet services. As a result, Broadband Wireless Access (BWA) has been introduced to efficiently provide Internet services with broadband enough to meet the demands of rapidly increasing users.

The broadband wireless access system is a system for integrating and supporting not only voice but also various low speed and high speed data services and multimedia application services such as high definition video. The broadband wireless access system can access PSTN and PSDN networks, Internet networks, IMT-2000 networks, ATM networks, etc. in a mobile or fixed environment based on wireless media using broadband such as 2 GHz, 5 GHz, 26 GHz and 60 GHz. It is a wireless communication system that can support more than a channel rate. The broadband wireless access system may be classified into a broadband wireless subscriber network, a broadband mobile access network, and a high-speed wireless LAN according to the mobility (fixed or mobile) and communication environment (indoor or outdoor) of a terminal, and a channel rate.

The wireless access method of the broadband wireless access system is being standardized by the IEEE 802.16 standardization group of the Institute of Electrical and Electronics Engineers, one of the international standardization organizations, and is currently used to provide wireless broadband Internet service to fixed terminals. As a standard, the IEEE 802.16d standard is being enacted.

The IEEE 802.16d / e standard has a wider bandwidth of data than a conventional wireless technology for voice service, and can perform a lot of data transmission in a short time, and can efficiently use a channel by sharing all user channels. Do. In addition, quality of service (QoS) is guaranteed so that users can receive different quality of services according to the characteristics of the service. In the IEEE 802.16d / e system, all users connected to the base station share and use a common channel, and the interval in which each user uses the channel is allocated by the base station in every up / down frame, so the base station is assigned to each user in every frame. The uplink / downlink connection information should be informed so that the user can divide the channel.

In the IEEE 802.16d / e system, channel information is divided into an uplink channel and a downlink channel, information about each channel is defined as a TLV (Type, Length, Value), a downlink channel descriptor (DCD), and an uplink channel descriptor (UCD) message. By including in the transmission to all users to inform the mobile terminal of the characteristic information on the channel. The base station broadcasts uplink / downlink information for accessing the base station every frame so that the mobile station can access uplink / downlink information, which is called an uplink map and a downlink map, respectively. . Together these are called MAP messages. In an 802.16d / e system, compressed MAP having a reduced size of a BS_ID field including base station information in a map message field may be used.

The IEEE 802.16d / e system broadcasts uplink / downlink access information, and the mobile terminal receiving the compressed MAP message can access the uplink / downlink link of the base station by interpreting the compressed MAP message. However, since a large sized up / down connection information message is repeatedly broadcasted every frame, the message occupies a space for carrying actual data and thus the transmission efficiency is lowered.

In addition, Table 1 below is an original compressed MAP message format for transmitting uplink / downlink access information of a base station.

Syntax Size (bit) Compressed DL-MAP () {   Compressed map indicator 2   Reserved = 0 One   UL-MAP appended = 1 One   CRC appended One   MAP message length 11   PHY synchronization field 32   DCD count 8   Operator ID, Sector ID 8, 8   DL IE count 8   List of DL IEs Variable   UCD Count 8   Allocation Start Time 32   List of UL IEs Variable

As shown in Table 1, the first Compressed MAP message includes a Compressed map indicator field for indicating the format of a 2-bit Compressed MAP message, and a UL-MAP value when the 1-bit UL-MAP appended value is 1; UL-MAP appended = 1 field to indicate appended, 1-bit reserved field, field to add 1-bit CRC, field indicating length of compressed MAP including 11-bit CRC, 32-bit A physical layer synchronization field (PHY synchronization field) indicating a frame number and frame period information, a DCD counter indicating a change in the count of the DCD, an operator ID indicating a lower 8 bits of the upper 24 bits of the 8-bit base station ID, The sector ID field indicating the lower bits of the 8-bit base station ID, the DL IE count field indicating the number of lists of the DL IE, the UCD counter indicating the change in the count of the 8-bit UCD, and the 32-bit UL MAP. An Allocation Start Time field indicating the allocated allocation start time, a List of DL IEs field indicating a DL IE x DL IE size and having a variable size, and indicating and varying a UL IE x UL IE size. Contains a List of UL IEs field of size.

The conventional base station broadcasts 120 bits of information every frame to inform the mobile station of uplink / downlink access information except for 'List of DL IEs' and 'List of UL IEs', which change in size. However, since the first MAP message must transmit information that does not change every frame, overhead occurs.

Accordingly, an object of the present invention is to provide a method for shortening uplink / downlink access information messages to be transmitted to a mobile station by a base station in a broadband wireless access system.

Another object of the present invention is to provide a method for a mobile terminal to receive and process up / down access information messages transmitted from a base station to a mobile terminal in a broadband wireless access system.

Another object of the present invention is to provide a method for increasing transmission efficiency by reducing overhead when a base station transmits an uplink / downlink access information message to a mobile terminal in a broadband wireless access system.                         

According to an embodiment of the present invention, a method for receiving channel access information in a broadband wireless access system includes a base station and a mobile terminal receiving a packet data service from the base station. In the method for processing by the step, when receiving a frame including the predetermined channel access information from the base station, the channel access information is reduced by excluding the overlapped information from the first channel access information, the frame containing the channel access information And determining whether a frame including the received channel is received, and performing initialization for access to the base station when the frame including the reduced channel access information is not received from the base station. .

According to another embodiment of the present invention, a method for transmitting channel information in a broadband wireless access system includes a base station and a mobile terminal provided with a packet data service from the base station. In the transmitting method, when transmitting a frame including predetermined channel access information to the mobile terminal, a frame containing reduced channel access information by excluding redundant information from the frame containing the first channel access information And broadcasting the generated frame to the mobile terminal.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention described below is applied to an IEEE 802.16d / e system, and an embodiment of the present invention relates to a method of reducing and broadcasting a large size uplink / downlink access information message repeatedly broadcast in the IEEE 802.16d / e. Let's explain.

The frame structure of the IEEE 802.16d / e is described below with reference to FIG. The frame of the IEEE 802.16d / e includes a downlink (DL) subframe 100 and an uplink (UL) subframe 140. The downlink subframe 100 is composed of a preamble 110, a MAP 120, and a DL burst. The MAP 120 information included in the uplink / downlink access information message proposed by the present invention includes a frame control header (FCH 121) and a reduced compressed compressed MAP (Reduced Compressed MAP) proposed by the present invention. In the following description, the reduced compressed MAP 122 is referred to as a reduced CM, and according to the present invention, a base station transmits an uplink / downlink access information message to a mobile station using the reduced CM 122. Suggest.

The conventional base station broadcasts 120 bits of information every frame to inform the mobile station of uplink / downlink access information except for 'List of DL IEs' and 'List of UL IEs' having variable sizes. However, the conventional MAP message has a problem of generating overhead because information that does not change frequently is transmitted every frame. In order to solve the above problems, the present invention proposes a compressed MAP in which the C.M shown in Table 1 is reduced. The reduced C.M 122 message format is shown in Table 2 below.

Syntax Size (bit) Compressed DL-MAP () {   Compressed map indicator 2   Reserved = 0 One   UL-MAP appended = 1 One  Full message = 0 One   DL IE count 3   List of DL IEs Variable   List of UL IEs Variable

<Table 2> is a reduced format compared to <Table 1>. In Table 2, the Compressed map indicator field, the reserved field, the UL-MAP appended = 1 field, the List of DL IEs field, and the List of UL IEs field are shown in Table 1 above. Same as the original CM format. However, the full message is a field indicating an indicator indicating a reduced C.M. At this time, it is assumed that CRC addition is always added regardless of the setting value of the CRC addition field, and the CRC addition field of Table 1 is replaced with the Full message field in Table 2. Therefore, it is possible to check whether the received MAP message is a conventional C.M or a reduced C.M through the CRC addition field of the conventional MAP message. The DL IE count is 8 bits in the prior art, but 3 bits in the present invention.

As described above, when the reduced C.M 122 is used, 8-bit information may be transmitted instead of fixed 120 bits. Therefore, by broadcasting only 8-bit information excluding the variable size, by broadcasting a C.M containing all the information at regular intervals, it is possible to prevent the occurrence of overhead caused by transmitting the redundant data repeatedly.

2 is a diagram for describing a method of receiving a reduced C.M 122 broadcast from the base station. The base station first transmits an original C.M frame (Original Compressed MAP Frame) 201, and then transmits a reduced compressed compressed MAP frame (202) reduced in the number of bits proposed by the present invention. In FIG. 2, the reduced C.M frame is transmitted four times from one base station. This is shown for convenience and there is no basis for the transmission period of the first C.M frame.

A mobile terminal broadcasting only the 8-bit information except for the variable size from the base station and receiving the C.M containing all the information at regular intervals must receive the first C.M frame once during the period to confirm the actual link access information. When the mobile terminal stores the first C.M frame and then receives the reduced C.M, the mobile terminal can check uplink / downlink access information by combining the first stored C.M and the reduced C.M. That is, if the C.M of the received frame is a reduced C.M, the mobile station must wait for a predetermined period until receiving the first C.M to enable communication with the base station.

As described above, the mobile terminal receives and interprets an uplink / downlink access information message with reference to FIG. 3.

When the mobile terminal initially accesses the base station, in step 301, synchronization is performed to synchronize with the base station. After completing the synchronization operation, the mobile terminal receives a frame including MAP information from the base station in step 302. In step 303, the mobile terminal determines whether the frame including the MAP information is a reduced C.M frame. If the frame including the MAP information is a reduced C.M frame, the process returns to step 302 to receive the frame again. However, if the frame including the MAP information is not a reduced CM frame, the mobile terminal determines that the frame including the MAP information is the first CM frame, and provides channel access information through the MAP information in the first CM frame. You get Accordingly, since the mobile terminal can communicate with the base station in step 304, the mobile terminal performs an initialization procedure for accessing the base station.

In the method proposed by the present invention, the longer the transmission period of the first CM frame in the base station increases the gain due to the reduction of overhead. However, the access time for the mobile terminal to access the base station is increased. Therefore, the mobile terminal must take the connection delay time to wait until receiving the first CM frame.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention has the effect of increasing the transmission efficiency by reducing the overhead when the base station transmits the up / down access information message to the mobile terminal in a broadband wireless access system.

In addition, in the broadband wireless access system, the base station repeatedly broadcasts a large size up / down access information message to each mobile terminal every frame, thereby occupying a space for carrying the actual data, thereby improving transmission efficiency. The problem of degradation is solved.

Claims (8)

In the broadband wireless access system comprising a base station and a mobile terminal receiving a packet data service from the base station, the mobile terminal receives and processes channel access information, If a frame including predetermined channel access information is received from the base station, does the frame including the channel access information receive a frame including reduced channel access information except for overlapping information in the first channel access information? Judging the process, And when the frame including the reduced channel access information is not received from the base station, performing initialization for connection with the base station. The method of claim 1, When the frame including the reduced channel access information is received from the base station, the reduced channel access information is received from the base station until the frame including the first channel access information is received from the base station for a predetermined period. Said method. The method of claim 1, The reduced channel access information includes a compressed map indicator field for indicating a format of a 2-bit compressed MAP message, an extra field of 1 bit, and a UL-MAP if the 1-bit UL-MAP appended value is 1. UL-MAP appended = 1 field indicating added, Full message field indicating an indicator indicating a reduced CM frame, Sector ID field indicating the lower bits of the 3-bit base station ID, and DL IE indicating the number of lists of DL IE. a count field, a List of DL IEs field having a size indicating a DL IE x DL IE size and being variable, and a List of UL IEs field having a size indicating and changing a UL IE x UL IE size, Said method. In the broadband wireless access system comprising a base station and a mobile terminal receiving a packet data service from the base station, the base station transmits the channel access information to the mobile terminal, Generating a frame including reduced channel access information by removing redundant information from a frame including first channel access information when transmitting a frame including predetermined channel access information to the mobile terminal; And broadcasting the generated frame to a mobile terminal. The method of claim 4, wherein The reduced channel access information includes a compressed map indicator field for indicating a format of a 2-bit compressed MAP message, an extra field of 1 bit, and a UL-MAP if the 1-bit UL-MAP appended value is 1. UL-MAP appended = 1 field indicating added, Full message field indicating an indicator indicating a reduced CM frame, Sector ID field indicating the lower bits of the 3-bit base station ID, and DL IE indicating the number of lists of DL IE. a count field, a List of DL IEs field having a size indicating a DL IE x DL IE size and being variable, and a List of UL IEs field having a size indicating and changing a UL IE x UL IE size, Said method. In the broadband wireless access system comprising a base station and a mobile terminal provided with a packet data service from the base station, the mobile terminal receives and processes channel access information, When the frame including the channel access information is received from the base station, the frame including the channel access information is reduced by checking a field indicating whether the channel access information is reduced channel access information. Cognitive judgment process, And if the frame received from the base station is not a frame including the reduced channel access information, performing initialization for access to the base station. In the broadband wireless access system comprising a base station and a mobile terminal provided with a packet data service from the base station, the mobile terminal receives and processes channel access information, When the frame including the channel access information is received from the base station, the frame including the channel access information is reduced by checking a field indicating whether the channel access information is reduced channel access information. Cognitive judgment, If the frame received from the base station is a frame including the reduced channel access information, it is determined whether the frame received thereafter includes the reduced channel access information, and a channel necessary for communication with the base station is determined. Receiving a frame including access information, and performing initialization for access with a base station. The method of claim 7, wherein And the frame including the channel access information necessary for communication with the base station and the frame including the reduced channel access information are repeatedly transmitted in a specific order.

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