JP2008085910A - Radio communication method and radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication method and device capable of effectively reducing an MAP area, thereby extending a data area. <P>SOLUTION: When a down burst is transmitted from a base station 1 to a mobile station 2 by using a frame structure to which an MAP area where MAP is allocated and a data area where data are allocated are allocated, the base station 1 generates MAP having information showing the number of frequencies controlling a modulation class and information showing a frequency range by a map generator 15. The generated MAP is transmitted from a radio communication section 18 of the base station 1 to a radio communication section 27 of the mobile station 2. Consequently, IE (information element) of the MAP can be extended to optimize the allocation information for AMC (Advanced Modulation and Coding). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless communication method and a wireless communication apparatus in a communication system including a mobile station and a base station corresponding to IEEE Std. 802.16e (WiMAX), for example.

  In such a communication system, a base station transmits a downlink burst to a mobile station using a frame structure having a MAP area to which MAP (data allocation information) is allocated and a data area to which data is allocated (for example, Patent Literature 1, Non-Patent Literature 1, 2).

  In the frame structure, a PUSC (Partial Used SubChannelization) method that assigns subcarriers to combine non-adjacent subcarriers and an AMC (Advanced Modulation and Coding) method that assigns subcarriers to combine adjacent subcarriers are applied. In the area, the PUSC method is applied, and in the data area, the PUSC method, the AMC method, and the like are applied based on the communication method.

  The PUSC scheme has a frame structure as shown in FIG. 1 when applied to the data area, and distributes allocated subcarriers to a plurality of subchannels using a certain rearrangement mechanism. Good characteristics even in highly mobile environments due to frequency diversity. In the PUSC scheme, each user basically has one MCS (Modulation Coding Scheme), and one MCS needs one MAP IE (information element) for allocation.

  When applied to the data area, the AMC scheme has a frame configuration as shown in FIG. 2, the frequency axis area is divided into units of 24 bands, and the BS (base station) determines the MCS for each band. The throughput can be maximized by selecting the optimum band for each SS (mobile station), that is, the user. The AMC method is applied to AAS (adaptive array antenna system). In the AMC scheme, each user has a plurality of MCS because the MCS differs for each band.

  In addition, for MAP, each scheme IE is configured so as to be able to cope with either a communication state in which the subchannels of the data area are allocated in the PUSC scheme or a communication state allocated in the AMC scheme. In other words, since the MCS for each PUSC method is different for each user, MAP IEs for allocation are required for the number of users, and for the AMC method, the MCSs are different for each band, so MAP IEs for allocation are required for the number of Bands. For example, in the case of 3SDMA (space division multiple access method), a maximum of 72 (24 Band × 3) MAP IEs for allocation are required.

  FIG. 3 is a diagram showing the current MAP IE (Downlink). In the current (IEEE802.16e) IE, the allocation is rectangular, and the number of Symbols / Subchannels indicating the start offset and the number of Symbols / Subchannels indicating the range of allocation are specified, so the amount of information is large. In addition, in this IE, only one DIUC (Downlink internal Usage Code) that designates MCS can be designated, and thus this IE is required for the number of Bands in the AMC method. In the case of the AMC method, the start offset value and the number of subchannels indicating the allocation range are fixed and need not be specified. Furthermore, the number of symbols indicating the range of the AMC area is determined by AAS_DL_IE, and thus becomes unnecessary.

  FIG. 4 is a diagram illustrating a current MAP IE and frame structure. In this case, the relationship between the MAP IE of DL burst # 3 and the frame is shown. The OFDMA symbol offset length and the Subchannel offset length at the start position of the used Band are designated, and the OFDMA symbol length and the Subchannel length indicating the allocation range are designated. Is specified.

FIG. 5 is a flowchart for generating a current MAP in the AMC method. In this case, MAC scheduling, which is a process of determining which (frequency axis and time axis) region of an OFDMA (orthogonal frequency division multiple access) frame is assigned to which user, is performed (step S1). Enter (step S2). In the band unit loop, DIUC, N_CID, CID, OFDMA Symbol Offset, Subchannel Offset, Boosting, No. OFDMA triple symbol, No. Subchannel, and Repetition Coding Indication are set (steps S3 to S11). When the band-unit loop has been processed for all the bands (step S12), IEs other than the allocation information are generated as necessary (step S13), and a MAP header is generated based on all the IEs to be used (step S14). ), This routine is terminated.
JP 2006-74325 A IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems (IEEE Std 802.16-2004), October 1, 2004 IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1 (IEEE Std 802.16e-2005) , February, 2006

  In the above communication system, for example, SDMA using AAS can be considered in order to increase frequency utilization efficiency and data transmission efficiency. In this case, however, when the BS transmits data to the SS. The sub-channels in the data area are preferably assigned by the AMC method.

  However, in this case, even when only the AMC scheme is applied to the data area, the MAP is configured with a PUSC or AMC IE, and as a result, the MAP area is wide in the frame structure. It occupies the range, and the data area cannot be secured efficiently.

  An object of the present invention is to provide a radio communication method and a radio communication apparatus that can effectively reduce a MAP area and expand a data area, and allow a mobile station to efficiently perform modulation class control. .

A wireless communication method according to claim 1 of the present invention comprises:
Using the orthogonal frequency division multiplexing method, using the frame structure in which the first region to which MAP is allocated and the second region to which data is allocated is allocated, a downlink burst is transmitted from the base station to the mobile station, and the mobile station A wireless communication method for receiving the downlink burst,
Among the frequencies assigned to the frame structure by the base station, information indicating a frequency region where modulation class control is performed, information indicating whether or not each frequency is used in the frequency region, and a frequency used Generating a MAP having information indicating a modulation class of
Transmitting a downlink burst having a frame structure including the generated MAP from the base station to the mobile station;
The mobile station that has received the downlink burst having the frame structure including the generated MAP grasps the modulation class for the used frequency based on the MAP included in the downlink burst, and sets the grasped modulation class to the grasped modulation class. And the step of communicating with the base station.

A wireless communication method according to claim 2 of the present invention is:
The MAP further includes information indicating a beam pattern for performing space division multiple access.

A wireless communication device according to a third aspect of the present invention provides:
A radio communication apparatus that transmits the downlink burst to another radio communication apparatus using an orthogonal frequency division multiplexing scheme and a frame structure in which a first area to which MAP is assigned and a second area to which data is assigned is assigned Because
Among the frequencies allocated to the frame structure, information indicating a frequency region for performing modulation class control, information indicating presence / absence of use of each frequency in the frequency region, and a modulation class for the used frequency Means for generating a MAP having information;
Means for transmitting a downlink burst having a frame structure including the generated MAP to the other wireless communication apparatus.

A wireless communication apparatus according to claim 4 of the present invention is provided.
The MAP further includes information indicating a beam pattern for performing space division multiple access.

  According to the present invention, the MAP IE is expanded and the allocation information is optimized for AMC. Therefore, even when SDMA is applied, the MAP area can be effectively reduced and the data area can be expanded. .

Embodiments of a wireless communication method and apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 6 is a diagram showing a communication system to which the wireless communication method according to the present invention is applied. The communication system shown in FIG. 6 includes a base station (BS) 1 and a mobile station (SS) 2 corresponding to WiMAX.

  The BS 1 includes an upper layer (ID packet processing unit) 11, a data queue management unit 12, a MAC scheduler 13, a MAC PDU (Protocol Data Unit) processing unit 14, a MAP generation unit 15, and a Band reception state acquisition unit 16. A PHY PDU processing unit 17 and a wireless communication unit 18. SS2 includes an upper layer (ID packet processing unit) 21, a data queue management unit 22, a MAC PDU processing unit 23, a MAP processing unit 24, a Band reception state notification unit 25, a PHY PDU processing unit 26, a wireless And a communication unit 27.

  The data queue managers 12 and 22 manage the transmission data queue and the reception data queue. The MAC scheduler 13 assigns the data in the transmission data queue to the optimum Band using the Band reception status of each user as an index. The MAC PDU processing units 14 and 23 perform upper data (for example, IP packet) -MAC PDU conversion. A MAC header is added to the MAC PDU. The MAC PDU processing units 14 and 23 also generate a MAC Message.

  The MAP generation unit 15 creates a MAP based on the allocation information determined by the MAC scheduler 13. The Band reception status acquisition unit 16 acquires the reception status of each user's usage band, and the usage status of each user's usage band is transmitted to the BS 1 as a PHY PDU using a dedicated channel. In this case, the reception state is indicated by RSSI or CINR.

  The MAP processing unit 24 acquires the MAP notified from the BS 1, acquires and transmits data based on the data allocation information addressed to itself. The Band reception state notification unit 25 transmits the reception state of the used Band to the BS 1 as a PHY PDU using a dedicated channel specified by the MAP. In this case, the reception state is indicated by RSSI or CINR. The PHY PDU processing unit 26 performs PHY PDU-MAC PDU conversion processing and Band reception state information-PHY PDU conversion processing.

  FIG. 7 is a diagram illustrating a MAP IE generated by the present invention. In order to optimize the MAP IE generated by the present invention for Band AMC, unnecessary information of the Burst Allocation IE is omitted, and information of all bands is collectively managed by one IE. In the Burst Allocation IE, the assignment is specified by an offset, but in the IE according to the present invention, the used Band is specified by a bitmap.

  The parameters specific to the present invention will be described below. Logical Band Grouping specifies the number of bands grouped as an MCS control unit in which the mobile station performs MCS control. In the case of 12 bands, the mobile station performs MCS control in units of 2 bands, and in the case of 24 bands, the mobile station The station performs MCS control in units of 1 Band. This Logical Band Grouping is indicated by 1 bit, and when it is “0”, it means “12 Band”, and when it is “1”, it means “24 Band”. The Beam Index is information indicating the index of the beam pattern when using the SDMA (Spatial Division Multiple Access) method, and is represented by 2 bits. In this case, since the Beam Index is 2 bits, it is possible to indicate up to 3 SDMA (in this case, “01” means connection to one user (no spatial multiplexing), and “10” means to two users. Connection (two multiplex) means “11” means connection to three users (three multiplex). The User Band Group Bitmap is indicated by 2 bits and indicates which of the two divided Band areas is used. Specifically, when the above-mentioned Logical Band Grouping indicates “0” bit (that is, in the case of a bit display meaning “12 Band”), when Bit # 0 = 1 (that is, “01”), Indicates that the area of Band 0-11 is used, and when Bit # 1 = 1 (ie, “11”), the area of Band 12-23 is used with the mobile station. The mobile station can perform modulation class control only for the indicated Band region. The Band Bitmap is indicated by 6 bits, 12 bits, or 24 bits, and each bit corresponds to an individual Band, and the bit indicated by “0” indicates that the corresponding Band is unused. , “1” indicates that the corresponding Band is used. The size of the Band Bitmap depends on the Logical Band Grouping and the Used Band Group Bitmap, and indicates whether or not each Band is used in at least the Band area indicated by the User Band Group Bitmap. In the case of the present embodiment, DIUC (UIUC) is information indicating a modulation class for each frequency used by the base station. This information includes information on the modulation class determined by the base station. Indicated.

  FIG. 8 is a diagram illustrating a MAP IE and a frame structure generated according to the present invention. In this case, each user can specify the band to be used based on the band bitmap, and as a result, the amount of information in the MAP area generated by the base station is significantly reduced compared to the current MAP.

  FIG. 9 is a flowchart of generating a MAP according to the present invention. In this case, MAC scheduling which is processing for determining which (frequency axis and time axis) region of an OFDMA (orthogonal frequency division multiple access) frame is assigned to which user is performed (step S21), and Extended DIUO, Band Grouping, RCID After setting type and N_RCID (step S22), a loop for each user is entered (step S23). In the loop for each user, RCID, Band Index, Used Band Group Bitmap, and Band Bitmap are generated (steps S24 to S27), and the loop for each band is entered (step S28). In the band unit loop, DIUC, N_CID, and Repetition Coding Indication are set (steps S29 and S30), respectively. When the band-unit loop has been processed for all the bands (step S31), and all the users of the user-unit loop have been processed (step S32), IEs other than the allocation information are generated as necessary (step S31). S33), a MAP header is generated based on all IEs to be used (step S34), and this routine is terminated. The MAP generated by this routine is transmitted from the wireless communication unit 18 of BS1 to the wireless communication unit 27 of SS2, and SS2 performs MCS based on the MAP.

  FIG. 10 is a diagram for comparing and explaining the MAP generated by the present invention and the current MAP. As can be seen from FIG. 10, the maximum 72 Burst Allocation IEs have been changed to one Enhanced AAS SDMA MAP IE. A comparison of the number of bits of the MAP generated by the present invention and the current MAP for 6 users 12 Bands Grouping, 6 users 24 Bands Grouping, 9 users 12 Bands Grouping, and 9 users 24 Bands Grouping is shown below.

この場合、３ＳＤＭＡで全Ｂａｎｄを使用し、本発明のＭＡＰにおいて、Used Band Group Bitmap=0b11の最悪値で計算している。また、削減ビット数における括弧内はビット削減率を表す。２４ＢａｎｄｓＧｒｏｕｐｉｎｇの場合、現行ＭＡＰではＭＡＰ繰り返し数が４のときに１フレームに収まらないため、通信が成立しない。［表１］に示すように、本発明によって生成されたＭＡＰの情報量は、現行ＭＡＰに比べて大幅に削減されており、情報の削減量は、ユーザ数が比較的少なく（例えば、１０ユーザ未満）、かつ、各ユーザの使用Ｂａｎｄ数が比較的多い（例えば、１２Ｂａｎｄ以上）場合に特に多くなる。

In this case, all Bands are used in 3SDMA, and calculation is performed with the worst value of Used Band Group Bitmap = 0b11 in the MAP of the present invention. Further, the parentheses in the number of reduction bits represent the bit reduction rate. In the case of 24 Bands Grouping, the current MAP does not fit in one frame when the number of MAP repetitions is 4, so communication cannot be established. As shown in [Table 1], the information amount of the MAP generated by the present invention is greatly reduced compared to the current MAP, and the information reduction amount is relatively small in number of users (for example, 10 users). Less) and the number of bands used by each user is relatively large (for example, 12 bands or more).

  According to the present embodiment, the MAP area is greatly reduced, the MAP reception PER (Packet Error Rate) of the mobile station is reduced, and the user throughput is improved. Further, since the allocation information is simplified, the map processing speed of the base station and the mobile station is improved.

  The present invention is not limited to the above-described embodiment, and many changes and modifications can be made. For example, in the above embodiment, the case where WiMAX is supported has been described, but the present invention can be applied to other than WiMAX.

It is a figure which shows the frame structure of a data area | region of a PUSC system. It is a figure which shows the frame structure of a data area | region of an AMC system. It is a figure which shows the present MAP IE (Downlink). It is a figure which shows the present MAP IE and frame structure. It is a production | generation flowchart of the present MAP. It is a figure which shows the communication system with which the radio | wireless communication method by this invention is applied. FIG. 3 is a diagram illustrating a MAP IE generated by the present invention. It is a figure which shows the MAP IE and frame structure which are produced | generated by this invention. 3 is a flowchart of generating a MAP according to the present invention. It is a figure for comparing and explaining MAP produced by the present invention and current MAP.

Explanation of symbols

1 Base station (BS)
2 Mobile station (SS)
11, 21 Upper layer (IP packet processing unit)
12, 22 Data queue management unit 13 MAC scheduler 14, 23 MAC PDU processing unit 15 MAP generation unit 16, 25 Band reception state acquisition unit 17, 26 PHY PDU processing unit 18, 27 Wireless communication unit 24 Map processing unit 25 Band reception state Notification section

Claims (4)

Using the orthogonal frequency division multiplexing method, using the frame structure in which the first region to which MAP is allocated and the second region to which data is allocated is allocated, a downlink burst is transmitted from the base station to the mobile station, and the mobile station A wireless communication method for receiving the downlink burst,
Among the frequencies assigned to the frame structure by the base station, information indicating a frequency region where modulation class control is performed, information indicating whether or not each frequency is used in the frequency region, and a frequency used Generating a MAP having information indicating a modulation class of
Transmitting a downlink burst having a frame structure including the generated MAP from the base station to the mobile station;
The mobile station that has received the downlink burst having the frame structure including the generated MAP grasps the modulation class for the used frequency based on the MAP included in the downlink burst, and sets the grasped modulation class to the grasped modulation class. And a step of communicating with the base station.   The wireless communication method according to claim 1, wherein the MAP further includes information indicating a beam pattern for performing space division multiple access. A radio communication apparatus that transmits the downlink burst to another radio communication apparatus using an orthogonal frequency division multiplexing scheme and a frame structure in which a first area to which MAP is assigned and a second area to which data is assigned is assigned Because
Among the frequencies allocated to the frame structure, information indicating a frequency region for performing modulation class control, information indicating presence / absence of use of each frequency in the frequency region, and a modulation class for the used frequency Means for generating a MAP having information;
A wireless communication apparatus comprising: means for transmitting a downlink burst having a frame structure including the generated MAP to the other wireless communication apparatus.   The wireless communication apparatus according to claim 3, wherein the MAP further includes information indicating a beam pattern for performing space division multiple access.

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