JP2010200001A - Radio communication station, receiving base station, and relay station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drastically reduce interference power by preventing a maximum eigenvalue from being used for communication. <P>SOLUTION: Transmissions of a transmitting base station 21 and a terminal station 31 are simultaneously suspended. A receiving base station 22 receives a preamble signal from the transmitting base station 21, estimates a propagation channel matrix H between a transmit antenna 11 of the transmitting base station 21 and a receive antenna 12 of the receiving base station 22 from the received preamble signal, and determines a matrix with elements which are 0 of its column vectors, to be multiplied to the maximum eigenvalue of eigenvalues of Σ obtained by singular value decomposition. The transmission of signals from the terminal station 31 is resumed, the each receiving base station 22 receives signals coming from the terminal station 31 and multiplies reception signals of the receive antenna 12 by the matrix to decode signals coming from the terminal station 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio system using the same frequency band in uplink and downlink, and relates to a radio communication method, a reception base station, and a relay station that reduce inter-base station interference.

  When there are at least two sets of radio stations that perform radio communication by transmitting and receiving signals to and from each other, and two sets use the same frequency at the same time, from one set of radio stations to the other When a signal arrives at a set of wireless stations, it becomes interference and the wireless communication quality is greatly degraded.

  An adaptive array antenna is an antenna that suppresses the power of received interference signals by using array antennas, multiplying the received signals of each antenna by weights, and combining these signals. FIG. 16 is a block diagram showing a configuration of a basic adaptive array antenna according to the prior art (see, for example, Non-Patent Document 1). The signals received by the respective antennas 1-1 to 1-3 are multiplied by weight information output from the signal processing circuit 4 in the multipliers 2-1 to 2-3, and synthesized by the adder 3, and output to the array. Is output as 5.

  In the illustrated example, since the number of antennas is 3, two interference waves A and B can be removed. If the number of antennas is defined as the degree of antenna freedom, the number of (antenna degrees of freedom-1) interference waves can be suppressed. On the other hand, even when there are desired waves of a plurality of different signals, an output for a plurality of different signals can be obtained by giving an appropriate weight to each signal. This is called spatial multiplexing, and aims to further improve the transmission rate by applying the adaptive array antenna not to interference cancellation but to multiplexing a plurality of different signals.

By Kikuma, Adaptive Antenna Technology, Ohmsha

  By the way, when spatial multiplexing is realized by the above-described adaptive array antenna, the maximum number of multiplexing is equal to the degree of freedom of the antenna. Similarly, the maximum number of multiplexing for the interference wave is equal to the degree of freedom of the antenna. That is, in the prior art, when there is an interference wave, there is a problem in that the number of multiplexed spatial multiplexing decreases according to the number of independent interference waves, and the transmission speed deteriorates. When signals arrive from an interfering station performing spatial multiplexing communication using multiple antennas, if interference cancellation is performed for all signals, many degrees of freedom are lost, and the effect of spatial multiplexing at the local station is lost. There is a problem of a significant decrease.

  The present invention has been made in view of such circumstances, and the object thereof is to provide a radio communication method, a receiving base station, and a radio base station that can significantly reduce interference power by not using the maximum eigenvalue in communication. And providing a relay station.

  In order to solve the above-described problem, the present invention provides a transmission device that has a plurality of antennas and is transmitted from the second transmission device at least between the first transmission device and the second transmission device. In the wireless communication method for receiving a signal, the steps of simultaneously stopping the transmission between the first transmission device and the second transmission device, the step of transmitting a preamble signal from the first transmission device, Receiving a preamble signal transmitted from one device at the receiving device, and between the antenna of the first transmitting device and the plurality of antennas of the receiving device from the preamble signal received by the receiving device. Estimating a propagation channel matrix, obtaining a left orthogonal matrix by singular value decomposition of the propagation channel matrix, and obtaining a maximum singularity obtained by singular value decomposition on the left orthogonal matrix Obtaining a matrix in which the element of the column vector of the left orthogonal matrix multiplied by 0 is multiplied by 0, restarting signal transmission from the second transmission device, and transmitting a signal arriving from the second transmission device to the Receiving at the receiving device; and decoding the transmission signal coming from the second transmitting device by multiplying the transmission signal from the second transmitting device received at the receiving device by the matrix. A wireless communication method characterized by including the wireless communication method.

  The present invention is the above invention, wherein the receiving device is a receiving base station having a plurality of antennas, the first transmitting device is a transmitting base station having a plurality of antennas, and the second The transmitting apparatus is a terminal station.

  The present invention is the above invention, wherein the receiving device is a relay station having a plurality of antennas, the first transmitting device is a transmitting base station having a plurality of antennas, and the second transmitting device. Is a transmission base station having a plurality of antennas.

  In order to solve the above-described problem, the present invention is a receiving apparatus having a plurality of antennas, which is transmitted from the second transmitting apparatus at least between the first transmitting apparatus and the second transmitting apparatus. In the wireless communication method for receiving a transmission signal, a step of stopping transmission of the first transmission device and the second transmission device all at once, a step of transmitting a transmission signal from the first transmission device, Receiving a transmission signal transmitted from the first device by the receiving device; calculating a correlation matrix of the transmission signal received by the receiving device; and corresponding to an eigenvalue and each eigenvalue from the correlation matrix Calculating a eigencolumn vector, obtaining a matrix in which all eigencolumn vectors are arranged using only the eigencolumn vector corresponding to the maximum eigenvalue as a zero vector, and the second Resuming signal transmission from the transmission device, receiving the transmission signal arriving from the second transmission device at the reception device, and multiplying the reception signal at each antenna of the reception device by the matrix, And a step of decoding a transmission signal arriving from the second transmission device.

  The present invention is the above invention, wherein the receiving device is a receiving base station having a plurality of antennas, the first transmitting device is a transmitting base station having a plurality of antennas, and the second The transmission device is a terminal device.

  The present invention is the above invention, wherein the receiving device is a relay station having a plurality of antennas, the first transmitting device is a transmitting base station having a plurality of antennas, and the second transmitting device. Is a transmission base station having a plurality of antennas.

  Further, in order to solve the above-described problem, the present invention includes a plurality of antennas that receive transmission signals transmitted from the terminal device between a transmission base station having at least a plurality of antennas and the terminal device. In the receiving base station, receiving means for receiving a preamble signal transmitted from the transmitting base station and a transmitting signal transmitted from the terminal device; and a preamble of the transmitting base station received by the receiving means A propagation channel matrix estimating means for estimating a propagation channel matrix between an antenna of the transmitting base station and a plurality of antennas of the receiving base station from a signal, and a propagation channel matrix estimated by the propagation channel matrix estimating means Singular value decomposition to obtain a left orthogonal matrix, and the column of the left orthogonal matrix multiplied by the maximum singular value obtained by singular value decomposition on the left orthogonal matrix Matrix calculating means for calculating a matrix with the elements of Kuttle as 0, and the transmission signal of the terminal apparatus received by the receiving means is multiplied by the matrix calculated by the matrix calculating means to arrive from the terminal apparatus And a decoding means for decoding the transmission signal to be received.

  Further, in order to solve the above-described problem, the present invention includes a plurality of antennas that receive transmission signals transmitted from the terminal device between a transmission base station having at least a plurality of antennas and the terminal device. In the receiving base station, receiving means for receiving a transmission signal transmitted from the transmitting base station and a transmitting signal transmitted from the terminal device, and transmission of the transmitting base station received by the receiving means A correlation matrix calculating means for calculating a correlation matrix of the signal, an eigenvector calculating means for calculating eigenvalues and eigensequence vectors corresponding to the eigenvalues from the correlation matrix calculated by the correlation matrix calculating means, and calculating by the eigenvector calculating means Matrix calculating means for calculating a matrix in which all eigencolumn vectors are arranged with only the eigencolumn vector corresponding to the maximum eigenvalue as a zero vector. And a decoding means for decoding the transmission signal coming from the terminal apparatus by multiplying the transmission signal of the terminal apparatus received by the receiving means by the matrix calculated by the matrix calculation means. The receiving base station.

  In order to solve the above-described problem, the present invention provides the first transmission base station between a first transmission base station having at least a plurality of antennas and a second transmission base station having a plurality of antennas. In a relay station having a plurality of antennas for receiving a transmission signal transmitted from a transmission base station, a transmission transmitted from the preamble signal transmitted from the second transmission base station and the first transmission device Between the antenna of the second transmission base station and the plurality of antennas of the relay station, based on the preamble signal of the second transmission base station received by the reception means and the reception signal received by the reception means A propagation channel matrix estimation means for estimating a propagation channel matrix of the signal, a singular value decomposition of the propagation channel matrix estimated by the propagation channel matrix estimation means to obtain a left orthogonal matrix, and the left orthogonal matrix Matrix calculating means for calculating a matrix in which the element of the column vector of the left orthogonal matrix to be multiplied by the maximum singular value obtained by singular value decomposition is 0, and the first transmission base station received by the receiving means And a decoding means for decoding the transmission signal arriving from the first transmission base station by multiplying the transmission signal by the matrix calculated by the matrix calculation means.

  In order to solve the above-described problem, the present invention provides a transmission signal transmitted from the first transmission base station at least between the first transmission base station and the second transmission base station. Receiving means for receiving a transmission signal transmitted from the first transmission base station and a transmission signal transmitted from the second transmission base station in a relay station having a plurality of antennas for receiving A correlation matrix calculating means for calculating a correlation matrix of the transmission signal of the second transmission base station received by the receiving means; an eigenvalue and an eigenvalue corresponding to each eigenvalue from the correlation matrix calculated by the correlation matrix calculating means An eigenvector calculating means for calculating a column vector; and a matrix in which all eigencolumn vectors are arranged with only the eigencolumn vector corresponding to the maximum eigenvalue calculated as the zero vector calculated by the eigenvector calculating means. The first transmission base station by multiplying the matrix calculated by the matrix calculation means by the matrix calculation means to be output and multiplying the transmission signal of the first transmission base station received by the reception means by the matrix calculation means A relay station comprising decoding means for decoding an incoming signal.

  According to the present invention, it is possible to significantly reduce the power of the interference signal by applying a weight to the receiving side to suppress the power of the maximum eigenvalue, and also compared to reducing the interference signal with the adaptive array antenna. Thus, it is possible to suppress the interference power without reducing all the antenna degrees of freedom.

It is a block diagram which shows the structure of the transmitting station by this invention. It is a block diagram which shows the structure of the receiving station by this invention. It is a block diagram which shows the structure of the terminal station (or relay station) by this invention. It is a block diagram which shows the structure of the radio | wireless communications system by this 1st Embodiment. It is a flowchart for demonstrating the operation | movement of this 1st Embodiment. It is a block diagram which shows the structure of the radio | wireless communications system by this 2nd Embodiment. It is a flowchart for demonstrating the operation | movement of this 2nd Embodiment. It is a block diagram which shows the structure of the radio | wireless communications system by this 3rd Embodiment. It is a flowchart for demonstrating the operation | movement of this 3rd Embodiment. It is a block diagram which shows the structure of the radio | wireless communications system by this 4th Embodiment. It is a flowchart for demonstrating operation | movement of this 4th Embodiment. In this 1st thru | or 4th embodiment, it is a figure which shows power ratio P (N) with respect to base station height hb. It is a block diagram which shows the measurement environment of FIG. In the first to fourth embodiments, the average channel capacity is shown when interference is not suppressed for the distance r between the receiving base station and the terminal station (or relay station) and when only P (1) is suppressed. FIG. It is a block diagram which shows the measurement environment of FIG. It is a block diagram which shows the structure of the basic adaptive array antenna by a prior art.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the present invention, in a receiving apparatus having a plurality of antennas, a propagation channel matrix between an antenna of a transmitting apparatus that transmits a signal that causes interference and an antenna of the own apparatus is estimated in advance, and the propagation channel matrix is singularly decomposed. The left orthogonal matrix U is obtained, a matrix UN having 0 as the element of the column vector multiplied by the maximum singular value in U is obtained, and the target received signal is multiplied by UN (first, Third embodiment).

  Further, in the present invention, in a receiving apparatus having a plurality of antennas, a correlation matrix of a signal received from a transmitting apparatus that transmits a signal that causes interference is calculated in advance, and an eigenvalue and an eigensequence corresponding to each eigenvalue are calculated from the correlation matrix. A vector is calculated, and in a matrix in which all eigencolumn vectors are arranged, a matrix UN in which the elements of the eigenvector corresponding to the maximum eigenvalue are set to 0 is obtained, and a target received signal is multiplied by UN ( Second and fourth embodiments).

  Therefore, in the present invention, the power of the interference signal can be greatly reduced without greatly reducing the degree of freedom of the receiving antenna.

A. Basic Configuration of the Present Invention First, the transmitting station, receiving station, and terminal station (or relay station) used in the present invention will be described. FIG. 1 is a block diagram showing a configuration of a transmitting station according to the present invention. In the figure, the transmission station 20 includes a data generation circuit 30, a data division circuit 31, an IFFT (Inverse Fast Fourier Transform) processing circuit 32, a transmission signal conversion circuit 33, radio units 34-1 to 34-n, and a transmission antenna 35-. 1 to 35-n. The data generation circuit 30 generates a transmission signal.

  The data dividing circuit 31 divides one transmission signal into designated signal sequences (N). The IFFT processing circuit 32 converts a signal on the frequency axis into a signal on the time axis by inverse fast Fourier transform. The transmission signal conversion circuit 33 performs vector conversion of the transmission signal. The radio units 34-1 to 34-n perform processing such as signal amplification and frequency conversion on the transmission signal, and transmit from the transmission antennas 35-1 to 35-n.

  FIG. 2 is a block diagram showing a configuration of a receiving station according to the present invention. In the figure, a receiving station 22 includes receiving antennas 40-1 to 40-n, radio units 41-1 to 41-n, a received signal converting circuit 42, an FFT (Fast Fourier Transform) processing circuit 43, a data combining circuit 44, a receiving unit. A data processing circuit 45, a channel information acquisition circuit 46, and a weight calculation circuit 47 are provided.

  The radio units 41-1 to 41-n independently perform processing such as signal amplification and frequency conversion on reception signals received by the reception antennas 40-1 to 40-n in each reception system. The reception signal conversion circuit 42 combines the weighted value (weight) from the weight calculation circuit 47 with the reception signal, thereby removing the interference wave from the desired reception signal.

  The FFT processing circuit 43 separates it into subcarriers by fast Fourier transform processing. The data combining circuit 44 combines received signals that have been divided into a plurality of signal sequences. The reception data processing circuit 45 performs predetermined processing on the received data. The channel information acquisition circuit 46 acquires channel transfer function information from the reception state of a known interference signal or preamble signal. The weight calculation circuit 47 calculates an appropriate weight value (weight) from the transfer function information and supplies it to the reception signal conversion circuit 42.

  FIG. 3 is a block diagram showing a configuration of a terminal station (or relay station) according to the present invention. It should be noted that portions corresponding to the transmitting station 20 shown in FIG. 1 and the receiving station 22 shown in FIG. In the figure, the terminal station (or relay station 41) 31 transmits and receives the total signals from the radio units 34-1 to 34-n on the transmitting side via the circulators 50-1 to 50-n. 51-n is supplied and transmitted. On the other hand, the received signals received by the transmission / reception antennas 51-1 to 51-n are supplied to the radio units 41-1 to 41-n on the receiving side via the circulators 50-1 to 50-n. ing. As described above, the configuration on the transmission side and the configuration on the reception side are the same as those of the transmission station 20 shown in FIG. 1 and the reception station 22 shown in FIG.

B. First Embodiment Next, a first embodiment of the present invention will be described.
FIG. 4 is a block diagram showing the configuration of the wireless communication system according to the first embodiment. In the figure, reference numeral 21 denotes a transmission base station, which has the configuration shown in FIG. Reference numeral 22 denotes a receiving base station, which has the configuration shown in FIG. 2 described above and includes a receiving antenna 12 composed of a plurality of antenna elements. Reference numeral 31 denotes a terminal station (transmission terminal apparatus), which has the configuration shown in FIG. 51 is an interference signal (propagation channel H), and 52 is a desired signal.

  Next, FIG. 5 is a flowchart for explaining the operation of the first embodiment. First, transmission of the transmission base station 21 and the terminal station (for transmission) 31 is stopped all at once (step S1), a preamble signal is transmitted from the transmission base station 21 and received by the reception base station 22 ( Step S2). Next, the reception base station 22 estimates the propagation channel matrix H between the transmission antenna 11 of the transmission base station 21 and the reception antenna 12 of the reception base station 22 from the received preamble signal (step S3).

  Next, the receiving base station 22 performs the singular value decomposition shown in Equation (1), and multiplies the maximum eigenvalue among the eigenvalues of Σ obtained by the singular value decomposition as shown in Equation (2). UN with the element of the column vector of U as 0 is obtained (step S4).

  In Equation (1), V is an orthonormal vector serving as the basis of the input of the propagation channel matrix H, Σ is a matrix having the square root (singular value) of the eigenvalue as a diagonal, and U is the propagation channel matrix H. Represents an orthonormal vector that is the basis of the output.

  Next, the transmission of the signal from the terminal station (for transmission) 31 is resumed, the signal arriving from the terminal station (for transmission) 31 is received by the reception base station 22 (step S5), and the reception base station 22 Then, a signal arriving from the terminal station (for transmission) 31 is decoded by multiplying the reception signal at each of the reception antennas 12 by the matrix UN (step S6).

  In the above-described operation, setting the column vector element to zero is equivalent to eliminating one degree of freedom of the receiving antenna 12. Since communication between base stations is often a line-of-sight environment, it is expected that the ratio of the power that the maximum eigenvalue extends is greater than other eigenvalues. Therefore, it is possible to suppress a large power with a maximum eigenvalue by eliminating one degree of freedom of the receiving antenna 12.

  Therefore, according to the first embodiment described above, the power from the transmitting base station 21 can be greatly reduced by reducing the degree of freedom of the receiving antenna 12 of the receiving base station 22 by one. Capacity can be increased.

C. Second Embodiment Next, a second embodiment of the present invention will be described.
FIG. 6 is a block diagram showing a configuration of a wireless communication system according to the second embodiment. In the figure, reference numeral 23 denotes a transmission base station, which has the configuration shown in FIG. 1 described above and includes a transmission antenna 11 composed of a plurality of antenna element groups. Reference numeral 22 denotes a receiving base station, which has the configuration shown in FIG. 2 described above and includes a receiving antenna 12 composed of a plurality of antenna elements. Reference numeral 31 denotes a terminal station (transmission terminal device), which has the configuration shown in FIG. 3 described above and includes a transmission / reception antenna 13 including a plurality of antenna element groups. 51 is an interference signal and 52 is a desired signal.

  Next, FIG. 7 is a flowchart for explaining the operation of the second embodiment. First, transmission of terminal stations (for transmission) 31 is stopped all at once (step S11), and a transmission signal (interference signal) 51 transmitted from the transmission base station 23 is received by the reception base station 22 (step S12). . Next, the receiving base station 22 calculates a correlation matrix of the received transmission signal (interference signal) 51 (step S13), and from the correlation matrix, eigenvalues and eigencolumn vectors corresponding to the eigenvalues {u1, u2, u3,. } Is calculated (step S14).

  Next, the receiving base station 22 obtains a matrix UN = {0, u2, u3,...] In which all eigencolumn vectors are arranged with only the eigencolumn vector corresponding to the maximum eigenvalue as a zero vector (step S15). Next, the transmission of the signal is resumed from the terminal station (for transmission) 31, the signal arriving from the terminal station (for transmission) 31 is received by the reception base station 22 (step S16), and the reception base station 22 A signal arriving from the transmission terminal apparatus 31 is decoded by multiplying the reception signal at each of the reception antennas 12 by the matrix UN (step S17).

  As described above, since communication between base stations is often in a line-of-sight environment, it is expected that the ratio of the power that the maximum eigenvalue extends is larger than other eigenvalues. Therefore, it is possible to suppress a large power with a maximum eigenvalue by eliminating one degree of freedom of the receiving antenna 12.

  Therefore, according to the second embodiment described above, the power from the transmitting base station 23 can be greatly reduced by reducing the degree of freedom of the receiving antenna 12 of the receiving base station 22 by one. Capacity can be increased.

D. Third Embodiment Next, a third embodiment of the present invention will be described.
FIG. 8 is a block diagram showing the configuration of the wireless communication system according to the third embodiment. In the figure, reference numeral 21 denotes a transmission base station (BS1), which has the configuration shown in FIG. 1 described above and includes a transmission antenna 11 composed of a plurality of antenna element groups. Reference numeral 24 denotes a transmission base station (BS2), which has the configuration shown in FIG. 1 and includes a transmission antenna 11 composed of a plurality of antenna element groups. Reference numeral 41 denotes a relay station, which has the configuration shown in FIG. 3 and includes a reception antenna 14 composed of a plurality of antenna element groups. 51 is an interference signal (propagation channel H), and 52 is a desired signal.

  Next, FIG. 9 is a flowchart for explaining the operation of the third embodiment. First, the transmission of the relay station 41, the transmission base stations (BS1) 21 and (BS2) 24 is stopped all at once (step S21), and the transmission base station which is not the transmission base station (BS1) 21 requiring the signal to be relayed (BS2) The preamble signal transmitted from 24 is received by the relay station 41 (step S22). The relay station 41 estimates the propagation channel H between the transmission antenna 11 of the transmission base station (BS2) 24 and the reception antenna 14 of the relay station 41 from the received preamble signal (step S23).

  Next, the relay station 41 performs the singular value decomposition shown in the above-described equation (1), and, as shown in the above-described equation (2), sets the maximum eigenvalue among the eigenvalues of Σ obtained by the singular value decomposition. UN is determined by setting the element of the U column vector to be multiplied to 0 (step S24). The relay station 41 receives the transmission signal arriving from the transmission base station (BS1) 21 (step S25), and multiplies the reception signal arriving at the reception antenna 14 of the relay station 41 by the matrix UN, thereby The signal coming from the base station (BS1) 21 is decoded (step S26).

  As described above, setting the column vector element to 0 is equivalent to eliminating one degree of freedom of the receiving antenna. Since communication between base stations is often in a line-of-sight environment, it is expected that the ratio of the power that the maximum eigenvalue extends is greater than other eigenvalues. Therefore, it is possible to suppress a large power with a maximum eigenvalue by eliminating one degree of freedom of the receiving antenna 12.

  Therefore, according to the third embodiment described above, the power from the transmission base station (BS1) 21 can be greatly reduced by reducing the degree of freedom of the reception antenna 14 of the relay station 41 by one, and the wireless The capacity of the system can be increased.

E. Fourth Embodiment Next, a fourth embodiment of the present invention will be described.
FIG. 10 is a block diagram showing a configuration of a wireless communication system according to the fourth embodiment. In the figure, reference numeral 21 denotes a transmission base station (BS1), which has the configuration shown in FIG. Reference numeral 24 denotes a transmission base station (BS2), which has the configuration shown in FIG. 1 and includes a transmission antenna 11 composed of a plurality of antenna element groups. Reference numeral 41 denotes a relay station, which has the configuration shown in FIG. 3 and includes a reception antenna 14 composed of a plurality of antenna element groups. 51 is an interference signal (propagation channel H), and 52 is a desired signal.

  Next, FIG. 11 is a flowchart for explaining the operation of the fourth embodiment. First, transmission of the relay station 41 and the transmission base station (BS1) 21 is stopped all at once (step S31), and the interference signal 51 transmitted from the transmission base station (BS2) 24, which is an interference station, is transmitted to the relay station 41. (Step S32). Next, the relay station 41 calculates a correlation matrix of the received transmission signal (interference signal) 51 (step S33), and from the correlation matrix, eigenvalues and eigensequence vectors {u1, u2, u3,. Is calculated (step S34).

  Next, the relay station 41 uses only the eigencolumn vector corresponding to the maximum eigenvalue as a zero vector, and obtains a matrix UN = {0, u2, u3,...} In which all eigencolumn vectors are arranged (step S35). Next, the transmission of the signal from the transmission base station (BS1) 21 is resumed, the signal arriving from the transmission base station (BS1) 21 is received by the relay station 41 (step S36), and the relay station 41 receives the reception antenna. The signal arriving from the transmission base station (BS1) 21 is decoded by multiplying the reception signal in each of 14 by the matrix UN (step S37).

  As described above, since communication between base stations is often in a line-of-sight environment, it is expected that the ratio of the power that the maximum eigenvalue extends is larger than other eigenvalues. Therefore, it is possible to suppress a large electric power with a maximum eigenvalue by eliminating only one degree of freedom of the receiving antenna.

  Therefore, according to the above-described fourth embodiment, the power from the transmission base station (BS1) can be significantly reduced by reducing the degree of freedom of the receiving antenna of the relay station 41 by one. The capacity can be increased.

F. Effects of First to Fourth Embodiments FIG. 12 is a diagram illustrating the power ratio P (N) with respect to the base station height hb in the first to fourth embodiments described above. FIG. 13 is a block diagram showing the measurement environment of FIG. From the propagation channel response obtained in the outdoor environment, if the i-th eigenvalue is λi, the ratio of the total interference power up to the first to N-th eigenvalues and the total power P0 of the incoming interference wave is It is defined as shown in Equation (3).

  In FIG. 13, the transmission base station 21 includes a transmission antenna 11 having a height of 25 m and including a plurality of antenna element groups. The receiving base station 22 includes a receiving antenna 12 composed of a plurality of antenna element groups, and a mechanism that can change the height of the receiving antenna 12 from the ground, that is, the receiving antenna height hb, to 7 m, 10 m, 13 m, and 16 m. ing. Further, as the receiving antenna height hb is changed from 7 m to 16 m, the environment changes from the non-line-of-sight environment to the line-of-sight environment. It can be seen from FIG. 12 that the ratio of the maximum eigenvalue exceeds 98% in a line-of-sight environment (an environment in which the receiving antenna height exceeds 10 m) between base stations or between a base station and a relay station. That is, it means that the electric power with the maximum eigenvalue is concentrated.

  Next, FIG. 14 shows a case where interference suppression for the distance r between the receiving base station and the terminal station (or relay station) is not performed (w / Interference cancellation) and P ( It is a figure which shows the average channel capacity | capacitance at the time of suppressing only (1) (w / o Interference cancellation). FIG. 15 is a block diagram showing the measurement environment of FIG.

  In FIG. 15, the transmission base station 21 has a height of 25 m and includes a transmission antenna 11 composed of four antenna elements. The receiving base station 22 has a height of 16 m and includes a receiving antenna 12 composed of four antenna elements. The terminal station 31 includes the transmission antenna 13 and the distance from the reception base station 22 is r. The spatial multiplexing number in this evaluation is 4-N because the number of elements is 4. As shown in FIG. 13, since the power spanned by the first eigenvalue is high, suppression of P (1) means that the channel capacity is greatly improved.

11 to 15 transmitting antenna, receiving antenna 21 to 23 transmitting base station, receiving base station 31 terminal station 41 relay station 51 to 55 interference signal, desired signal 30 data generation circuit 31 data division circuit 32 IFFT processing circuit 33 transmission signal conversion Circuit 34-1 to 34-n Radio section 35-1 to 35-n Transmit antenna 40-1 to 40-n Receive antenna 41-1 to 41-n Radio section 42 Receive signal conversion circuit 43 FFT processing circuit 44 Data combination circuit 45 reception data processing circuit 46 channel information acquisition circuit 47 weight calculation circuit 50-1 to 50-n circulator 51-1 to 50-n transmission / reception antenna

Claims (10)

In a wireless communication method for receiving a transmission signal transmitted from the second transmission device at least between the first transmission device and the second transmission device by a reception device having a plurality of antennas,
Stopping transmission of the first transmission device and the second transmission device simultaneously;
Transmitting a preamble signal from the first transmission device;
Receiving a preamble signal transmitted from the first device at the receiving device;
Estimating a propagation channel matrix between an antenna of the first transmitting device and a plurality of antennas of the receiving device from a preamble signal received by the receiving device;
A singular value decomposition is performed on the propagation channel matrix to obtain a left orthogonal matrix, and a matrix in which the element of the column vector of the left orthogonal matrix multiplied by the maximum singular value obtained by the singular value decomposition on the left orthogonal matrix is obtained is obtained. Steps,
Resuming transmission of a signal from the second transmission device and receiving the transmission signal arriving from the second transmission device at the reception device;
Decoding the transmission signal arriving from the second transmission device by multiplying the transmission signal from the second transmission device received by the reception device by the matrix. Method. The receiving device is a receiving base station having a plurality of antennas,
The first transmission device is a transmission base station having a plurality of antennas,
The second transmission device is a terminal station;
The wireless communication method according to claim 1. The receiving device is a relay station having a plurality of antennas,
The first transmission device is a transmission base station having a plurality of antennas,
The second transmission device is a transmission base station having a plurality of antennas.
The wireless communication method according to claim 1. In a wireless communication method for receiving a transmission signal transmitted from the second transmission device at least between the first transmission device and the second transmission device by a reception device having a plurality of antennas,
Stopping transmission of the first transmission device and the second transmission device simultaneously;
Transmitting a transmission signal from the first transmission device;
Receiving a transmission signal transmitted from the first device at the receiving device;
Calculating a correlation matrix of a transmission signal received by the receiving device;
Calculating eigenvalues and eigencolumn vectors corresponding to each eigenvalue from the correlation matrix;
Obtaining a matrix in which all eigencolumn vectors are arranged with only the eigencolumn vector corresponding to the maximum eigenvalue as a zero vector;
Resuming transmission of a signal from the second transmission device and receiving the transmission signal arriving from the second transmission device at the reception device;
Decoding a transmission signal arriving from the second transmission device by multiplying the reception signal at each antenna of the reception device by the matrix. The receiving device is a receiving base station having a plurality of antennas,
The first transmission device is a transmission base station having a plurality of antennas,
The second transmission device is a terminal device;
The wireless communication method according to claim 4. The receiving device is a relay station having a plurality of antennas,
The first transmission device is a transmission base station having a plurality of antennas,
The second transmission device is a transmission base station having a plurality of antennas.
The wireless communication method according to claim 4. In a receiving base station having a plurality of antennas for receiving transmission signals transmitted from the terminal device, between the transmitting base station having at least a plurality of antennas and the terminal device,
Receiving means for receiving a preamble signal transmitted from the transmission base station and a transmission signal transmitted from the terminal device;
Propagation channel matrix estimation means for estimating a propagation channel matrix between the antenna of the transmission base station and a plurality of antennas of the reception base station from the preamble signal of the transmission base station received by the reception means; ,
A column vector of the left orthogonal matrix multiplied by the maximum singular value obtained by singular value decomposition of the propagation channel matrix estimated by the propagation channel matrix estimation means to obtain a left orthogonal matrix and singular value decomposition on the left orthogonal matrix Matrix calculation means for calculating a matrix with the elements of 0 as 0,
Decoding means for decoding a transmission signal arriving from the terminal device by multiplying the transmission signal of the terminal device received by the reception means by the matrix calculated by the matrix calculation means. Receiving base station. In a receiving base station having a plurality of antennas for receiving transmission signals transmitted from the terminal device, between the transmitting base station having at least a plurality of antennas and the terminal device,
Receiving means for receiving a transmission signal transmitted from the transmission base station and a transmission signal transmitted from the terminal device;
Correlation matrix calculating means for calculating a correlation matrix of a transmission signal of the transmission base station received by the receiving means;
Eigenvector calculating means for calculating eigenvalues and eigencolumn vectors corresponding to the eigenvalues from the correlation matrix calculated by the correlation matrix calculating means;
Matrix calculation means for calculating a matrix in which all eigencolumn vectors are arranged with only the eigencolumn vector corresponding to the maximum eigenvalue calculated as the zero vector calculated by the eigenvector calculation means;
Decoding means for decoding a transmission signal arriving from the terminal device by multiplying the transmission signal of the terminal device received by the reception means by the matrix calculated by the matrix calculation means. Receiving base station. A plurality of receiving signals transmitted from the first transmission base station between a first transmission base station having at least a plurality of antennas and a second transmission base station having a plurality of antennas. In a relay station with an antenna,
Receiving means for receiving a preamble signal transmitted from the second transmission base station and a transmission signal transmitted from the first transmission device;
A propagation channel for estimating a propagation channel matrix between the antenna of the second transmission base station and the plurality of antennas of the relay station from the preamble signal of the second transmission base station received by the receiving means Matrix estimation means;
A column vector of the left orthogonal matrix obtained by singular value decomposition of the propagation channel matrix estimated by the propagation channel matrix estimation means to obtain a left orthogonal matrix and multiplying the maximum singular value obtained by singular value decomposition on the left orthogonal matrix Matrix calculation means for calculating a matrix with the elements of 0 as 0,
A transmission signal arriving from the first transmission base station is decoded by multiplying the transmission signal of the first transmission base station received by the reception means by the matrix calculated by the matrix calculation means. And a decoding means. In a relay station having a plurality of antennas for receiving transmission signals transmitted from the first transmission base station at least between the first transmission base station and the second transmission base station,
Receiving means for receiving a transmission signal transmitted from the first transmission base station and a transmission signal transmitted from the second transmission base station;
Correlation matrix calculating means for calculating a correlation matrix of a transmission signal of the second transmission base station received by the receiving means;
Eigenvector calculating means for calculating eigenvalues and eigencolumn vectors corresponding to the eigenvalues from the correlation matrix calculated by the correlation matrix calculating means;
Matrix calculation means for calculating a matrix in which all eigencolumn vectors are arranged with only the eigencolumn vector corresponding to the maximum eigenvalue calculated as the zero vector calculated by the eigenvector calculation means;
Decoding for decoding a signal arriving from the first transmission base station by multiplying the transmission signal of the first transmission base station received by the reception means by the matrix calculated by the matrix calculation means And a relay station.

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