WO2015083475A1

WO2015083475A1 - Receiving device, receiving method and receiving program

Info

Publication number: WO2015083475A1
Application number: PCT/JP2014/079265
Authority: WO
Inventors: 加藤　勝也; 良太山田; 梢横枕; 宏道留場
Original assignee: シャープ株式会社
Priority date: 2013-12-06
Filing date: 2014-11-04
Publication date: 2015-06-11
Also published as: JP2017028335A

Abstract

Provided are an MIMO receiving device, a receiving method, and a receiving program that can achieve exceptional transmission properties with a low amount of computation and reduced circuit scale. The receiving device is characterized by the following: using as a start signal at least one base signal that is the sum of a channel value and the size of a real part or imaginary part of a modulation point; and generating the base signals not included in the start signal by bit shift to the start signal and addition and subtraction. The present invention is also characterized in that the start signal is the smallest base signal that is the sum of the channel value and the smallest value for the size of the real part or imaginary part of the modulation point.

Description

Reception device, reception method, and reception program

The present invention relates to a receiving device, a receiving method, and a receiving program.

In recent years, MIMO (Multiple Input Multiple Output) communication has attracted attention as a technique for realizing large-capacity high-speed information communication. Figure 10 is a schematic diagram showing an example of the MIMO communication, the transmitting device a1 is provided with a transmitting antenna a1-1 ~ _{a1-N T,} the receiving device b1 is equipped with a receiving antenna b1-1 ~ _{b1-N R} . N _T is the number of transmitting antennas, and N _R is the number of receiving antennas. In this MIMO communication, different information can be transmitted and received at the same time and the same frequency, and the information bit rate can be greatly increased.

The following non-patent document 1 describes a reception method in MIMO communication. MLD (Maximum Likelihood Detection) is described as a reception method with excellent transmission characteristics. MLD is a reception method for selecting a transmission candidate that minimizes a square norm with respect to a reception signal among possible transmission candidates.

However, the method of Non-Patent Document 1 has a problem that the number of multiplications and the circuit scale increase because it is necessary to multiply the transmission candidate and the channel value.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a MIMO receiving apparatus, receiving method, and receiving program capable of realizing excellent transmission characteristics with a low calculation amount and a low circuit scale. It is in.

In order to solve the above-described problems, the configuration of the receiving apparatus, receiving method, and receiving program according to the present invention is as follows.

(1) The reception device according to one aspect of the present invention uses at least one base signal, which is a product of a real part or an imaginary part of a modulation point, and a channel value as a start signal, and is not included in the start signal. The signal is generated by bit shift and addition / subtraction to the start signal.

(2) In the receiving apparatus of the present invention, the start signal is a minimum base signal that is a product of a minimum value of a real part or an imaginary part of a modulation point and a channel value.

(3) In the receiving apparatus of the present invention, the start signal further includes a signal 12 times the minimum base signal.

(4) In the receiving apparatus of the present invention, the start signal includes the minimum base signal, a signal three times the minimum base signal, a signal five times the minimum base signal, and seven times the minimum base signal. And at least one of a signal, a signal 9 times the minimum base signal, a signal 11 times the minimum base signal, a signal 13 times the minimum base signal, and a signal 15 times the minimum base signal. Features.

(5) In the receiving apparatus of the present invention, the start signal further includes at least one signal that is 16 times the base signal and not a power of two.

(6) The receiving apparatus of the present invention is characterized in that a replica signal that is a product of each modulation point and the channel value is generated using addition / subtraction to the base signal.

(7) In the receiving apparatus of the present invention, by using addition / subtraction to the base signal, a one-sided replica signal that is a product of the modulation point of two adjacent quadrants on the IQ plane and the channel value is generated, and the one-sided replica The replica signal not included in the one-side replica signal is generated by inverting the sign of the signal.

(8) In the receiving apparatus of the present invention, a signal that is 11 times the minimum base signal and a signal that is 13 times the minimum base signal are stored, and the start signal, the signal that is 11 times the minimum base signal, and the minimum base signal are stored. The base signal is obtained based on a signal that is 13 times the signal.

(9) In the reception method of the reception device according to the aspect of the present invention, at least one base signal that is a product of the real part or imaginary part of the modulation point and the channel value is used as a start signal, The base signal not included is generated by bit shift and addition / subtraction to the start signal.

(10) Further, a reception program according to an aspect of the present invention causes a computer to execute the reception method described above.

According to the present invention, in the MIMO communication, the receiving apparatus can realize good transmission characteristics with a low calculation amount and a low circuit scale.

It is the schematic which shows the structural example of the transmitter a1 which concerns on the 1st Embodiment of this invention. This is an example of 64QAM (Quadrature Amplitude Modulation). It is an example of the pilot symbol which transmission apparatus a1 which concerns on the 1st Embodiment of this invention transmits. It is the schematic which shows the structural example of the receiver b1 which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the receiver b1 which concerns on the 1st Embodiment of this invention. It is the schematic which shows the structural example of the receiver b2 which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the receiver b2 which concerns on the 2nd Embodiment of this invention. It is the schematic which shows the structural example of the receiver b3 which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of the receiver b3 which concerns on the 3rd Embodiment of this invention. It is the schematic which shows an example of a MIMO communication system.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the following embodiment, an example will be described in which a transmission apparatus performs data transmission using an OFDM (Orthogonal Frequency Division Multiplexing) scheme. However, in the following embodiments, other transmission schemes such as single carrier transmission, SC-FDMA (Single Carrier-Frequency Division Multiple Access), DFT-s-OFDM (Discrete Fourier Transform- A single carrier transmission scheme such as spread-OFDM (discrete Fourier transform spread OFDM) or a multicarrier transmission scheme such as MC-CDMA (Multiple Carrier-Code Division Multiple Access) may be used.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a schematic block diagram illustrating a configuration of the transmission device a1. In this figure, a transmission device a1 includes an S / P (Serial / Parallel) conversion unit a101, an encoding unit a102-v, a modulation unit a103-v, a layer mapping unit a104, a pilot generation unit a105, a precoding unit a106, an RE. A (Resource Element) mapping unit a107-k, an OFDM (Orthogonal Frequency Division Multiplexing) signal generation unit a108-k, and a transmission unit a109-k are configured. Here, v = 1, ···, a _{N C, k = 1, ···} , a _{N T.} N _C is the number of code words and represents the number to be encoded. The resource element is a physical resource that represents one subcarrier in one OFDM symbol and arranges modulation symbols and pilot symbols. FIG. 1 also shows the transmission antennas a1-k.

The S / P conversion unit a101 performs serial / parallel conversion on the input information bits and outputs the information bits to the encoding unit a102-v.

The encoding unit a102-v encodes the bits input from the S / P conversion unit a101 using an error correction code such as a convolutional code, a turbo code, or an LDPC (Low Density Parity Check) code. , Generate encoded bits. The encoding unit a102-v outputs the encoded bits to the modulation unit a103-v.

The modulation unit a103-v converts the encoded bits input from the encoding unit a102-v into BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), M- A modulation symbol is generated by modulation using a modulation method such as QAM (M-Quadrature Amplitude Modulation; M = 4, 16, 64, 256, 1024, 4096). However, QPSK and 4QAM are the same. The modulation unit a103-v outputs the generated modulation symbol to the layer mapping unit a104. Note that the modulation unit a103-v may have a function of rearranging and interleaving the generated modulation symbols.

In M-QAM, log (M) / 2 bits can be assigned to each of the real part and the imaginary part. Where log (x) represents the logarithm of x with 2 as the base. Hereinafter, only the real part will be considered. One bit of log (M) / 2 bits represents the sign of the real part. _Let this bit be b _sign . If the number of bits other than b _sign is N _base , N _base can be expressed by the following equation (1).

When the amplitude number is M _base , M _base can be expressed by the following equation (2).

When the amplitude is s _base (m), the following equation (3) is obtained. However, m = 0,..., M _base −1.

Assuming that the nth bit associated with the amplitude is b (n), b (n) and the amplitude number m can be associated as in the following equations (4) and (5). However, n = 0,..., N _base −1.

However, a symbol in which + is circled represents exclusive OR, and a superscript line represents logic negation. In the case of QPSK (4QAM), since N _base = 0, m = 0 is always set. Note that b ′ (0) to b ′ (N _base −1) are also binary representations of m. If the other bit assigned to the real part is 0, s _base (m) is the final real part signal. _{-S base} (m) is the final real part signal if the bit is a 1. The assignment of bits and signal points described so far is merely an example, and other assignments are also included in the present invention.

The layer mapping unit a104 allocates the modulation symbol input from the modulation unit a103-v to any one of 1,..., _NT streams, and outputs it to the precoding unit a106.

Pilot generation section a105 generates a pilot symbol for the receiving apparatus to perform channel estimation, and outputs the pilot symbol to precoding section a106.

The precoding unit a106 precodes the modulation symbol input from the layer mapping unit a104 and the pilot symbol input from the pilot generation unit a105. Specifically, a unitary matrix based on a codebook or a submatrix of a unitary matrix can be multiplied. Alternatively, STBC (Space Time Block Code), SFBC (Space Frequency Block Code), or the like may be used.

The RE mapping unit a107-k maps the modulation symbol and pilot symbol that have been precoded and input from the precoding unit a106, to resource elements. The RE mapping unit a107-k outputs the mapped symbol of the resource element to the OFDM signal generation unit a108-k.

The OFDM signal generation unit a108-k performs frequency time conversion on the symbol input from the RE mapping unit a107-k to generate a time domain signal. Specifically, IFFT (Inverse Fast Fourier Transform) can be used for frequency time conversion. The OFDM signal generation unit a108-k adds a CP (Cyclic Prefix) to the generated time domain signal to generate an OFDM signal. Here, CP is a part of the rear of the time domain signal obtained by frequency-time conversion, and the part of the signal is added in front of the signal of the time domain. Note that CP may be a partial copy of the front of the time domain signal, and the copy may be added after the time domain signal. Note that the CP may be a known sequence generated by a Golay code or the like. The OFDM signal generation unit a108-k outputs the generated OFDM signal to the transmission unit a109-k.

The transmission unit a109-k performs digital / analog conversion on the OFDM signal input from the OFDM signal generation unit a108-k, and shapes the converted analog signal. The transmission unit a109-k upconverts the waveform-shaped signal from the baseband to the radio frequency band, and transmits the signal from the transmission antenna a1-k to the reception device b1.

FIG. 2 shows a 64QAM modulation point arrangement. In 64QAM, since M _base = 4, there are four amplitudes 201-204. N _base (2 in 64QAM) bits allocated to 201 to 204 are expressed by the following equation (6).

Note that 205 to 208 are also described in Equation (6), and the bits assigned to b _sign are inverted bits of the bits assigned to 201 to 204.

Although the real part has been described above, the same applies to the imaginary part.

FIG. 3 shows an output example of the RE mapping unit a107-k. For example, when N _T = 8, resource element # 1 may be a pilot position of k = 1, 2, 5, 7 and resource element # 2 may be a pilot position of k = 3, 4, 6, 8 it can. The receiving device b1 can perform channel estimation using the received signals in these resource elements. The pilot symbols of each stream may be code-multiplexed, for example.

FIG. 4 is a schematic block diagram showing the configuration of the receiving device b1 according to the first embodiment of the present invention. In this figure, the receiving device b1 includes a receiving unit b101-r, a time frequency converting unit b102-r, a demapping unit b103-r, a channel estimating unit b104, a MIMO signal detecting unit b105, and a decoding unit b106. . Here, r = 1,..., N _R. FIG. 4 also shows the receiving antenna b1-r.

The reception unit b101-r receives the OFDM transmission signal transmitted by the transmission device a1 via the reception antenna b1-r. The receiving unit b101-r performs frequency conversion and analog-digital conversion on the received signal. The reception unit b101-r outputs the converted reception signal to the time frequency conversion unit b102-r.

The time frequency conversion unit b102-r removes the CP from the reception signal input from the reception unit b101-r. The time frequency conversion unit b102-r performs time frequency conversion on the signal from which the CP has been removed. Specifically, FFT (Fast Fourier Transform) can be used for time frequency conversion. The time-frequency conversion unit b102-r outputs the converted received signal in the frequency domain to the demapping unit b103-r.

The demapping unit b103-r separates the resource element to which the data is transmitted and the resource element to which the pilot symbol is transmitted from the frequency domain signal input from the time-frequency conversion unit b102-r. The demapping unit b103-r outputs the received signal of the resource element to which the data has been transmitted to the MIMO signal detection unit b105. The demapping unit b103-r outputs the received signal of the resource element to which the pilot symbol is transmitted to the channel estimation unit b104.

The channel estimation unit b104 performs channel estimation using the received signal of the resource element to which the pilot symbol input from the demapping unit b103-r is transmitted, and calculates a channel value. The channel estimation unit b104 outputs the calculated channel value to the MIMO signal detection unit b105. In general, the channel value is a complex number, but in the first embodiment, the channel value is divided into a real part and an imaginary part, and is output to the MIMO signal detection unit b105 as separate real numbers.

The MIMO signal detection unit b105 performs MIMO signal detection using MLD (Maximum Likelihood Detection), QRM (QR Decomposition and M-algorithm) -MLD, SD (Sphere Decoding), and the like. At this time, the MIMO signal detection unit b105 generates a minimum base signal that is a product of the channel value input from the channel estimation unit b104 and s _base (0) expressed by Expression (3). The MIMO signal detection unit b105 uses the minimum base signal as a start signal. The MIMO signal detection unit b105 uses a bit shift to the start signal and addition / subtraction for the base signal, which is the product of the channel value input from the channel estimation unit b104 and s _base (m) shown in Expression (3). Generate. The MIMO signal detection unit b105 calculates an LLR (Log Likelihood Ratio) of the transmission bits and outputs the LLR (Log Likelihood Ratio) to the decoding unit b106. This operation will be described later together with the operation principle.

Based on the LLR input from the MIMO signal detection unit b105, the decoding unit b106, for example, a maximum likelihood decoding method, maximum a posteriori probability (MAP), log-MAP, Max-log-MAP, SOVA ( Decoding processing is performed using Soft (Output (Viterbi Algorithm)).

<About the operating principle>
The operation principle of the first embodiment according to the present invention will be described below. First, the reception signal vector of size _{N R} of the reception signal of the resource element data input to the MIMO signal detection section b105 from demapping section b103-r was sent, aligned r = 1, · · ·, for _{N R} y is expressed by the following equation (7).

However, information about the position of the resource element is omitted. H is an N _R × N _T channel matrix, and the elements in the r-th row and k-th column are channel values from the transmission antenna a 1 -k to the reception antenna b 1 -r. Further, s is a transmission signal vector of size _NT in which transmission signals transmitted from the transmission antennas a1-k are arranged for k = 1,..., _NT . Further, n represents a noise size _{N R.}

Next, Expression (7) is expressed separately for the real part and the imaginary part. For a scalar or vector z, Re [z] is the real part of z and Im [z] is the imaginary part of z. Re [y] and Im sizes arranged [y] of the order 2N vectors of _R y 'is expressed by the following equation (8) to (11).

When MLD is used, LLRλ (b _{k, n} ) of _{the n-} _th transmission bit b _{k, n} of the k-th stream can be calculated as in the following equation (12).

Where σ ² is noise power. Equation (12), b _k, which means the minimum metric for fixed _n to 1, b _k, that is divided by the noise power subtraction between the minimum metric for fixed _n to 0. Note that the minimum value may not be obtained, and the number of bits to be searched may be reduced.

In Equation (12), since the amount of computation of the square Euclidean norm is enormous, QRM-MLD or SD can be used instead of MLD. However, it is necessary to calculate H's' many times, and there is still a problem that this calculation amount is large. In the present invention, the amount of computation for generating H's' is reduced.

First, a base signal vector y _{k, base} (m) represented by the following equation (13) is generated. _{However, m = 0, ···, M} base -1, k = 1, ···, a 2N _T.

Here, h ′ _k is the k-th column vector of H ′. Moreover, s _base (m) is the amplitude shown by Formula (3).

Using the equation (13), the metric calculated by the equation (12) can be expressed by the following equation (14).

Here, b _sign (k) represents b _sign of the k-th element of s ′, and m _k represents the amplitude number represented by Expression (4) in the k-th element of s ′. Therefore, the amount of calculation can be reduced by efficiently generating y _{k, base} (m). Hereinafter, for the sake of simplicity, only one element y _{k, base} (m) will be described. This base signal is expressed as y _base (m).

First, the minimum base signal y _base (0) is generated. The base signal y _base (m) for m = 1,..., M _base −1 can be realized by (2m + 1) times y _base (0). In the present invention, the minimum base signal y _base (0) is used as a start signal, and a base signal not included in the start signal is generated using bit shift and addition / subtraction to the start signal. If bit shift and addition / subtraction are used, multiplication can be prevented. m = 1,..., 7 can be generated by the following equations (15) to (21), for example. However, y _base (0) is omitted and indicated as y _base .

However, multiplication of 2 ^x is realized by x bit shift. This means that no multiplication is actually required. At this time, the bit sequence representing y _base (m) may be a fixed point or a floating point. In the case of a floating point, x is added to the exponent part. Note that up to 256 QAM where M _base = 8 can be covered in equations (15) to (21). Since y _base (5) and y _base (6) require two additions, circuit delay may be a problem. Therefore, these two may be calculated in advance and stored in a memory or the like. Alternatively, 12y _{i and base} may be generated in advance and included in the start signal, and generated as in the following equations (22) and (23).

In this way, the number of memories and the like can be reduced compared to storing both y _base (5) and y _base (6).

Next, m = 8,..., 15 can be generated by the following equations (24) to (31), for example.

It is possible to cover up to 1024 QAM where M _base = 16 in equations (24) to (31). Since y _base (13) and y _base (14) have a large number of additions, these two may be calculated in advance and stored in a memory or the like. Alternatively, 12y _base may be included in the start signal and generated as in the following equations (32) and (33).

Alternatively, y _base (1),..., Y _base (6) may be stored and included in the start signal, and generated as in the following equations (34) to (39).

In this way, the number of additions can be made 1, and the circuit scale can be reduced.

Next, m = 16,..., 23 can be generated by the following equations (40) to (47), for example.

Since y _base (21) and y _base (22) have a large number of additions, these two may be calculated in advance and stored in a memory or the like. Alternatively, 12y _base may be included in the start signal and generated as in the following equations (48) and (49).

Alternatively, y _base (1),..., Y _base (7) may be stored and included in the start signal, and generated as in the following equations (50) to (56).

Next, m = 24,..., 31 can be generated by the following equations (57) to (64), for example.

Here, 48y _base may be realized by calculating 2 ⁵ y _base +2 ⁴ y _base every time, or may be generated once and stored and included in the start signal. Up to 4096 QAM can be covered by the result of y _base (17),..., y _base (31).

Since y _base (29) and y _base (30) have a large number of additions, these two may be calculated in advance and stored in a memory or the like. Alternatively, 12y _base may be stored and included in the start signal, and generated as in the following equations (65) and (66).

Alternatively, y _base (1),..., Y _base (6) may be stored and included in the start signal, and generated as in the following equations (67) to (72).

Note that y _base (1),..., Y _base (7) is stored and included in the start signal, and a signal that is 16 times y _base (0) and not a power of 2 is stored in the start signal. By including, even multi-level modulation higher than 4096QAM can be realized by one addition.

<Operation of Receiving Device b1>
FIG. 5 is a flowchart showing the operation of the receiving apparatus according to this embodiment. The operation shown in this figure is processing after the demapping unit b103-r in FIG. 4 separates the received signal of the resource element to which data is transmitted from the received signal of the resource element to which the pilot symbol is transmitted. .

(Step S101) The channel estimation unit b104 performs channel estimation based on the received signal of the resource element to which the pilot symbol is transmitted. Then, it progresses to step S102.

(Step S102) The MIMO signal detection unit b105 generates a minimum base signal based on the channel value obtained in Step S101. Thereafter, the process proceeds to step S103.

(Step S103) The MIMO signal detection unit b105 generates a base signal based on the minimum base signal obtained in Step S102. Thereafter, the process proceeds to step S104.

(Step S104) The MIMO signal detection unit b105 calculates the LLR of the transmission bit based on the base signal obtained in step S103 and the received signal of the resource element to which the data is transmitted. Thereafter, the process proceeds to step S105.

(Step S105) The decoding unit b106 performs decoding using the LLR obtained in step S104. Thereafter, the receiving device b1 ends the operation.

Thus, according to the present embodiment, it is possible to reduce the amount of calculation and the circuit scale necessary for detecting the MIMO signal.

In the first embodiment, the case where the minimum base signal y _base is used as the start signal has been described. However, a power of 2 of y _base may be used as the start signal. Since the power of 2 can be expressed by a bit shift, the minimum base signal can be easily extracted from the power of 2 of the stored y _base . The same applies to the floating point, and it can be easily extracted by changing the value of the exponent part. _Thus, saving the exponentiation of 2 _{y base} _is regarded as saving the _{y base.} Further, the base signal y _base (m) that is not m = 0 may be used as the start signal.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. In the first embodiment, the reception device b1 uses the minimum base signal or the like as a start signal, generates a base signal using bit shift to the start signal, and addition / subtraction, and uses the base signal and the reception signal to transmit a transmission bit LLR. Was calculated. At that time, the received signal, the channel matrix, and the transmitted signal were calculated separately for the real part and the imaginary part. In the present embodiment, a method for calculating the LLR without dividing the real part and the imaginary part will be described.

Note that the transmission device according to the second embodiment of the present invention has the same configuration as the transmission device a1 according to the first embodiment, and thus the description thereof is omitted.

FIG. 6 is a schematic block diagram showing the configuration of the receiving device b2 according to the second embodiment of the present invention. When the receiving apparatus b2 (FIG. 6) according to the present embodiment is compared with the receiving apparatus b1 (FIG. 4) according to the first embodiment, the MIMO signal detecting unit b205 is different. However, the functions of other components (reception unit b101-r, time frequency conversion unit b102-r, demapping unit b103-r, channel estimation unit b104, decoding unit b106) are the same as those in the first embodiment. . A description of the same functions as those in the first embodiment is omitted.

The MIMO signal detection unit b205 first generates a base signal as in the first embodiment. Next, the MIMO signal detection unit b205 generates a replica signal that is the product of each modulation point and the channel value by addition / subtraction to the base signal. The MIMO signal detection unit b205 calculates the LLR of the transmission bit using the generated replica signal and the reception signal.

When the received signal is not divided into a real part and an imaginary part, the LLRλ (b _{k, n} ) of _{the nth} transmission bits b _{k, n} of the _k- th stream can be calculated as in the following equation (73).

Unlike equation (12), y, H, and s are complex numbers. The metric in the equation (73) can be expressed as the following equation (74).

h _k is the k-th column vector of H, and s _k is the k-th element of s. s _k is one of the modulation points. For example, when 64QAM is used, it is one of the 64 points in FIG. A method for efficiently calculating the replica signal h _k s _k will be described.

Also in the second embodiment, the base signal y _{k, base} (m) is calculated as in the following equation (15) as in the first embodiment. However, m = 0,..., M _base .

Unlike the first embodiment, the channel value multiplied by s _base (m) is a complex number. In this way, the replica signal h _k s _k can be calculated by the following equation (76).

j is an imaginary unit, b _{i, sign} (k) is the sign bit b _sign of the real part of the k-th stream, _mi _{, k} is the amplitude number of the real part of the k-th stream, and b _{q, sign} (k) is the k-th The sign bits b _sign , m _{q, k} of the imaginary part of the stream represent the amplitude number of the imaginary part of the kth stream. The amplitude number is expressed by equation (4). Since the multiplication of the imaginary number can be realized by the replacement of the real part and the imaginary part and the sign inversion, no multiplication actually occurs. Therefore, a replica signal can be generated by addition / subtraction to the base signal. The LLR can be calculated by calculating the metric of Expression (74) using Expression (76).

<Operation of Receiving Device b2>
FIG. 7 is a flowchart showing the operation of the receiving apparatus according to this embodiment. The operation shown in this figure is processing after the demapping unit b103-r in FIG. 6 separates the received signal of the resource element to which data is transmitted from the received signal of the resource element to which the pilot symbol is transmitted. .

(Step S201) The channel estimation unit b104 performs channel estimation based on the received signal of the resource element to which the pilot symbol is transmitted. Thereafter, the process proceeds to step S202.

(Step S202) The MIMO signal detection unit b205 generates a minimum base signal based on the channel value obtained in Step S201. Then, it progresses to step S203.

(Step S203) The MIMO signal detection unit b205 generates a base signal based on the minimum base signal obtained in Step S202. Thereafter, the process proceeds to step S204.

(Step S204) The MIMO signal detection unit b205 generates a replica signal based on the base signal obtained in step S203. Thereafter, the process proceeds to step S205.

(Step S205) The MIMO signal detection unit b205 calculates the LLR of the transmission bit based on the replica signal obtained in step S204 and the reception signal of the resource element to which the data is transmitted. Thereafter, the process proceeds to step S206.

(Step S206) The decoding unit b106 performs decoding using the LLR obtained in step S205. Thereafter, the receiving device b2 ends the operation.

Thus, according to the present embodiment, a replica signal is generated by addition / subtraction to the base signal, and an LLR is calculated using the replica signal. As a result, the amount of calculation and the circuit scale can be reduced.

(Third embodiment)
Hereinafter, the third embodiment of the present invention will be described in detail with reference to the drawings. In the second embodiment, the receiving device b2 generates a replica signal by addition / subtraction to the base signal. In the third embodiment, a one-sided replica signal that is the product of a modulation point in the first and fourth quadrants of the IQ plane and a channel value is generated, and the remaining replica signal is obtained by sign inversion to the one-sided replica signal. explain.

Note that the transmission apparatus according to the third embodiment of the present invention has the same configuration as the transmission apparatus a1 according to the first embodiment, and thus the description thereof is omitted.

FIG. 8 is a schematic block diagram showing the configuration of the receiving device b3 according to the third embodiment of the present invention. When the receiving apparatus b3 (FIG. 8) according to the present embodiment is compared with the receiving apparatus b1 (FIG. 4) according to the first embodiment, the MIMO signal detecting unit b305 is different. However, the functions of other components (reception unit b101-r, time frequency conversion unit b102-r, demapping unit b103-r, channel estimation unit b104, decoding unit b106) are the same as those in the first embodiment. . A description of the same functions as those in the first embodiment is omitted.

The MIMO signal detection unit b305 generates a one-sided replica signal that is the product of the modulation point in the first and fourth quadrants of the IQ plane and the channel value. The one-side replica signal can be calculated by addition / subtraction to the base signal. Further, the MIMO signal detection unit b305 generates a replica signal not included in the one-side replica signal by sign inversion to the one-side replica. The MIMO signal detection unit b305 calculates the LLR of the transmission bit using the replica signal.

<About the operation of the receiving device b3>
FIG. 9 is a flowchart showing the operation of the receiving apparatus according to this embodiment. The operation shown in this figure is processing after the demapping unit b103-r in FIG. 8 separates the received signal of the resource element to which data is transmitted from the received signal of the resource element to which the pilot symbol is transmitted. .

(Step S301) The channel estimation unit b104 performs channel estimation based on the received signal of the resource element to which the pilot symbol is transmitted. Thereafter, the process proceeds to step S302.

(Step S302) The MIMO signal detection unit b305 generates a one-sided replica signal based on the channel value obtained in Step S301. Thereafter, the process proceeds to step S303.

(Step S303) The MIMO signal detection unit b305 generates a replica signal based on the one-sided replica signal obtained in Step S302. Thereafter, the process proceeds to step S304.

(Step S304) The MIMO signal detection unit b305 calculates the LLR of the transmission bit based on the replica signal obtained in step S303 and the received signal of the resource element to which the data is transmitted. Thereafter, the process proceeds to step S305.

(Step S305) The decoding unit b106 performs decoding using the LLR obtained in step S304. Thereafter, the receiving device b3 ends the operation.

As described above, according to the present embodiment, a replica signal that is not a one-side replica signal can be generated by sign inversion using the one-side replica signal, the required number of additions is reduced, and the amount of computation and the circuit scale are reduced. be able to.

In the first to third embodiments, the method for generating a replica signal has been described for the case where MLD is used. However, the method is applicable to all methods that use the product of a transmission candidate and a channel value, even if not MLD. Can do. Further, what is multiplied by the transmission candidate may not be a channel value.

The program that operates in the transmission device a1 and the reception devices b1, b2, and b3 related to the present invention is a program that controls the CPU or the like (a program that causes a computer to function) so as to realize the functions of the above-described embodiments related to the present invention. is there. Information handled by these devices is temporarily stored in the RAM at the time of processing, then stored in various ROMs and HDDs, read out by the CPU as necessary, and corrected and written. As a recording medium for storing the program, a semiconductor medium (for example, ROM, nonvolatile memory card, etc.), an optical recording medium (for example, DVD, MO, MD, CD, BD, etc.), a magnetic recording medium (for example, magnetic tape, Any of a flexible disk etc. may be sufficient. In addition, by executing the loaded program, not only the functions of the above-described embodiment are realized, but also based on the instructions of the program, the processing is performed in cooperation with the operating system or other application programs. The functions of the invention may be realized.

Also, when distributing to the market, the program can be stored and distributed on a portable recording medium, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer is also included in the present invention. In the above-described embodiment, a part or all of the transmission device a1 and the reception devices b1, b2, and b3 described with reference to the drawings may be realized as an LSI that is typically an integrated circuit. Each functional block of the transmission device a1, the reception devices b1, b2, and b3 may be individually formed into chips, or a part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention. The present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention. It is. Moreover, it is the element described in each said embodiment, and the structure which substituted the element which has the same effect is also contained.

Note that the present invention is not limited to the above-described embodiment. The terminal device of the present invention is not limited to application to a mobile station device, but is a stationary or non-movable electronic device installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment Needless to say, it can be applied to air conditioning equipment, office equipment, vending machines, and other daily life equipment.

The present invention is suitable for use in a receiving device, a receiving method, and a receiving program.

This international application claims priority based on Japanese Patent Application No. 2013-252667 filed on Dec. 6, 2013. The entire contents of Japanese Patent Application No. 2013-252667 are hereby incorporated by reference. Included in international applications.

a1 Transmitting devices a1-1 to a1- _{NT T} transmitting antennas b1, b2, and b3 Receiving devices b1-1 to b1-N _R receiving antennas a101 S / P conversion units a102-1 to a102-N _C encoding unit a103-1 A103-N _C modulation unit a104 layer mapping unit a105 pilot generation unit a106 precoding units a107-1 to a107-N _T RE mapping units a108-1 to a108-N _T OFDM signal generation units a109-1 to a109-N _T Transmitters 201 to 208 Real part of modulation points b101-1 to b101-NR _R receivers b102-1 to b102-NR _R time frequency converters b103-1 to b103-NR _R demapping unit b104 Channel estimation units b105 and b205 , B305 MIMO signal detection unit b106 decoding unit

Claims

At least one base signal, which is the product of the real part or imaginary part of the modulation point and the channel value, is used as a start signal,
The base signal not included in the start signal is generated by bit shift and addition / subtraction to the start signal.
A receiving apparatus.
The start signal is a minimum base signal that is a product of the minimum value of the real part or imaginary part of the modulation point and the channel value.
The receiving apparatus according to claim 1.
The start signal further includes a signal 12 times the minimum base signal,
The receiving device according to claim 2.
The start signal includes the minimum base signal, a signal three times the minimum base signal, a signal five times the minimum base signal, a signal seven times the minimum base signal, and a signal nine times the minimum base signal. At least one of a signal, a signal 11 times the minimum base signal, a signal 13 times the minimum base signal, and a signal 15 times the minimum base signal,
The receiving device according to claim 2.
The start signal further includes at least one signal that is 16 times the base signal and not a power of 2;
The receiving apparatus according to claim 4.
Generating a replica signal that is the product of each modulation point and the channel value using addition and subtraction to the base signal;
The receiving apparatus according to claim 1, wherein the receiving apparatus is a receiving apparatus.
Using addition / subtraction to the base signal, a one-sided replica signal that is the product of the modulation point of two adjacent quadrants on the IQ plane and the channel value is generated,
The replica signal not included in the one-side replica signal is generated by inverting the sign of the one-side replica signal,
The receiving apparatus according to claim 6.
A signal that is 11 times the minimum base signal and a signal that is 13 times the minimum base signal are stored, and based on the start signal, a signal that is 11 times the minimum base signal, and a signal that is 13 times the minimum base signal. The receiving apparatus according to claim 2, wherein the base signal is obtained.
At least one base signal, which is the product of the real part or imaginary part of the modulation point and the channel value, is used as a start signal,
The base signal not included in the start signal is generated by bit shift and addition / subtraction to the start signal.
And a receiving method.
A reception program for causing a computer to execute the reception method according to claim 9.