JP2005217506A - Wireless communication apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus capable of realizing wireless communication employing the MIMO technology with a realistic circuit scale and computing complexity while realizing excellent characteristics. <P>SOLUTION: The wireless communication apparatus comprises: reception antennas 1-1 to 1-2, wireless sections 2-1 to 2-2, a channel estimate circuit 3, a received signal management section 4; a transfer function matrix management circuit 5; a replica signal generating circuit 6; a transmission signal generating circuit 7; Euclidean distance approximation circuits 8a to 8c; a selection circuit 9; and a data composite circuit 10, and the Euclidean distance approximation circuits 8a to 8c carry out approximation of an Euclidian distance by using only adder circuits. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention obtains a replica of an estimated reception signal for a transmission signal based on a transfer function between a transmission antenna and a reception antenna in a wireless system that performs communication via a wireless line, and is closest to the actual reception signal, that is, The distance between the signal points used when extracting the replica when performing the MLD (Maximum Likelihood Detection) method that performs the demodulation process by extracting the replica that minimizes the Euclidean distance and using this replica as the transmission signal Related to technology.
In particular, the present invention uses the same frequency channel, transmits independent data from a plurality of different transmission antennas, receives signals using a plurality of reception antennas, and based on a transfer function matrix between the transmission and reception antennas. The present invention relates to a receiving technique for realizing good transmission characteristics while suppressing a circuit scale in a high-speed wireless access system that realizes wireless communication by demodulating data on the receiving station side.
In addition, the present invention is particularly used for increasing the transmission speed of a high-speed wireless access system using the 2.4 GHz band or the 5 GHz band.

In recent years, the IEEE802.11g standard, the IEEE802.11a standard, etc. have been remarkably spread as high-speed wireless access systems using the 2.4 GHz band or the 5 GHz band.
In these systems, a maximum transmission rate of 54 Mbps is realized. However, with the spread of wireless LAN, further increase in transmission rate is required.
For this purpose, MIMO (Multiple-Input Multiple-Output) technology is promising. This MIMO technology is such that different independent signals are transmitted on the same channel from a plurality of transmitting antennas on the transmitting station side, and signals are received using the same plurality of antennas on the receiving station side, between each transmitting antenna / receiving antenna. The transfer function matrix is obtained, the independent signal transmitted from each antenna on the transmitting station side is estimated using this matrix, and the data in the transmitted signal is reproduced.

Here, in the MIMO wireless transmission / reception system, a case is considered where N signals are transmitted using N transmitting antennas and the transmitted N signals are received using M antennas.
First, there are N × M transmission paths between the antennas of the transmitting station and the receiving station, and the transfer function when transmitted from the j-th transmitting antenna and received by the i-th receiving antenna is h _{j, i.} A matrix of M rows and N columns having this as the (i, j) th component is denoted as H. Furthermore, the transmission signal from the i transmit antenna and _{t i (t 1, t 2} , t 3, ···, t N) column vector whose components Tx, a reception signal at the i-th receive antenna r and _{i (r 1, r 2,} r 3, ···, r M) column vector whose components Rx, the thermal noise of the i receiving antenna and _{n i (n 1, n 2} , n 3, · ... A column vector whose component is n _M ) is expressed as n.
In this case, the following relationship (1) is established.
Rx = H × Tx + n (1)

Therefore, there is a need for a technique for estimating the transmission signal Tx based on the signal Rx received on the receiving station side. As the most basic one of the MIMO technology, there is a method generally called a ZF (Zero Forcing) method. (See Non-Patent Document 1)
Here, an inverse matrix H ⁻¹ of the transfer function matrix is obtained for (Equation 1) above, and a process of multiplying it from the left of both sides of the equation is performed. As a result, the following equation (2) is obtained.
H ⁻¹ × Rx = Tx + H ⁻¹ × n (2)
That is, when the signals received by the respective receiving antennas are combined and processing for removing interference caused by signals from other than the desired transmitting antenna is performed, a minute thermal noise H ⁻¹ × n is added to the actual transmitted signal vector Tx. A signal point is obtained.
Here, when a signal subjected to multilevel modulation such as BPSK, QPSK, 16QAM, or 64QAM is used as a transmission signal, possible signal points (signals obtained by mapping a digital signal by multilevel modulation) are discontinuous. It is.

Therefore, a hard decision process for searching for a signal point with the shortest Euclidean distance on the transmission constellation is performed on H ⁻¹ × Rx, and a true transmission signal is estimated.
In the above ZF method, when the thermal noise term H ⁻¹ × n is sufficiently small and the components for each transmitting antenna can be assumed to be uniform among the transmitting antennas, good signal reproduction characteristics are expected. it can.
However, in general, this assumption does not hold, and the expected value of the absolute value of the thermal noise H ⁻¹ × n for each reception antenna is different for a certain transfer function matrix (transmission characteristics between the transmission antennas are different).
Furthermore, if the transfer function matrix H is a matrix that does not have an inverse matrix (or the determinant of the inverse matrix is very small), the estimation of the transmission signal becomes very unstable.
In the situation as described above, the reception characteristics of the receiving antenna at the receiving station may be significantly degraded.
As a method for solving such problems, a method having the most excellent characteristics is a method called an MLD method. (See Non-Patent Document 2)

In this MLD method, first, when the modulation method of a transmission signal from each antenna on the transmission side is determined, the number of signal points that can be taken by a signal transmitted from one antenna (hereinafter referred to as N _max ) is determined. There are N _max ^N types of variations of signal vectors transmitted by the entire N antennas.
Also, in the MLD method, the prediction of the received signal when the signal is transmitted is performed for all candidates (total of N _{max and} ^N types) that can be taken as the transmission signal, and the most actual among them Is selected as the highest signal point of the estimation system. That is, if a transmission signal candidate Tx arbitrarily selected, for example, the kth transmission signal candidate is represented by Tx ^[k] , the Euclidean distance E defined by the following equation (3) is minimized. Select a value for k.
E = (Rx−H × Tx ^[k] ) ^H × (Rx−H × Tx ^[k] ) (3)

Note that ^{MH with} respect to the matrix M indicates a matrix that is Hermitian conjugate of the matrix M. With the above processing, the MLD method can perform stable reception processing for any matrix H, and reception characteristics are greatly improved compared to the ZF method.
Here, FIG. 6 shows a configuration of a transmission section of a transmission station to which the MIMO technique in the prior art is applied. In this figure, the transmission unit of the transmission station includes a data division circuit 101, a preamble assignment circuit 102-1, modulation circuits 103-1 to 103-2, radio units 104-1 to 104-2, and transmission antennas 105-1 to 105. -2.
As an example, a case where the transmitting station transmits two systems of data using two transmitting antennas will be described as an example.

When the data to be transmitted is input from the external circuit, the data dividing circuit 101 separates this data into two systems and outputs each to different preamble circuits.
For example, the data division circuit 101 outputs the first system data to the preamble provision circuit 102-1. As a result, the preamble circuit 102-1 is input to the modulation circuit 103-1 (Chl) with the preamble signal applied.
In the modulation circuit 103-1, predetermined modulation (multilevel modulation such as BPSK, QPSK, 16QAM, 64QAM, etc.) is performed on the data to which the input preamble signal is added, and the modulated transmission signal is wirelessly transmitted. Output to unit 104-1.

The radio unit 104-1 converts the transmission signal into a radio frequency, and transmits the radio signal to the reception station via the transmission antenna 105-1 (radiated as a radio wave).
Similarly to the “Ch1” system described above, the second system data output from the data dividing circuit 101 is converted into a preamble assigning circuit 102-2, a modulation circuit 103-2 (Ch2), a radio unit 104-2, and It is processed by the radio unit 104-2 and transmitted from the antenna 105-2. Thereby, the data to be transmitted divided by the data dividing circuit 101 is individually transmitted from different antennas.

Next, FIG. 7 shows a configuration of a receiving unit of a receiving station using the MLD method in the prior art.
The receiving unit of the receiving station includes receiving antennas 111-1 to 111-2, radio units 112-1 to 112-2, a channel estimation circuit 113, a received signal management unit 114, a transfer function matrix management circuit 115, and a replica signal generation circuit 116. , A transmission signal generation circuit 117, Euclidean distance calculation circuits 118 a to 118 c, a selection circuit 119, and a data synthesis circuit 120.
Further, the first receiving antenna 111-1 to the second receiving antenna 111-2 receive the received signals individually.

The channel estimation circuit 113 inputs the signal transmitted from the transmission unit via the radio units 112-1 to 112-2.
Then, the channel estimation circuit 113 acquires a transfer function between each of the transmission antennas 105-1 to 105-2 and the reception antennas 111-1 to 111-2 from the reception status of a predetermined preamble signal given on the transmission side. (Pilot data in the preamble signal is determined in advance by both the transmission and reception units, and a transfer function is obtained based on the reception status of this pilot data).
The channel estimation circuit 113 outputs the acquired information h _{j, i} of each transfer function to the transfer function matrix management circuit 115 and outputs a data signal subsequent to the preamble signal to the reception signal management circuit 114 one symbol at a time. .
Here, the transfer function matrix management circuit 115 manages _{hi, j} input from the channel estimation circuit 113 as the transfer function matrix H.

Then, the reception signal management circuit 114 temporarily converts the data signal input in symbol units into a reception signal vector Rx having the reception signals (r ₁ , r ₂ ) of the reception antennas 111-1 and 111-2 as components. It is managed by the storage unit.
On the other hand, the transmission signal generation circuit 117 uses N _max types of transmission signal candidates {Tx [k]} (1 ≦ k ≦) as signal patterns of all data signals that can be output from the transmission antennas 105-1 to 105-2. N _max ^N ).
The replica signal generation circuit 116 multiplies the transmission signal candidate Tx [k] input from the transmission signal generation circuit 117 by the transfer function matrix H managed by the transfer function matrix management circuit 115 to obtain a product H × Tx. [k] is obtained, and a plurality of obtained replica signal vectors are respectively input to the Euclidean distance arithmetic circuits 118a to 118c.

Similarly, the reception signal management circuit 114 outputs the managed reception signal vector Rx to the Euclidean distance calculation circuits 118a to 118c.
In the Euclidean distance calculation circuits 118a to 118c, the difference between the replica signal vector and the received signal vector is calculated, and the sum of squares of the absolute values of the components of the difference vector is obtained. (Euclidean distance itself). The above Euclidean distance calculation processing is performed for all the values of k (1 ≦ k ≦ N _max ^N , total N _max ^N ).
The selection circuit 119 selects a signal having the shortest Euclidean distance (or its square value) among them, and determines that the transmission signal has the highest estimation accuracy.
These data are continuously processed in time series over a plurality of symbols, but after receiving a series of data, the data synthesis circuit 120 synthesizes the symbols and reconstructs them as data.

FIG. 8 shows a configuration of the Euclidean distance calculation circuit (118a to 118c) in the prior art. Here, as an example of the configuration, the case of Euclidean distance calculation of a two-dimensional vector having a complex number component will be described.
In this figure, Euclidean distance calculation circuits (118a to 118c) are first component extraction circuits 130a to 130b, second component extraction circuits 131a to 131b, addition circuits 132a to 130e, and real part extraction circuits 133a to 133b are 134a to 134b includes imaginary part extraction circuits 134a to 134b and integration circuits 135a to 135d.
Vectors (x ₁ , y ₁ ) having complex number components are input from the reception signal management circuit 114 and the replica generation circuit 116 to the first component extraction circuit 130a and the second component extraction circuit 131a, respectively.

The first component extraction circuit 130a outputs from the vector received as input by extracting only x ₁ and x component, the second component extraction circuit 131a is to extract only y ₁ is a y component input output.
Similarly, the vector (x2, y2) are are inputted to the first component extraction circuit 130b and a second component extraction circuit 131b, only x ₂ of the x-component in the first component extraction circuit 130b, the second component extraction circuit 131b Then, only y2 of the y component is extracted and output.
Adder circuit 132a is the _{x 1} and the sign inverted _{x 2} plus (i.e. subtract _{x 2} from _{x 1),} Similarly, the adder circuit 132b performs the addition of _{y 1} and the sign inverted _{y 2.}
The input vector signals are separated into a real part and an imaginary part by the real part extraction circuits 133a and 133b and the imaginary part extraction circuits 134a and 134b.
Further, the respective signals are squared by the integrating circuits 135a to 135d, added by the adders 132c to 132e, and output.

Here, the so-called Euclidean distance often refers to the square root of the output result, but the selection circuit 119 in FIG. 7 performs a process of searching for a candidate with a short Euclidean distance, so that the exact square root is taken. There is no difference in the results whether the Euclidean distance is used or the square value of the Euclidean distance is used.
S. Kurosaki et. Al., “A SDM-COFDM Scheme Employing a Simple Feed-Forward Inter-Channel Interference Canceller for MIMO Based Broadband Wireless LANs”, IEICE TRANS. COMMUN, Vol.E86 B. No.l, January 2003 A.van Zelst et.al., “Space Division Multiplexing (SDM) for OFDM Systems”, Proc, VTC2000 Spring, Vol. 2, pp.1070 -1074

The biggest problem in using this MLD method in the MIMO technology is the size of the circuit for realizing the function.
In other words, since the calculation process for _obtaining the Euclidean distance must be performed N _max ^N times, even if the circuit scale of a single Euclidean distance calculation circuit is small, the overall circuit scale becomes enormous. is there.
For example, when 64QAM is used as the modulation method, N _max = 64. Using this example, the number of Euclidean distance calculations is 642 (= 4096) when N = 2, 64 ³ (= 26214464) when N = 3, and 64 ⁴ (= 1677726) when N = 4. Diversify exponentially with times.

When the above-described functional configuration is realized as a circuit, there is a method in which serial execution is performed over a plurality of times in addition to parallel processing as in processing S118a to S118c in FIG.
However, parallel processing is essential in order to suppress processing delay, and therefore a circuit scale proportional to the number of Euclidean arithmetic processing is required. If the circuit scale increases explosively in proportion to N in this way, mounting on LSI becomes very difficult.
In particular, the integration circuits 135a to 135d in FIG. 8 are larger in circuit scale than the addition circuits 132a to 132e, and are about 20 times larger.
Therefore, an object of the present invention is to provide a wireless communication apparatus that can be realized with a realistic circuit scale and calculation amount while realizing good characteristics when performing wireless communication using MIMO technology. is there.

In order to solve the above-described problem, a wireless communication apparatus of the present invention includes a transmitting station and a receiving station that perform communication via a wireless line, and the receiving station includes means for receiving a signal transmitted by the transmitting station; , Means for obtaining a transfer function H of a transmission path between the transmitting station and the receiving station, and N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N) that the transmitting station may transmit means for performing an operation of H × Tx (k) on an arbitrary k-th transmission signal Tx (k) in _tx : k and N _tx are integers), and in a series of received signal sequences Means for calculating Rx−H × Tx (k) for arbitrary k, and means for performing calculation Re [z] for obtaining the real part of complex number z when the received signal of the symbol is Rx Means for performing the operation Im [z] for obtaining the imaginary part of the complex number z, means for performing the operation Abs [z] for obtaining the absolute value of the complex number z, and x ₀ (k) = Means for obtaining x ₀ (k) as Abs [Re [Rx−H × Tx (k)]] and y as y ₀ (k) = Abs [Im [Re [Rx−H × Tx (k)]] _The means for obtaining ₀ (k), the means for obtaining F ₀ (k) = x ₀ (k) + y ₀ (k), and the value of F 0 (k) is the smallest among all or some k And a means for reproducing received data using the selected Tx (k) as a transmission signal for each symbol.

The wireless communication apparatus of the present invention includes a transmitting station and a receiving station that perform communication via a wireless line, and the receiving station receives a signal transmitted by the transmitting station, and between the transmitting station and the receiving station. Means for obtaining a transfer function H of the transmission path of the transmission line, and N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit ), A means for performing an operation of H × Tx (k) for an arbitrary k, and a received signal of a symbol in a series of received signal sequences , Rx for any k, means for performing the operation Rx−H × Tx (k), means for performing the operation Re [z] for obtaining the real part of the complex number z, and the complex number z A means for performing an operation Im [z] for obtaining an imaginary part of the input and an operation for obtaining an absolute value of a real part Re [z] of the complex number z and an absolute value of the real part Im [z] of the complex number Abs [R means for performing e [z]] and operation Abs [Im [z]], means for performing operation Max [rl, r2] for selecting the larger absolute value of positive real numbers r1 and r2, and positive Means for performing the operation Min [rl, r2] for selecting the smaller absolute value of the real numbers r1 and r2 (these means are magnitude judgment circuits), x ₁ (k) = Max [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]] means for obtaining x ₁ (k), y ₁ (k) = Min [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]], means for obtaining y ₁ (k), and F ₁ (k) = x ₁ (k) −y ₁ ( k) + √2 × y ₁ (k), means for selecting k that minimizes the value of F ₁ (k) among all or part of k, and selected Tx (k And a means for reproducing the received data as a transmission signal for each symbol.

The wireless communication apparatus of the present invention includes a transmitting station and a receiving station that perform communication via a wireless line, and the receiving station receives a signal transmitted by the transmitting station, and between the transmitting station and the receiving station. Means for obtaining a transfer function H of the transmission path of the transmission line, and N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit ) For any k-th transmission signal Tx (k) in (), and Rx is a reception signal of a symbol in a series of reception signal sequences. In this case, for any k, means for performing Rx−H × Tx (k) calculation, means for performing the calculation Re [z] for obtaining the real part of the complex number z, and obtaining the imaginary part of the complex number z Means for performing the operation Im [z], means for performing the operation Abs [z] for obtaining the absolute value of the complex number z, and x ₀ (k) = Abs [Re [Rx−H × Tx (k)]] x ₀ means for obtaining a _{(k), y 0 (k} ) = Abs [Im [Rx-H × Tx (k)]] means for obtaining y _{0 (k)} is a, n ≧ 0 becomes an arbitrary integer n respect, the _{x n + 1 (k) =} Cos (π / 2 n + 1) × x n (k) + Sin (π / 2 n + 1) × yn (k), (x n (k), y n (k)) X _{n + 1} (k) and an arbitrary integer n satisfying n ≧ 0, y _{n + 1} (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n (k) + Cos (π / _{^{2 n + 1) × y n}} (k)] as the _{(x n} (k), means for obtaining y n _(k)) from the y _{n + 1 (k),} to m ≧ 0 becomes a predetermined integer m, are sequentially determined and _{(x m (k), y} m, (k)) from _{F m (k) = x m} (k) + y m (k) × {(1-Cos (π / 2 m + 1)) / Sin (π / 2 ^{m + 1)} means for obtaining F _{m (k)} ^as}, means for selecting a k value of F _{m (k)} is the smallest of all or part of k, Tx for the selected k ( k) received data as a transmission signal for each symbol Characterized by comprising a means for reproducing.

A radio communication apparatus according to the present invention is a radio communication system including a transmission station having one or more transmission antennas and a reception station having M (M> 1: integer) reception antenna groups. The transmitting station includes means for transmitting a signal to which a known pattern signal is added from one of the transmitting antennas, and the receiving station individually transmits a radio signal using the M receiving antenna groups. Means for receiving, means for obtaining a transfer function h _i between the transmitting antenna and the i-th antenna of the group of receiving antennas using a known signal pattern given to the received signal as a reference signal, and the transmission N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the station may transmit include the k th transmission signal Tx (k). On the other hand, a transfer function vector having the transfer function hi as the i-th component. Means for performing a calculation to obtain a product with Toru H, that is, Tx (k) × H, and an arbitrary reception having a signal point of a certain symbol in a series of reception signal sequences in each antenna of the reception antenna group as an element Means for performing an operation of Rx−Tx (k) × H on the signal vector Rx, and when the i-th component of an arbitrary column vector V is expressed as [V] _i , [Rx− Tx (k) × H] means for performing the operation _i , means for performing the operation Re [z] for obtaining the real part of the complex number z, and means for performing the operation Im [z] for obtaining the imaginary part of the complex number z And a means for performing the calculation Abs [zl for obtaining the absolute value of the complex number z and x ₀ ^[i] (k) = Abs [Re [[Rx−Tx for any integer H with 1 ≦ i ≦ M (k) × H] _i ]] as a means for obtaining x ₀ ^[i] (k), y ₀ ^[i] (k) = Abs [Im [[Rx−Tx (k) × H] _i ]] means for obtaining a _y ^{0 [i]} (k) as, Against ≧ 0 becomes an arbitrary integer ^{_{n, x n + 1 [i}} ] (k) = Cos (π / 2 n + 1) × x n [i] (k) + Sin (π / 2 n + 1) × y n [i] ( k) as a means for obtaining x _{n + 1} ^[i] (k) from (x _n ^[i] (k), y _n ^[i] (k)), and for any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^[i] (k)] (x _n ^{[ i]} (k), y _n ^[i] (k)) to obtain y _{n + 1} ^[i] (k), and for a predetermined integer m with m ≧ 0, (x _m ^[i] (k) , y _m ^[i] (k)), F _m ^[i] (k) = x _m ^[i] (k) + y _m ^[i] (k) × {(1-Cos (π / 2 ^{m + 1} ) / Sin means for obtaining F _m ^[i] (k) as (π / 2 ^{m + 1} )} and means for obtaining the total TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M. When the TF m _(k) is the smallest among all or part of the k Means for selecting comprising k, characterized in that a means for reproducing the received data transmission signals Tx for the selected k and (k) as a transmission signal for each symbol.

The wireless communication apparatus according to the present invention includes a transmission station including N (N> 1: integer) or more first antenna groups and a reception station including M (M> 1: integer) second antenna groups. In the wireless communication system constituted by a station, the transmitting station provides means for dividing user data into N systems, and assigns a signal of an individual known pattern to the data divided into the N systems to provide N systems. Means for generating the first signal sequence, and means for simultaneously superimposing and transmitting the first signal sequence at the same frequency using the N first antenna groups, the receiving station comprising: , A means for individually receiving radio signals using the M second antenna groups, and a jth antenna in the first antenna group using a known signal pattern given to the received signals as a reference signal And the i-th antenna in the second antenna group. Means for obtaining the number h _{i, j} and N _tx types of transmission signal vectors {Tx (k)} that the transmitting station may transmit (1 ≦ k ≦ N _tx : k and N _tx are integers) The product of the transfer function matrix H having the transfer function h _{i, j} as the (i, j) component, that is, H × Tx (k) is obtained for the kth transmission signal vector Tx (k) Rx−H × with respect to an arbitrary k with respect to a reception signal vector Rx having elements as elements of a symbol in a series of reception signal sequences in each antenna of the second antenna group. Means for performing the operation of Tx (k) and the i-th component of an arbitrary column vector V are expressed as [V] _i , the operation of [Rx−H × Tx (k)] _i for an arbitrary k Means for performing the operation Re [z] for obtaining the real part of the complex number z, means for performing the operation Im [z] for obtaining the imaginary part of the complex number z, Means for executing calculation Abs [z] to determine the relative value, with respect to 1 ≦ i ≦ M made any integer ^{_{i, x 0 [i] (}} k) = Abs [Re [[Rx-H × Tx (k )] _i ]] to obtain x ₀ ^[i] (k) as y ₀ ^[i] (k) = Abs [Im [[Rx−H × Tx (k)] _i ]] y ₀ ^{[I] For} a means for obtaining (k) and an arbitrary integer n such that n ≧ 0, x _{n + 1} ^[i] (k) = Cos (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Sin means for obtaining x _{n + 1} ^[i] (k) from (x _n ^[i] (k)> y _n ^[i] (k)) as (π / 2 ^{n + 1} ) × y _n ^[i] (k); For any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^{[i] (k)]} as the ^{_{(x n [i] (k}} ), y n [i] (k)) and y _{n + 1 ^[i]} means for obtaining a ^(k)) than, m ≧ 0 becomes a predetermined integer to m, from ^{_{(x m [i] (k}} ), y m [i] (k)) ^{_{F m [i] (k)}} = x m [i] (k) + y m [i] (k) × {(1-Cos (π / 2 m + 1)) / Sin (π / 2 m + 1)} as _{F m} ^[I] means for obtaining (k), means for obtaining the total TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M, and all or part of k Means for selecting k that minimizes TF _m (k), and means for reproducing received data using each element of the column vector Tx (k) for the selected k as a transmission signal for each symbol and each antenna. It is characterized by comprising.

  A radio communication apparatus according to the present invention is the radio communication apparatus according to any one of claims 1 to 5, wherein orthogonal frequency division multiplexing using a plurality of subcarriers between the transmitting station and the receiving station ( It is characterized by using OFDM (Orthogonal Frequency Division Multiplexing) modulation system.

The wireless communication method of the present invention is a wireless communication method in a wireless communication system configured by a transmitting station and a receiving station that perform communication via a wireless line, and transmitted by the transmitting station in a receiving process at the receiving station. A step of receiving a signal, a step of obtaining a transfer function H of a transmission path between the transmitting station and the receiving station, and an Ntx type transmission signal group {Tx (k)} ( 1 ≦ k ≦ Ntx: k and Ntx are integers) a step of performing an operation of H × Tx (k) on an arbitrary kth transmission signal Tx (k), and a series of received signal sequences When a received signal of a certain symbol is Rx, a step of performing an operation of Rx−H × Tx (k) for an arbitrary k, and an operation Re [z] for obtaining a real part of a complex number z Implementing, performing an operation Im [z] for obtaining an imaginary part of a complex number z, and complex And performing a calculation Abs [z] to obtain the absolute value of the number z, acquiring x _{0 (k)} as _{x 0 (k) = Abs [} Re [Rx-H × Tx (k)]], The step of obtaining y ₀ (k) as y ₀ (k) = Abs [Im [Re [Rx−H × Tx (k)]], and F ₀ (k) = x ₀ (k) + y ₀ (k) , A step of selecting k that minimizes the value of F0 (k) among all or a part of k, and received data using the selected Tx (k) as a transmission signal for each symbol. And a step of reproducing.

The wireless communication method of the present invention is a communication method in a wireless communication system configured by a transmitting station and a receiving station that perform communication via a wireless line, and a signal transmitted by the transmitting station in a receiving process in the receiving station. , A step of obtaining a transfer function H of the transmission path between the transmitting station and the receiving station, and a group of N _tx types of transmission signals {Tx (k)} ( _Performing an operation of H × Tx (k) on an arbitrary k for the k-th transmission signal Tx (k) in 1 ≦ k ≦ N _tx : k and N _tx are integers); When a received signal of a certain symbol in a series of received signal sequences is Rx, a step of performing an operation of Rx−H × Tx (k) for an arbitrary k and a real part of a complex number z are obtained. A step of performing an operation Re [z] and an operation Im [z] for obtaining an imaginary part of the complex number z A step Abs [Re [z]] and an operation Abs [Im [z]] for obtaining the absolute value of the real part Re [z] of the complex number z and the absolute value of the real part Im [z] of the complex number z A step of executing, a step of executing an operation Max [rl, r2] for selecting the larger absolute value of the positive real numbers r1 and r2, and an operation Min for selecting the smaller of the absolute values of the positive real numbers r1 and r2. [rl, r2] and x ₁ (k) = Max [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]] x ₁ (k) is obtained, and y ₁ (k) = Min [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]] obtaining y ₁ (k), obtaining F ₁ (k) = x ₁ (k) −y ₁ (k) + √2 × y ₁ (k), and all or part of k A step of selecting k that minimizes the value of F ₁ (k), and a step of reproducing received data using the selected Tx (k) as a transmission signal for each symbol. And features.

The wireless communication method of the present invention is a communication method in a wireless communication system configured by a transmitting station and a receiving station that perform communication via a wireless line, and a signal transmitted by the transmitting station in a receiving process in the receiving station. , A step of obtaining a transfer function H of the transmission path between the transmitting station and the receiving station, and a group of N _tx types of transmission signals {Tx (k)} ( A step of performing an operation of H × Tx (k) on an arbitrary kth transmission signal Tx (k) in 1 ≦ k ≦ N _tx (k and N _tx are integers), and a series of received signals When a received signal of a certain symbol in the column is Rx, a step of performing an operation of Rx−H × Tx (k) for an arbitrary k, and an operation Re [z for obtaining a real part of a complex number z And a step of performing an operation Im [z] for obtaining an imaginary part of the complex number z. If, acquiring and performing a calculation Abs [z] for obtaining the absolute value of a complex number _{z, x 0 (k) =} Abs [Re [Rx-H × Tx (k)]] as x _{0 (k)} is And y ₀ (k) = Abs [Im [Rx−H × Tx (k)]] to obtain y ₀ (k), and for any integer n where n ≧ 0, x _{n + 1} (k ) = obtained (as ^{π / 2 n + 1) ×} x n (k) + Sin (π / 2 n + 1) × yn (k), (x n (k) Cos the, y n _(k)) from x _{n + 1 (k)} a step of, with respect to n ≧ 0 becomes an arbitrary integer _{n, y n + 1 (k} ) = Abs [-Sin (π / 2 n + 1) × x n (k) + Cos (π / 2 n + 1) × y n (k )] As a step of obtaining y _{n + 1} (k) from (x _n (k), y _n (k)) and a predetermined integer m with m ≧ 0 (x _m (k), y _{m, (k))} from _{F m (k) = x m} (k) + y m (k) × {(1-Cos (π / 2 m + 1)) / Sin (π / 2 m + 1)} as F _m ( k) and all or some of the steps Characterized by comprising the steps of values of F _{m (k)} selects k that minimizes, and means for reproducing the received data Tx (k) for the selected k as a transmission signal for each symbol in the And

The wireless communication method of the present invention is a wireless communication system configured by a transmission station having one or a plurality of transmission antennas and a reception station having M (M> 1: integer) reception antenna groups. A communication method, comprising: a step of transmitting a signal to which a known pattern signal is added from one of the transmission antennas in the transmission processing of the transmitting station, and in the processing of the receiving station, A step of individually receiving a radio signal using the reception antenna group and a known signal pattern given to the reception signal as a reference signal between the transmission antenna and the i-th antenna in the reception antenna group In the step of obtaining the transfer function h i and the N tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N tx : k and N tx are integers) that the transmitting station may transmit Kth transmission of Calculating a product of a transfer function vector H having the transfer function hi as the i-th component, that is, Tx (k) × H, for each signal Tx (k), and each antenna of the receiving antenna group Performing a calculation of Rx−Tx (k) × H on an arbitrary received signal vector Rx having a signal point of a certain symbol in a series of received signal sequences in FIG. When the i component is expressed as [V] i , the step of performing the operation of [Rx−Tx (k) × H] i for an arbitrary k, and the operation Re [z] for obtaining the real part of the complex number z A step of performing an operation Im [z] for obtaining an imaginary part of the complex number z, a step of performing an operation Abs [zl for obtaining an absolute value of the complex number z, and an arbitrary integer H satisfying 1 ≦ i ≦ M relative, to obtain the x 0 [i] (k) = Abs [Re [[Rx-Tx (k) × H] i]] x 0 [i] as (k) And step, y 0 [i] (k ) = Abs [Im [[Rx-Tx (k) × H] i]] as y 0 [i] (k) acquiring, n ≧ 0 becomes any For an integer n, x n + 1 [i] (k) = Cos (π / 2 n + 1 ) × x n [i] (k) + Sin (π / 2 n + 1 ) × y n [i] (k) (x x n + 1 [i] (k) from n [i] (k), y n [i] (k)), and y n + 1 [i] ( k) = Abs [−Sin (π / 2 n + 1 ) × x n [i] (k) + Cos (π / 2 n + 1 ) × y n [i] (k)] (x n [i] (k) , y n [i] (k)) to obtain y n + 1 [i] (k), and for a predetermined integer m such that m ≧ 0, (x m [i] (k), y m [i ] (K)) F m [i] (k) = x m [i] (k) + y m [i] (k) × {(1-Cos (π / 2 m + 1 ) / Sin (π / 2 m + 1) )} To obtain F m [i] (k) and 1 ≦ i ≦ M Obtaining a total TF m (k) of F m [i] (k) for all i; selecting a k that minimizes the TF m (k) among all or part of k; And a step of reproducing received data using the transmission signal Tx (k) for the selected k as a transmission signal for each symbol.

The wireless communication method of the present invention includes a transmitting station having N (N> 1: integer) or more first antenna groups and a receiving station having M (M> 1: integer) second antenna groups. A wireless communication method in a wireless communication system configured with a station, wherein in the transmission processing of the transmitting station, a step of dividing user data into N systems, and a separate known individual for the data divided into the N systems A step of generating a first signal sequence of N systems by applying a pattern signal, and simultaneously transmitting the first signal sequence superimposed at the same frequency using the N first antenna groups A step of receiving a radio signal individually using the M second antenna groups in the processing of the receiving station, and using a known signal pattern given to the received signal as a reference signal, Of the first antenna group. obtaining a transfer function h _{i, j} between the j antenna and the i-th antenna of the second antenna group, and a group of N _tx types of transmission signal vectors that the transmitting station may transmit { For the k-th transmission signal vector Tx (k) in Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers), the transfer function h _{i, j} is expressed as (i, j ) A step of calculating a product of the transfer function matrix H as a component, that is, H × Tx (k), and a signal point of a symbol in a series of received signal sequences at each antenna of the second antenna group. A step of performing an operation of Rx−H × Tx (k) on an arbitrary k with respect to the received signal vector Rx as an element, and a case where an _i- th component of an arbitrary column vector V is expressed as [V] _i , [Rx−H × Tx (k)] The step of performing the operation of _i for an arbitrary k, and the operation Re [ z], a step Im [z] for obtaining the imaginary part of the complex number z, a step Abs [z] for obtaining the absolute value of the complex number z, and 1 ≦ i ≦ M for any integer i, obtaining a set to ^{_{x 0 [i] (k)}} = Abs [Re [[Rx-H × Tx (k)] i]] x 0 [i] as ^(k), obtaining y ₀ ^[i] (k) as y ₀ ^[i] (k) = Abs [Im [[Rx−H × Tx (k)] _i ]], and an arbitrary integer n satisfying n ≧ 0 in ^{_{contrast, x n + 1 [i]}} (k) = Cos (π / 2 n + 1) × x n [i] (k) + Sin (π / 2 n + 1) × y n [i] as _{(k) (x} ^{n [i ] For} (k)> y _n ^[i] (k)) to obtain x _{n + 1} ^[i] (k), and for any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^[i] (k)] (x _n ^[i] (k), y _n ^{[ i]} (k) ) To obtain y _{n + 1} ^[i] (k)), and for a predetermined integer m such that m ≧ 0, F _m from (x _m ^[i] (k), y _m ^[i] (k)) ^[I] (k) = x _m ^[i] (k) + y _m ^[i] (k) × {(1-Cos (π / 2m ^{+ 1} )) / Sin (π / ^{2m + 1} )} F _m ^{[i ]} Obtaining (k), obtaining a total TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M, and among all or some of k Selecting k that minimizes TF _m (k), and regenerating received data using each element of the column vector Tx (k) for the selected k as a transmission signal for each symbol and each antenna. It is characterized by having.

  A radio communication method according to the present invention is the radio communication method according to any one of claims 7 to 11, wherein orthogonal frequency division multiplexing using a plurality of subcarriers between the transmitting station and the receiving station ( It is characterized by using OFDM (Orthogonal Frequency Division Multiplexing) modulation system.

As described above, the present invention is configured by a transmitting station and a receiving station that communicate via a wireless line, and the reception sum includes means for receiving a signal transmitted by the transmitting station, and the transmission sum and the receiving station. Means for obtaining the transfer function H of the transmission path between the transmission lines and N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx integers) that the transmission station may transmit ), A means for performing an operation of H × Tx (k) for an arbitrary k, and a received signal of a symbol in a series of received signal sequences , Rx, means for performing an operation of Rx−H × Tx (k) for an arbitrary k, means for performing an operation Re [z] for obtaining the real part of the complex number z, means for executing calculation Im [z] to determine the imaginary part, and means for executing calculation Abs [z] for obtaining the absolute value of a complex number _{z, x 0 (k) =} Abs [Re [Rx-H × means for obtaining a x _{o (k)} as x (k)]], and _{y 0 (k) = Abs [} Im [ means for acquiring the Rx-H × Tx (k) ]] as y _{0 (k),} Means for obtaining F ₀ (k) = x ₀ (k) + y ₀ (k), means for selecting k that minimizes the value of F ₀ (k) among all or part of k, and selection The main feature is that it includes a means for reproducing received data using the Tx (k) as a transmission signal for each symbol.
As a result, in the conventional technique, the Euclidean distance is used to determine the signal point. However, the conventional technique includes means for acquiring F ₀ (k) = x ₀ (k) + y ₀ (k) as an evaluation function, and all or one This is different in that means for selecting k that minimizes the value of F ₀ (k) among the k of the part is used.
As a result, it is possible to approximate the Euclidean distance and suppress the circuit scale with the addition circuit having a small circuit scale and a simple configuration instead of using an integration circuit with a large circuit scale, as described in the embodiment. An effect can be obtained.

Further, the transmission station includes a transmission station and a reception station that communicate via a wireless line, and the reception station receives a signal transmitted by the transmission station, and a transfer function of a transmission path between the transmission station and the reception station. Means for obtaining H, and k th of N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx integers) that the transmitting station may transmit Means for performing an operation of H × Tx (k) with respect to an arbitrary k and a received signal of a certain symbol in a series of received signal sequences as Rx. Means for performing an operation of Rx−H × Tx (k) for an arbitrary k, means for performing an operation Re [z] for obtaining a real part of a complex number z, and an operation Im [for obtaining an imaginary part of a complex number z z], means for performing the operation Abs [z] for obtaining the absolute value of the complex number z, and the larger of the absolute values of the positive real numbers r1 and r2 are selected. Means for performing the calculation Max [r1, r2], and means for executing calculation Min [rl, r2] to select a smaller positive absolute value of the real r1 and _{r2, x 1 (k) =} Max [Abs Means for obtaining x1 (k) as [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]], y ₁ (k) = Min [Abs [ Means for obtaining y ₁ (k) as Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]], and F ₁ (k) = x ₁ (k ) −y ₁ (k) + √2 × y ₁ (k), a means for selecting k that minimizes the value of F ₁ (k) among all or part of k, and selection It is also preferable to comprise means for reproducing the received data using Tx (k) as a transmission signal for each symbol.

Similarly, it is composed of a transmitting station and a receiving station that communicate via a wireless line, and the receiving station receives a signal transmitted by the transmitting station and a transmission path between the transmitting station and the receiving station. Means for obtaining the function H, and the k th of the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx integer) that the transmitting station may transmit Means for performing an operation of H × Tx (k) on an arbitrary k for the second transmission signal Tx (k), and when a received signal of a symbol in a series of received signal sequences is Rx , Means for performing an operation of Rx−H × Tx (k) for arbitrary k, means for performing an operation Re [z] for obtaining the real part of the complex number z, and an operation Im for obtaining the imaginary part of the complex number z means for implementing the [z], and means for executing calculation Abs [z] for obtaining the absolute value of a complex number _{z, x 0 (k) =} Abs [Re [Rx-H × Tx (k)]] x 0 as (k) Means for obtaining y ₀ (k) as y _o (k) = Abs [Im [Rx−H × Tx (k)]], and x _{n + 1} for any integer n where n ≧ 0 (k) = Cos (π / 2 n + 1) × x n (k) + Sin (π / 2 n + 1) as _{× yn (k) x n +} 1 from the _{(x n (k), y} n (k)) to _(k) For the acquisition means and an arbitrary integer n such that n ≧ 0, y _{n + 1} (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n (k) + Cos (π / 2n + 1) × y _n (k )] As a means for obtaining y _{n + 1} (k) from (x _n (k), y _n (k)) and a predetermined integer m such that m ≧ 0 (x _m (k), y m _(k)) from _{F m (k) = x m} (k) + y m (k) × {(1-Cos (π / 2 m + 1)) / Sin (π / 2 m + 1)} as F _{m (k} ), Means for selecting k that minimizes the value of F _m (k) among all or part of k, and Tx (k) for the selected k as a transmission signal for each symbol. As a hand to play the received data It is also preferable to provide a step.

The above is a simple implementation method for realizing a method of improving the accuracy of the Euclidean distance approximation as the first-order approximation and the m-th order approximation.
Further, in order to apply the present invention to the MIMO technology, F _m ^[i] (k) is acquired for each of M reception antennas at a reception station having M (M> 1: integer) reception antenna groups. And means for obtaining the total TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M, and the TF _m (k) is minimum among all or part of k It is also preferable to include means for selecting k.
It is also preferable to apply the above method to a wireless communication system using an orthogonal frequency division multiplexing (OFDM) modulation scheme using a plurality of subcarriers.
In particular, when MIMO technology and OFDM technology are applied and reception processing is performed on the receiving side using the MLD method or a method equivalent thereto, it is necessary to perform a large number of Euclidean arithmetic processing. By performing the approximation process with a small circuit, the circuit scale can be reduced and the power consumption can be reduced.

As described above in detail, according to the present invention, when performing highly efficient wireless communication using MIMO technology, the integration circuit is added to the Euclidean distance by the adder circuit while realizing the good characteristics of the MLD method. Therefore, it is possible to obtain an effect that the circuit scale and the calculation amount can be greatly reduced as compared with the conventional MLD method.
As a result, according to the present invention, the circuit scale can be greatly reduced, so that the receiving circuit can be mounted in a one-chip LSI. Further, the above-described reduction in circuit scale and reduction in the amount of calculation can be expected to have a secondary effect of directly reducing power consumption.

Hereinafter, a wireless communication apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment.
Embodiments of the present invention will be described below with reference to the drawings. Although claims 1 to 3 of the present invention are not necessarily premised on the application of the MIMO technology, the main effect of the present invention is a reduction in circuit scale, which is particularly effective in combination with the MIMO technology.
Therefore, in the embodiment of the present invention, the MLD method combined with the MIMO technique will be described as an example. The difference between the present invention and the prior art is in the configuration of the receiving unit, and the configuration on the transmission side of the present invention is the same as that of the conventional example already described.
Therefore, only the receiving station will be described below. As in the conventional method, a case where the transmitting station transmits two systems of data using two transmitting antennas is used as an example.

FIG. 1 is a diagram illustrating a configuration of a receiving unit of a receiving station using the MLD method according to an embodiment of the present invention. In the figure, the receiving unit of the present invention includes receiving antennas 1-1 to 1-2, radio units 2-1 to 1-2, channel estimation circuit 3, received signal management unit 4, transfer function matrix management circuit 5, replica signal. A generation circuit 6, a transmission signal generation circuit 7, an Euclidean distance approximation circuit 8 a to 8 c, a selection circuit 9, and a data synthesis circuit 10 are included.
The only difference between the present invention shown in FIG. 1 and the conventional example shown in FIG. 6 is that the Euclidean distance calculation circuits 118a to 118c of the conventional example are replaced with Euclidean distance approximation circuits 8a to 8c.
In the configuration of the Euclidean distance calculation circuits 118a to 118c shown in FIG. 8, each Euclidean distance calculation circuit, for example, the Euclidean distance calculation circuit 118a of FIG. When combined, it becomes a huge scale. The Euclidean distance approximation circuits 8a to 8c of FIG. 1 according to the present invention are intended to greatly reduce the circuit scale.

The inputs to the Euclidean distance approximation circuits 8a to 8c are the received signal vector Rx from the received signal management circuit 4 and the replica signal H × Tx (k) from the replica generation circuit 6, and the calculation of the Euclidean distance. The result (approximate value) is output to the selection circuit 9.
Here, since the reception signal management circuit 4 and the replica generation circuit 6 have the same functions as the reception signal management circuit 114 and the replica generation circuit 116 of the conventional example, detailed description thereof is omitted.
Furthermore, the antennas 1-1 and 1-2, the channel estimation circuit 3, the transfer function matrix H management circuit 5, the selection circuit 9 and the data synthesis circuit 10 are also respectively the antennas 111-1 and 111-2 and the channel estimation circuit in the conventional example. 113, the transfer function matrix H management circuit 115, the selection circuit 119, and the data synthesis circuit 120 have the same functions.

Next, the configuration of the Euclidean distance approximation circuit (8a to 8c) according to the embodiment of the present invention will be described. FIG. 2 is a diagram showing a configuration example of the Euclidean distance approximation circuit of the present invention.
In FIG. 2, Euclidean distance approximation circuits (8a to 8c) include first component extraction circuits 11a to 11b, second component extraction circuits 12a to 12b, addition circuits 13a to 13e, real part extraction circuits 14a to 14b, and imaginary part. Extraction circuits 15a to 15b and absolute value extraction circuits 16a to 16d are provided.
Here, the first component extraction circuits 11a to 11b, the second component extraction circuits 12a to 12b, the addition circuits 13a to 13e, the real part extraction circuits 14a to 14b, and the imaginary part extraction circuits 15a to 15b are each shown in FIG. The first component extraction circuits 130a to 130b, the second component extraction circuits 131a to 131b, the addition circuits 132a to 132e, the real part extraction circuits 133a to 133b, and the imaginary part extraction circuits 134a to 134b in the example have the same functions. Yes.
The present invention is characterized in that absolute value extraction circuits 16a to 16d are used in place of the multipliers 135a to 135d of the conventional example.

Next, an operation example of the Euclidean distance approximation circuit (8a to 8c) according to the embodiment of the present invention will be described. Similar to the example shown in the conventional example of FIG. 8, the input vector information is a two-dimensional vector having a complex component, and is expressed as a vector (x ₁ , y ₁ ) and a vector (x ₂ , y ₂ ). Here, (x ₁ , y ₁ ) = Rx, (x ₂ , y ₂ ) = H × Tx (k).
Vectors (x ₁ , y ₁ ) having complex number components are input to the first component extraction circuit 11a and the second component extraction circuit 12a, respectively.
The first component extraction circuit 11a and outputs the extracted only x ₁ and x component from the vector (x _1, y _1), also the second component extraction circuit 12a from the vector (x _1, y ₁₎ by extracting only y ₁ and y component outputs.

Further, in parallel with the vector (x ₁ , y ₁ ), the vector (x ₂ , y ₂ ) is input to the first component extraction circuit 11b and the second component extraction circuit 12b, respectively.
Then, similarly to the first component extraction circuit 11a, the first component extraction circuit 11b extracts and outputs only x ₂ which is the x component from the vector (x ₂ , y ₂ ), and outputs the second component extraction circuit 12b. Extracts only y ₂ which is only the y component from the vector (x ₂ , y ₂ ) and outputs it.
The addition circuit 13a, and the x _1, performs a sign inverted x ₂ plus dove (i.e. subtraction of x ₁ and x _2), and outputs the operation result as the difference .delta.x.
Similarly, adder circuit 13b, and the y _1, performs addition of sign inverted y ₂ (i.e. subtraction of y ₁ and y _2), and outputs the operation result as the difference .delta.y.

The real part extraction circuit 14a extracts and outputs the real part of the difference δx as Re [δx], and the imaginary part extraction circuit 15a extracts and outputs the imaginary part of the difference δx as Im [δx]. That is, the difference δx is separated into a real part and an imaginary part by the real part extraction circuit 14a and the imaginary part extraction circuit 15a. Similarly, the difference δy is separated into a real part Re [δy] and an imaginary part Im [δy] by the real part extraction circuit 14b and the imaginary part extraction circuit 15b.
The absolute value extraction circuit 16a calculates the absolute value | Re [δx] | of Re [δx] and outputs it to the adder 13c, and the absolute value extraction circuit 16b outputs the absolute value | Im [δx] of Im [δx] | Is calculated and output to the adder 13c.
Similarly, the absolute value extraction circuit 16c calculates the absolute value | Re [δy] | of Re [δy] and outputs it to the adder 13d. The absolute value extraction circuit 16d outputs the absolute value | Im [δy] ] | Is calculated and output to the adder 13d.

Next, the adder 13c adds the input absolute values | Re [δx] | and | Im [δx] | to give | Re [δx] | + | Im [δx] | (F ₀ ^[1] (equivalent to (k)) is output to the adder 13e.
Similarly, the adder 13d adds the input absolute values | Re [δy] | and | Im [δy] | to | Re [δy] | + | Im [δy] | (F ₀ ^[2] (equivalent to (k)) is output to the adder 13e.
Then, the adder 13e adds the input | Re [δx] | + | Im [δx] | and | Re [δy] | + | Im [δy] |, and calculates | Re [δx] | + | Im [δx] | + | Re [δy] | + | Im [δy] | (corresponding to TF ₀ (k)) is output as the Euclidean distance. Since the subsequent processing is the same as that of the conventional example, description thereof is omitted.
The conventional Euclidean distance arithmetic circuit shown in FIG. 8 is provided with integrating circuits 135a to 135d subsequent to the real part extracting circuits 133a to 133b and the imaginary part extracting circuits 134a to 134b. In the embodiment, this is replaced with absolute value extraction circuits 16a to 16d. Thereby, it is possible to greatly reduce the circuit scale.

Next, FIG. 3 is a block diagram showing a configuration example of a Euclidean distance approximation circuit according to another embodiment of the present invention.
The basic configuration is the same as in FIG. 2, but the difference from the configuration in FIG. 2 is that a (√2-1) multiplier circuit 17a is arranged between the absolute value extraction circuit 16b and the adder 13c, thereby extracting the absolute value. That is, a (√2-1) multiplication circuit 17b is arranged between the circuit 16d and the adder 13c.
The magnitude determination circuit 30 determines the magnitude of the numerical value of the output | Re [δx] | of the absolute value circuit 16a and the output | Im [δx] | of the absolute value circuit 16b, and determines that the numerical value is large. Is output to the adder 13c, and the value determined to be small is output to the (√2−1) multiplication circuit 17a.
Similarly, the magnitude determination circuit 31 determines the magnitude of the numerical value of the output | Re [δy] | of the absolute value circuit 16c and the output | Im [δy] | of the absolute value circuit 16d, and determines that the numerical value is large. Is output to the adder 13d, and the value determined to be small is output to the (√2−1) multiplication circuit 17b.
In FIG. 2, the Euclidean distance is approximated by | Re [δx] | + | Im [δx] | + | Re [δy] | + | Im [δy] |. However, in the configuration of FIG. The distance may be, for example, | Re [δx] | + (√2−1) | Im [δx] | + | Re [δy] | + (√2-1) | Im [δy] | (TF ₁ (k) ). At this time, it is assumed that the size determination circuit 30 determines | Re [δx] |> | Im [δx] |, and the size determination circuit 31 determines | Re [δy] |> | Im [δy] |.

Note that the (√2-1) multiplication circuits 17a to 17b can perform approximate calculation using an adder circuit without strictly performing calculation using an integration circuit.
In this case, the (√2-1) multiplication circuit 17a and the addition circuit 17c, and the (√2-1) multiplication circuit 17b and the addition circuit 16d in FIG. 3 can be simplified as follows.
FIG. 4 is a diagram showing the configuration of the {A + B × (√2−1)} arithmetic approximation circuit in the embodiment of the present invention. In the figure, the {A + B × (√2−1)} operation approximation circuit includes adder circuits 21a to 21c, 1/2 circuit 22 and 24, and 1/8 circuit 23. This {A + B × (√2-1)} operation approximation circuit is, for example, a circuit that combines an adder circuit 13c and a (√2-1) multiplier circuit 17a.

When real numbers A (| Re [δx] |) and B (| Im [δx] |) are input, B is halved by a 1/2 multiplier circuit and output as (1/2) B. The (1/2) B and A are added by the adder circuit 21a and output as A + (1/2) B.
The output (1/2) B from the 1/2 multiplication circuit 22 is multiplied by 1/8 by the 1/8 multiplication circuit 23 and output as (1/16) B.
The adder circuit 21b subtracts the (1/16) B from A + (1/2) B and outputs A + (1/2) B- (1/16) B.
Further, the output (1/16) B from the 1/8 multiplier circuit 23 is halved by the 1/2 multiplier circuit 24 and is output as (1/32) B.
Next, the adder 21c subtracts (1/32) B from A + (1/2) B- (1/16) B to obtain A + (1/2) B- (1/16) B-. (1/32) B is output.

The {A + B × (√2−1)} operation approximation circuit finally gives the operation result of A + (1/2) B− (1/16) B− (1/32) B.
Here, it corresponds to approximating the original (√2-1) by (1 / 2-1 / 16-1 / 32), but as a value, 0.414213... Is approximated by 0.40625.
Note that, like the 1/2 times circuits 22 and 24, and the 1/8 times circuit 23, 1/2 ⁿ times processing can be easily realized by simple bit shift in a circuit using binary numbers. For example, if it is ½ times, a 1-bit shift may be performed, and if it is / times, a 3-bit shift may be performed. That is, it can be realized by a simple bit shift circuit.

FIG. 5 is a diagram showing the Euclidean distance approximation method according to claim 3 in the embodiment of the present invention. First, for the complex number x ′ + j × y ′, consider the two-dimensional coordinates (x, y) where x = Abs [x ′] and y = Abs [y ′].
A circle with a radius R (R = {x ² + y ² } 1/2) is drawn around the origin, and this (x, y) is assumed to be in the range of O to π / 2 ^{n + 1} from the origin of the coordinates. Here, it is assumed that x _n = R × Cos (π / ^{2n + 1} ) and y ⁿ = R × Sin (π / 2 ^{n + 1} ).
Next, a straight line L is drawn from the coordinate point (x _n , y _n ) to the coordinate point (R, 0). Thereafter, a straight line L ′ parallel to the straight line L is drawn from the coordinate point (x, y) for which the Euclidean distance is to be obtained.
If the intersection of this straight line L ′ and the x-axis is (R ′, 0), the distance R to be obtained can be approximated by R ′, and this R ′ (Fm (k) in claim 3) is as follows: 4) It is expressed by the formula.
R ′ = x + y × (1-Cos (π / ^{2n + 1} )) / Sin (π / ^{2n + 1} ) (4)
The coordinate point (x, y) is the case that exists between the angle O~π / 2 ⁿ is the coordinate point (x, y) to rotate in the clockwise direction by π / 2 ^{n + 1,} after rotation transformation Taking the absolute value of the Y coordinate value, a new coordinate is moved between 0 and π / 2 ^{n + 1} . By repeating this operation, the accuracy of approximation can be increased. If it is still not within the range, repeat this operation.

In the above equation (4), as a general solution for an arbitrary integer n where n ≧ 0, x is x _{n + 1} (k) = Cos (π / 2 ^{n + 1} ) × x _n (k) + Sin (π / 2 ^{n + 1} ) × yn (k) as obtained as _{(x n (k), y} n (k)) from x _{n + 1 (k),} also, y _{is, y n + 1 (k)} = Abs [-Sin (π / 2 n + 1) × x _n (k) + Cos (π / 2 ^{n + 1} ) × y _n (k)] is obtained as y _{n + 1} (k) from (x _n (k), y _n (k)). In these general solutions, x _n (k) corresponds to | Re [δx] | or | Re [δy] |, and y _n (k) corresponds to | Im [δx] | or | Im [δy] | doing. Therefore, F _m (k) is calculated as the sum of the above x _m (k) and y _m (k) according to the equation (4).
The configuration corresponding to claim 1 is a case where n = 0 is substituted into the above equations, and R ′ is a circuit approximated as R ′ = x + y.
Further, the configuration corresponding to claim 2 is a case where n = 1 is substituted into the above equations, and R ′ is a circuit approximated as R ′ = x + y (√2−1). . At this time, since x> y is required, when x <y, x and y are interchanged as R ′ = y + x (√2−1).
Furthermore, in order to improve the accuracy of approximation of the Euclidean distance, it is possible to consider a configuration in which n ≧ 2 is substituted (claims 3, 4, and 5 correspond to general solutions where n> 1), Although the calculation for obtaining the general solution is performed, it is preferable to set n = 0 or n = 1 in consideration of the original purpose of circuit scale reduction.

In the above description, the MIMO technique is assumed as an adaptation area of the present invention, but the number of antennas on the transmission side is one, and transmission is normally performed without superimposing a plurality of signal sequences, On the other hand, the present invention can also be effectively used for diversity reception using a plurality of reception antennas only on the reception side.
The fourth aspect defines the case of diversity reception using a plurality of reception antennas only on the reception side.
Further, claim 5 is a stipulation clearly specifying the case where the present embodiment is combined with the MIMO technique, and if the number of antennas N on the transmission side is set to N = 1, it is effectively equivalent to the configuration of claim 4.
That is, a transmission signal transmitted from a transmission station by N (N> 1: integer) transmission antennas is received at a reception station including M (M> 1: integer) reception antenna groups. For each antenna, as described in the embodiment, Euclidean distance approximation circuits (corresponding to the number of signals detected by each of the Euclidean distance approximation circuits 8a, 8b, and 8c) provided corresponding to signals received by a plurality of antennas are provided. F _m ^[i] (k) is obtained from the difference for each antenna, and the total TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M. , That is, the total sum of the Euclidean distance approximation circuits (for example, the integrated value of F _m (k) output from the plurality of Euclidean distance approximation circuits 8a to 8c). TF _m (k) is minimized in k will be selected.

The above-described embodiments are all illustrative of the present invention and are not limited, and the present invention can be implemented in other various modifications and changes.
Therefore, the scope of the present invention is defined only by the claims and their equivalents.

  Note that a program for realizing the function of the receiving unit in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed, whereby data of the received data is received. Regeneration may be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

It is a block diagram which shows the example of 1 structure of the receiving part of the receiving station using MLD method by one Embodiment of this invention. It is a block diagram which shows one structural example of the Euclidean distance approximation circuit (8a-8c) in FIG. It is a block diagram which shows the other structural example of the Euclidean distance approximation circuit (8a-8c) in FIG. FIG. 3 is a block diagram illustrating a configuration example of a {A + B × (√2-1)} operation approximation circuit (a composite circuit of a (√2-1) multiplication circuit (17a or 17b) and an addition circuit (13c or 13d)) in FIG. It is. It is a conceptual diagram for demonstrating the Euclidean distance approximation method (corresponding to description of Claim 3) used with the Euclidean distance approximation circuit of embodiment of this invention. It is a block diagram which shows the structure of the transmission part of the transmission station to which the MIMO technique in a prior art is applied. It is a block diagram which shows the structure of the receiving part of the receiving station using the MLD method in a prior art. It is a block diagram which shows the structure of the Euclidean distance calculating circuit in a prior art.

Explanation of symbols

1-1, 1-2 ... receiving antennas 2-1 and 2-2 ... radio section 3 ... channel estimation circuit 4 ... received signal management section 5 ... transfer function matrix management circuit 6 .. Replica signal generation circuit 7... Transmission signal generation circuits 8a, 8b, 8c... Euclidean distance approximation circuit 9... Selection circuit 10... Data synthesis circuits 11a, 11b. 12a, 12b ... second component extraction circuits 13a, 13b, 13c, 13d, 13e ... addition circuits 14a, 14b ... real part extraction circuits 15a, 15b ... imaginary part extraction circuits 16a, 16b, 16c , 16d ... absolute value extraction circuits 17a, 17b (√2-1) multiplier circuits 21a, 21b, 21c ... adder circuit 22 ... 1/2 multiplier circuit 23 ... 1/8 times Circuit 24... 1/2 circuit 101... Data dividing circuit 102-1 , 102-2 ... Preamble applying circuits 103-1 and 103-2 ... Modulation circuits 104-1 and 104-2 ... Radio units 105-1 and 105-2 ... Transmitting antenna 111-1 111-2 ... Reception antennas 112-1, 112-2 ... Radio section 113 ... Channel estimation circuit 114 ... Reception signal management section 115 ... Transfer function matrix management circuit 116 ... Replica signal Generation circuit 117 ... Transmission signal generation circuit 118a, 118b, 118c ... Euclidean distance calculation circuit 119 ... Selection circuit 120 ... Data synthesis circuit 130a, 130b ... First component extraction circuits 131a, 131b .. Second component extraction circuits 132a, 132b, 132c... Addition circuits 132d, 132e... Addition circuits 133a, 133b. Circuits 134a, 134b ... Imaginary part extraction circuits 135a, 135b, 135c, 135d ... Integration circuits

Claims (12)

Consists of a transmitting station and a receiving station that communicate via a wireless line,
The receiving station is
Means for receiving a signal transmitted by the transmitting station;
Means for obtaining a transfer function H of a transmission path between the transmitting station and the receiving station;
Any k-th transmission signal Tx in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. means for performing an operation of H × Tx (k) for (k);
Means for performing an operation of Rx−H × Tx (k) for an arbitrary k, where Rx is a received signal of a symbol in a series of received signal sequences;
Means for performing the operation Re [z] for obtaining the real part of the complex number z;
Means for performing an operation Im [z] for obtaining an imaginary part of the complex number z;
Means for performing an operation Abs [z] for obtaining an absolute value of the complex number z;
means for obtaining x ₀ (k) as x ₀ (k) = Abs [Re [Rx−H × Tx (k)]];
means for obtaining y ₀ (k) as y ₀ (k) = Abs [Im [Re [Rx−H × Tx (k)]];
Means for obtaining F ₀ (k) = x ₀ (k) + y ₀ (k);
Means for selecting k that minimizes the value of F ₀ (k) among all or part of k;
And a means for reproducing received data using the selected Tx (k) as a transmission signal for each symbol. Consists of a transmitting station and a receiving station that communicate via a wireless line,
The receiving station is
Means for receiving a signal transmitted by the transmitting station;
Means for obtaining a transfer function H of a transmission path between the transmitting station and the receiving station;
The k th transmission signal Tx (k) in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. ) With respect to an arbitrary k, means for performing an operation of H × Tx (k),
Means for performing an operation of Rx−H × Tx (k) for an arbitrary k, where Rx is a received signal of a symbol in a series of received signal sequences;
Means for performing the operation Re [z] for obtaining the real part of the complex number z;
Means for performing an operation Im [z] for obtaining an imaginary part of a complex number z;
Means for performing an operation Abs [z] for obtaining an absolute value of the complex number z;
Means for performing the operation Max [rl, r2] for selecting the larger absolute value of the positive real numbers r1 and r2,
Means for performing an operation Min [rl, r2] for selecting a smaller absolute value of the positive real numbers r1 and r2;
means for obtaining x ₁ (k) as x ₁ (k) = Max [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]];
means for obtaining y ₁ (k) as y ₁ (k) = Min [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]];
Means for obtaining F ₁ (k) = x ₁ (k) −y ₁ (k) + √2 × y ₁ (k);
Means for selecting k that minimizes the value of F ₁ (k) among all or part of k;
And a means for reproducing received data using the selected Tx (k) as a transmission signal for each symbol. Consists of a transmitting station and a receiving station that communicate via a wireless line,
The receiving station is
Means for receiving a signal transmitted by the transmitting station;
Means for obtaining a transfer function H of a transmission path between the transmitting station and the receiving station;
Any k-th transmission signal Tx in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. means for performing an operation of H × Tx (k) on (k);
When a received signal of a symbol in a series of received signal sequences is Rx, a means for performing an operation of Rx−H × Tx (k) for an arbitrary k and an operation for obtaining a real part of a complex number z Means for performing Re [z];
Means for performing an operation Im [z] for obtaining an imaginary part of a complex number z;
Means for executing calculation Abs [z] to obtain the absolute value of a complex number z, and _{x 0 (k) = Abs [} Re [Rx-H × Tx (k)]] means for obtaining x _{0 (k)} as,
means for obtaining y ₀ (k) as y ₀ (k) = Abs [Im [Rx−H × Tx (k)]];
For any integer n where n ≧ 0, x _{n + 1} (k) = Cos (π / 2 ^{n + 1} ) × x _n (k) + Sin (π / 2 ^{n + 1} ) × yn (k)
means for obtaining x _{n + 1} (k) from (x _n (k), y _n (k));
For any integer n where n ≧ 0, y _{n + 1} (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n (k) + Cos (π / 2 ^{n + 1} ) × y _n (k)] ( means for obtaining y _{n + 1} (k) from x _n (k), y _n (k));
F _m (k) = x _m (k) + y _m (k) × {(1 from (x _m (k), y _m , (k)) sequentially obtained for a predetermined integer m where m ≧ 0. Means for obtaining F _m (k) as −Cos (π / 2 ^{m + 1} )) / Sin (π / 2 ^{m + 1} )};
Means for selecting k that minimizes the value of F _m (k) among all or part of k;
And a means for reproducing received data using Tx (k) for the selected k as a transmission signal for each symbol. In a radio communication system including a transmitting station having one or a plurality of transmitting antennas and a receiving station having M (M> 1: integer) receiving antenna groups,
The transmitting station comprises means for transmitting a signal to which a signal of a known pattern is added from one of the transmitting antennas,
The receiving station is
Means for individually receiving radio signals using the M receiving antenna groups;
Means for obtaining a transfer function h _i between the transmitting antenna and the i-th antenna of the receiving antenna group using a known signal pattern given to the received signal as a reference signal;
The k th transmission signal Tx (k) in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. ) For calculating the product of the transfer function h _i with the transfer function vector H having the i-th component, that is, Tx (k) × H,
Means for performing an operation of Rx−Tx (k) × H on an arbitrary received signal vector Rx having a signal point of a symbol in a series of received signal sequences in each antenna of the receiving antenna group as an element;
When the i-th component of an arbitrary column vector V is expressed as [V] _i , means for performing an operation of [Rx−Tx (k) × H] _i for an arbitrary k;
Means for performing the operation Re [z] for obtaining the real part of the complex number z;
Means for performing an operation Im [z] for obtaining an imaginary part of a complex number z;
Means for performing the operation Abs [zl for obtaining the absolute value of the complex number z;
Against 1 ≦ i ≦ M made any integer ^{_{i, x 0 [i] (}} k) = Abs [Re [[Rx-Tx (k) × H] i]] x 0 [i] as the (k) Means to obtain,
means for obtaining y ₀ ^[i] (k) as y ₀ ^[i] (k) = Abs [Im [[Rx−Tx (k) × H] _i ]];
For any integer n with n ≧ 0, x _{n + 1} ^[i] (k) = Cos (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Sin (π / 2 ^{n + 1} ) × y _n ^[i] means for obtaining x _{n + 1} ^[i] (k) from (x _n ^[i] (k), y _n ^[i] (k)) as (k);
For any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^{[i] (k)]} as the ^{_{(x n [i] (k}} ), y n [i] (k)) and means for obtaining from the ^{_{y n + 1 [i] (}} k),
For a predetermined integer m such that m ≧ 0, F _m ^[i] (k) = x _m ^[i] (k) + y _m from (x _m ^[i] (k), y _m ^[i] (k)) Means to obtain F _m ^[i] (k) as ^[i] (k) × {(1-Cos (π / 2 ^{m + 1} ) / Sin (π / 2 ^{m + 1} )};
Means for obtaining a sum TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M;
Means for selecting k that minimizes TF _m (k) among all or part of k;
Means for reproducing received data using a transmission signal Tx (k) for the selected k as a transmission signal for each symbol. Wireless communication composed of a transmitting station having N (N> 1: integer) or more first antenna groups and a receiving station having M (M> 1: integer) second antenna groups. In the system,
The transmitting station is
Means for dividing user data into N systems;
Means for generating a first signal sequence of N systems by giving a signal of an individual known pattern to the data divided into the N systems;
Means for simultaneously superimposing and transmitting the first signal sequence at the same frequency using N first antenna groups,
The receiving station is
Means for individually receiving radio signals using the M second antenna groups;
A transfer function h _{i, j} between the _j- th antenna in the first antenna group and the i-th antenna in the second antenna group using a known signal pattern given to the received signal as a reference signal. Means for obtaining
The k th transmission signal vector Tx in the N _tx types of transmission signal vector groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. means for performing a calculation for (k) with a transfer function matrix H having the transfer function h _{i, j} as an (i, j) component, that is, H × Tx (k);
Calculation of Rx−H × Tx (k) for an arbitrary k with respect to a received signal vector Rx having a signal point of a symbol in a series of received signal sequences in each antenna of the second antenna group as an element Means for performing
Means for performing an operation of [Rx−H × Tx (k)] _i for an arbitrary k when the i-th component of an arbitrary column vector V is expressed as [V] _i ;
Means for performing the operation Re [z] for obtaining the real part of the complex number z;
Means for performing an operation Im [z] for obtaining an imaginary part of a complex number z;
Means for performing an operation Abs [z] for obtaining an absolute value of the complex number z;
For any integer i with 1 ≦ i ≦ M, x ₀ ^[i] (k) = Abs [Re [[Rx−H × Tx (k)] _i ]] as x ₀ ^[i] (k) Means for obtaining
means for obtaining y ₀ ^[i] (k) as y ₀ ^[i] (k) = Abs [Im [[Rx−H × Tx (k)] _i ]];
For any integer n where n ≧ 0, x _{n + 1} ^[i] (k) = Cos (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Sin (π / 2 ^{n + 1} ) × y _n ^[i] means for obtaining x _{n + 1} ^[i] (k) from (x _n ^[i] (k)> y _n ^[i] (k)) as (k);
For any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^[i] and (k)] as the ^{_{(x n [i] (k}} ), y n [i] (k)) means for obtaining from the ^{_{y n + 1 [i] (}} k)),
For a predetermined integer m such that m ≧ 0, F _m ^[i] (k) = x _m ^[i] (k) + y _m from (x _m ^[i] (k), y _m ^[i] (k)) Means to obtain F _m ^[i] (k) as ^[i] (k) × {(1-Cos (π / 2 ^{m + 1} )) / Sin (π / 2 ^{m + 1} )};
Means for obtaining a sum TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M;
Means for selecting k that minimizes TF _m (k) among all or part of k;
Means for reproducing received data using each element of column vector Tx (k) for the selected k as a transmission signal for each symbol and for each antenna.   6. The wireless communication apparatus according to claim 1, wherein orthogonal frequency division multiplexing (OFDM) modulation using a plurality of subcarriers between the transmitting station and the receiving station. A wireless communication apparatus using the method. A communication method in a wireless communication system configured by a transmitting station and a receiving station that perform communication via a wireless line,
In the reception process at the receiving station,
Receiving a signal transmitted by the transmitting station;
Obtaining a transfer function H of a transmission path between the transmitting station and the receiving station;
Any k-th transmission signal Tx (k) in the Ntx transmission signal group {Tx (k)} (1 ≦ k ≦ Ntx: k and Ntx are integers) that the transmission station may transmit. For performing the operation of H × Tx (k),
Rx−H × Tx (k) is calculated for an arbitrary k, where Rx is a received signal of a symbol in a series of received signal sequences;
Performing the operation Re [z] for obtaining the real part of the complex number z;
Performing an operation Im [z] for obtaining an imaginary part of the complex number z;
Performing the operation Abs [z] for obtaining the absolute value of the complex number z;
acquiring x ₀ (k) as x ₀ (k) = Abs [Re [Rx−H × Tx (k)]];
obtaining y ₀ (k) as y ₀ (k) = Abs [Im [Re [Rx−H × Tx (k)]];
Obtaining F ₀ (k) = x ₀ (k) + y ₀ (k);
Selecting k that minimizes the value of F ₀ (k) among all or part of k;
And a step of reproducing received data using the selected Tx (k) as a transmission signal for each symbol. A communication method in a wireless communication system configured by a transmitting station and a receiving station that perform communication via a wireless line,
In the reception process at the receiving station,
Receiving a signal transmitted by the transmitting station;
Obtaining a transfer function H of a transmission path between the transmitting station and the receiving station;
The k th transmission signal Tx (k) in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. ) With respect to an arbitrary k, performing a calculation of H × Tx (k);
Rx−H × Tx (k) is calculated for an arbitrary k, where Rx is a received signal of a symbol in a series of received signal sequences;
Performing the operation Re [z] for obtaining the real part of the complex number z;
Performing the operation Im [z] for obtaining the imaginary part of the complex number z;
Performing the operation Abs [z] for obtaining the absolute value of the complex number z;
Performing an operation Max [rl, r2] that selects the larger absolute value of the positive real numbers r1 and r2, and
Performing the operation Min [rl, r2] for selecting the smaller of the absolute values of the positive real numbers r1 and r2;
obtaining x ₁ (k) as x ₁ (k) = Max [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]];
obtaining y ₁ (k) as y ₁ (k) = Min [Abs [Re [Rx−H × Tx (k)]], Abs [Im [Rx−H × Tx (k)]]];
Obtaining F ₁ (k) = x ₁ (k) −y ₁ (k) + √2 × y ₁ (k);
Selecting k that minimizes the value of F ₁ (k) among all or part of k;
And a step of reproducing received data using the selected Tx (k) as a transmission signal for each symbol. A communication method in a wireless communication system configured by a transmitting station and a receiving station that perform communication via a wireless line,
In the reception process at the receiving station,
Receiving a signal transmitted by the transmitting station;
Obtaining a transfer function H of a transmission path between the transmitting station and the receiving station;
Any k-th transmission signal Tx in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. performing an operation of H × Tx (k) on (k);
When a received signal of a symbol in a series of received signal sequences is Rx, a step of performing an operation of Rx−H × Tx (k) for an arbitrary k and an operation for obtaining a real part of a complex number z Performing Re [z],
Performing the operation Im [z] for obtaining the imaginary part of the complex number z;
Acquiring and performing a calculation Abs [z] for obtaining the absolute value of a complex number _{z, x 0 (k) =} Abs [Re [Rx-H × Tx (k)]] x 0 as a _(k),
obtaining y ₀ (k) as y ₀ (k) = Abs [Im [Rx−H × Tx (k)]];
For any integer n where n ≧ 0, x _{n + 1} (k) = Cos (π / 2 ^{n + 1} ) × x _n (k) + Sin (π / 2 ^{n + 1} ) × y _n (k)
obtaining a _{(x n (k), y} n (k)) from x _{n + 1 (k),}
For any integer n where n ≧ 0, y _{n + 1} (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n (k) + Cos (π / 2 ^{n + 1} ) × y _n (k)] ( x _n (k), y _n (k)) to obtain y _{n + 1} (k);
F _m (k) = x _m (k) + y _m (k) × {(1 from (x _m (k), y _m , (k)) sequentially obtained for a predetermined integer m where m ≧ 0. Obtaining F _m (k) as −Cos (π / 2 ^{m + 1} )) / Sin (π / 2 ^{m + 1} )};
Selecting k that minimizes the value of F _m (k) among all or part of k;
And a means for reproducing received data using Tx (k) for the selected k as a transmission signal for each symbol. A wireless communication method in a wireless communication system configured by a transmission station having one or a plurality of transmission antennas and a reception station having M (M> 1: integer) reception antenna groups,
In the transmission processing of the transmitting station, the step of transmitting a signal to which a signal of a known pattern is added from one of the transmitting antennas,
In the processing of the receiving station,
Individually receiving wireless signals using the M receiving antenna groups;
Obtaining a transfer function h _i between the transmitting antenna and the i-th antenna of the receiving antenna group using a known signal pattern given to the received signal as a reference signal;
The k th transmission signal Tx (k) in the N _tx types of transmission signal groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. ) For calculating the product of the transfer function h _i with the transfer function vector H having the i-th component, that is, Tx (k) × H,
Performing an operation of Rx−Tx (k) × H on an arbitrary received signal vector Rx having a signal point of a certain symbol in a series of received signal sequences in each antenna of the receiving antenna group;
When the i-th component of an arbitrary column vector V is expressed as [V] _i , a step of performing an operation of [Rx−Tx (k) × H] _i for an arbitrary k;
Performing the operation Re [z] for obtaining the real part of the complex number z;
Performing the operation Im [z] for obtaining the imaginary part of the complex number z;
Performing the operation Abs [zl to obtain the absolute value of the complex number z;
Against 1 ≦ i ≦ M made any integer ^{_{H, x 0 [i] (}} k) = Abs [Re [[Rx-Tx (k) × H] i]] x 0 [i] as the (k) A step to obtain,
obtaining y ₀ ^[i] (k) as y ₀ ^[i] (k) = Abs [Im [[Rx−Tx (k) × H] _i ]];
For any integer n with n ≧ 0, x _{n + 1} ^[i] (k) = Cos (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Sin (π / 2 ^{n + 1} ) × y _n ^[i] obtaining x _{n + 1} ^[i] (k) from (x _n ^[i] (k), y _n ^[i] (k)) as (k);
For any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^{[i] (k)]} as the ^{_{(x n [i] (k}} ), y n [i] (k)) acquiring from the ^{_{y n + 1 [i] (}} k),
For a predetermined integer m such that m ≧ 0, F _m ^[i] (k) = x _m ^[i] (k) + y _m from (x _m ^[i] (k), y _m ^[i] (k)) Obtaining F _m ^[i] (k) as ^[i] (k) × {(1-Cos (π / 2 ^{m + 1} ) / Sin (π / 2 ^{m + 1} )};
Obtaining a total TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M;
Selecting k that minimizes TF _m (k) among all or part of k;
And a step of reproducing received data using a transmission signal Tx (k) for the selected k as a transmission signal for each symbol. Wireless communication composed of a transmitting station having N (N> 1: integer) or more first antenna groups and a receiving station having M (M> 1: integer) second antenna groups. A wireless communication method in a system, comprising:
In the transmission process of the transmitting station,
Dividing user data into N systems;
Providing a signal of an individual known pattern to the data divided into the N systems to generate a first signal sequence of the N systems;
And simultaneously superimposing and transmitting the first signal sequence at the same frequency using N first antenna groups,
In the processing of the receiving station,
Individually receiving radio signals using the M second antenna groups;
A transfer function h _{i, j} between the _j- th antenna in the first antenna group and the i-th antenna in the second antenna group using a known signal pattern given to the received signal as a reference signal. Step to get the
The k th transmission signal vector Tx in the N _tx types of transmission signal vector groups {Tx (k)} (1 ≦ k ≦ N _tx : k and N _tx are integers) that the transmission station may transmit. a step of calculating a product of a transfer function matrix H having the transfer function h _{i, j} as an (i, j) component, that is, H × Tx (k), with respect to (k);
Calculation of Rx−H × Tx (k) for an arbitrary k with respect to a received signal vector Rx having a signal point of a symbol in a series of received signal sequences in each antenna of the second antenna group as an element Performing steps,
When the i-th component of an arbitrary column vector V is expressed as [V] _i , a step of performing an operation of [Rx−H × Tx (k)] _i for an arbitrary k;
Performing the operation Re [z] for obtaining the real part of the complex number z;
Performing the operation Im [z] for obtaining the imaginary part of the complex number z;
Performing the operation Abs [z] for obtaining the absolute value of the complex number z;
For any integer i with 1 ≦ i ≦ M, x ₀ ^[i] (k) = Abs [Re [[Rx−H × Tx (k)] _i ]] as x ₀ ^[i] (k) Step to get the
obtaining y ₀ ^[i] (k) as y ₀ ^[i] (k) = Abs [Im [[Rx−H × Tx (k)] _i ]];
For any integer n where n ≧ 0, x _{n + 1} ^[i] (k) = Cos (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Sin (π / 2 ^{n + 1} ) × y _n ^[i] (k) as ^{_{(x n [i] (k}} ), y n [i] (k)) acquiring from the ^{_{x n + 1 [i] (}} k),
For any integer n where n ≧ 0, y _{n + 1} ^[i] (k) = Abs [−Sin (π / 2 ^{n + 1} ) × x _n ^[i] (k) + Cos (π / 2 ^{n + 1} ) × y _n ^[i] a step of acquiring (k)] as the ^{_{(x n [i] (k}} ), y n [i] (k)) from the ^{_{y n + 1 [i] (}} k),
For a predetermined integer m such that m ≧ 0, F _m ^[i] (k) = x _m ^[i] (k) + y _m from (x _m ^[i] (k), y _m ^[i] (k)) Obtaining F _m ^[i] (k) as ^[i] (k) × {(1-Cos (π / 2 ^{m + 1} )) / Sin (π / 2 ^{m + 1} )};
Obtaining a sum TF _m (k) of F _m ^[i] (k) for all i satisfying 1 ≦ i ≦ M;
Selecting k that minimizes TF _m (k) among all or part of k;
And a step of reproducing received data using each element of the column vector Tx (k) for the selected k as a transmission signal for each symbol and each antenna. The wireless communication method according to any one of claims 7 to 11, wherein orthogonal frequency division multiplexing (OFDM) modulation using a plurality of subcarriers between the transmitting station and the receiving station is performed. A wireless communication method using the method.

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