WO2009084907A2

WO2009084907A2 - Apparatus and method for receiving data in a communication system

Info

Publication number: WO2009084907A2
Application number: PCT/KR2008/007805
Authority: WO
Inventors: Hyung-Joon Jeon
Original assignee: Posdata Co., Ltd.
Priority date: 2007-12-31
Filing date: 2008-12-30
Publication date: 2009-07-09
Also published as: WO2009084907A3; KR100939707B1; KR20090073916A

Abstract

The present invention receives a burst concatenated a plurality of packet data units (PDUs), checks whether a first decoding is successfully performed on a first PDU based on a Header Check Sequence (HCS) of the first PDU in the burst, and performs decoding on the plurality of the PDUs by updating a decoding count according to the whether the first decoding is successfully performed and checking, when the first decoding is unsuccessfully performed, whether a second decoding is successfully performed on a second PDU based on a HCS of the second PDU in the burst.

Description

Description Apparatus and method for receiving data in a communication system Technical Field

[1] The present invention relates to a communication system and, in particular, to a reception apparatus and method for performing decoding on data normally in a wireless access communication system. Background Art

[2] Research on the next-generation communication system is being conducted to provide users with various Quality-of-Service (QoS) services at a high data rate. Particularly, study of the next-generation communication system is made to support highspeed services guaranteeing mobility and QoS for a BWA communication system.

[3] In the standards for a Broadband Wireless Access (BWA) communication system, various error checking mechanisms for checking whether the received data, i.e. Packet Data Unit (PDU) of Media Access Control (MAC) layer (hereinafter called 'MAC PDU') and Hybrid Automatic Repeat Request (HARQ) packets are successfully performed decoding, and most error checking mechanisms are implemented based on Header Check Sequence (HCS), Cyclic Redundancy Check 32 (CRC32), or CRC16. In more detail, the HCS-based error checking mechanism is used to check whether the decoded MAC header information is correct, the CRC32-based error checking mechanism is used to check whether the MAC payload including the MAC header is correct, and the CRC16-based error checking mechanism is used to check whether the HARQ subburst is correctly received in physical (PHY) layer.

[4] Typically, MAC PDUs can be concatenated in a burst or in an HARQ burst. In this case, if the decoding of MAC header including the whole length information fails in a MAC PDU, then the following concatenated MAC PDU also fails because the receiver cannot know where the start point of the next MAC PDU. Through the concatenation is widely used in Worldwide Interoperability for Microwave Access (WiMAX) system due to its can reduce the control overhead such as MAP Information Element (IE), the aforementioned decoding problem caused by concatenated feature may degrade the system performance. Accordingly, there is a need to develop a decoding manner that is capable of reducing decoding failure rate of the concatenated MAC PDUs. Disclosure of Invention Technical Problem

[5] Accordingly, an aspect of the present invention is to provide an apparatus and method for receiving data in a communication system. [6] Another aspect of the present invention is to provide an apparatus and method for receiving data by performing decoding on PDUs in a communication system.

[7] Furthermore, another aspect of the present invention is to provide an apparatus and method for receiving data that is capable of improving a decoding success rate of concatenated PDUs in a communication system. Technical Solution

[8] According to one aspect of the present invention, there is provided a method for receiving data in a wireless communication system. The method includes receiving a burst concatenated a plurality of packet data units (PDUs) and checking whether a first decoding is successfully performed on a first PDU based on a Header Check Sequence (HCS) of the first PDU in the burst; and performing decoding on the plurality of the PDUs by updating a decoding count according to the whether the first decoding is successfully performed and checking, when the first decoding is unsuccessfully performed, whether a second decoding is successfully performed on a second PDU based on a HCS of the second PDU in the burst.

[9] According to another aspect of the present invention, there is provided a method for receiving data in a wireless communication system. The method includes receiving a burst concatenated a plurality of Media Access Control Packet Data Units (MAC PDUs); performing a first decoding on a first MAC PDU in the burst; performing, if the first decoding is unsuccessfully performed, a second decoding on a second MAC PDU in the burst using a length information within the first MAC PDU.

[10] According to further another aspect of the present invention, there is provided an apparatus for receiving data in a wireless communication system. The apparatus includes a receiver for receiving a burst concatenated a plurality of packet data units (PDUs); and wherein the receiver checks whether a first decoding is successfully performed on a first PDU based on a Header Check Sequence (HCS), a specific header field, or a Cyclic Redundancy Check (CRC) of the first PDU in the burst; updates a decoding count according to the whether the first decoding is successfully performed; checks, when the first decoding is unsuccessfully performed, whether a second decoding is successfully performed on a HCS, a specific header field, or a CRC of the second PDU in the burst; and performs decoding on the plurality of the PDUs.

Advantageous Effects

[11] The present invention provides an apparatus and method for receiving data that is capable of improving a data reception rate by correctly performing decoding on a MAC PDU and a following MAC PDU in the concatenated PDUs depending on whether each PDU is successfully performed decoding. Accordingly, the data reception apparatus and method can reduce overhead of control information and improves the data reception efficiency. Brief Description of Drawings

[12] The above and other aspects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[13] FIG. 1 is a diagram schematically illustrating a structure of a communication system according to an embodiment of the present invention;

[14] FIG. 2 is a diagram schematically illustrating a format of a MAC PDU in the communication system according to an embodiment of the present invention;

[15] FIG. 3 is a flow chart illustrating an operating process of a receiver in the communication system; and

[16] FIGs. 4 to 6 are a flow chart illustrating an operating process of a receiver in a communication system according to an embodiment of the present invention. Mode for the Invention

[17] Preferred embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for clarity and conciseness.

[18] The present invention provides apparatus and method for receiving data in a communication system, for example, in an Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system, which is a Broadband Wireless Access (BWA) communication system. Although a description of the present invention will be made herein with reference to an IEEE 802.16 communication system employing Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA), by way of example, the data reception apparatus and method proposed by the present invention can also be applied to other communication systems.

[19] The present invention a data reception apparatus and method that is capable of improving a decoding success rate on Packet Data Unit (PDU) of Media Access Control (MAC) layer (hereinafter called 'MAC PDU') in a communication, in which a Base Station (BS) that manages a predetermined cell, and a Mobile Station (MS), which is located in the predetermined cell and receives a communication service provided from the BS, transmit/receive the PDUs corresponding to the type of service in order to provide service to the MS.

[20] In the following embodiments, the transmitter of a BS or MS transmits more than two MAC PDUs in concatenated form in order to reduce the control overhead such as MAC PDU information including a position of MAC PDU and modulation and coding information, and the receiver of the BS or MS receives the concatenated MAC PDUs at high decoding success rate. That is, the present invention enables a receiver to receive data by correctly performing decoding on one MAC PDU in the concatenated MAC PDUs, e.g. the first MAC PDU and the following concatenated MAC PDUs. Particularly, even when failed to perform decoding on the one MAC PDU in the concatenated MAC PDUs, the receiver receives the data by performing decoding on the following concatenated MAC PDUs.

[21] In the following embodiment, the receiver checks whether a MAC PDU is successfully performed decoding using a Header Check Sequence (HCS) or a header field (e.g. a Header Type (HT) field, or an Encryption Control (EC) field) including MAC header of MAC PDU, or a Cyclic Redundancy Check (CRC) of the MAC PDU, accordingly checks whether the MAC PDU is normally performed decoding. Even when it is checked that the one MAC PDU in the concatenated MAC PDUs, e.g. the first MAC PDU is unsuccessfully performed based on the HCS, HT field, EC field, and CRC of the first MAC PDU, the receiver checks whether the following MAC PDU is successfully performed based on the HCS, HT field, EC field, and CRC of the following MAC PDU, and the receiver receives data by performing decoding on the following MAC PDU. That is, the receiver normally performs decoding on the concatenated MAC PDUs using the HCS, HT, EC, or CRC field of the one MAC PDU and the following MAC PDU in the concatenated MAC PDUs, and receives the data. With reference to FIG. 1, a description will now be made of a structure for a communication system according to an embodiment of the present invention.

[22] FIG. 1 is a diagram schematically illustrating a structure of a communication system according to an embodiment of the present invention.

[23] Referring to FIG. 1, the communication system includes a BS 110 managing a cell

100 and MSs, i.e. MSl 120 and MS2 130, provided service from the BS 110 within the cell 100. The MSl 120 and MS2 130 can have mobility and fixity and exchange signal with the BS 110 using the OFDM/OFDMA.

[24] As aforementioned, the transmitters of the BS 110 and MSs 120 and 130 are configured to transmit more than two MAC PDUs in concatenated manner for reducing control information overhead, and the receivers of the BS 110 and MSs 120 and 130 are configured to receive the MAC PDUs correctly performed decoding by checking whether each of MAC PDUs is successfully performed using the HCS, HT field, EC field, and/or CRC of the concatenated MAC PDUs. With reference to FIG. 2, a description will now be made of a format for a MAC PDU in the communication system according to an embodiment of the present invention.

[25] FIG. 2 is a diagram schematically illustrating a format of a MAC PDU in the communication system according to an embodiment of the present invention. [26] Referring to FIG. 2, the MAC PDU formats can be classified MAC PDUl 210 without payload and MAC PDU2 220 with payload corresponding to the data for being transmitted to receiver by transmitter. Also, the MAC PDUs can be classified non- concatenated MAC PDUs 200 such as the MAC PDUl 210 and the MAC PDU2 220, and concatenated MAC PDUs 250 by being concatenated more than two MAC PDUs, i.e. first MAC PDU 260, second MAC PDU 270, and third MAC PDU 280.

[27] The MAC PDUl 210 without payload includes an MAC header 212 of first 6 bytes, and an HCS 214 allocated in last 1 byte of the MAC header 212 (i.e. sixth 1 byte of the MAC header 212), but no CRC. The MAC PDU2 220 with payload includes a MAC header 222, a MAC payload 224, and a CRC 226 allocated in last. The receiver checks whether the MAC header 212 of the MAC PDU 210 is successfully performed decoding using the HCS 214. That is, the receiver receives the MAC PDUl 210 normally performed decoding by checking whether the MAC header information performed decoding is correct. Also, the receiver receives the MAC PDUl 220 normally performed decoding by checking whether the MAC payload 224 information performed decoding is correct using the CRC 226 of the MAC PDU 220.

[28] In the meantime, the first MAC PDU 260, second MAC PDU 270, and third MAC

PDU 280 of the concatenated MAC PDUs 250 include individual MAC headers 262, 272, and 282 allocated in first 6 bytes; individual HCSs 264, 274, and 284 allocated in last 1 byte of the MAC headers 262, 272, and 282 (i.e. sixth 1 byte of the MAC headers 262, 272, and 282); individual MAC payloads 266, 276, and 286 allocated in following the MAC headers 262, 272, and 282; and individual CRCs 268, 278, and 288 allocated in last bytes following the MAC payloads 266, 276, and 286. In an embodiment of the present invention, the receiver checks whether the MAC headers 262, 272, and 283 is successfully performed decoding using the HCSs 264, 274, and 284 allocated in each of the sixth one bytes, or the HT and EC fields each of the MAC headers 262, 272, and 282 in the MAC PDUs, i.e. the first MAC PDU 260, second MAC PDU 270, and third MAC PDU 280 of the concatenated MAC PDUs 250. That is, the receiver individually checks whether the MAC header information performed decoding is correct, whether the MAC payloads 266, 276 is correct using the CRCs 268, 278, and 288 allocated in each of the last bytes, and whether the first MAC PDU 260, second MAC PDU 270, and third MAC PDU 280 is successfully performed decoding. The receiver receives the first MAC PDU 260, second MAC PDU 270, and third MAC PDU 280 of the concatenated MAC PDUs 250 normally performed decoding.

[29] At this time, the receiver compares the HCS allocated in the last byte of the MAC header with the HCS calculated by 5 bytes except for the last byte, and checks whether MAC header information performed decoding is correct based on the comparison result. If bits of the HT and EC fields are set to T, then it means the MAC PDU is for the Uplink (UL), has 6 bytes, and includes neither pay load nor CRC such that it is possible to deduce the concatenated MAC PDU boundary with reference to the HT and EC bit. Also, the length of the concatenated MAC PDUs is length information having 11 bytes for Generic MAC header (GMH) and downlink (DL) Compressed MAP, and determines the concatenated MAC PDU boundary. With reference to FIG. 3, a description will now be made of an operating process of a receiver in the communication system.

[30] FIG. 3 is a flow chart illustrating an operating process of a receiver in the communication system.

[31] Referring to FIG. 3, in step S302, as described in FIG. 2, the receiver receives a burst including the concatenated MAC PDUs 250 by being concatenated more than two MAC PDUs (e.g. first MAC PDU 260, second MAC PDU 270, and third MAC PDU 280). Next, in step S304, the receiver reads the first 6 bytes of the burst, i.e. the MAC header of the first MAC PDU 260 in the concatenated MAC PDUs 250 and, in step S306, the receiver checks whether there are padding bits in the read first 6 bytes.

[32] If it there is no padding bits in the read first 6 bytes in step S306, then in step S308, the receiver calculates an HCS value by 5 bytes non-including the last byte from the first 6 bytes. Next, in step S310, the receiver checks whether the calculated HCS value is identical with the HCS value of the sixth 1 byte of the MAC header. If the calculated HCS value is identical with the HCS value of the sixth 1 byte, then in step S312, the receiver checks whether there is a padding Connection Identifier (CID) in the MAC header. If it is checked that there is no padding CID in the MAC header in step S312, then in step S314, the receiver checks whether the HT field of the MAC header is set to 1O'. Herein, if the HT field of the MAC header is set to ¹O', the MAC header is a GMH for UL or DL.

[33] If the HT field of the MAC header is set to '0' in step S314, then in step S316, the receiver reads the rest bytes non-including the first 6 bytes from the length of the MAC PDU. That is, the receiver reads the MAC payload and CRC bytes of the MAC PDU.

[34] Next, in step S318, the receiver calculates the CRC value and, in step S320, the receiver checks whether the calculated CRC value is identical with the CRC value of the last 4 bytes of the MAC PDU. If the calculated CRC values are not identical with each other, in step S322, the receiver discards the first MAC PDU, i.e. the first MAC PDU 260. Next, in step S324, the receiver checks whether there are further bytes to read in the burst, if there are, the receiver proceeds to step S304.

[35] Meanwhile, if the HT field of the MAC header is not set to '0' in step S314, in step

S326, the receiver checks whether both the HT and EC fields are set to T. Herein, if the HT and EC fields of the MAC header are set to T, the MAC header includes in- formation for indicating to perform decoding on the DL MAP message as a compressed DL MAP message in MAC PDU. In the case of DL, if both the HT and EC fields are set to T in step S326, then in step S328, the receiver reads the rest bytes non-including the first 6 bytes from length of the compressed MAP message, and the receiver calculates the CRC by proceeding to step S318.

[36] If the HT field is set to T and the EC field is set to ¹O,' or the HT field is set to '0' for

UL in step S326, then in step S330, the receiver transmits to the upper layer MAC PDU performed correctly decoding (e.g. the first MAC PDU 260 correctly performed decoding by being successfully performed decoding MAC header of the first MAC PDU 260).

[37] If there are padding bits in the first 6 bytes in step S306 or padding CID in the MAC header in step S312, or there are no further bytes to read in the burst in step S324, then in step S322, the receiver checks that the MAC burst is successfully performed decoding, and ends the decoding procedure. In the meantime, if the calculated HCS value is not identical with the HCS value of the sixth 1 byte in step S310, in step S334, the receiver checks that the MAC header is unsuccessfully performed decoding and the MAC burst is abnormally performed decoding and ends the decoding procedure.

[38] As described above, the receiver checks whether the first MAC PDU (e.g. the first

MAC PDU 260) in the concatenated MAC PDUs is successfully performed decoding, receives the MAC PDU performed decoding when it is successfully performed decoding. But, when receiver unsuccessfully performs decoding on the first MAC PDU, the receiver unsuccessfully performs decoding on the following MAC PDU. With reference to FIGs. 4 to 6, a description will now be made of illustrating an operating process of a receiver, which checks each individual MAC PDUs whether the concatenated MAC PDUs are successfully performed decoding, receives the concatenated MAC PDUs, in a communication system according to another embodiment of the present invention.

[39] FIGs. 4 to 6 are a flow chart illustrating an operating process of a receiver in a communication system according to another embodiment of the present invention.

[40] Referring to FIGs. 4 to 6, in step S402, as described in FIG. 2, the receiver receives a burst 250 including the concatenated MAC PDU 250 by being concatenated more than two MAC PDUs (e.g. first MAC PDU 260, second MAC PDU 270, and third MAC PDU 280). Next, in step S404, the receiver reads the first 6 bytes of the burst, i.e. the MAC header of the first MAC PDU 250, and, in step S406, the receiver checks whether there are padding bits in the red first 6 bytes.

[41] If there is no padding bits in the read first 6 bytes of the burst 250 in step 406, then in step S408, the receiver calculates an HCS value by the 5 bytes non-including the last byte from the first 6 bytes. Next, in step S410, the receiver checks whether the calculated HCS value is identical with the HCS value of the sixth 1 byte of the MAC header. If the calculated HCS value is identical with the HCS value of the sixth 1 byte in step S410, then in step S412, the receiver checks whether there is a padding CID in the MAC header. If there is no padding CID in the MAC header in step S412, then in step S414, the receiver checks whether the HT field of the MAC header is set to '0'. Herein, if the HT field of the MAC header is set to '0', the MAC header is a GMH for UL or DL.

[42] If the HT field of the MAC header is set to '0' in step S414, then in step S416, the receiver reads the rest bytes non-including the first 6 bytes from the length of the MAC PDU. That is, the receiver reads the MAC payload and CRC bytes of the MAC PDU. Next, in step S418, the receiver calculates the CRC value and, in step S420, checks whether the calculated CRC value is identical with the CRC value of the last 4 bytes of the MAC PDU. If the calculated CRC values are not identical with each other in step S420, then in step S422, the receiver discards the MAC PDU, i.e. the first MAC PDU 260. Next, in step S424, the receiver checks whether there are further bytes to read in the burst, if there are, the receiver proceeds to step S404.

[43] Meanwhile, if the HT field of the MAC header is not set to '0' in step S414, then in step S426, the receiver checks whether both the HT and EC fields are set to T. Herein, if the HT and EC fields of the MAC header are set to T, the MAC header includes information for indicating to perform decoding on the DL MAP message as a compressed DL MAP message in MAC PDU. In the case of DL, if both the HT and EC fields are set to T in step S426, then in step S428, the receiver reads the rest bytes non-including the first 6 bytes from length of the compressed MAP message, the receiver calculates the CRC by proceeding to step S418.

[44] If the HT and EC fields of the MAC header is set to ' 1 ' and '0' for DL, or the HT field is set to'O' for UL in step S426, then in step S430, the receiver updates a MAC PDU decoding success count and, in step S432, the receiver transmits to the upper layer MAC PDU performed correctly decoding (e.g. the first MAC PDU 260 correctly performed decoding by being successfully performed decoding MAC header of the first MAC PDU 260). If the calculated CRC values are identical with each other in step S420, then in step S430, the receiver transmits to the upper layer MAC PDU performed correctly decoding (e.g. the first MAC PDU 260 correctly performed decoding by the CRC).

[45] If there are padding bits in the first 6 bytes of the burst 250 in step S406 or padding

CID in the MAC header in step S412, or there is no further byte to read in the burst in step S424, then in step S434, the receiver checks that the MAC burst is successfully performed decoding, and ends the decoding procedure. Meanwhile, if the HCS values are not matched to each other in step S410, then the receiver checks that the MAC header, of which the MAC PDU corresponds to the first MAC PDU (e.g. the first MAC PDU 260), is unsuccessfully performed decoding and the MAC burst is abnormally performed decoding, and in step S436, the receiver updates a decoding failure count, and checks whether the decoding failure count is equal to a maximum decoding failure count. Here, the decoding failure count is set based on an environment of system in order to receive the following MAC PDUs successfully according to whether the following MAC PDUs are correctly performed decoding, even when the re ceiver successfully performs decoding on the first MAC PDU 260 of the concatenated MAC PDUs 250, i.e. the receiver abnormally performs decoding on the first MAC PDU 260.

[46] If the decoding failure count does not reach the maximum decoding failure count in step S438, then in step S438, the receiver checks whether the HC field of the MAC header of the first MAC PDU is set to ¹O'. If the HC field of the MAC header of the first MAC PDU is set to'O' in step S438, then in step S440, the receiver checks that the first MAC PDU is abnormally performed decoding, and discards the bytes corresponding to the first MAC PDU and, in step S442, the receiver checks whether there are further bytes to read in the burst 250.

[47] If there are further bytes to read in the burst in step S442, then in step S444, the receiver reads the first 6 bytes in the rest bytes of the burst, i.e. the first 6 bytes of the second MAC PDU 260 corresponding to the following MAC PDU (i.e. the MAC header of the second MAC PDU 260) and, in step S446, the receiver checks whether there are padding bits in the first 6 bytes.

[48] If there is no padding bits in the first 6 bytes of the second MAC PDU in step S446, then in step S448, the receiver calculates the HCS value by the 5 bytes non-including the last byte form the first 6 bytes. Next, in step S450, the receiver checks whether the calculated HCS value is identical with the HCS value of the sixth 1 byte of the MAC header. If the HCS values are identical with each other in step S450, then in step S452, the receiver checks whether there is a padding CID in the MAC header. If there is no padding CID in the MAC header in step S452, then in step S454, the receiver checks whether the HT field of the MAC header is set to ¹O'. Herein, if the HT field of the MAC header is set to '0', the MAC header is a GMH for UL or DL.

[49] If the HT field of the MAC header is set to '0' in step S454, then in step S456, the receiver reads the rest bytes non-including the first 6 bytes from the length of the MAC PDU. That is, the receiver reads the MAC payload and CRC bytes of the MAC PDU. Next, in step S458, the receiver calculates the CRC value and, in step S460, checks whether the calculated CRC value is identical with the CRC value of the last 4 bytes of the MAC PDU. If the CRC values are not matched to each other in step S460, the receiver checks that the MAC header, of which the MAC PDU corresponds to the flowing MAC PDU (e.g. the second MAC PDU 270), is unsuccessfully performed decoding and the second MAC PDU 270 is abnormally performed decoding, and in step S436, the receiver updates a decoding failure count, and checks whether the decoding failure count is equal to a maximum decoding failure count.

[50] Otherwise, if the CRC values are matched to each other in step S460, the receiver checks that the MAC header, of which the MAC PDU corresponds to the flowing MAC PDU (e.g. the second MAC PDU 270), is successfully performed decoding and the second MAC PDU 270 is performed decoding, and in step S462, the receiver transmits the upper with the MAC PDU. Next, in step S464, the receiver initializes both the decoding failure count and decoding success count to '0' and, in step S466, checks whether there are further burst to read in the burst 250.

[51] If there are further burst to read in the burst 250 in step S466, the receiver proceeds to step S418 and, otherwise, in step S468, the receiver checks that the burst is successfully performed decoding, and ends the decoding procedure. Also, if there are padding bits in the first 6 bytes or padding CID in the MAC header in step S452, then in step S468, the receiver checks that the burst is successfully decoding, and ends the decoding procedure.

[52] Meanwhile, if the HT field of the MAC header is not set to '0' in step S438, then in step S470, the receiver checks whether both the HT and EC fields are set to T. Herein, if the HT and EC fields of the MAC header are set to T, the MAC header includes information for indicating to perform decoding on the DL MAP message as a compressed DL MAP message in MAC PDU. In the case of DL, if both the HT and EC fields are set to T in step S470, then in step S472, the receiver reads the rest bytes non-including the first 6 bytes from length of the compressed MAP message and checks whether there are further bytes to read in step S442.

[53] If the HT and EC field of the MAC header are set to T and '0' respectively, or the HT field is not set to '0' in UL, in step S470, then in step S474, the receiver discards the first 6 bytes of the MAC header and, in step S442, checks whether there are further bytes to read in the burst. In the meantime, if the decoding failure count is equal to the maximum decoding failure count in step S436, then in step S476, the receiver initializes both the decoding failure count and decoding success count to '0' and, in step S478, the receiver checks that the concatenated PDUs are unsuccessfully performed decoding and the burst is abnormally performed decoding, and ends the decoding procedure.

[54] If the HT field of the MAC header is not set to '0' in step S454, then in step S480, the receiver checks whether both the HT and EC fields of the MAC header are set to T. Herein, if the HT and EC fields of the MAC header are set to T, the MAC header includes information for indicating to perform decoding on the DL MAP message as a compressed DL MAP message in MAC PDU. If the HT and EC fields of the MAC header are both set to T in step S480, then in step S482, the receiver reads the rest bytes non-including the first 6 bytes from the length of the compressed MAP message, and calculates the CRC by proceeding to step S458.

[55] If the HT and EC fields of the MAC header are set to T and '0' respectively or the

HT field is not set to '0' in UL in step S480, then in step S484, the receiver buffers the MAC PDU and, in step S486, the receiver checks whether the decoding success count is equal to a minimum decoding success count. If the decoding success count is equal to or greater than the minimum decoding success count in step S486, the receiver checks that the MAC header of the buffered MAC PDU is successfully performed decoding and, in step S488, transmits the MAC PDU to the upper layer. Consequently, in step S490, the receiver checks that the burst is successfully performed decoding, and ends the decoding procedure. Otherwise, if the decoding success count is not equal to the minimum decoding success count, in step S442, the receiver checks whether there are further burst to read in the burst.

[56] As described above, the receiver of a communication system according to an embodiment of the present invention, even though the first MAC PDU in the concatenated MAC PDUs is abnormally performed, can receive the MAC PDU normally performed decoding by checking whether the rest MAC PDU in the concatenated MAC PDUs is successfully performed decoding based on the HCS of the MAC PDU, HT, and EC fields of the MAC header, and CRC.

[57] Although embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention, as defined in the appended claims.

Claims

[1] A method for receiving data in a wireless communication system, comprises: receiving a burst concatenated a plurality of packet data units (PDUs) and checking whether a first decoding is successfully performed on a first PDU based on a Header Check Sequence (HCS) of the first PDU in the burst; and performing decoding on the plurality of the PDUs by updating a decoding count according to the whether the first decoding is successfully performed and checking, when the first decoding is unsuccessfully performed, whether a second decoding is successfully performed on a second PDU based on a HCS of the second PDU in the burst.

[2] The method of claim 1, wherein the checking whether a first decoding is successfully performed is characterized by obtaining a calculated the HCS using specific bytes of the burst, checking whether the first decoding is successfully performed based on the calculated HCS.

[3] The method of claim 1, wherein the checking whether a second decoding is successfully performed is characterized by discarding the first PDU, obtaining a calculated the HCS using specific bytes of the burst non-including the discarded first PDU, and checking whether the second decoding is successfully performed based on the calculated HCS.

[4] The method of claim 2, wherein the checking whether a first decoding is successfully performed is characterized by checking the HCS.

[5] The method of claim 1, wherein the checking whether a first decoding or a second decoding is successfully performed is characterized by checking based on a specific header field or a Cyclic Redundancy Check (CRC) corresponding to the first PDU or the second PDU.

[6] The method of claim 5, wherein the checking whether a first decoding is successfully performed is characterized by reading specific bytes of the burst, calculating the CRC using the read bytes, and checking whether the first decoding is successfully performed based on the calculated CRC.

[7] The method of claim 5, wherein the checking whether a second decoding is successfully performed is characterized by discarding the first PDU in the burst, reading specific bytes of the burst non-including the discarded first PDU, calculating the CRC using the read bytes, and checking whether the second decoding is successfully performed based on the calculated CRC.

[8] The method of claim 6, wherein the checking whether a first decoding or a second decoding is successfully performed is characterized by checking the CRCs.

[9] The method of claim 5, wherein the checking whether a first decoding or a second decoding is successfully performed is characterized by recognizing a header type by checking a set value in the specific header field, and reading specific bytes in the burst according to the recognized header type.

[10] The method of claim 1, wherein the updating a decoding count is characterized by updating if the decoding is unsuccessfully performed on the PDUs.

[11] The method of claim 10, wherein the checking whether a second decoding is successfully performed is determined to check depending on the updated decoding count.

[12] An apparatus for receiving data in a wireless communication system, comprising: a receiver for receiving a burst concatenated a plurality of packet data units (PDUs); and wherein the receiver checks whether a first decoding is successfully performed on a first PDU based on a Header Check Sequence (HCS), a specific header field, or a Cyclic Redundancy Check (CRC) of the first PDU in the burst; updates a decoding count according to the whether the first decoding is successfully performed; checks, when the first decoding is unsuccessfully performed, whether a second decoding is successfully performed on a HCS, a specific header field, or a CRC of the second PDU in the burst; and performs decoding on the plurality of the PDUs.

[13] The apparatus of claim 12, wherein the receiver updates the decoding count when decoding is unsuccessfully performed on the PDUs.

[14] A method for receiving data in a wireless communication system, comprising: receiving a burst concatenated a plurality of Media Access Control Packet Data Units (MAC PDUs); performing a first decoding on a first MAC PDU in the burst; performing, if the first decoding is unsuccessfully performed, a second decoding on a second MAC PDU in the burst using a length information within the first MAC PDU.

[15] The method of claim 14, wherein the step of performing a second decoding further comprising: if the second MAC PDU includes a Cyclic Redundancy Check (CRC) code, checking whether the second decoding is successfully performed depending on a CRC code error check.

[16] The method of claim 15, wherein the step of performing a second decoding further comprising: if the second MAC PDU dose not include the CRC code, checking whether the second decoding is successfully performed depending on a Header Check Sequence (HCS) error check.