Wireless communication device

Abstract

To prevent errors from occurring and obtain the maximum transmission rate by appropriately switching the total number of modulation bits in an SVD-MIMO transmission system.SOLUTION: For the total number of modulation bits Ni, a bit / power allocation control unit 100-i of an adaptive control determination unit 21 of a wireless communication device 2 determines a combination of modulation schemes and a power allocation ratio when the MER margins after power allocation for each eigenmode are equal and the MER margins are maximum. A coding rate selection unit 42-i uses a table 43 for the total number of modulation bits Ni to extract the coding rate whose MER margin exceeds the required MER margin, and selects the coding rate with the maximum number of effective transmission bits. A maximum transmission efficiency selection unit 44 selects the one with the largest effective transmission bit number from among the total modulation bit numbers N1, ..., and NI, and selects the combination of modulation schemes and the power allocation ratio corresponding thereto, and the coding rate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a MIMO (Multiple Input and Multiple Output) eigenmode transmission system, and more particularly to a wireless communication device that adaptively controls a modulation scheme, etc., to be assigned to each eigenmode. [Background technology]

[0002] The wireless transmission device for transmitting program material is called an FPU (Field Pickup Unit), and is important as a device for transmitting program broadcasting, video, or interviewed video to the broadcasting station. In particular, it is essential for broadcasting programs such as relay races and marathons, in order to transmit video and audio from a moving broadcast van.

[0003] Conventionally, the Singular Value Decomposition-Multiple-Input Multiple-Output (SVD-MIMO) method has been under study as a transmission method for FPU (see, for example, Patent Document 1 and Non-Patent Document 1).

[0004] In the SVD-MIMO system, the MIMO channel is converted into a single channel called an eigenmode using weights obtained by singular value decomposition of the channel matrix, and the modulation method and power allocation of each eigenmode are adaptively controlled according to the quality of each eigenmode, thereby enabling high-capacity transmission.

[0005] 7 is a diagram for explaining a conventional adaptive modulation technique using the SVD-MIMO method described in Patent Document 1. A bit and power allocation control unit 100 provided in a wireless communication device includes a power allocation calculation unit 101, a MER (Modulation Error Ratio) margin calculation unit 102, and a modulation scheme and power determination unit 103. The total number of modulation bits transmitted across all eigenmodes is fixed.

[0006] The bit and power allocation control unit 100 determines the difference between the initial MER of each eigenmode and the MER threshold as the MER margin, and determines the combination of modulation schemes and power allocation ratios when the MER margins after power allocation of each eigenmode are equal and maximum.

[0007] The initial MER is a value that indicates the degree of quality of an eigenmode, and can be obtained by a method of calculating based on an eigenvalue obtained by singular value decomposition of a propagation path matrix, a method of measuring the MER during communication at equal power allocation using a training signal, etc. The MER threshold is a value that achieves a predetermined BER (Bit Error Rate). As described above, the MER margin is the difference between the initial MER and the MER threshold, and the larger the value, the lower the BER.

[0008] The power allocation calculation unit 101 calculates a power allocation ratio based on an initial MER and a MER threshold, and the MER margin calculation unit 102 calculates an MER margin based on the power allocation ratio. Then, the modulation scheme and power determination unit 103 determines the combination of modulation schemes and the power allocation ratio that provides the maximum MER margin based on the MER margins for all combinations of modulation schemes. For details of the bit and power allocation control unit 100, please refer to Patent Document 1.

[0009] 8 is a diagram for explaining an example of a calculation result of the MER margin in the adaptive modulation method of the conventional technology. In a transmission system of the SVD-MIMO scheme using four eigenmodes, the total number of modulation bits transmitted in all eigenmodes is 16 bits, and the maximum number of modulation bits transmitted in each eigenmode is 10. In this case, there are 48 possible combinations of modulation schemes.

[0010] For ease of explanation, a case will be considered in which the combination of modulation schemes is selected from the following three combinations (1) to (3). (1) Number of modulation bits: 10 bits (modulation method: 1024QAM), 6 bits (64QAM) (2) 7-bit (128QAM), 5-bit (32QAM), 4-bit (16QAM) (3) 6-bit (64QAM), 5-bit (32QAM), 3-bit (8QAM), 2-bit (QPSK)

[0011] As shown on the left side of FIG8, it is assumed that the initial MER of the first eigenmode is calculated as 27.8 dB, the initial MER of the second eigenmode is calculated as 21.6 dB, the initial MER of the third eigenmode is calculated as 16.7 dB, and the initial MER of the fourth eigenmode is calculated as 8.9 dB. Also, as shown in FIG8(1) to (3), it is assumed that each modulation scheme achieves a predetermined BER (for example, BER=10 without correction code). -4 ) is set in advance.

[0012] Fig. 11 is a diagram showing an example of the MER threshold for each modulation method. The MER threshold for the modulation method BPSK with the number of modulation bits being 1 is 8.4 [dB], and the MER threshold for the modulation method QPSK with the number of modulation bits being 2 is 11.4 [dB]. The MER thresholds for other modulation methods such as 8QAM are as shown in Fig. 11. It is assumed that such MER thresholds are set in advance for each modulation method. For example, the MER threshold of 36.1 [dB] for the modulation method 1024QAM with the number of modulation bits being 10 shown in Fig. 11 is set as the MER threshold for eigenmode 1 in Fig. 8(1).

[0013] Returning to Fig. 8, in each of (1) to (3), power allocation is determined so that the MER margin, which is the difference between the initial MER and the MER threshold, is equal for all eigenmodes, the gain due to power allocation (power allocation ratio) is determined, and the converted MER after power allocation is calculated. Then, the MER margin after power allocation is calculated. Note that the gain due to power allocation is the gain relative to the transmission power per stream (=0.25) when power allocation is not performed, when the total transmission power is 1.

[0014] Among (1) to (3), the combination of modulation schemes that maximizes the MER margin after power allocation is selected. In the example of Fig. 8, the MER margin (+1.0 dB) after power allocation of (2) is the largest, so the combination of modulation schemes and power allocation ratio of (2) is selected.

[0015] For simplicity of explanation, Fig. 8 shows an example of calculating the MER margin in three cases (1) to (3), but in actual operation, the MER margin is calculated for all 48 cases. Fig. 9 is a diagram for explaining an example of the calculation result of the MER margin in actual operation in the adaptive modulation method of the conventional technology.

[0016] No. 1 to 48 indicate combinations of modulation methods. The four numbers [n1, n2, n3, n4] within the brackets indicate the number of modulation bits to be assigned to the first to fourth eigenmodes, respectively. In n1 to n4, "10" indicates the number of modulation bits: 10 bits (modulation method: 1024QAM), and "9" indicates the number of modulation bits: 9 bits (modulation method: 512QAM). In addition, "8" indicates the number of modulation bits: 8 bits (modulation method: 256QAM), "7" indicates the number of modulation bits: 7 bits (modulation method: 128QAM), "6" indicates the number of modulation bits: 6 bits (modulation method: 64QAM), "5" indicates the number of modulation bits: 5 bits (modulation method: 32QAM), "4" indicates the number of modulation bits: 4 bits (modulation method: 16QAM), "3" indicates the number of modulation bits: 3 bits (modulation method: 8QAM), "2" indicates the number of modulation bits: 2 bits (modulation method: QPSK), and "1" indicates the number of modulation bits: 1 bit (modulation method: BPSK). "0" indicates that the number of modulation bits is 0 bits, that is, the corresponding eigenmode is not used for transmission.

[0017] For example, No.1[10,6,0,0] indicates that the number of modulation bits for the first eigenmode is 10 bits (modulation method: 1024QAM), the number of modulation bits for the second eigenmode is 6 bits (modulation method: 64QAM), and the third and fourth eigenmodes are not used, similar to (1) shown in Figure 8.

[0018] As in FIG. 8, for each of Nos. 1 to 48, the MER margin after power allocation is calculated, and the combination of modulation schemes that maximizes the MER margin after power allocation is selected.

[0019] In the example of Figure 9, since the MER margin (1.00 dB) after power allocation of No. 16 [7, 5, 4, 0] is the largest, the combination of the modulation method for the first eigenmode: 7 bits (128QAM), the modulation method for the second eigenmode: 5 bits (32QAM), and the modulation method for the third eigenmode: 4 bits (16QAM) is selected. [Prior art documents] [Patent documents]

[0020] [Patent Document 1] Patent No. 6328021 [Non-patent literature]

[0021] [Non-Patent Document 1] Portable Quasi-Microwave OFDM Digital Wireless Transmission System for Ultra-High Definition Television Broadcasting Program Material Transmission, ARIB STD-B75, Version 1.0, Association of Radio Industries and Businesses Summary of the Invention [Problem to be solved by the invention]

[0022] Generally, in a single digital transmission, the larger the modulation level, such as 64QAM (6 bits) and 256QAM (8 bits), the more data can be transmitted, but errors are more likely to occur. On the other hand, the smaller the modulation level, such as QPSK (2 bits) and BPSK (1 bit), the less data can be transmitted, but errors are less likely to occur. Therefore, if the propagation path conditions are severe, the modulation level should be lowered, and if the conditions are good, the modulation level should be raised.

[0023] The same is true for the adaptive modulation technique using the SVD-MIMO method described above. For example, when comparing the total number of modulation bits transmitted across all eigenmodes (total number of modulation bits) of 16 bits with that of 20 bits, 20 bits allows more data to be transmitted, but errors are more likely to occur. In contrast, 16 bits allows less data to be transmitted, but errors are less likely to occur. Therefore, when the propagation path conditions are poor, the total number of modulation bits should be reduced, and when the conditions are good, the total number of modulation bits should be increased.

[0024] In this way, in the adaptive modulation technique using the SVD-MIMO system, by adaptively controlling the total number of modulation bits according to the propagation path conditions, it is possible to achieve both stable transmission and large-capacity transmission, and to respond to a wide range of fluctuations in propagation path conditions.

[0025] However, even if different total modulation bit numbers are applied to the conventional adaptive modulation method using the SVD-MIMO method described in the above-mentioned Patent Document 1, there was a problem that the total modulation bit number cannot be adaptively controlled.

[0026] In the method of Patent Document 1 mentioned above, bit and power allocation is determined under the condition that the total number of modulation bits is fixed. In this method, in order to perform control including the total number of modulation bits, it is necessary to assume multiple total numbers of modulation bits and perform bit and power allocation for each total number of modulation bits.

[0027] Generally, the smaller the total number of modulation bits, the larger the MER margin. This is because the MER threshold is larger when the total number of modulation bits is smaller, even if the initial MER is the same. Therefore, when selecting a combination of modulation methods with the largest MER margin, the combination of modulation methods with the smallest total number of modulation bits is inevitably selected.

[0028] 10 is a diagram illustrating a case where two different total modulation bit numbers are applied to the conventional adaptive modulation method using the SVD-MIMO system described in Patent Document 1. In a transmission system of the SVD-MIMO system using four eigenmodes, the total modulation bit numbers are 16 bits and 20 bits.

[0029] Figure 10(1) shows the case where the total number of modulation bits is 16 bits, and this modulation method has 48 combinations. Figure 10(2) shows the case where the total number of modulation bits is 20 bits, and this modulation method has 55 combinations. The initial MER is the value shown on the left side of Figure 8.

[0030] Referring to Fig. 10(1), the MER margin (1.00 dB) after power allocation of No. 16[7,5,4,0] is the largest, as in Fig. 9. Therefore, when the total number of modulation bits is 16 bits, the combination of the modulation method of the first eigenmode: 7 bits (128QAM), the modulation method of the second eigenmode: 5 bits (32QAM), and the modulation method of the third eigenmode: 4 bits (16QAM) is selected.

[0031] 10(2), the MER margin (-2.31 dB) after power allocation of No. 38 [8, 6, 4, 2] is the largest. Therefore, when the total number of modulation bits is 20 bits, the combination of the modulation method of the first eigenmode: 8 bits (256QAM), the modulation method of the second eigenmode: 6 bits (64QAM), the modulation method of the third eigenmode: 4 bits (16QAM), and the modulation method of the fourth eigenmode: 2 bits (QPSK) is selected.

[0032] Comparing the MER margin (1.00 dB) after power allocation of No. 16 [7, 5, 4, 0] selected when the total number of modulation bits is 16 bits with the MER margin (-2.31 dB) after power allocation of No. 38 [8, 6, 4, 2] selected when the total number of modulation bits is 20 bits, the MER margin for the total number of modulation bits of 16 bits is larger. Therefore, ultimately, the modulation scheme combination of No. 16 [7, 5, 4, 0] when the total number of modulation bits is 16 bits is selected.

[0033] As mentioned above, the smaller the total number of modulation bits, the larger the MER margin. Therefore, if the combination with the largest MER margin is selected, the combination of modulation methods with a total number of modulation bits of 16 bits will always be selected.

[0034] Even if the propagation path conditions are good and a combination of modulation methods for a total modulation bit number of 20 bits can be selected, a combination of modulation methods for a total modulation bit number of 16 bits will be selected.

[0035] As described above, the adaptive modulation technique using the SVD-MIMO method described in the above-mentioned Patent Document 1 is unable to adaptively control the total number of modulation bits in accordance with the propagation path conditions.

[0036] Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a wireless communication device that is less likely to cause errors and is capable of obtaining the maximum transmission rate by appropriately switching the total number of modulation bits in an SVD-MIMO transmission system. [Means for solving the problem]

[0037] In order to solve the above-mentioned problem, a wireless communication device according to claim 1 is a wireless communication device that determines the coding rate, the combination of modulation schemes, and the power allocation ratio when transmitting by an SVD-MIMO scheme by performing error correction coding on an information bit sequence at a predetermined coding rate, allocating eigenmodes, modulating the information bits of each eigenmode with a predetermined combination of modulation schemes, and allocating transmission power at a predetermined power allocation ratio, the wireless communication device comprising: an adaptive control determiner that determines the total number of modulation bits, the combination of modulation schemes used for the modulation, the power allocation ratio used for allocating the transmission power, and the coding rate used for the error correction coding, with a total number of modulation bits being a total number of information bits of each eigenmode, an initial MER being a degree of quality of the eigenmode, a value that achieves a predetermined BER being an MER threshold, a MER margin being a difference between the initial MER and the MER threshold, and an effective transmission bit number being a product of the total number of modulation bits and the coding rate; a bit and power allocation control unit that determines the combination of modulation schemes and the power allocation ratio when the MER margin after power allocation of each of the multiple total modulation bit numbers is equal and the MER margin is maximum; a coding rate selection unit that selects, for each of the multiple total modulation bit numbers, the coding rate at which the maximum MER margin when the combination of modulation schemes and the power allocation ratio are determined by the bit and power allocation control unit exceeds a predetermined required MER margin and the effective transmission bit number is maximum; and a maximum transmission efficiency selection unit that selects, from the multiple total modulation bit numbers, the total modulation bit number corresponding to the maximum value among the maximum effective transmission bit numbers corresponding to each of the multiple total modulation bit numbers when the coding rate is selected by the coding rate selection unit, selects the combination of modulation schemes and the power allocation ratio determined for the total modulation bit number by the bit and power allocation control unit, and selects the coding rate selected for the total modulation bit number by the coding rate selection unit.

[0038] Moreover, the wireless communication device of claim 2 is the wireless communication device according to claim 1, wherein the adaptive control decision unit further includes a table that holds a combination of the coding rate, the effective transmission bit number, and the required MER margin for each of the plurality of total modulation bit numbers, and the coding rate selection unit compares, for each of the plurality of total modulation bit numbers, the maximum MER margin with the required MER margin held in the table, extracts from the table the coding rate whose MER margin exceeds the required MER margin, compares the effective transmission bit number held in the table with the extracted coding rate, and selects the coding rate whose effective transmission bit number is maximum. Effect of the Invention

[0039] As described above, according to the present invention, in an SVD-MIMO transmission system, by appropriately switching the total number of modulation bits, it is possible to reduce the occurrence of errors and obtain the maximum transmission rate. [Brief description of the drawings]

[0040] [Figure 1] 1 is a block diagram showing an example of the configuration of a transmission system including a wireless communication device according to an embodiment of the present invention. [Diagram 2] 4 is a block diagram showing a configuration example of an adaptive control determination unit. FIG. [Diagram 3] 13 is a flowchart illustrating an example of processing by an adaptive control determination unit. [Figure 4] FIG. 4 is a diagram illustrating an example of a data configuration of a table. [Diagram 5] 11A and 11B are diagrams illustrating a specific example of processing by an adaptive control determination unit. [Figure 6] FIG. 13 is a diagram showing a specific example of a data configuration of a table. [Figure 7] FIG. 1 is a diagram illustrating an adaptive modulation technique according to the prior art. [Figure 8] 1A and 1B are diagrams illustrating an example of a calculation result of a MER margin in an adaptive modulation method of the related art. [Figure 9]1 is a diagram for explaining an example of a calculation result of a MER margin in actual operation in an adaptive modulation method of the related art. [Figure 10] FIG. 1 is a diagram illustrating a case where two different total modulation bit numbers are applied to a conventional adaptive modulation method. [Figure 11] FIG. 13 is a diagram illustrating an example of a MER threshold for each modulation method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. [Transmission System] First, a transmission system including a wireless communication device according to an embodiment of the present invention will be described. Fig. 1 is a block diagram showing an example of the configuration of a transmission system including a wireless communication device according to an embodiment of the present invention, and shows a functional configuration block of an Mt×Mr SVD-MIMO method that realizes an eigenmode transmission method using Mt transmitting antennas and Mr receiving antennas. In Fig. 1, it is assumed that eigenmodes of K channels are formed. The number of eigenmodes is K. Mt, Mr, and K are positive integers.

[0042] This transmission system 1 realizes two-way communication by including a wireless communication device 2 that transmits broadcast waves including an information bit sequence and receives channel information and an initial MER, and a wireless communication device 3 that receives broadcast waves including an information bit sequence and transmits channel information and an initial MER.

[0043] 1 shows an antenna and a configuration for transmitting and receiving an information bit sequence, and omits a configuration for transmitting and receiving channel information and an initial MER. Hereinafter, the wireless communication device 2 will be referred to as the wireless communication device 2 on the transmitting side, and the wireless communication device 3 will be referred to as the wireless communication device 3 on the receiving side.

[0044] The wireless communication device 2 on the transmitting side includes an adaptive control determination unit 21, an error correction coding unit 22, an S (serial) / P (parallel) conversion unit 23, a modulation unit 24, a power allocation unit 25, a singular value decomposition unit 26, a transmission weight unit 27, and Mt transmission antennas 28. The modulation unit 24 includes K modulation units 24-1, 24-2, ..., 24-K.

[0045] The receiving side wireless communication device 3 includes Mr receiving antennas 31, a singular value decomposition unit 32, a receiving weight unit 33, a demodulation unit 34, a P / S conversion unit 35, an error correction decoding unit 36, and an initial MER calculation unit 37. The demodulation unit 34 includes K demodulation units 34-1, 34-2, . . . , 34-K.

[0046] Incidentally, FIG. 1 shows only components directly related to the present invention, and components not directly related thereto are omitted.

[0047] [Sender] Next, a description will be given of the transmitting wireless communication device 2 shown in Fig. 1. The transmitting wireless communication device 2 receives as input an information bit sequence to be transmitted.

[0048] The adaptive control determination unit 21 inputs the initial MER of each eigenmode and performs adaptive control according to the MER and the propagation path conditions to determine the total number of modulation bits, the optimal coding rate to be used in the error correction coding process of the error correction coding unit 22, the optimal combination of modulation schemes to be allocated to each eigenmode of the modulation units 24-1, 24-2, ..., 24-K, and the optimal power allocation ratio to be allocated to each eigenmode of the power allocation unit 25.

[0049] The adaptive control determination unit 21 outputs the coding rate to the error correction coding unit 22 , outputs the total number of modulation bits and the combination of modulation methods to the modulation unit 24 , and outputs the power allocation ratio to the power allocation unit 25 .

[0050] Specifically, the adaptive control determination unit 21 determines a combination of modulation schemes and a power allocation ratio when the MER margin after power allocation of each eigenmode is equal and maximum for each of a plurality of different total modulation bit numbers.Then, the adaptive control determination unit 21 identifies, for each total modulation bit number, the coding rate with the maximum effective transmission bit number among the coding rates at which the MER margin exceeds the required MER margin, for example, by using a table 43 described later.

[0051] The adaptive control determination unit 21 identifies the maximum effective number of transmission bits from among the maximum effective numbers of transmission bits for each total number of modulation bits, and selects the corresponding total number of modulation bits.

[0052] The adaptive control determination unit 21 determines the coding rate, the combination of modulation methods, and the power allocation ratio corresponding to the selected total number of modulation bits as the optimal coding rate, the optimal combination of modulation methods, and the optimal power allocation ratio. The details of the adaptive control determination unit 21 will be described later.

[0053] 9, when the modulation scheme to be assigned to each eigenmode is determined, the number of modulation bits to be assigned to each eigenmode is uniquely determined. The power allocation ratios of the eigenmodes are assumed to sum to 1. The adaptive control determiner 21 acquires the initial MER of each eigenmode calculated by the initial MER calculator 37 of the wireless communication device 3 on the receiving side from the wireless communication device 3 on the receiving side via a separate transmission path (wireless communication path or wired communication path).

[0054] The error correction coding unit 22 receives the information bit sequence and also receives the coding rate from the adaptive control determination unit 21. Then, the error correction coding unit 22 performs error correction coding on the information bit sequence at the input coding rate, and outputs the error correction coded information bit sequence to the S / P conversion unit 23.

[0055] The S / P conversion unit 23 receives the error correction coded information bit sequence from the error correction coding unit 22, converts the serial information bit sequence into K parallel sub-stream information bits, and distributes them. The S / P conversion unit 23 then outputs the K sub-stream information bits to the modulation unit 24.

[0056] Here, K is equal to the smaller of the numbers Mt and Mr, and K=min(Mt,Mr). In addition, in the SVD-MIMO transmission system 1 that realizes the eigenmode transmission method, the substream is synonymous with the eigenmode. In the following description, the independent orthogonal substreams are referred to as eigenmodes.

[0057] Modulation units 24-1, 24-2, ..., 24-K constituting modulation unit 24 each receive information bits of the substream (information bits of the eigenmode) from S / P conversion unit 23. Modulation units 24-1, 24-2, ..., 24-K each receive a total number of modulation bits and a combination of modulation schemes from adaptive control determination unit 21, and each identify a modulation scheme indicated by the combination of the total number of modulation bits and the modulation schemes.

[0058] The modulation units 24-1, 24-2, . . . , 24-K perform independent modulation on the information bits by the number of modulation bits corresponding to the identified modulation method, and output the modulated information bits to the power distribution unit 25.

[0059] Power allocator 25 receives modulated information bits of the eigenmodes from modulators 24-1, 24-2, ..., 24-K constituting modulator 24, and also receives the power allocation ratio from adaptive control determiner 21. Power allocator 25 then multiplies the information bits for each eigenmode by a weight corresponding to the power allocation ratio. Power allocator 25 outputs the multiplied information bits for each eigenmode to transmission weight unit 27.

[0060] The singular value decomposition unit 26 acquires channel information of the propagation paths formed between the Mt transmitting antennas 28 and the Mr receiving antennas 31, for example, from the wireless communication device 3. Then, the singular value decomposition unit 26 performs singular value decomposition on the channel matrix H representing the channel information to obtain a right singular matrix, and outputs the right singular matrix to the transmission weight unit 27 as a transmission weight.

[0061] The singular value decomposition unit 26 acquires channel information of the propagation path estimated by the wireless communication device 3 on the receiving side from the wireless communication device 3 on the receiving side via a separate transmission path. Alternatively, the singular value decomposition unit 32 of the wireless communication device 3 on the receiving side may instruct the wireless communication device 2 on the calculated right singular matrix via a separate transmission path. Alternatively, in a bidirectional communication system using a TDD (Time Division Duplex) method, the propagation path from the wireless communication device 2 to the wireless communication device 3 and the propagation path from the wireless communication device 3 to the wireless communication device 2 may be regarded as being the same, and the wireless communication device 2 on the transmitting side may estimate channel information of the propagation path, and the singular value decomposition unit 26 may directly acquire and use this information.

[0062] The transmission weight unit 27 inputs information bits of each eigenmode from the power allocation unit 25 and also inputs transmission weights from the singular value decomposition unit 26, multiplies the information bits by the transmission weights, and generates signals for each transmission antenna system corresponding to each of the Mt transmission antennas 28. In this way, orthogonal eigenbeams are generated for each eigenmode. Moreover, the broadcast waves of the signals generated by the transmission weight unit 27 are transmitted from the transmission antennas 28 for each transmission antenna system.

[0063] [Receiving side] Next, a description will be given of the receiving-side wireless communication device 3 shown in Fig. 1. The receiving-side wireless communication device 3 receives the broadcast wave transmitted by the transmitting-side wireless communication device 2.

[0064] The singular value decomposition unit 32 acquires channel information of the propagation path estimated by a propagation path estimation unit (not shown). Then, the singular value decomposition unit 32 performs singular value decomposition on the channel matrix H representing the channel information to obtain a left singular matrix, and outputs the complex conjugate transpose of the left singular matrix to the reception weight unit 33 as the reception weight.

[0065] The reception weight unit 33 receives the reception signals for each reception antenna system via the Mr reception antennas 31, and also receives the reception weights from the singular value decomposition unit 32. The reception weight unit 33 then multiplies the reception signals for each reception antenna system by the reception weights to generate reception signals for each eigenmode. As a result, signals transmitted for each eigenmode are ideally detected without interference. The reception weight unit 33 then outputs the reception signals for each eigenmode to the demodulation unit 34.

[0066] The demodulation units 34-1, 34-2, ..., 34-K constituting the demodulation unit 34 each receive a received signal of a corresponding eigenmode from the reception weight unit 33. Then, the demodulation units 34-1, 34-2, ..., 34-K perform independent demodulation using the same modulation method as the corresponding modulation units 24-1 to 24-K, and output the demodulated information bits that have been error-correction coded (information bits of K parallel sub-streams) to the P / S conversion unit 35.

[0067] It is assumed that the demodulation units 34-1, 34-2, ..., 34-K obtain and hold the modulation schemes (optimum combination of modulation schemes) used by the modulation units 24-1, 24-2, ..., 24-K provided in the transmitting wireless communication device 2 from control information such as a header received from the transmitting wireless communication device 2. Alternatively, when the wireless communication device 3 determines the modulation scheme and instructs the wireless communication device 2 via a separate transmission path, the demodulation units 34-1, 34-2, ..., 34-K hold the modulation scheme determined by the wireless communication device 3.

[0068] The P / S conversion unit 35 receives the eigenmode information bits from the demodulation units 34-1, 34-2, . . . , 34-K constituting the demodulation unit 34. The P / S conversion unit 35 then converts the error correction coded information bits of the K parallel sub-streams into a serial error correction coded information bit sequence, and outputs the serial error correction coded information bit sequence to the error correction decoding unit 36.

[0069] The error correction decoding unit 36 ​​inputs the serial error correction coded information bit sequence from the P / S conversion unit 35, performs error correction decoding on the error correction coded information bit sequence at the same coding rate as the corresponding error correction coding unit 22, and restores and outputs the original information bit sequence.

[0070] The error correction decoding unit 36 ​​is assumed to hold the coding rate used by the error correction coding unit 22 provided in the transmitting wireless communication device 2 from control information such as a header received from the transmitting wireless communication device 2. Alternatively, when the wireless communication device 3 determines the coding rate and instructs the wireless communication device 2 via a separate transmission path, the error correction decoding unit 36 ​​is assumed to hold the coding rate determined by the wireless communication device 3.

[0071] The initial MER calculation unit 37 calculates an initial MER for each eigenmode when the transmitting wireless communication device 2 transmits signals of each eigenmode with the same power allocation (when the eigenmodes are transmitted with equal transmission power allocation). Then, a communication unit (not shown) transmits the initial MER for each eigenmode calculated by the initial MER calculation unit 37 to the transmitting wireless communication device 2 via a separate transmission path.

[0072] The initial MER may be calculated, for example, by utilizing the fact that the square of the singular value of the channel matrix H represents the channel gain of each eigenmode in eigenmode transmission. That is, the initial MER calculation unit 37 calculates the singular values ​​of the channel matrix H, divides the square of the singular value by a separately estimated Gaussian noise power, and converts the value of the division result into an MER to calculate the initial MER of each eigenmode. As another method for calculating the initial MER, the MER at the time of equal power allocation may be actually measured during communication using a training signal.

[0073] Incidentally, a communication section (not shown) transmits channel information of the propagation path estimated by a propagation path estimating section (not shown) to the wireless communication device 2 on the transmitting side via a separate transmission path.

[0074] In this way, the broadcast wave transmitted from the transmitting wireless communication device 2 is received by the receiving antenna 31, and restored to the substreams of each eigenmode, and then restored to the original information bit sequence.

[0075] (Adaptive control determination unit 21) Next, a detailed description will be given of the adaptive control decision unit 21 shown in Fig. 1. Fig. 2 is a block diagram showing an example of the configuration of the adaptive control decision unit 21, and Fig. 3 is a flowchart showing an example of the processing of the adaptive control decision unit 21.

[0076] 2, the adaptive control determination unit 21 includes I (systems) of bit and power allocation control units 100-1, . . . , 100-i, . . . , 100-I that handle different total numbers of modulation bits, and a selection unit 41. I is a positive integer. The total number of modulation bits handled by the bit and power allocation control unit 100-1 is N1, . . . , and the total number of modulation bits handled by the bit and power allocation control unit 100-i is N i The total number of modulation bits handled by the bit / power distribution control unit 100-I is N I For i = 1, , I.

[0077] Each of the bit and power distribution control units 100-1, . . . , 100-i, . . . , 100-I performs the same process. Hereinafter, the bit and power distribution control units 100-1, . . . , 100-i, . . . , 100-I will be collectively referred to as the "bit and power distribution control unit 100-i."

[0078] The selection unit 41 includes I (systems) coding rate selection units 42-1, . . ., 42-i, . . ., 42-I and a maximum transmission efficiency selection unit 44. The coding rate selection units 42-1, . . ., 42-i, . . ., 42-I correspond to the bit and power allocation control units 100-1, . . ., 100-i, . . ., 100-I, respectively.

[0079] Each of the coding rate selection units 42-1, . . . , 42-i, . . . , 42-I performs the same process. Hereinafter, the coding rate selection units 42-1, . . . , 42-i, . . . , 42-I will be collectively referred to as the "coding rate selection unit 42-i."

[0080] 2 and 3, when the wireless communication device 2 receives the initial MER of each eigenmode calculated by the initial MER calculation unit 37 of the wireless communication device 3 via a separate transmission path, the bit and power allocation control units 100-1,...,100-i,...,100-I input the initial MER of each eigenmode (step S301).

[0081] The bit / power distribution control unit 100-i performs the same process as the bit / power distribution control unit 100 shown in Fig. 7. That is, the bit / power distribution control unit 100-i performs the same process as the bit / power distribution control unit 100 shown in Fig. 7. i Then, the combination of modulation schemes and the power allocation ratios for which the MER margins (differences between the initial MER and the MER threshold) after the power allocation of each eigenmode are equal and the MER margins are maximum are determined (step S302). i ,···,N I For each of the eigenmodes, the MER margin when minimizing the BER, as well as the combination of modulation schemes and power allocation ratios for each eigenmode are obtained.

[0082] The bit / power distribution control unit 100-i calculates the total number of modulation bits N i , and outputs the combination of modulation schemes for each eigenmode, the power allocation ratio, and the MER margin (maximum MER margin) to the selection unit 41 (the coding rate selection unit 42-i).

[0083] The coding rate selection unit 42-i of the selection unit 41 receives the total number of modulation bits N i , the combination of modulation schemes for each eigenmode, the power allocation ratio, and the MER margin are input.

[0084] The coding rate selection unit 42-i uses a preset table 43 to compare the input MER margin with the required MER margin stored in the table 43, and extracts a coding rate at which the desired BER characteristic can be obtained with the input MER margin, i.e., a coding rate at which the MER margin exceeds the required MER margin. The coding rate selection unit 42-i then compares the effective transmission bit numbers corresponding to the extracted coding rates, and selects the coding rate with the largest effective transmission bit number (step S303). As a result, the total number of modulation bits N1,...,N i ,···,N I For each of these, the maximum effective number of transmitted bits and the corresponding coding rate are obtained.

[0085] The coding rate selection unit 42-i selects the total number of modulation bits N i , the combination of modulation schemes for each eigenmode, the power allocation ratio, the selected coding rate, and the effective number of transmission bits corresponding to the coding rate are output to a maximum transmission efficiency selection unit 44.

[0086] 4 is a diagram showing an example of the data structure of the table 43. The total number of modulation bits is arranged in ascending order as {N1, . . . , N i ,···,N I}(i=1, ,I). The coding rates used in the error correction coding process are expressed in ascending order as {R1, R2, , R j ,···,R J-1 ,R J}(j = 1, ,J).

[0087] Total number of modulation bits N i , coding rate R j The SVD-MIMO transmission in -4 ) required MER margin M(N i ,R j ) is prepared in advance. The required MER margin M(N i ,R j ) may be a value obtained by computer simulation, or may be a value measured in the actual transmission system 1 shown in FIG.

[0088] The effective number of transmission bits is the total number of modulation bits N i and the coding rate R j Product of N i ×R j The number of bits is calculated by the above formula and is prepared in advance.

[0089] As shown in FIG. 4, table 43 stores the total number of modulation bits N1, . . . , N i ,···,N I For each of the above, a combination of coding rate R, effective number of transmission bits N×R, and required MER margin M(N,R) is stored.

[0090] Specifically, Table 43 shows the total number of modulation bits N1, the coding rate R J ,R J-1 ,···,R j ,···,R2,R1, Effective number of transmission bits N1×R J ,N1×R J-1 ,···,N1×R j , ,N1×R2,N1×R1, and the required MER margin M(N1,R J ),M(N1,R J-1 ),···,M(N1,R j ),···,M(N1,R2),M(N1,R1),···,total number of modulation bits N i For the coding rate R J ,R J-1 ,···,Rj ,···,R2,R1, Effective number of transmission bits N i ×R J ,N i ×R J-1 ,···,N i ×R j ,···,N i ×R2,N i ×R1, and the required MER margin M(N i ,R J ),M(N i ,R J-1 ),···,M(N i ,R j ),···,M(N i ,R2),M(N i , R1), and the total number of modulation bits N I For the coding rate R J ,R J-1 ,···,R j ,···,R2,R1, Effective number of transmission bits N I ×R J ,N I ×R J-1 ,···,N I ×R j ,···,N I ×R2,N I ×R1, and the required MER margin M(N I ,R J ),M(N I ,R J-1 ),···,M(N I ,R j ),···,M(N I ,R2),M(N I ,R1).

[0091] In addition, the table 43 shown in FIG. 4 is a table showing the total number of modulation bits N1, . . . , N i ,···,N I For each of all coding rates R j , the effective number of transmission bits N i ×R j and the required MER margin M(N i ,R j ) combination is now retained.

[0092] On the other hand, table 43 may hold only combinations that are actually used. For example, if coding rate R1 is not used when the total number of modulation bits is N1, table 43 shown in Fig. 4 does not need to hold the combination of coding rate R1, effective number of transmission bits N1 x R1, and required MER margin M (N1, R1) shown in the lower left. This allows the amount of data in table 43 to be reduced.

[0093] Table 43 also shows the total number of modulation bits N1,...,N i ,···,N I The effective number of transmission bits N i ×R j The total number of modulation bits N1, ,N i ,···,N I For each of the above, a combination of the coding rate R, the effective number of transmission bits N×R, and the required MER margin M(N,R) may be stored. This makes it possible to reduce the amount of data in the table 43.

[0094] For example, in table 43 shown in FIG. 6 described later, the effective transmission bit numbers of 6.60, 8.80, 10.80, and 13.00 for the total number of modulation bits N2=20 bits are included in the range of effective transmission bit numbers between 5.28 and 13.92 for the total number of modulation bits N1=16 bits.

[0095] Therefore, in order to avoid duplication of the effective transmission bit numbers, table 43 holds all combinations of (coding rate R1 (=0.33), effective transmission bit number = 5.28, required MER margin = -13.5), (R2 (=0.44), 7.04, -11.0), ..., (R7 (=0.92), 14.72, -2.0) for the total modulation bit number N1 = 16 bits, as described above. Also, table 43 holds only the combinations of (coding rate R5 (=0.76), effective transmission bit number = 15.20, required MER margin = -6.0), (R6 (=0.87), 17.40, -3.5), (R7 (=0.92), 18.40, -2.5) for the total modulation bit number N2 = 20 bits.

[0096] Returning to FIG. 2 and FIG. 3, the maximum transmission efficiency selection unit 44 inputs the total number of modulation bits N1, the combination of modulation schemes for each eigenmode and the power allocation ratio, as well as the coding rate and effective number of transmission bits from the coding rate selection unit 42-1, . . . , and the total number of modulation bits N i , the combination of modulation schemes for each eigenmode, the power allocation ratio, the coding rate, and the effective number of transmission bits are input, and the total number of modulation bits N I , the combination of modulation schemes for each eigenmode, the power allocation ratio, the coding rate, and the effective number of transmission bits are input.

[0097] The maximum transmission efficiency selection unit 44 selects the total number of modulation bits N1, . . . , N i ,···,N I Then, the maximum transmission efficiency selection unit 44 compares the effective number of transmission bits corresponding to the total number of modulation bits N1, . . . , N i ,···,N I Among these, the total number of modulation bits that has the largest effective number of transmission bits is selected (step S304).

[0098] The maximum transmission efficiency selection unit 44 selects and outputs the combination of modulation schemes for each eigenmode, the power allocation ratio, and the coding rate corresponding to the selected total number of modulation bits (step S305). The maximum transmission efficiency selection unit 44 outputs the coding rate to the error correction coding unit 22, the total number of modulation bits and the combination of modulation schemes for each eigenmode to the modulation unit 24, and the power allocation ratio of each eigenmode to the power allocation unit 25.

[0099] [Specific examples] Next, a specific example will be given of the process by the adaptive control decision unit 21 shown in Fig. 2 and Fig. 3. Fig. 5 is a diagram for explaining a specific example of the process by the adaptive control decision unit 21, and Fig. 6 is a diagram showing a specific example of the data configuration of table 43.

[0100] In the SVD-MIMO transmission using four eigenmodes, two total modulation bit numbers are used: N1 = 16 bits and N2 = 20 bits. The initial MER is calculated to be the same as the example shown in FIG.

[0101] 5, the adaptive control determination unit 21 includes a bit / power allocation control unit 100-1 that handles a total number of modulation bits N1=16 bits, a bit / power allocation control unit 100-2 that handles a total number of modulation bits N2=20 bits, and a selection unit 41. The selection unit 41 also includes a coding rate selection unit 42-1 that handles a total number of modulation bits N1=16 bits, a coding rate selection unit 42-2 that handles a total number of modulation bits N2=20 bits, a table 43, and a maximum transmission efficiency selection unit 44.

[0102] 6, table 43 holds the combination of (coding rate R1 (=0.33), effective number of transmission bits = 5.28, required MER margin = -13.5), (R2 (=0.44), 7.04, -11.0), ···, (R7 (=0.92), 14.72, -2.0) for the total number of modulation bits N1 = 16 bits. Also, table 43 holds the combination of (coding rate R1 (=0.33), effective number of transmission bits = 6.60, required MER margin = -15.0), (R2 (=0.44), 8.80, -12.5), ···, (R7 (=0.92), 18.40, -2.5) for the total number of modulation bits N2 = 20 bits.

[0103] In this configuration, the bit / power allocation control unit 100-1 determines the combination of modulation schemes [7, 5, 4, 0] and power allocation ratios [0.27, 0.29, 0.44, 0.0] for the total number of modulation bits N1 = 16 bits, such that the MER margin after power allocation for each eigenmode is equal and the MER margin is maximum.

[0104] As a result, for a total number of modulation bits N1=16 bits, a combination of modulation schemes [7, 5, 4, 0], power allocation ratios [0.27, 0.29, 0.44, 0.0], and a MER margin of 1.0 dB are obtained.

[0105] In addition, the bit and power allocation control unit 100-2 determines the combination of modulation methods [8, 6, 4, 2] and power allocation ratios [0.20, 0.22, 0.08, 0.50] for the total number of modulation bits N2 = 20 bits, such that the MER margin after power allocation for each eigenmode is equal and the MER margin is maximum.

[0106] As a result, for a total number of modulation bits N2=20 bits, a combination of modulation schemes [8, 6, 4, 2], power allocation ratios [0.20, 0.22, 0.08, 0.50], and a MER margin of -2.31 dB are obtained.

[0107] Next, the coding rate selection unit 42-1 extracts coding rates R1 (=0.33),...,R7 (=0.92) at which the MER margin of 1.0 dB exceeds the required MER margin, using table 43 shown in Fig. 6. Then, the coding rate selection unit 42-1 selects the coding rate R7 (=0.92) with the maximum effective number of transmission bits (14.72) from the extracted coding rates R1 (=0.33),...,R7 (=0.92).

[0108] As a result, for a total number of modulation bits N1=16 bits, a combination of modulation methods [7, 5, 4, 0], power allocation ratios [0.27, 0.29, 0.44, 0.0], a coding rate of 0.92, and an effective number of transmission bits of 14.72 are obtained.

[0109] Furthermore, the coding rate selection unit 42-2 extracts coding rates R1 (=0.33),...,R7 (=0.92) at which the MER margin of -2.31 dB exceeds the required MER margin, using table 43 shown in Fig. 6. Then, the coding rate selection unit 42-2 selects the coding rate R7 (=0.92) with the maximum effective number of transmission bits (18.40) from among the extracted coding rates R1 (=0.33),...,R7 (=0.92).

[0110] As a result, for a total number of modulation bits N2=20 bits, a combination of modulation methods [8, 6, 4, 2], power allocation ratios [0.20, 0.22, 0.08, 0.50], a coding rate of 0.92, and an effective number of transmission bits of 18.40 are obtained.

[0111] Next, the maximum transmission efficiency selection unit 44 compares the effective transmission bit number of 14.72, which corresponds to the total modulation bit number N1=16 bits, with the effective transmission bit number of 18.40, which corresponds to the total modulation bit number N2=20 bits, and selects the total modulation bit number N2=20 bits, which corresponds to the maximum effective transmission bit number (18.40).

[0112] In this way, the total number of modulation bits N2 = 20 bits, the combination of modulation methods [8, 6, 4, 2], the power allocation ratios [0.20, 0.22, 0.08, 0.50], and the coding rate 0.92 that maximize the effective number of transmission bits are selected.

[0113] On the other hand, as another example, in the configuration shown in FIG. 5 and table 43 shown in FIG. 6, assume that a MER margin of −2.9 dB is obtained by bit / power distribution control unit 100-1 and a MER margin of −6.21 dB is obtained by bit / power distribution control unit 100-2.

[0114] In this case, the coding rate selection unit 42-1 extracts coding rates R1 (=0.33),...,R6 (=0.87) at which the MER margin of -2.9 dB exceeds the required MER margin, using table 43 shown in Fig. 6. Then, the coding rate selection unit 42-1 selects the coding rate R6 (=0.87) at which the effective number of transmission bits is maximum (13.92).

[0115] As a result, for a total number of modulation bits N1=16 bits, a combination of modulation methods [7, 5, 4, 0], power allocation ratios [0.27, 0.29, 0.44, 0.0], a coding rate of 0.87, and an effective number of transmission bits of 13.92 are obtained.

[0116] Furthermore, the coding rate selection unit 42-2 extracts coding rates R1 (=0.33), . . . , R4 (=0.65) at which the MER margin of -6.31 dB exceeds the required MER margin, using table 43 shown in Fig. 6. Then, the coding rate selection unit 42-2 selects coding rate R4 (=0.65) at which the effective number of transmission bits is maximum (13.00).

[0117] As a result, for a total number of modulation bits N2=20 bits, a combination of modulation methods [8, 6, 4, 2], power allocation ratios [0.20, 0.22, 0.08, 0.50], a coding rate of 0.65, and an effective number of transmission bits of 13.00 are obtained.

[0118] Next, the maximum transmission efficiency selection unit 44 compares the effective transmission bit number of 13.92 corresponding to the total modulation bit number N1 = 16 bits with the effective transmission bit number of 13.00 corresponding to the total modulation bit number N2 = 20 bits, and selects the total modulation bit number N1 = 16 bits with the maximum effective transmission bit number (13.92).

[0119] In this way, the total number of modulation bits N1=16 bits, the combination of modulation methods [7, 5, 4, 0], the power allocation ratios [0.27, 0.29, 0.44, 0.0], and the coding rate 0.87 that maximize the effective number of transmission bits are selected.

[0120] As described above, according to the wireless communication device 2 of the embodiment of the present invention, the bit / power allocation control unit 100-i of the adaptive control determination unit 21 determines the total number of modulation bits N i Then, the combination of modulation schemes and power allocation ratios for which the MER margins after power allocation of each eigenmode are equal and maximum are determined.

[0121] This results in a total modulation bit count of N1,...,N i ,···,N I For each of the eigenmodes, the MER margin when minimizing the BER, as well as the combination of modulation schemes and power allocation ratios for each eigenmode are obtained.

[0122] The coding rate selection unit 42-i of the selection unit 41 selects the total number of modulation bits N i For this, table 43 is used to extract coding rates whose MER margin exceeds the required MER margin, and from the extracted coding rates, the coding rate with the maximum effective number of transmission bits is selected.

[0123] This results in a total modulation bit count of N1,...,N i ,···,N I For each of these, the maximum effective number of transmitted bits and the corresponding coding rate are obtained.

[0124] The maximum transmission efficiency selection unit 44 selects the total number of modulation bits N1, . . ., N i ,···,N I Then, a combination of modulation schemes and power allocation ratios of the eigenmodes, and a coding rate corresponding to the total modulation bit number are selected.

[0125] As a result, error correction coding is performed in error correction coding unit 22 using the selected coding rate, and modulation is performed in modulation unit 24 using the selected combination of the total number of modulation bits and the modulation scheme of each eigenmode. Also, power allocation is performed in power allocation unit 25 using the selected power allocation ratio of each eigenmode.

[0126] In this way, adaptive control is performed according to the MER and the propagation path conditions, and the total number of modulation bits, the optimal coding rate to be used in the error correction coding unit 22, the optimal combination of modulation schemes to be assigned to each eigenmode in the modulation unit 24, and the optimal power allocation ratio to be assigned to each eigenmode in the power allocation unit 25 are determined.

[0127] In the embodiment of the present invention, the total number of modulation bits can be appropriately switched so as to maximize the effective number of transmission bits while maintaining the characteristics of adaptive control when the total number of modulation bits is fixed.

[0128] Therefore, in the SVD-MIMO transmission system 1, by appropriately switching the total number of modulation bits that maximizes the effective number of transmission bits, instead of the MER margin, it is possible to obtain the maximum transmission rate while reducing the occurrence of errors, and adaptive control including the total number of modulation bits is possible.

[0129] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the technical concept thereof.

[0130] 1, the wireless communication device 2 on the transmitting side is provided with the adaptive control determination unit 21. In contrast, the wireless communication device 3 on the receiving side may be provided with the adaptive control determination unit 21.

[0131] In this case, an adaptive control determination unit 21 provided in the wireless communication device 3 determines the total number of modulation bits, the combination of modulation methods, the power allocation ratio, and the coding rate by the configuration and processing shown in Figures 2 and 3. Then, a communication unit (not shown) transmits the total number of modulation bits, the combination of modulation methods, the power allocation ratio, and the coding rate to the wireless communication device 2 on the transmitting side via a separate transmission path. [Explanation of symbols]

[0132] 1. Transmission System 2,3 Wireless communication devices 21 Adaptive control decision unit 22 Error correction coding section 23 S / P conversion section 24 Modulation section 25 Power Distribution Section 26,32 Singular Value Decomposition 27 Transmission wait section 28 Transmitting Antenna 31 Receiving antenna 33 Reception wait section 34 Demodulation section 35 P / S conversion section 36 Error correction decoding section 37 Initial MER calculation section 41 Selection section 42 Coding rate selection unit 43 Table 44 Maximum transmission efficiency selection section 100-bit power distribution control unit 101 Power distribution calculation unit 102 MER Margin Calculation Unit 103 Modulation method and power determination section

Claims

1. A wireless communication device that performs error correction coding on an information bit sequence at a predetermined coding rate, assigns eigenmodes, modulates information bits of each eigenmode using a combination of predetermined modulation methods, and allocates transmission power at a predetermined power allocation ratio when transmitting using a Singular Value Decomposition-Multiple-Input Multiple-Output (SVD-MIMO) system, the wireless communication device determining the coding rate, the combination of modulation methods, and the power allocation ratio, the sum of the information bits of each eigenmode is defined as a total number of modulation bits, the degree of quality of the eigenmode is defined as an initial MER (Modulation Error Ratio), a value that achieves a predetermined BER (Bit Error Rate) is defined as an MER threshold, the difference between the initial MER and the MER threshold is defined as an MER margin, and the product of the total number of modulation bits and the coding rate is defined as an effective number of transmission bits, an adaptive control determination unit that determines the total number of modulation bits, a combination of the modulation methods used for the modulation, the power allocation ratio used for allocating the transmission power, and the coding rate used for the error correction coding, The adaptive control determination unit is a bit / power allocation control unit that determines, for each of a plurality of total modulation bit numbers, a combination of the modulation schemes and the power allocation ratio when the MER margin after power allocation of each eigenmode is equal and the MER margin is maximum; a coding rate selection unit that selects, for each of the plurality of total modulation bit numbers, the coding rate at which the maximum MER margin exceeds a predetermined required MER margin when the combination of the modulation schemes and the power allocation ratio are determined by the bit / power allocation control unit, and the coding rate at which the effective transmission bit number is maximized; a maximum transmission efficiency selection unit that selects, from among the plurality of total modulation bit numbers, the total modulation bit number corresponding to a maximum value among the maximum effective transmission bit numbers corresponding to each of the plurality of total modulation bit numbers when the coding rate is selected by the coding rate selection unit, selects the combination of the modulation schemes and the power allocation ratio determined for the total modulation bit number by the bit / power allocation control unit, and selects the coding rate selected for the total modulation bit number by the coding rate selection unit; A wireless communication device comprising:

2. 2. The wireless communication device according to claim 1, The adaptive control determination unit further a table for storing a combination of the coding rate, the effective number of transmission bits, and the required MER margin for each of the plurality of total modulation bit numbers; The coding rate selection unit is a wireless communication device which compares, for each of the plurality of total modulation bit numbers, a maximum MER margin with the required MER margin stored in the table, extracts from the table the coding rate at which the MER margin exceeds the required MER margin, compares the effective transmission bit numbers stored in the table with the extracted coding rate, and selects the coding rate with the maximum effective transmission bit number.

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