Radio communication device

Abstract

To reduce an arithmetic amount when computing a MER margin on a bit distribution basis with respect to a plurality of total modulation bit numbers in an SVD-MIMO radio communication system.SOLUTION: A bit / power distribution control section 42-1 of a radio communication device 2 calculates on a bit distribution (Na) basis a MER margin Ma(α) and a power distribution ratio Pa(α, k) on the basis of an initial MER, etc. In a case where there is no parental relation with the bit distribution (Na), a bit / power distribution control section 42-2 calculates on a bit distribution (Nb) basis a MER margin Mb(β) and a power distribution ratio Pb(β, k) on the basis of the initial MER. etc. In a case where there is the parental relation, the MER margin Mb(β) is calculated by an expression Mb(β)=Ma(α)+3×d using the MER margin Ma(α) of the bit distribution (Na) and a differential bit number (d) and the power distribution ratio Pa(α, k) is set to the power distribution ratio Pb(β, k).SELECTED DRAWING: Figure 3

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 bit allocation and the like of a modulation scheme assigned to each eigenmode. [Background technology]

[0002] The wireless transmission device for transmitting program material is called an FPU (Field Pickup Unit: portable wireless transmission device), 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 vehicle.

[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 Documents 1 and 2 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 bit allocation and power allocation of the modulation method of each eigenmode are adaptively controlled according to the quality of each eigenmode, thereby enabling large-capacity transmission.

[0005] The technology of Patent Document 1 provides an algorithm for determining bit allocation and power allocation ratios under the condition that the total number of modulation bits is fixed.

[0006] Fig. 11 is a diagram for explaining an example of determining bit allocation and power allocation ratio under the condition that the total number of modulation bits is fixed in the conventional technology, and shows the technology of Patent Document 1. In a wireless 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.

[0007] For ease of explanation, a case will be considered in which the combination of modulation methods, that is, bit allocation 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)

[0008] Here, the terms are defined. The initial MER (Modulation Error Ratio) is the MER value that represents the quality of the eigenmode. The MER threshold (reference MER) is the value that represents the quality of the eigenmode at a predetermined BER (Bit Error Rate) (e.g., BER=10 without a correction code). -4 ) is the value of MER to achieve the initial MER. The MER margin is the difference between the initial MER and the MER threshold. The total number of modulation bits is the sum of the number of modulation bits (number of information bits) for each eigenmode.

[0009] As shown on the left side of Fig. 11, it is assumed that the initial MER of the first eigenmode is calculated to be 27.8 dB, and the initial MERs of the second, third, and fourth eigenmodes are calculated to be 21.6 dB, 16.7 dB, and 8.9 dB, respectively. In addition, it is assumed that the MER thresholds at which each modulation scheme achieves a predetermined BER are set in advance, as shown in Fig. 11 (1) to (3).

[0010] 11(1) to (3), the power allocation ratio is determined so that the MER margin is equal for all eigenmodes, the gain due to power allocation 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 (=0.25) per stream (one eigenmode) when power allocation is not performed, assuming that the total transmission power is 1.

[0011] Among (1) to (3) in Fig. 11, the bit allocation that is the combination of modulation schemes that maximizes the MER margin after power allocation is selected. In the example of Fig. 11, the MER margin (+1.0 dB) after power allocation in (2) is the largest, so the bit allocation and power allocation ratio in (2) are selected.

[0012] For ease of explanation, FIG. 11 shows an example in which the MER margin is calculated in three ways (1) to (3), but in actual operation, the MER margin is calculated for all 48 ways.

[0013] FIG. 12 is a diagram for explaining an example of selecting a bit allocation and a power allocation ratio that maximizes the MER margin in the conventional technology.

[0014] No. 1 to 48 indicate the numbers of the combinations of modulation methods, i.e., the bit allocation numbers. The four numbers [n1, n2, n3, n4] within the brackets indicate the numbers of modulation bits to be allocated 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.

[0015] For each of Nos. 1 to 48, the MER margin after power allocation is calculated, and the bit allocation that maximizes the MER margin after power allocation is selected.

[0016] In the example of Figure 12, since the MER margin (1.00 dB) after power allocation of No. 16 [7, 5, 4, 0] is the largest, the following bit allocation is selected: modulation method for the first eigenmode: 7 bits (128QAM), modulation method for the second eigenmode: 5 bits (32QAM), and modulation method for the third eigenmode: 4 bits (16QAM).

[0017] On the other hand, in the SVD-MIMO system, the technology of Patent Document 2 is an extension of the technology of Patent Document 1, and performs control including the total number of modulation bits. This technology determines bit allocation and power allocation ratio for each of a plurality of total numbers of modulation bits, and provides an algorithm for appropriately switching the total number of modulation bits.

[0018] FIG. 13 is a diagram for explaining an example of selecting the total number of modulation bits in the conventional technology, and shows the technology of Patent Document 2.

[0019] In the SVD-MIMO transmission using four eigenmodes, the total number of modulation bits is N 1 = 16 bits and N 2 = 20 bits. The initial MER is calculated to be the same as the example shown in FIG.

[0020] As shown in Figure 13, the total number of modulation bits N 1 For the 16 bits, processing is performed by the bit / power distribution control unit 100-1 and the coding rate selection unit 102-1 of the selection unit 101, and the total number of modulation bits N 2 For the total number of modulation bits N 1 = 16 bits, N 2 = 20 bits are selected.

[0021] In such a configuration, the total number of modulation bits N 1 For 16 bits, the bit and power allocation control unit 100-1 selects the bit allocation [7, 5, 4, 0] and power allocation ratio [0.27, 0.29, 0.44, 0.0] when the MER margin after power allocation for each eigenmode is equal and the MER margin is maximum. This results in a MER margin of 1.0 dB.

[0022] In addition, the total number of modulation bits N 1 For 16 bits, the coding rate selection unit 102-1 of the selection unit 101 extracts multiple coding rates with a MER margin of 1.0 dB that exceeds the required MER margin using table 103, and selects the coding rate that maximizes the effective number of transmission bits, which is the product of the total number of modulation bits and the coding rate, from among the multiple coding rates. This results in a coding rate of 0.92 and an effective number of transmission bits of 14.72.

[0023] Similarly, the total number of modulation bits N 2 For 20 bits, the bit and power allocation control unit 100-2 selects the bit allocation [8, 6, 4, 2] and power allocation ratio [0.20, 0.22, 0.08, 0.50] that results in the same MER margin after power allocation for each eigenmode and the maximum MER margin. This results in a MER margin of -2.31 dB.

[0024] In addition, the total number of modulation bits N 2 For 20 bits, the coding rate selection unit 102-2 of the selection unit 101 extracts multiple coding rates whose MER margin of -2.31 dB exceeds the required MER margin using the table 103, and selects the coding rate with the maximum effective number of transmission bits from among the multiple coding rates. As a result, a coding rate of 0.92 and an effective number of transmission bits of 18.40 are obtained.

[0025] Then, the maximum transmission efficiency selection unit 104 selects the total number of modulation bits N 1 = 14.72 effective transmission bits corresponding to 16 bits and N total modulation bits 2 The effective number of transmission bits corresponding to 18.40 is compared with the effective number of transmission bits corresponding to 20 bits, and the total number of modulation bits N corresponding to the maximum effective number of transmission bits (18.40) is calculated. 2 = 20 bits are selected.

[0026] In this way, the total number of modulation bits N when the effective number of transmission bits is maximized is 2 = 20 bits, bit allocation [8,6,4,2], power allocation ratio [0.20,0.22,0.08,0.50] and coding rate 0.92 are selected. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] Patent No. 6328021 [Patent Document 2] JP 2023-43653 A [Non-patent literature]

[0028] [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 1.1, Association of Radio Industries and Businesses Summary of the Invention [Problem to be solved by the invention]

[0029] In the technique of the above-mentioned Patent Document 2, it is necessary to calculate the MER margin for each bit allocation for each of a plurality of total modulation bit numbers using the algorithm described in the above-mentioned Patent Document 1.

[0030] In the example shown in FIG. 13, the bit / power distribution control unit 100-1 determines the total number of modulation bits N 1 The bit and power allocation control unit 100-2 calculates the MER margin for each bit allocation for the total number of modulation bits N 2 Calculate the MER margin per bit allocation for =20 bits.

[0031] Here, the total number of modulation bits N 1 For 16 bits, there are 48 possible bit allocations, and the total number of modulation bits is N 2 For =20 bits, there are 55 different bit allocations, and it is necessary to calculate the MER margin for all of these bit allocations. This causes a problem of a high computation load.

[0032] Moreover, in order to realize a compact device as a whole, it is desirable to reduce the amount of calculation as much as possible.

[0033] 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 can reduce the amount of calculation required when calculating the MER margin for each bit allocation for multiple total modulation bit numbers in an SVD-MIMO wireless transmission system. [Means for solving the problem]

[0034] In order to solve the above problem, the wireless communication device of claim 1 is a wireless communication device using a Singular Value Decomposition-Multiple-Input Multiple-Output (SVD-MIMO) scheme, and is configured to: define a total number of information bits of eigenmodes as a total modulation bit number; define an allocation of the total modulation bit number according to a combination of modulation schemes in the eigenmodes as a bit allocation; define a degree of quality of the eigenmodes as an initial MER (Modulation Error Ratio);a first bit / power allocation control unit that calculates, for each of a plurality of bit allocations for a first total number of modulation bits, based on the initial MER and the MER threshold, where a value that achieves a certain bit error rate (bit error rate: bit error rate) is defined as an MER threshold, a difference between the initial MER and the MER threshold is defined as an MER margin, and a ratio of power to be allocated to the eigenmode is defined as a power allocation ratio; and, for a plurality of bit allocations for a second total number of modulation bits different from the first total number of modulation bits, for a bit allocation having a predetermined parent-child relationship with respect to the bit allocation of the first total number of modulation bits, the first bit / power allocation control unit adds or subtracts a value corresponding to a difference bit number of the bit allocation having the predetermined parent-child relationship to the MER margin calculated for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship, thereby calculating an MER margin for the bit allocation for the second total number of modulation bits and calculating the MER margin for the bit allocation for the first bit / power allocation. and a second bit / power allocation control unit that sets the power allocation ratio calculated for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship by a bit allocation control unit to a power allocation ratio of the bit allocation in the second total number of modulation bits, and calculates the MER margin and the power allocation ratio for a bit allocation having no predetermined parent-child relationship among the multiple bit allocations, based on the initial MER and the MER threshold. The predetermined parent-child relationship is set to a relationship that satisfies a first condition indicating that the difference bit number of eigenmodes to be used is the same between the bit allocation of the first total number of modulation bits and the bit allocation of the second total number of modulation bits, a second condition indicating that the eigenmodes to be used are the same, and a third condition indicating that a>2≧b is not satisfied, where a is the number of bits of an eigenmode in the bit allocation of the first total number of modulation bits and b is the number of bits of the eigenmode in the bit allocation of the second total number of modulation bits.

[0035] The wireless communication device of claim 2 performs error correction coding on an information bit sequence to be transmitted at a predetermined coding rate, assigns eigenmodes, modulates the information bits of the eigenmodes using a predetermined combination of modulation schemes, and assigns transmission power at a predetermined power allocation ratio, thereby performing transmission in an SVD-MIMO (Singular Value Decomposition-Multiple-Input Multiple-Output) scheme. In this wireless communication device, the degree of quality of the eigenmodes is determined as an initial MER (Modulation Error Ratio), a predetermined BER (Bit ... a bit and power allocation unit that determines, for each of a plurality of different total numbers of modulation bits, the bit allocation and the power allocation ratio when the MER margin after power allocation of the eigenmodes is equal and the MER margin is maximum, with an MER threshold being a value that achieves a bit error rate (bit error rate) and a difference between the initial MER and the MER threshold being an MER margin; and a selection unit that selects one total number of modulation bits from the plurality of different total numbers of modulation bits, and selects the coding rate, the bit allocation, and the power allocation ratio corresponding to the total number of modulation bits, wherein the bit and power allocation unit determines, for a first total number of modulation bits from the plurality of different total numbers of modulation bits, the bit and power allocation unit determines, for each of a plurality of bit allocations, the initial M a first bit / power allocation control unit that calculates the MER margin and the power allocation ratio based on an ER and the MER threshold, obtains a maximum MER margin among the MER margins corresponding to each of the plurality of bit allocations, and obtains the bit allocation and the power allocation ratio corresponding to the maximum MER margin; and for a second total modulation bit number different from the first total modulation bit number among the plurality of different total modulation bit numbers, for a bit allocation having a predetermined parent-child relationship with the bit allocation of the first total modulation bit number among the plurality of bit allocations,a power allocation ratio of the bit allocation in the second total number of modulation bits calculated by the first bit / power allocation control unit for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship, to a power allocation ratio of the bit allocation in the second total number of modulation bits; and a MER margin and a power allocation ratio are calculated for bit allocations having no predetermined parent-child relationship among the plurality of bit allocations based on the initial MER and the MER threshold, and a maximum MER margin among the MER margins corresponding to each of the plurality of bit allocations is calculated. and a second bit / power allocation control unit which calculates an R margin and calculates the bit allocation and the power allocation ratio corresponding to the maximum MER margin, and the predetermined parent-child relationship is a relationship which satisfies a first condition indicating that the differential bit number of eigenmodes to be used is the same between the bit allocation of the first total number of modulation bits and the bit allocation of the second total number of modulation bits, a second condition indicating that the eigenmodes to be used are the same, and a third condition indicating that, where the number of bits of an eigenmode in the bit allocation of the first total number of modulation bits is a and the number of bits of the eigenmode in the bit allocation of the second total number of modulation bits is b, a>2≧b is not satisfied.

[0036] The wireless communication device according to claim 3 is the wireless communication device according to claim 1 or 2, wherein the second bit / power allocation control section sets the first total number of modulation bits to N a , the second total number of modulation bits is N b , N a >N b The MER margin calculated by the first bit / power allocation control unit for the bit allocation of the first total number of modulation bits is M a [dB], the MER margin of the bit allocation in the second total number of modulation bits is M b [dB], and the number of differential bits is d, the bit allocation having the predetermined parent-child relationship is expressed by the formula: M b =M a+ 3 × d, the MER margin M b or the first total number of modulation bits is calculated as N b , the second total number of modulation bits is N a , N a >N b The MER margin calculated by the first bit / power allocation control unit for the bit allocation of the first total number of modulation bits is M b [dB], the MER margin of the bit allocation in the second total number of modulation bits is M a [dB], and the number of differential bits is d, the bit allocation having the predetermined parent-child relationship is expressed by the formula: M a =M b -3×d, the MER margin M a The method is characterized in that:

[0037] Moreover, the wireless communication device of claim 4 is characterized in that, in the wireless communication device described in claim 1 or 2, the specified parent-child relationship defines a bit allocation of the first total number of modulation bits, a bit allocation of the second total number of modulation bits, and the differential bit number so as to satisfy the first condition, the second condition, and the third condition. Effect of the Invention

[0038] As described above, according to the present invention, in an SVD-MIMO wireless transmission system, it is possible to reduce the amount of calculation required when calculating the MER margin for each bit allocation for a plurality of total modulation bit numbers. [Brief description of the drawings]

[0039] [Figure 1] FIG. 11 is a diagram showing characteristics of reception MER versus BER for each modulation scheme. [Diagram 2] 1 is a block diagram showing an example of the configuration of a wireless transmission system including a wireless communication device according to an embodiment of the present invention. [Diagram 3] 4 is a block diagram showing a configuration example of an adaptive control determination unit. FIG. [Figure 4]13 is a block diagram showing a configuration example of a bit / power distribution control unit (Na=20 bits). FIG. [Diagram 5] 13 is a diagram for explaining an example of processing by a bit / power distribution control unit (Na=20 bits). FIG. [Figure 6] FIG. 13 is a diagram showing an example of data in a NaNb parent-child table (Na=20 bits, Nb=16 bits). [Figure 7] 13 is a block diagram showing a configuration example of a bit / power distribution control unit (Nb=16 bits). FIG. [Figure 8] 13 is a diagram for explaining an example of processing by a bit / power distribution control unit (Nb=16 bits). FIG. [Figure 9] 1A and 1B are diagrams comparing examples of specific MER margin calculation results in the embodiment of the present invention and the conventional technology. [Figure 10] FIG. 13 is a block diagram showing an example of the configuration of an adaptive control determination unit in another embodiment of the present invention. [Figure 11] FIG. 1 is a diagram for explaining an example of determining bit allocation and power allocation ratio under a condition that the total number of modulation bits is fixed in the prior art. [Figure 12] FIG. 1 is a diagram illustrating an example of selecting a bit allocation and a power allocation ratio that maximizes the MER margin in the conventional technology. [Figure 13] FIG. 1 is a diagram illustrating an example of selecting a total number of modulation bits in the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Hereinafter, the present invention will be described in detail with reference to the drawings. The present inventors have conducted extensive research to reduce the amount of calculation required to calculate the MER margin for each bit allocation for a plurality of total modulation bit numbers in an SVD-MIMO wireless transmission system.

[0041] As a result, we noticed that in the required MER characteristics of appropriately designed digital modulation, the difference in the required MER is approximately 3 dB for every 1-bit change in the number of bits in the modulation method, and found that by utilizing this fact, the amount of calculations can be reduced.

[0042] FIG. 1 is a diagram showing the characteristics of the received MER versus BER for each modulation scheme. The horizontal axis is the received MER, and the vertical axis is the BER. As mentioned above, the MER margin is the difference between the MER of each stream (each eigenmode) and the MER threshold. The MER threshold is the required MER value for achieving a reference BER in each modulation scheme. In the above-mentioned Non-Patent Document 1, the MER margin is set to BER=10 -4 The required MER value that satisfies the following is used.

[0043] As shown in Figure 1, the required MER (BER=10 -4 ), it is generally known that there is a difference of about 3 dB in the MER for every 1-bit change in the number of bits in the modulation format (see the solid arrow). For example, when the modulation format changes by 1 bit from 1024QAM (10 bits) to 512QAM (9 bits), the required MER to achieve the reference BER drops (improves) by about 3 dB. The same is true when the modulation format changes by 1 bit from 512QAM (9 bits) to 256QAM (8 bits), ..., when it changes from 16QAM (4 bits) to 8QAM (3 bits), and when it changes from QPSK (2 bits) to BPSK (1 bit).

[0044] However, when the modulation format changes by one bit, from 8QAM (3 bits) to QPSK (2 bits), the required MER to achieve the reference BER drops by about 4 dB instead of about 3 dB (see dotted arrow).

[0045] The inventors of the present invention utilize this characteristic to reduce the amount of calculation required to calculate the MER margin. That is, the wireless communication device of the wireless transmission system performs a simplified calculation of the MER margin by assuming that a difference of 3 dB per bit also occurs in the MER margin when the difference between the values ​​of multiple elements constituting the bit allocation in a pair of bit allocation of a first modulation scheme and bit allocation of a second modulation scheme is the same.

[0046] For example, if the bit allocation of the first modulation method is [10,6,2,2] and the bit allocation of the second modulation method is [9,5,1,1], the difference in the number of bits for each of the multiple elements that make up the bit allocation is the same, that is, 1. In this case, it is treated as if a difference of 3 dB also occurs in the MER margin.

[0047] More specifically, the wireless communication device calculates the MER margin for the bit allocation of a first modulation method ([10,6,2,2] in the above example) for a certain total number of modulation bits based on the initial MER, etc., in a manner similar to that of the above-mentioned Patent Documents 1 and 2. Then, the wireless communication device calculates the MER margin for the bit allocation of a second modulation method ([9,5,1,1] in the above example) that has a predetermined relationship (parent-child relationship to be described later) with the bit allocation of the first modulation method for a total number of modulation bits different from the above-mentioned total number of modulation bits, assuming a difference of 3 dB per bit depending on the bit difference of the elements of the bit allocation.

[0048] As a result, the MER margin for bit allocation of the second modulation scheme can be calculated easily, unlike the methods of Patent Documents 1 and 2. Therefore, in a wireless transmission system using the SVD-MIMO scheme, the amount of calculation required to calculate the MER margin for each bit allocation for a plurality of total modulation bit numbers can be reduced.

[0049] [Wireless Transmission System] First, a wireless transmission system including a wireless communication device according to an embodiment of the present invention will be described. FIG. 2 is a block diagram showing an example of the configuration of a wireless transmission system including a wireless communication device according to an embodiment of the present invention. t 1 transmitting antenna and M r M receiving antennas are used to realize eigenmode transmission. t ×M r The functional configuration block of the SVD-MIMO method is shown in FIG. 2. In FIG. 2, K channel eigenmodes are formed. M t ,M r , K is a positive integer.

[0050] This wireless transmission system 1 realizes bidirectional communication by including a wireless communication device 2 that transmits a signal including an information bit sequence and receives channel information and an initial MER, and a wireless communication device 3 that receives a signal including an information bit sequence and transmits channel information and an initial MER.

[0051] 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 an M t The modulator 24 includes K modulators 24-1, 24-2, . . . , 24-K.

[0052] The receiving wireless communication device 3 is r The signal receiving unit 30 includes a receiving antenna 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.

[0053] (Sender) Next, a description will be given of the transmitting wireless communication device 2 shown in Fig. 2. The transmitting wireless communication device 2 receives as input an information bit sequence to be transmitted.

[0054] The adaptive control decision unit 21 inputs the initial MER of each eigenmode and performs adaptive control according to the MER and propagation path conditions to select the bit allocation and power allocation ratio corresponding to the optimal combination of the total number of modulation bits, coding rate, and modulation scheme.

[0055] The adaptive control determination unit 21 outputs the coding rate to the error correction coding unit 22, outputs the bit allocation corresponding to the combination of the total number of modulated bits and the modulation scheme to the modulation unit 24, and outputs the power allocation ratio to the power allocation unit 25.

[0056] Specifically, the adaptive control determination unit 21 selects, for each of a plurality of different total modulation bit numbers, a bit allocation and a power allocation ratio that results in an equal and maximum MER margin after power allocation for each eigenmode.

[0057] In an embodiment of the present invention, when calculating the MER margin for each bit allocation for each of a number of different total modulation bit numbers, the MER margin for bit allocations in a parent-child relationship, which will be described later, is calculated simply assuming a difference of 3 dB per bit.

[0058] The adaptive control decision unit 21 identifies, for each total number of modulation bits, the coding rate with the largest number of effective transmission bits among the coding rates whose MER margin exceeds the required MER margin, identifies the largest effective transmission bit number among the largest effective transmission bit numbers for each total number of modulation bits, and selects the corresponding total number of modulation bits.

[0059] The adaptive control determination unit 21 selects the coding rate, bit allocation, and power allocation ratio corresponding to the selected total number of modulation bits as the optimal coding rate, bit allocation, and power allocation ratio. The simple calculation process of the MER margin by the adaptive control determination unit 21 will be described in detail later.

[0060] The error correction coding unit 22 inputs the information bit sequence and the coding rate from the adaptive control decision unit 21, performs error correction coding on the information bit sequence at the coding rate, and outputs the error correction coded information bit sequence to the S / P conversion unit 23.

[0061] 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, distributes them, and outputs the K parallel sub-stream information bits to the modulation unit 24. The number of these information bits corresponds to the number of modulation bits.

[0062] Modulation units 24-1, 24-2, ..., 24-K constituting modulation unit 24 input information bits (information bits of eigenmodes) of the corresponding substreams from S / P conversion unit 23. Modulation units 24-1, 24-2, ..., 24-K also input bit allocations corresponding to the combination of the total number of modulation bits and modulation schemes from adaptive control determination unit 21, and identify the modulation schemes indicated by the total number of modulation bits and the bit allocations, respectively.

[0063] 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.

[0064] 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, and outputs the multiplied information bits for each eigenmode to transmission weight unit 27.

[0065] The singular value decomposition unit 26 t 28 transmitting antennas and M r The channel information of the propagation path formed between the receiving antennas 31 is acquired, 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, sets the right singular matrix as a transmission weight, and outputs the right singular matrix to the transmission weight unit 27.

[0066] The transmission weight unit 27 receives the information bits of each eigenmode from the power allocation unit 25 and the transmission weights from the singular value decomposition unit 26, multiplies the information bits by the transmission weights, and obtains M t The transmission weight unit 27 generates a transmission signal for each transmission antenna system corresponding to each of the transmission antennas 28. As a result, an eigenbeam that is orthogonal to each eigenmode is generated. Furthermore, the transmission signal generated by the transmission weight unit 27 is transmitted from the transmission antenna 28 for each transmission antenna system.

[0067] (Receiving side) Next, a description will be given of the receiving wireless communication device 3 shown in Fig. 2. The receiving wireless communication device 3 receives the signal transmitted by the transmitting wireless communication device 2.

[0068] 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.

[0069] The reception wait unit 33 receives M r The reception weight unit 33 inputs the reception signals for each reception antenna system via one reception antenna 31, and also inputs 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. The reception weight unit 33 outputs the reception signals of each eigenmode to the demodulation unit 34.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] In this way, the signal transmitted from the transmitting wireless communication device 2 is received by the receiving antenna 31, restored to the substreams of each eigenmode, and restored to the original information bit sequence.

[0076] [Adaptive control decision unit 21] Next, the adaptive control determination unit 21 shown in Fig. 2 will be described in detail. Fig. 3 is a block diagram showing an example of the configuration of the adaptive control determination unit 21. a = 20 bits, N b 16 bits as an example, the case of determining the optimum total number of modulation bits, bit allocation, power allocation ratio and coding rate is shown.

[0077] The adaptive control determination unit 21 includes a bit / power allocation unit 41 and a selection unit 101. The bit / power allocation unit 41 includes bit / power allocation control units 42-1 and 42-2. a = 20 bits is the bit allocation (N a ) and the total number of modulation bits is N b = Bit allocation in 16 bits is bit allocation (N b )

[0078] The bit / power distribution control unit 42-1 receives the initial MER and calculates the total number of modulation bits N a For =20 bits, bit allocation (N a ) for each MER margin M based on the initial MER and the predefined MER threshold. a (α) and power distribution ratio P a Calculate (α, k). α is the bit allocation (N a ) and k denotes the eigenmode number.

[0079] The bit / power allocation control unit 42-1 determines the bit allocation (N a ) is the bit allocation (N b ), if they are in a parent-child relationship as described below, their bit allocation (N a ), number of differential bits d, MER margin M a (α) and power distribution ratio P a (α, k) is output to the bit / power allocation control unit 42-2. The number of difference bits d is calculated based on the bit allocation with parent-child relationship (N a ) and bit allocation (N b ) indicates the difference in the number of bits at element positions of the same eigenmode used. Details will be described later.

[0080] The bit and power allocation control unit 42-1 determines the bit allocation and power allocation ratio when the MER margin after the power allocation of each eigenmode is equal and the MER margin is maximum. Then, the bit and power allocation control unit 42-1 calculates the total number of modulation bits N aThe bit / power allocation control unit 42-1 outputs the bit allocation (when the MER margin is maximum), the MER margin and the power allocation ratio to the selection unit 101. The bit / power allocation control unit 42-1 will be described in detail later.

[0081] The bit and power allocation control unit 42-2 receives the initial MER and also receives the bit allocation with parent-child relationship (N a ), number of differential bits d, MER margin M a (α) and power distribution ratio P a Input (α, k).

[0082] The bit / power distribution control unit 42-2 calculates the total number of modulation bits N b = 16 bits, bit allocation (N b ), the bit allocation (N b ) is the bit allocation (N a ), the MER margin M is calculated based on the initial MER and a preset MER threshold value in the same manner as the bit / power distribution control unit 42-1. b (β) and power allocation ratio P b Calculate (β, k). β is the bit allocation (N b ) number.

[0083] On the other hand, the bit / power allocation control unit 42-2 determines the bit allocation (N b ) are in a parent-child relationship, the difference bit number d and the MER margin M input from the bit / power distribution control unit 42-1 a (α) and power distribution ratio P a Using (α, k), the MER margin M b (β) and power allocation ratio P b Find (β,k).

[0084] The bit / power allocation control unit 42-2 determines the bit allocation (N b ) and the power distribution ratio. Then, the bit / power distribution control unit 42-2 calculates the total number of modulation bits N bThe bit / power allocation control unit 42-2 outputs the bit allocation (when the MER margin is maximum), the MER margin and the power allocation ratio to the selection unit 101. The bit / power allocation control unit 42-2 will be described in detail later.

[0085] The selection unit 101 receives the total number of modulation bits N a , bit allocation, MER margin and power allocation ratio are input, and the total number of modulation bits N b , the bit allocation, the MER margin and the power allocation ratio are input.

[0086] The selection unit 101 performs the same process as the selection unit 101 shown in FIG. 13 to obtain the total number of modulation bits N a ,N b and selects and outputs the corresponding bit allocation, power allocation ratio, and coding rate.

[0087] (Parent-child relationship) Here, bit allocation (N a ) and bit allocation (N b ) and the parent-child relationship between the total number of modulation bits N a The bit allocation of [a 1 ,a 2 ,···,a K ], and the total number of modulation bits is N b The bit allocation of [b 1 ,b 2 ,···,b K ], where a 1 ~a K The sum of is N a , b 1 ~b k The sum of is N b is equal to

[0088] 1,2,...,K are the eigenmode numbers. Also, N a >N b The total number of modulation bits is N a Bit allocation of [a 1 ,a 2 ,···,a K ] on the parent side, and the total number of modulation bits Nb Bit allocation [b 1 ,b 2 ,···,b K ] is called the child side. As mentioned above, the difference bit number d is the parent-child bit allocation (N a ) and bit allocation (N b ) is the difference (integer) in the number of bits at the element positions of the same eigenmode used, and d=a 1 -b 1 =a 2 -b 2 ==a K -b K It is.

[0089] The parent-child relationship described here is based on the total number of modulation bits N a = 20 bits, N b = 16 bits, but also N a >N b The total number of modulation bits N that satisfies the relationship a ,N b This applies to:

[0090] Bit allocation [a 1 ,a 2 ,···,a K ] and bit allocation [b 1 ,b 2 ,···,b K ]A combination that satisfies all of the following conditions 1, 2, and 3 is considered to have a parent-child relationship.

[0091] <Condition 1> For all eigenmode numbers k (k=1,2,...,K) (for all eigenmode elements), the formula: k -d=b k This is because the bit allocation [a 1 ,a 2 ,···,a K ] and bit allocation [b 1 ,b 2 ,···,b K ] means that the number of differential bits d is the same between the elements of each eigenmode.

[0092] For example, in the case of K=4, the bit allocation [a 1 ,a 2 ,a 3 ,a 4 ]=[9,5,4,2] and bit allocation [b 1 ,b 2 ,b 3 ,b 4 ]=[8,4,3,1], then condition 1 is satisfied. In this case, the number of differential bits d=1.

[0093] <Condition 2> If condition 1 is met, the child bit allocation [b 1 ,b 2 ,···,b K ] for all eigenmode numbers k (k = 1, 2, . . . , K), b k ≦0. This is because the bit allocation [a 1 ,a 2 ,···,a K ] and the number of eigenmodes (streams) used in [b 1 ,b 2 ,···,b K ] is the same (the number of eigenmodes used does not change (the number of streams does not change)).

[0094] For example, in the case of K=4, the bit allocation [a 1 ,a 2 ,a 3 ,a 4 ]=[10,5,4,1] and bit allocation [b 1 ,b 2 ,b 3 ,b 4 If [10,5,4,1]=[9,4,3,0], condition 1 is satisfied but condition 2 is not satisfied. Therefore, the bit allocations [10,5,4,1] and [9,4,3,0] are not in a parent-child relationship.

[0095] <Condition 3> For all eigenmode numbers k (k = 1, 2, . . . , K), k >2≧b kThis means that the calculation of condition 1 results in the bit allocation value not crossing 2 (not including a change from 8QAM (3 bits) to QPSK (2 bits)). As shown in Figure 1, when the modulation method changes by 1 bit from 8QAM (3 bits) to QPSK (2 bits), the required MER drops by about 4 dB instead of about 3 dB, and the change in the required MER cannot be approximated by 3 dB, so this must be excluded.

[0096] For example, in the case of K=4, the bit allocation [a 1 ,a 2 ,a 3 ,a 4 ]=[9,6,3,2] and bit allocation [b 1 ,b 2 ,b 3 ,b 4 ]=[8,5,2,1], conditions 1 and 2 are satisfied, but the bit allocation a of the third eigenmode 3 =3 and b 3 =2 does not satisfy condition 3. Therefore, the bit allocations [9,6,3,2] and [8,5,2,1] are not in a parent-child relationship.

[0097] In this way, the bit allocation (N a ) and bit allocation (N b ) If all of the above conditions 1 to 3 are satisfied, the two bit allocations are deemed to have a parent-child relationship.

[0098] (Bit / power distribution control unit 42-1) Next, the bit / power distribution control unit 42-1 shown in FIG. 3 will be described in detail. a When N is 20 bits, the bit / power distribution control unit 42-1 (N a FIG. 5 is a block diagram showing a configuration example of a bit / power distribution control unit 42-1 (N a FIG. 1 is a diagram for explaining an example of processing (=20 bits).

[0099] The bit / power allocation control unit 42-1 includes a power allocation calculation unit 51, an MER margin calculation unit 52, a bit / power determination unit 53, and an N aBit allocation table 54 and N a N b It is equipped with a parent and child table 55. a The bit allocation table 54 includes the number α shown in FIG. 5 and the bit allocation (N a ) is stored.

[0100] The power allocation calculation unit 51 receives the initial MER and a preset MER threshold. Then, as shown in FIG. a By referring to the bit allocation table 54, 55 kinds of bit allocation (N a ) for each of (number α bit allocation (N a )), the power allocation ratio P a (α, k), and the MER margin calculation unit 52 calculates the MER margin M a Calculate (α).

[0101] The MER margin calculation unit 52 calculates the bit allocation (N a ), MER margin M a (α) and power distribution ratio P a (α, k) is output to the bit / power determining unit 53 .

[0102] Specifically, the power allocation calculation unit 51 calculates the bit allocation (N a ) for each eigenmode, the MER margin M' before power allocation for each eigenmode is calculated based on the initial MER and MER threshold of each eigenmode. a (α) and set the power allocation ratio P a Then, the power allocation calculation unit 51 calculates the bit allocation (N a ), the MER margin M' before power allocation for each eigenmode a (α) and power distribution ratio P a (α, k) is output to the MER margin calculation unit 52.

[0103] The MER margin calculation unit 52 receives the bit allocation (Na ), the MER margin M' before power allocation for each eigenmode a (α) and power distribution ratio P a (α, k). The MER margin calculation unit 52 then determines the power allocation ratio so that the MER margin of each eigenmode is equal to that of all eigenmodes, and calculates the MER margin M a (α) is calculated. For details, see Patent Document 1.

[0104] The bit / power determination unit 53 receives the bit allocation (N a ), MER margin M a (α) and power distribution ratio P a Then, the bit and power determination unit 53 selects 55 different bit allocations (N a ) for each of the N a N b Refer to the parent-child table 55 to determine the bit allocation (N a ) has a parent-child relationship, the bit allocation (N a ) and bit allocation (N b Then, the bit / power determination unit 53 determines the bit allocation (number α) with parent-child relationship (N a ), number of differential bits d, MER margin M a (α) and power distribution ratio P a (α, k) is output to the bit / power distribution control unit 42-2.

[0105] Figure 6 shows the N a N b Parent and child table 55(N a = 20 bits, N b 1 is a diagram showing an example of data for a total modulation bit number N a = 20 bits, N b = Bit allocation for 16 bits (N a ,N b ) a parent-child relationship that satisfies conditions 1 to 3 above is defined.

[0106] This N a Nb Parent and child table 55(N a = 20 bits, N b = 16 bits) is the total number of modulation bits N a = 20 bits of number α and bit allocation of the number α (N a ), bit allocation of the number α (N a ) and the total number of modulation bits N b = 16-bit number β and bit allocation of that number β (N b ), and the number of differential bits d.

[0107] Bit allocation with parent-child relationships (N a ,N b Of these, there are 15 combinations where the number of difference bits is d=1, there is one combination where the number of difference bits is d=2, and there is no combination where the number of difference bits is d≧3.

[0108] N a N b Parent and child table 55(N a = 20 bits, N b In the bit allocation table (16 bits = 16 bits), the bit allocation [8,8,0,0] and number of differential bits d=2 of number β=3, which has a parent-child relationship with the bit allocation [10,10,0,0] of number α=1, the bit allocation [9,5,1,1] and number of differential bits d=1 of number β=22, which has a parent-child relationship with the bit allocation [10,6,2,2] of number α=18, and the bit allocation [4,4,4,4] and number of differential bits d=1 of number β=48, which has a parent-child relationship with the bit allocation [5,5,5,5] of number α=55.

[0109] Returning to FIG. 4 and FIG. 5, the bit / power determination unit 53 determines the bit allocation (N a ) MER margin M a The maximum MER margin M a Identify (α) and the maximum MER margin M a (α) a ) and power distribution ratio P a Identify (α, k).

[0110] The bit power determination unit 53 determines the total number of modulation bits N a , bit allocation (specified bit allocation (N a )), MER margin (the maximum MER margin M a (α)) and the power allocation ratio (the specified power allocation ratio P a (α, k)) is output to the selection unit 101.

[0111] (Bit / power distribution control unit 42-2) Next, the bit / power distribution control unit 42-2 shown in FIG. 3 will be described in detail. b When N is 16 bits, the bit power distribution control unit 42-2 (N b FIG. 8 is a block diagram showing a configuration example of a bit / power distribution control unit 42-2 (N = 16 bits). b FIG. 1 is a diagram for explaining an example of processing (=16 bits).

[0112] The bit / power allocation control unit 42-2 includes a power allocation calculation unit 61, an MER margin calculation unit 62, a simplified MER margin calculation unit 63, a bit / power determination unit 64, and an N b Bit Allocation Table 65 and N a N b It is equipped with a parent-child table 66.

[0113] The power allocation calculation unit 61 calculates N b Bit Allocation Table 65 and N a N b Refer to parent-child table 66 and enter N b The 48 bit allocations (N b ) (Bit allocation of number β (N b )) of the bit allocations without parent-child relationships (N b ) is specified. Note that N b The bit allocation table 65 includes the number β shown in FIG. b ) is stored. Also, N a N b The parent-child table 66 is the Na N b It is assumed to be the same as parent-child table 55.

[0114] The power allocation calculation unit 61 receives the initial MER and a preset MER threshold. Then, as shown in FIG. 8, the power allocation calculation unit 61 calculates a bit allocation without a parent-child relationship (N b ) (bit allocation of number β without “*”), the power allocation ratio P b (β, k), and the MER margin calculation unit 62 calculates the MER margin M b Calculate (β).

[0115] The MER margin calculation unit 62 calculates bit allocation without parent-child relationships (N b ), MER margin M b (β) and power allocation ratio P b (β, k) is output to the bit / power determining unit 64 .

[0116] The simplified MER margin calculation unit 63 receives the bit allocation (number α) with parent-child relationship (N a ), number of differential bits d, MER margin M a (α) and power distribution ratio P a (α, k). The simple MER margin calculation unit 63 then inputs N b Bit Allocation Table 65 and N a N b Refer to parent-child table 66 to find 48 bit allocations (N b ) (Bit allocation of number β (N b )) with parent-child relationships (N b ) to identify the

[0117] As shown in FIG. 8, the simplified MER margin calculation unit 63 calculates the bit allocation with parent-child relationship (N b ) (bit allocation of number β marked with "*"), the MER margin Ma Based on (α) and the number of difference bits d, the MER margin M b (β) and calculate the power distribution ratio P a (α, k) is the power allocation ratio P b Set it to (β, k).

[0118] For example, the bit allocation of number α=1 (N a ) and bit allocation for number β=3 (N b ) has a parent-child relationship (see FIG. 6). In this case, the simplified MER margin calculation unit 63 receives the bit allocation of number α=1 (N a ), number of difference bits d=2, MER margin M a (1) and power distribution ratio P a Enter (1,k).

[0119] Since the number of difference bits d=2, the simplified MER margin calculation unit 63 calculates M b (3)=M a (1) + 6 gives the MER margin M b (3) is calculated, and the power distribution ratio P b (3, k) as the power allocation ratio P a (1,k) is used (see number β=3 in Figure 8).

[0120] Also, for example, the bit allocation of number α=18 (N a ) and bit allocation for number β=22 (N b ) has a parent-child relationship (see FIG. 6). In this case, the simplified MER margin calculation unit 63 receives the bit allocation of number α=18 (N a ), number of difference bits d=1, MER margin M a (18) and power distribution ratio P a Enter (18,k).

[0121] Since the number of difference bits d=1, the simplified MER margin calculation unit 63 calculates Mb (22)=M a (18)+3 gives the MER margin M b (22) and calculate the power allocation ratio P b (22,k) is the power allocation ratio P a (18,k) is used (see number β=22 in Figure 8).

[0122] In other words, the parent-child bit allocation (N a ) MER margin is M a and bit allocation (N b ) MER margin is M b If the difference in bits is d, the MER margin M a and the number of difference bits d are used to calculate the MER margin M b is calculated. [Number 1] M b =M a +3×d (1)

[0123] The above formula (1) is the bit allocation of the number α with parent-child relationship (N a ) and bit allocation of number β (N b ) is N a >N b In the case of a ) MER margin M a [dB] and the number of differential bits d are used to calculate the bit allocation (N b ) MER margin M b This is a formula for easily calculating the MER margin M b This is a formula for easily calculating the above.

[0124] In addition, the bit allocation on the child side (N b ) MER margin M b [dB] and the number of differential bits d are used to calculate the parent bit allocation (N a ) MER margin M a To calculate the MER margin M[dB] simply, the following formula is used. This is done by using the calculation result of the child side to calculate the MER margin M aThis is the formula for calculating [Number 2] M a =M b -3×d (2)

[0125] The simplified MER margin calculation unit 63 calculates the bit allocation with parent-child relationship (N b ), MER margin M b (β) and power allocation ratio P b (β, k) is output to the bit / power determining unit 64 .

[0126] The bit / power determination unit 64 receives the bit allocation (N b ), MER margin M b (β) and power allocation ratio P b (β, k) is input, and the bit allocation with parent-child relationship (N b ), MER margin M b (β) and power allocation ratio P b Input (β,k).

[0127] The bit / power determination unit 64 determines the bit allocation (N b ) MER margin M b (β) Maximum MER margin M b (β) and the maximum MER margin M b (β) corresponding bit allocation (N b ) and power distribution ratio P b Identify (β, k).

[0128] The bit power determination unit 64 determines the total number of modulation bits N b , bit allocation (specified bit allocation (N b )), MER margin (the maximum MER margin M b (β)) and the power allocation ratio (the specific power allocation ratio P b (β, k)) is output to the selection unit 101.

[0129] [Specific calculation results] Next, the calculation result of the MER margin according to the embodiment of the present invention will be compared with the calculation result of the MER margin according to the conventional technology shown in Fig. 13. Fig. 9 is a diagram for comparing specific examples of the calculation result of the MER margin in the embodiment of the present invention and the conventional technology. The distribution of the initial MER is assumed to be the same as that shown in Fig. 11.

[0130] FIG. 9(1) shows the total number of modulation bits N by the bit / power distribution control unit 42-1 shown in FIG. a = 20 bits, and bit allocation with parent-child relationship when the difference bit number d = 1 (N a ) and MER margin M a The calculation results are shown in [dB]. MER margin M a Let be X.

[0131] FIG. 9(2) shows the total number of modulation bits N b = 16 bits, and bit allocation with parent-child relationship when the difference bit number d = 1 (N b ) and MER margin M b The calculation results are shown in [dB]. MER margin M b Let Y be the MER margin in this case. b Since the number of differential bits d is 1, Y=X+3 according to the above formula (1).

[0132] FIG. 9(3) shows the total number of modulation bits N 1 =N b 9(2) is a diagram showing the calculation result of the MER margin at 16 bits, and the error from the calculation result in the embodiment of the present invention shown in FIG. 9(2). If this MER margin is Z, the error is YZ.

[0133] According to FIG. 9(3), the MER margin M bIt can be seen that the error between Y and the MER margin Z calculated in the usual way in the conventional technology is small. a = 20 bits, N b The MER margin for each bit allocation can be easily calculated for 16 bits, thereby reducing the amount of calculation.

[0134] As described above, according to the wireless communication device 2 of the embodiment of the present invention, the bit / power allocation control unit 42-1 of the bit / power allocation unit 41 provided in the adaptive control determination unit 21 determines the total number of modulation bits N a For bit allocation (N a ), the MER margin M' before power allocation for each eigenmode is calculated based on the initial MER and the MER threshold. a (α) and set the power allocation ratio P a Calculate (α, k) and calculate the MER margin M' before power allocation for each eigenmode. a (α) and power distribution ratio P a Based on (α, k), the MER margin after power allocation M a By calculating (α), the MER margin after power allocation M a (α) and power distribution ratio P a Find (α, k).

[0135] Then, the bit / power distribution control unit 42-1 calculates all the MER margins M a The maximum MER margin M a Identify (α) and the maximum MER margin M a (α) a ) and power distribution ratio P a By specifying (α, k), the total number of modulation bits N a The bit allocation, MER margin, and power allocation ratio are calculated for each.

[0136] The bit / power distribution control unit 42-2 calculates the total number of modulation bits N b = 16 bits, bit allocation (Nb ), the bit allocation (N b ) is the bit allocation (N a ), if the parent-child relationship does not satisfy any of the above conditions 1 to 3, the MER margin M b (β) and power allocation ratio P b Find (β,k).

[0137] On the other hand, the bit / power allocation control unit 42-2 determines the bit allocation (N b ) is the bit allocation (N a ), if the parent-child relationship satisfies conditions 1 to 3 above, the parent-child bit allocation (N a ) for the number of differential bits d, the MER margin M a (α) and power distribution ratio P a Based on (α, k), the MER margin M b (β) is calculated, and the power allocation ratio P b (β,k)(=P a Set (α, k) as the

[0138] Then, the bit / power distribution control unit 42-2 calculates all the MER margins M b (β) Maximum MER margin M b (β) and the maximum MER margin M b (β) corresponding bit allocation (N b ) and power distribution ratio P b By identifying (β, k), the total number of modulation bits N b The bit allocation, MER margin, and power allocation ratio are calculated for each.

[0139] Thus, in the embodiment of the present invention, different total modulation bit numbers N a ,N b Bit allocation (N a ,N b ) if there is a parent-child relationship that satisfies the above conditions 1 to 3, bit allocation with parent-child relationship (N a) is calculated by the simple formula (1) using the calculation result of the corresponding bit allocation (N b ) MER margin M b We have tried to obtain an approximation value of (β) with high accuracy.

[0140] As a result, the bit / power distribution control unit 42-2 detects the MER margin M b A part of the calculation for calculating (β) can be replaced with the simple formula (1) above. a ,N b ), multiple multiplication and division processes, which are highly load-bearing in hardware, can be replaced with a single addition process in the case of formula (1) (a single subtraction process in the case of formula (2)).

[0141] For example, the total number of modulation bits N a = 20 bits, N b = 16 bits, bit allocation (N b There are 48 combinations of bit allocations (N a ) there are 16 possible parent-child combinations.

[0142] In the conventional technology, all 48 bit allocations (N b ) requires a computation based on the initial MER and the MER threshold, which is very expensive. In contrast, in the embodiment of the present invention, 16 bit allocations (N b ), or about 1 / 3 of the bit allocation (N b ) for MER margin M b The calculation of (β) can be performed using the simple formula (1) above.

[0143] Therefore, in the SVD-MIMO wireless transmission system 1, a total number of modulation bits N a ,N b Bit allocation (N a ,N b ) the amount of calculation required to calculate the MER margin can be reduced.

[0144] Other embodiments of the present invention Next, another embodiment of the present invention will be described. Fig. 10 is a block diagram showing an example of the configuration of the adaptive control determination unit 21 in another embodiment of the present invention. a = 20 bits, N b = 16 bits, N c 12 bits as an example, the case of determining the optimum total number of modulation bits, bit allocation, power allocation ratio and coding rate is shown.

[0145] In the adaptive control determination unit 21 shown in FIG. a = 20 bits, N b The total number of modulation bits N a = 20 bits, N b = 16 bits, N c = 12 bits for a total of three modulation bits.

[0146] The adaptive control determination unit 21 includes a bit / power allocation unit 41' and a selection unit 101'. The bit / power allocation unit 41' includes bit / power allocation control units 42-1, 42'-2, and 42-3. a = 20 bits is the bit allocation (N a ) and the total number of modulation bits is N b = Bit allocation in 16 bits is bit allocation (N b ), the total number of modulation bits N c = Bit allocation in 12 bits is bit allocation (N c )

[0147] The bit / power distribution control unit 42-1 is the same as the bit / power distribution control unit 42-1 shown in FIG. 3 and FIG. 4, so a description thereof will be omitted here. a ) is the bit allocation (N b ), the bit allocation (N a ), number of differential bits d, MER margin M a(α) and power distribution ratio P a (α, k) is output to the bit / power distribution control unit 42'-2.

[0148] The bit / power distribution control unit 42'-2 has the same configuration as the bit / power distribution control unit 42-2 shown in FIG. b N c It has parent and child tables. b N c The parent-child table is shown in Figure 6. a N b As shown in the data structure of parent-child table 55, the total number of modulation bits N b = 16 bits, N c = 12-bit bit allocation (N b ,N c ) a parent-child relationship that satisfies conditions 1 to 3 above is defined.

[0149] The bit / power distribution control unit 42'-2 performs the processes of the bit / power distribution control unit 42-2 shown in FIG. b N c Refer to the parent-child table and calculate the bit allocation (N b ) is the bit allocation (N c ), the bit allocation (N b ), number of differential bits d, MER margin M b (β) and power allocation ratio P b The process outputs (β, k) to the bit / power distribution control unit 42-3.

[0150] The bit / power allocation control unit 42-3 performs processing corresponding to the bit / power allocation control unit 42-2 shown in Fig. 7. In other words, the bit / power allocation control unit 42-3 performs processing corresponding to the total number of modulation bits N b = 16 bits instead of the total number of modulation bits N c The processing of the bit / power distribution control unit 42-3 is basically the same as that of the bit / power distribution control unit 42-2 shown in FIG.

[0151] The bit / power distribution control unit 42-3 calculates the total number of modulation bits N c , bit allocation (specified bit allocation (N c )), MER margin (the maximum MER margin M c (γ)) and the power allocation ratio (the specified power allocation ratio P c (γ, k)) to the selection unit 101′. γ is the bit allocation (N c ) number.

[0152] The selector 101' receives the total number of modulation bits N a , bit distribution, etc., and the total number of modulation bits N b , bit distribution, etc., and the total number of modulation bits N c , bit allocation, etc.

[0153] The selection unit 101' performs a process corresponding to the selection unit 101 shown in FIG. a ,N b ,N c and selects and outputs the corresponding bit allocation, power allocation ratio, and coding rate.

[0154] As described above, the wireless communication device 2 according to the other embodiment of the present invention provides the same effects as the wireless communication device 2 according to the previously described embodiment of the present invention.

[0155] That is, in other embodiments of the present invention, different total modulation bit numbers N a ,N b Bit allocation (N a ,N b ) if there is a parent-child relationship that satisfies the above conditions 1 to 3, bit allocation with parent-child relationship (N a ) is calculated by the simple formula (1) using the calculation result of the corresponding bit allocation (N b ) MER margin M b We tried to obtain an approximation value of (β) with high accuracy. Also, we tried to obtain a different total modulation bit number N b ,N cBit allocation (N b ,N c ) if there is a parent-child relationship that satisfies the above conditions 1 to 3, bit allocation with parent-child relationship (N b ) is calculated by a simple formula that uses the results of the calculation of the corresponding bit allocation (N c ) MER margin M c We have attempted to obtain an approximation value of (γ) with high accuracy.

[0156] As a result, the bit / power distribution control units 42'-2 and 42-3 adjust the MER margin M b (β), M c A part of the calculations for calculating (γ) can be replaced with the simple formula (1) or the like.

[0157] Therefore, in the SVD-MIMO wireless transmission system 1, a total number of modulation bits N a ,N b ,N c Bit allocation (N a ,N b ,N c ) the amount of calculation required to calculate the MER margin can be reduced.

[0158] 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.

[0159] For example, in the above embodiment, the total number of modulation bits N a ,N b N a >N b In the case of parent bit allocation (N a ) MER margin M a Using the calculation result of (α), the bit allocation of the child side (N b ) MER margin M b An example of a simple calculation of (β) has been described.

[0160] In contrast, the child's bit allocation (N b ) MER margin M bUsing the calculation result of (β), the parent's bit allocation (N a ) MER margin M a In this case, the bit / power distribution control unit 42-1 shown in FIG. b = 16 bits, child bit allocation (N b ), and the bit / power distribution control unit 42-2 processes the total number of modulation bits N a = 20 bits, parent's bit allocation (N a That is, the bit and power allocation control unit 42-2 performs the process of bit allocation (N b ) MER margin M b (β) and the number of differential bits d are used to determine the parent's bit allocation (N a ) MER margin M a Calculate (α) easily.

[0161] In the above embodiment, the total number of modulation bits N a = 20 bits, N b In the above-mentioned other embodiment, the total number of modulation bits N a = 20 bits, N b = 16 bits, N c In the above description, a total number of modulation bits of three, ie, 12 bits, is used, but the present invention is also applicable to a total number of modulation bits of four or more.

[0162] Here, like the bit and power allocation units 41, 41' shown in Fig. 3 and Fig. 10, bit and power allocation control units 42-1,...,42-I are assumed to correspond to a plurality (I units (I is an integer of 2 or more)) of different total modulation bit numbers in descending order. The bit and power allocation units 41, 41' are assumed to include bit and power allocation control units 42-1,...,42-I.

[0163] In this case, in the bit / power distribution control unit 42-i (i=2, . . . , I), a parent-child table (N shown in FIG. 7) is used to determine the parent-child relationship and perform calculations using the above formula (1).a N b In the parent-child table (corresponding to parent-child table 66), a parent-child relationship that satisfies the above-mentioned conditions 1 to 3 is defined for the bit allocation of the i-th total modulation bit number and the bit allocation of the (i-1)th total modulation bit number that is one bit number before that.

[0164] In addition, the bit / power distribution control unit 42-i (i=1, . . . , I−1) determines the parent-child relationship and outputs the bit distribution and the number of difference bits d, etc. to the bit / power distribution control unit 42-(i+1) in the subsequent stage. a N b In the parent-child table 55), parent-child relationships that satisfy the above-mentioned conditions 1 to 3 are defined for the bit allocation of the i-th total modulation bit number and the bit allocation of the (i+1)-th total modulation bit number that is one bit number smaller than the i-th total modulation bit number.

[0165] On the other hand, assuming multiple (I (I is an integer equal to or greater than 2)) different ascending order total modulation bit numbers, in the bit power allocation control unit 42-1,...,42-I, a parent-child table used to determine the parent-child relationship and perform calculations using the above formula (2) in the bit power allocation control unit 42-i (i=2,...,I) defines parent-child relationships that satisfy the above conditions 1 to 3 for the bit allocation of the i-th total modulation bit number and the bit allocation of the (i-1)th total modulation bit number, which has the smaller number of bits in the previous stage.

[0166] In addition, in the bit / power allocation control unit 42-i (i=1,...,I-1), a parent-child table used to determine the parent-child relationship and output the bit allocation and the differential bit number d, etc. to the subsequent bit / power allocation control unit 42-(i+1) defines a parent-child relationship that satisfies the above-mentioned conditions 1 to 3 for the bit allocation of the i-th total modulation bit number and the bit allocation of the (i+1)-th total modulation bit number that is one stage later and has a larger number of bits. [Explanation of symbols]

[0167] 1. Wireless 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 41,41' bit power distribution section 42, 42', 100 bit power distribution control unit 51,61 Power distribution calculation unit 52,62 MER margin calculation section 53,64 bit power decision unit 54 N a Bit Allocation Table 55,66 N a N b Parent-child table 65 N b Bit Allocation Table 63 Simple MER Margin Calculation Unit 101,101' Selection section 102 Coding rate selection unit 103 Table 104 Maximum transmission efficiency selection section

Claims

1. In a wireless communication device using a Singular Value Decomposition-Multiple-Input Multiple-Output (SVD-MIMO) system, the sum of the numbers of information bits of eigenmodes is defined as a total modulation bit number, the allocation of the total modulation bit number according to the combination of modulation schemes in the eigenmodes is defined as a bit allocation, the degree of quality of the eigenmodes 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 ratio of power allocated to the eigenmodes is defined as a power allocation ratio, a first bit / power allocation control unit that calculates the MER margin and the power allocation ratio for each of a plurality of bit allocations for a first total number of modulation bits based on the initial MER and the MER threshold; Among a plurality of bit allocations for a second total number of modulation bits different from the first total number of modulation bits, for a bit allocation having a predetermined parent-child relationship with respect to the bit allocation of the first total number of modulation bits, a value corresponding to a difference bit number of the bit allocation having the predetermined parent-child relationship is added or subtracted from the MER margin calculated for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship by the first bit / power allocation control unit to calculate an MER margin for the bit allocation in the second total number of modulation bits, and the power allocation ratio calculated for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship by the first bit / power allocation control unit is set to the power allocation ratio of the bit allocation in the second total number of modulation bits; a second bit / power allocation control unit that calculates the MER margin and the power allocation ratio based on the initial MER and the MER threshold for a bit allocation that does not have the predetermined parent-child relationship among the plurality of bit allocations; a number of bits of an eigenmode in the bit allocation of the first total number of modulation bits is a number of bits that is the same as that of the eigenmode in the bit allocation of the second total number of modulation bits; and a number of bits of an eigenmode in the bit allocation of the first total number of modulation bits is a number of bits that is the same as that of the eigenmode in the bit allocation of the second total number of modulation bits.

2. A wireless communication device that performs error correction coding on an information bit sequence to be transmitted at a predetermined coding rate, assigns eigenmodes, modulates the information bits of the eigenmodes using a predetermined combination of modulation methods, and allocates transmission power at a predetermined power allocation ratio when transmitting using an SVD-MIMO (Singular Value Decomposition-Multiple-Input Multiple-Output) method, and selects a total number of modulation bits that is the sum of the numbers of information bits of the eigenmodes, the coding rate, the bit allocation according to the combination of the modulation methods, and the power allocation ratio, 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, and the difference between the initial MER and the MER threshold is defined as an MER margin. a bit and power allocation unit that determines the bit allocation and the power allocation ratio when the MER margin after the power allocation of the eigenmode is equal and the MER margin is maximum for each of a plurality of different total modulation bit numbers; a selection unit that selects one total number of modulation bits from the plurality of different total numbers of modulation bits, and selects the coding rate, the bit allocation, and the power allocation ratio corresponding to the total number of modulation bits; The bit and power allocation unit For a first total number of modulation bits among the plurality of different total numbers of modulation bits, for each of a plurality of bit allocations, calculate the MER margin and the power allocation ratio based on the initial MER and the MER threshold; a first bit / power allocation control unit that determines a maximum MER margin among the MER margins corresponding to each of the plurality of bit allocations, and determines the bit allocation and the power allocation ratio corresponding to the maximum MER margin; For a second total number of modulation bits different from the first total number of modulation bits among the plurality of different total numbers of modulation bits, for a bit allocation having a predetermined parent-child relationship with respect to a bit allocation of the first total number of modulation bits among the plurality of bit allocations, a value corresponding to a difference bit number of the bit allocation having the predetermined parent-child relationship is added or subtracted from the MER margin calculated for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship by the first bit / power allocation control unit to calculate an MER margin of the bit allocation in the second total number of modulation bits, and the power allocation ratio calculated for the bit allocation of the first total number of modulation bits having the predetermined parent-child relationship by the first bit / power allocation control unit is set to the power allocation ratio of the bit allocation in the second total number of modulation bits; Calculating the MER margin and the power allocation ratio for a bit allocation having no predetermined parent-child relationship among the plurality of bit allocations based on the initial MER and the MER threshold; a second bit / power allocation control unit that determines a maximum MER margin among the MER margins corresponding to each of the plurality of bit allocations, and determines the bit allocation and the power allocation ratio corresponding to the maximum MER margin; a number of bits of an eigenmode in the bit allocation of the first total number of modulation bits is a number of bits that is the same as that of the eigenmode in the bit allocation of the second total number of modulation bits; and a number of bits of an eigenmode in the bit allocation of the first total number of modulation bits is a number of bits that is the same as that of the eigenmode in the bit allocation of the second total number of modulation bits.

3. 3. The wireless communication device according to claim 1, The second bit / power distribution control unit includes: The first total number of modulation bits is N a , the second total number of modulation bits is N b , N a >N b The MER margin calculated by the first bit / power allocation control unit for the bit allocation of the first total number of modulation bits is M a [dB], the MER margin of the bit allocation in the second total number of modulation bits is M b [dB], where the number of differential bits is d. For the bit allocation with the predetermined parent-child relationship, the formula: M b = M a + 3 × d, the MER margin M b Calculate Alternatively, the first total number of modulation bits is N b , the second total number of modulation bits is N a , N a >N b The MER margin calculated by the first bit / power allocation control unit for the bit allocation of the first total number of modulation bits is M b [dB], the MER margin of the bit allocation in the second total number of modulation bits is M a [dB], where the number of differential bits is d. For the bit allocation with the predetermined parent-child relationship, the formula: M a = M b -3×d gives the MER margin M a A wireless communication device comprising:

4. 3. The wireless communication device according to claim 1, a bit allocation of the first total number of modulation bits, a bit allocation of the second total number of modulation bits, and the differential bit number are defined in the specified parent-child relationship so as to satisfy the first condition, the second condition, and the third condition.

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