JP2005318328A - Radio communications apparatus and transmission power control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the influence imposed on calculation of antenna weight by SINR of a receiving signal. <P>SOLUTION: A radio communications apparatus is provided with a relative matrix operator 32 for calculating the antenna weight, on the basis of reception outputs of a plurality of antennas; and a transmitter 56 for controlling the antenna directivity of a transmission signal, on the basis of the antenna weight. The apparatus comprises the relative matrix operator 32 for measuring information about the reception strength for each reception signal of each antenna, and a pseudo noise control unit 36 and a pseudo-noise adder 38 for increasing the noise strength of each reception signal, in response to the information about the reception strength of the reception signal of each antenna. The operator 32 calculates the antenna weight, on the basis of the reception signal in which noise is increased. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radio communication apparatus and a transmission power control method.

  In a mobile communication system such as a PHS system, an adaptive array technology such as an SDMA (Space Division Multiple Access) system may be used. In a wireless communication system using the adaptive array technology, data transmission is performed using a plurality of antennas. In this case, the received signals received by the plurality of antennas are regenerated using antenna weights calculated based on the correlation between the received signal and the reference signal. Further, the directivity of the transmission signal is determined based on the antenna weight.

Patent Document 1 discloses an invention relating to control of a terminal adaptive array antenna reception operation that enables good data reception independent of the reception state without increasing power consumption. Non-Patent Document 1 is a book that is widely used as a textbook on adaptive antenna technology.
JP 2003-37547 A Nobuyoshi Kikuma, “Adaptive Antenna Technology”, Ohmsha, October 10, 2003, p. 11-54

  However, as will be described in detail later, in the conventional method, when calculating the antenna weight using an information processing device such as a computer, the signal to interference and noise ratio (SINR) is large. On the contrary, the error of the antenna weight may increase. For this reason, the directivity of the transmission signal becomes inadequate, and communication with the mobile station apparatus serving as a communication partner is hindered, as well as interference with other mobile station apparatuses.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a radio communication apparatus and a transmission power control method capable of reducing the influence of received signal SINR on calculation of antenna weight. is there.

  In order to solve the above problems, a wireless communication apparatus according to the present invention controls an antenna weight calculating unit that calculates an antenna weight based on reception outputs of a plurality of antennas, and controls an antenna directivity of a transmission signal based on the antenna weight. And a control means for performing reception level measurement means for measuring information related to reception strength for each of the reception signals of each antenna, and the information relating to reception strength of the reception signal of each antenna according to the information Noise increasing means for increasing the noise intensity of each received signal, wherein the antenna weight calculating means calculates an antenna weight based on each received signal whose noise intensity has been increased.

  By doing so, the influence of the SINR of the received signal on the calculation of the antenna weight can be reduced.

  In the wireless communication apparatus, the noise increasing unit may increase the noise intensity of each received signal by adding noise to the received signal.

  In the wireless communication apparatus, the information regarding the reception strength of the reception signal may be the reception strength of the reception signal.

  In the wireless communication apparatus, the information regarding the reception intensity of the reception signal may be a signal-to-interference noise ratio of the reception signal.

  Further, in the wireless communication apparatus, a signal-to-interference noise ratio correction amount determining unit that determines a signal-to-interference noise ratio correction amount according to the reception strength of each antenna, the received signal added with the pseudo noise, and the Transmission signal transmission power determining means for determining the transmission power or modulation scheme of the transmission signal based on the signal-to-interference noise ratio correction amount may be further included.

  In addition, the transmission power control method according to the present invention includes a reception level measurement step of measuring information on reception strength for each of the reception signals of a plurality of antennas, and the information according to information on reception strength of the reception signals of each antenna. A noise increasing step for increasing the noise intensity of each received signal, an antenna weight calculating step for calculating an antenna weight based on each received signal whose noise intensity has been increased, and an antenna directivity of the transmitted signal based on the antenna weight And a control step for controlling.

  Embodiments of the present invention will be described with reference to the drawings.

  A mobile communication system 1 according to the present embodiment includes a base station apparatus 2, a mobile station apparatus 3, and a communication network 4 as shown in FIG. The base station device 2 communicates with the normal communication network 4 and the mobile station device 3.

  As shown in FIG. 2, the communication device 5 used as the base station device 2 includes a control unit 10, a wireless communication unit 11, a storage unit 12, and a network interface unit 13. The control unit 10 controls each unit of the communication device 5 and executes processes related to telephone calls and data communication. Specifically, the radio section signal input from the wireless communication unit 11 is demodulated / decoded, processed to be output to the network interface unit 13, and the signal input from the network interface unit 13 is encoded / modulated. Processing to output to the wireless communication unit 11 is also performed. The network interface unit 13 is connected to the communication network 4 and receives an audio signal, a communication packet, and the like from the communication network 4 and outputs them to the control unit 10, or according to an instruction from the control unit 10. A packet or the like is transmitted to the communication network 4. The wireless communication unit 11 includes an antenna, receives a voice signal, a communication packet, and the like from the mobile station device 3 and performs frequency conversion to output to the control unit 10 or according to an instruction input from the control unit 10 Processing such as generating a signal in the carrier frequency band based on an audio signal or a communication packet input from the control unit 10 and outputting the signal via an antenna is performed. The storage unit 12 operates as a work memory for the control unit 10. Further, the storage unit 12 holds programs and parameters related to various processes performed by the control unit 10.

  As shown in FIG. 3, the communication device 6 used as the mobile station device 3 includes a control unit 14, a wireless communication unit 15, a storage unit 16, a display unit 17, and an operation unit 18. Has been. The control unit 14 controls each unit of the communication device 6 and executes processing related to a call and data communication. The wireless communication unit 15 includes an aerial line, and modulates an audio signal, a communication packet, and the like according to an instruction input from the control unit 14 and outputs the modulated signal or the like via the aerial line. Is received, demodulated, and output to the control unit 14. The storage unit 16 operates as a work memory for the control unit 14. The storage unit 16 holds programs and parameters related to various processes performed by the control unit 14. The display unit 17 includes, for example, a liquid crystal display device, and displays and outputs information according to a signal input from the control unit 14. The operation unit 18 is, for example, a numeric keypad, and receives a telephone number or character string input from the user and outputs it to the control unit 14.

  As an antenna provided in the wireless communication unit 11 or the wireless communication unit 15, an adaptive array antenna that can adaptively change the antenna directivity by electrically combining reception outputs of a plurality of antenna elements is used. Is done. FIG. 4 is a more detailed functional block diagram of the wireless communication unit 11 or the wireless communication unit 15. As shown in the figure, the radio communication unit 11 or the radio communication unit 15 includes n adaptive array antennas, and provides an analog radio circuit that generates a signal in a carrier frequency band, and provides a modulation frequency to the analog radio circuit. A reference signal circuit, a digital upsampling converter (DUC) for converting the frequency of a transmission signal input to the analog radio circuit, and a digital downsampling for converting the frequency of a reception signal output by the analog radio circuit -The transmission / reception part 24-1-24-n comprised including a converter (DDC) is included. The control unit 10 or the control unit 14 includes a signal processing unit 20 including a transmission / reception digital signal processor (DSP) that performs signal processing of an input transmission signal to the DUC and an output reception signal from the DDC, A path control unit 22 including a path control circuit that outputs a reception signal from the DDC to the DSP, combines a transmission signal from the DSP and a transmission antenna weight, and conveys the weight to the DUC. Is done. Furthermore, the control unit 10 or the control unit 14 includes a central processing element (CPU) connected to the DSP included in the control unit 10.

  Here, the technology as the background of the present invention will be described again in detail.

  In a time-division multicarrier system employed in a mobile communication system such as a PHS (Personal Handyphone System), signals are multiplexed on the frequency axis using orthogonality between signals. When using an adaptive array antenna, it is possible to insert a reference signal for each time-divided received signal and obtain signal reproduction using the antenna weight calculated based on the correlation between the received signal and the reference signal. I have to. In other words, in order to mitigate the effects of selective fading, time-division signals are transmitted by multicarrier and interference waves existing in the transmission band are removed using an adaptive array antenna. We are trying to improve.

As described in Non-Patent Document 1, the antenna weight can be generally obtained by the calculation shown in Expression (1). Here, w is an antenna weight vector, R _xx is a correlation matrix of the received signal, and r _xr is a correlation vector of the received signal and the reference signal. R _xx and r _xr are obtained by calculations shown in equations (2) and (3), respectively. X (t) is an input vector in which input signals from the adaptive array antenna are arranged. Further, r (t) is a reference signal, and the reference signal is acquired in the base station apparatus 2 as preliminary knowledge regarding the desired signal. Specifically, for example, a known pilot signal can be used as a reference signal. H represents Hermitian conjugate, * represents complex conjugate, and E [] represents an operation for obtaining an expected value.

From equation (1), the calculation of the inverse matrix of R _xx is required to determine the antenna weight. Since the correlation matrix is a positive definite symmetric matrix, it is common to perform calculations using a conventionally known Cholesky factorization in a computer. The principle of calculation for _obtaining the inverse matrix of R _{xx by} Cholesky decomposition will be described below.

Decomposing the positive definite symmetric matrix R _xx using the lower triangular matrix L as shown in Equation (4) is generally called Cholesky decomposition. T represents a transposed matrix.

Then, _{assuming that} the element of R _{xx in} the i row and j column is r _ij , and the element in the i row and j column of L is l _ij , these elements are expressed by the equation (5) from the equation (4).

Here, since L is a lower triangular matrix, l _ij = 0 when i <j. For this reason, Formula (5) can be replaced with the following Formula (6). However, i and j are integers, and min (i, j) is a function for obtaining the smaller one of i and j.

Furthermore, since R _xx is a symmetric matrix, if r _ij is obtained for i ≧ j, all elements of R _xx can be obtained. Therefore, only the following equation (7) is calculated.

When equation (7) is written down for each component, r _ij can be described using l _ij as in equation (8) below.

In this way, the positive definite symmetric matrix R _xx can be expressed using the lower triangular matrix L. As for the elements of the lower triangular matrix L, l _ij can be obtained in order as shown in Equation (9).

_Since inverse matrix _R ^{xx -1} of _{R xx} is a matrix satisfying the equation (10), when written by decomposing the inverse matrix _R ^{xx -1} for each column, of elements _r ^{ij -1} column j The vector r _j satisfies the following expression (11). That is, as shown in Expression (12), an inverse matrix R _xx ⁻¹ is represented using a vector r _j . Note that I is a unit matrix, and I _j is a vector composed of elements of j columns of the unit matrix I.

  Furthermore, Expression (11) is expressed as Expression (13) below from Expression (4).

Since the elements of L from equation (9) are sought, r _j as shown in the following expression (14) _'by calculating to define a first (16) or equation (17) by r _j' And then the vector r _j can be calculated from equation (14) or equation (15). This process is simply a process in which L is a lower triangular matrix, and is suitable for calculation by a computer.

By obtaining the inverse matrix _R ^{xx -1} of _{R xx} In this way, it is possible to obtain the antenna weights w the equation (1). The calculation can theoretically be performed strictly. However, when the calculation is performed by a computer, operations such as addition and subtraction are frequently used, so that a rounding error occurs. The rounding error increases as the value difference between the elements of the matrix _Rxx increases. Further, as can be seen from the equations (8) and (9), when 0 is included in the diagonal component of R _xx , division by 0 and the square root of a negative number occur, and calculation is impossible. .

One case where the antenna weight cannot be calculated accurately is when the SINR of the received signal is large. That is, this is a case where the ratio between the desired signal, which is a signal transmitted by the mobile station device 3, and the interference signal or noise is large. Here, as an extreme case, let us consider a case where there is no interference signal or noise and a desired signal is incident at an incident angle of 0 °. In this case, the signals received by all the antennas are the same signal, and the elements of the correlation matrix R _xx representing the correlation of the signals received by each antenna all have the same value. In such a case, the elements l _i1 (i = 1, 2,..., N) of the lower triangular matrix L represented by the equation (9) all have the same value, and the other elements all become zero. In such a case, R _xx ⁻¹ can be obtained with high accuracy by the equations (16) and (14).

However, when the interference signal or noise is not 0 but is a very small value compared to the desired signal, the elements l _i1 (i = 1, 2) of the lower triangular matrix L in the equations (16) and (14). ,..., N) have very small absolute values compared to the absolute value of the element l _i1 . That is, the ratio of the sizes of the elements of the lower triangular matrix L becomes very large. In this case, the influence of the rounding error appears, and R _xx ^-1 cannot be obtained with high accuracy.

  In other words, the fixed-point arithmetic unit tends to cause an error in the calculations of Expressions (16) and (14), particularly as the calculation proceeds. For this reason, even when the antenna weight vector w is calculated in Equation (1), if SINR is large, the errors in Equation (16) and Equation (14) are accumulated to repeat the calculation, and the antenna weight The accuracy of each element of the vector w deteriorates. This accuracy deterioration increases as the number of calculations increases, and thus increases as the number of antennas increases. Then, due to the accuracy deterioration in the calculation of the antenna weight vector w, it is impossible to maintain the appropriate directivity of the transmission signal. As a result, the mobile station apparatus 3 cannot obtain appropriate received power, increases frame errors, and degrades the transmission rate. In addition, a transmission signal whose directivity cannot be maintained is transmitted in a direction that should not be transmitted, and acts as an interference wave on communication performed by another mobile station device 3. Communication quality of communication is also deteriorated.

Therefore inventors of the present invention is to reduce the difference in values between the elements of R _xx, with SINR of the received signal it is possible to reduce the impact on the calculation of the antenna weights, the diagonal elements of R _xx Invented means to prevent 0 from being included. Hereinafter, a configuration for realizing the means in the present embodiment will be described.

  FIG. 5 is a functional block diagram of the signal processing unit 20 of the communication device 5 or 6 in the present embodiment. A reception signal received by the adaptive array antenna is input to the reception unit 30 via the path control unit 22. The received signal is output as an input vector X (t) to the correlation matrix calculator 32 and the reference signal generator 34.

  The reference signal generator 34 generates a reference signal r (t) from the input received signal. Specifically, for example, when the mobile station device 3 transmits a known signal called a training sequence as a reference signal included in all frames, the reference signal is generated by acquiring the training sequence. be able to. Then, the reference signal is output to the correlation matrix calculation unit 32.

The correlation matrix calculation unit 32 calculates a correlation matrix between the reception signal obtained by adding the pseudo noise input from the pseudo noise addition unit 38 described later and the reference signal input from the reference signal generation unit 34. That is, the autocorrelation matrix R _xx is calculated by performing the calculation of Expression (2) in a known reference signal section included in one burst of the received signal. Then, the reception signal, the reference signal and the autocorrelation matrix R _xx added with the pseudo noise are output to the matrix processing unit 40. Further, the RSSI (reception strength) of the received signal input from the receiving unit 30 is measured and output to the pseudo noise control unit 36 together with the received signal.

The matrix processing unit 40 calculates the lower triangular matrix L by performing the above-described Cholesky decomposition from the input autocorrelation matrix R _xx , and outputs it to the frequency compensation unit 42 together with the received signal and the reference signal.

The frequency compensation unit 42 calculates the correlation vector r _xr between the reception signal and the reference signal input from the matrix processing unit 40 according to Equation (3), and compensates the processing timing and frequency from the reception signal and the lower triangular matrix L. And the offset from the reference frequency and the error coefficient between the reference signal and the received signal, and the inverse matrix R _xx ⁻¹ of the autocorrelation matrix R _xx is calculated by the above-described method. The received signal, the reference time, and the reference frequency are output to the demodulation unit 44. The correlation vector r _xr and the error coefficient are output to the reception variable calculation unit 48, and the reception signal, the inverse matrix R _xx ^−1, and the correlation vector r _xr are output to the optimum weight calculation unit 50.

  The pseudo noise control unit 36 generates pseudo noise and corrects the pseudo noise power amount and the SINR error amount generated by adding the pseudo noise based on the RSSI input from the correlation matrix calculation unit 32. A correction amount is calculated. That is, when the RSSI that is the information related to the reception strength of the received signal at a certain antenna is large, the SINR that is other information related to the reception strength at the antenna is regarded as large, and the pseudo noise power stored in correspondence with the RSSI Determine the amount. Further, a value corresponding to the pseudo noise power amount is determined as the SINR correction amount. Of course, by calculating the SINR of the received signal, a pseudo noise power amount and a correction amount for correcting the SINR error amount generated by adding the pseudo noise may be calculated based on the SINR. Further, the pseudo noise power amount may be calculated as a function of RSSI or SINR of the received signal. The SINR correction amount may be the same value as the pseudo noise power amount. Moreover, since it is desirable that the generated pseudo noise has no correlation with a desired signal included in the received signal, uncorrelated noise such as white noise is desirable. The pseudo noise power amount and the SINR correction amount may be calculated for each antenna, or the same pseudo noise power amount and SINR correction amount may be calculated for a plurality of antennas. The pseudo noise, pseudo noise power amount, SINR correction amount, and reception signal input from the correlation matrix calculation unit 32 are output to the pseudo noise addition unit 38.

  The pseudo noise adding unit 38 adjusts the electric energy of the input pseudo noise based on the input pseudo noise power. Specifically, for example, adjustment can be made so that the electric energy of the pseudo noise becomes the pseudo noise electric energy as it is. Then, the noise intensity of the received signal is increased by adding the pseudo noise to the received signal, and the received signal added with the pseudo noise is output to the correlation matrix calculating unit 32 and input from the pseudo noise control unit 36. The SINR correction amount is input to the demodulation unit 44. When the pseudo noise power amount and the SINR correction amount are calculated for each antenna, the pseudo noise may be added to the reception signal for each antenna.

  The demodulation unit 44 compensates the processing timing and frequency of the received signal with the time and frequency offset obtained from the time and frequency compensation unit 42, combines the received signal and the antenna weight, and extracts only the desired signal. In addition, a process for link adaptation for determining a modulation scheme of a received signal from a plurality of modulation schemes is also performed. Further, the added pseudo noise is canceled by subtracting the SINR correction amount input from the pseudo noise adding unit 38 from the power amount of the received signal. Then, the desired signal is output to the decoding unit 46.

  The decoding unit 46 appropriately decodes the input desired signal using the modulation scheme determined by the demodulation unit 44, and outputs the digital signal data to an upper processing unit (not shown).

The optimum weight calculator 50 calculates the optimum antenna weight for reception by performing the calculation shown in Expression (1) based on the input received signal, the inverse matrix R _xx ^−1, and the correlation vector r _xr . Then, the antenna weight is output to the combining unit 52.

The reception variable calculation unit 48 calculates a signal-to-interference noise ratio (SINR) and a desired signal strength (DSSI) based on the input correlation vector r _xr and the error coefficient, and the received signal is processed by the signal processing unit 20. A synchronization error determination coefficient for determining whether synchronization with the timing has been achieved is calculated. The SINR, the DSSI, and the synchronization error determination coefficient are output to a higher-level processing unit (not shown), and transmission power control is performed based on the reception strength of the received signal demodulated according to the SINR correction amount by the demodulation unit 44. And determination of a modulation method at the time of transmission in link adaptation.

  Next, processing when transmitting from the communication device 5 or 6 will be described. The combining unit 52 controls the transmission power of the transmission signal based on the antenna weight calculated by the optimum weight calculation unit 50. Specifically, the antenna weight may be stored in the calibration vector by multiplying the calibration vector that corrects the hardware distortion caused by the change in characteristics on the circuit by the antenna weight.

  Based on the signal-to-interference and noise ratio (SINR), desired signal strength (DSSI), and synchronization error determination coefficient calculated by the reception variable calculation unit 48, the power control unit 54 is configured to transmit the optimum antenna weight amplitude for transmission. And transmit antenna weight is adjusted. Also in this case, the transmission antenna weight may be adjusted by adjusting the antenna weight stored in the calibration vector.

  Further, the digital signal data to be transmitted is encoded by an encoding unit 58 that encodes it according to a necessary modulation method as appropriate, and the encoded data carried on the specific modulation signal is mapped from the encoding unit 58 to a specific modulation. The signal is modulated through the modulation unit 60 that converts the signal into a system signal, and the transmitter unit 56 outputs the signal to the path control unit 22 after adding a weight for each antenna by the antenna weight stored in the calibration vector. In this way, the antenna weight calculated from the received signal is used to determine the directivity of the transmitted signal.

  The processing of the pseudo noise control unit 36 and the pseudo noise addition unit 38 will be described more specifically based on the flowchart.

  FIG. 6 is a flowchart showing an example of processing of the pseudo noise control unit 36 and the pseudo noise addition unit 38. First, a storage area for the variable q is secured, and 0 is substituted for q (S100). Next, storage areas for variables N and K are secured, and the number of antenna elements of the adaptive array antenna and the number of symbols included in the reference signal (S102) are substituted. Then, PNSig [N] [K], which is a pseudo noise signal array, is generated (S104). The value of PNSig [N] [K] is preferably a value that causes white noise as described above. The pseudo noise signal arrangement may be different for each antenna, or may be the same. As the pseudo noise signal array, for example, a random number from 0 to 65536 generated by a known algorithm or a code string such as a PN code that can be regarded as having no correlation with the received signal can be set.

  Next, it is determined whether or not the received power for each antenna is larger than P [q] (S106). P [q] is received power range data for determining the range of received power, and is used to determine the pseudo noise power amount and SINR correction amount determined according to the received power for each antenna. The P [q] may be stored in association with q as in the table shown in FIG. If the received power is larger than P [q], 1 is added to q (S107), and if q is smaller than qmax (S108), it is determined again whether the received power is larger than P [q] (S106). ). That is, when the received power is in a range determined by P [q], the process proceeds to S110 which is the next process. Alternatively, the process proceeds to S110 in the same manner when the value of q exceeds qmax, which also means that the process proceeds to S110 when the received power is in a range larger than P [qmax].

  Then, according to the value of q, that is, according to the received power range data, for example, the SINR correction amount SINRMargin [q] stored in the table shown in FIG. 7 is output (S110). The output SINR correction amount is subtracted from the received signal by the demodulator 44 as described above.

  Next, the storage areas for the variables i and j are secured, and 0 is substituted for both (S112). Then, the amount of power of the pseudo noise signal array PNSig [N] [K] is changed according to the value of q, that is, according to the received power range data, for example, the pseudo noise power amount Scale [q stored in the table shown in FIG. ] (S114). Then, i is incremented (S116), j is further incremented (S118), and the pseudo noise signal array PNSig [i] [j] is added to the received signal array RxSig [i] [j] (S120). Then, the process from S116 to S118 is repeated until the number of elements of the received signal array, that is, the number N of antennas and the number K of symbols of the reference signal (S117, S119), thereby adding a pseudo noise signal to the received signal.

  As described above, the influence of the SINR of the received signal on the calculation of the antenna weight can be reduced. That is, errors in calculation of antenna weight can be reduced, and the directivity of the adaptive antenna in transmission can be determined appropriately.

  The present invention is not limited to the above embodiment.

  For example, although the above embodiment has been described for the case where the present invention is applied to a mobile communication system, the antenna directivity can be adaptively changed by electrically combining the reception outputs of a plurality of antenna elements. The present invention can be applied to any wireless communication device. Further, the present invention can be applied to the case where the antenna directivity of a transmission signal is controlled based on the received power in a plurality of antenna elements, even if not an adaptive array antenna.

  8 to 10 show the results of experiments by simulation of the above embodiment of the present invention.

In FIG. 8 to FIG. 10, calculation is performed with SNR (signal to noise ratio), assuming that the interference signal included in SINR (signal to interference and noise ratio) is zero. It is assumed that there are 12 antenna elements. FIG. 8 is a simulation of an electric field having a moderate strength, FIG. 9 is a simulation of a case where the SNR is large, and FIG. 10 is a simulation of a case where the SNR is small. Then, by adding white noise to the input signal so that the SNR becomes 13 dB, 30 dB, and −10 dB for the input signal X (t), the correlation matrix R is calculated based on the equations (2) and (9). _xx and the lower triangular matrix L are calculated.

Each figure shows the elements of the correlation matrix R _xx and the lower triangular matrix L, and the actual calculation is a complex operation, but only the real part is shown for simplicity. Noise is added as white noise for each antenna element. The smaller the SNR, the greater the noise compared to the desired received signal.

In FIG. 9, as described above, the absolute values of the diagonal elements other than the element l _i1 (i = 1, 2,..., N) of the lower triangular matrix L are much higher than the absolute value of the element l _i1. It is shown that it takes a small value. On the other hand, FIG. 10 shows that the absolute values of the diagonal elements of the lower triangular matrix L are equal in value. Similarly, FIG. 8 also shows that the absolute values of the diagonal elements of the lower triangular matrix L have equal values.

  As described above, as a result of the simulation experiment, it is clear that as the SINR increases, the difference between the absolute values of the elements of the lower triangular matrix increases. In such a case, the calculation accuracy in calculating the antenna weight is deteriorated as described above. On the other hand, if the SINR is too small, the received signal cannot be demodulated. For this reason, for example, as shown in FIG. 8, by adding pseudo-noise so that the calculation accuracy in the calculation of the antenna weight becomes an optimum SINR within an allowable range, the antenna weight can be calculated accurately and demodulated without problems. Is also possible. In the above embodiment, pseudo noise is generated and added. However, for example, the noise intensity of the received signal can be increased by increasing the amount of noise power included in the received signal.

1 is a configuration diagram of a mobile communication system according to an embodiment of the present invention. 1 is a configuration block diagram of a communication device according to an embodiment of the present invention. 1 is a configuration block diagram of a communication device according to an embodiment of the present invention. It is a functional block diagram of the communication apparatus which concerns on embodiment of this invention. It is a functional block diagram of the communication apparatus of the signal which concerns on embodiment of this invention. It is a flowchart of the process which concerns on embodiment of this invention. It is an example of the table which matches and memorize | stores the received power range data based on embodiment of this invention, SINR correction amount, and pseudo noise electric energy. It is an experimental result of the simulation which concerns on embodiment of this invention. It is an experimental result of the simulation which concerns on embodiment of this invention. It is an experimental result of the simulation which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mobile communication system, 2 Base station apparatus, 3 Mobile station apparatus, 4 Communication network, 5, 6 Communication apparatus, 10, 14 Control part, 11, 15 Wireless communication part, 12, 16 Storage part, 13 Network interface part, 17 display unit, 18 operation unit, 20 signal processing unit, 22 path control unit, 24 transmission / reception unit, 30 reception unit, 32 correlation matrix calculation unit, 34 reference signal generation unit, 36 pseudo noise control unit, 38 pseudo noise addition unit, 40 matrix processing unit, 42 frequency compensation unit, 44 demodulation unit, 46 decoding unit, 48 reception variable calculation unit, 50 optimum weight calculation unit, 52 combining unit, 54 power control unit, 56 transmission unit, 58 encoding unit, 60 modulation Department.

Claims (6)

Antenna weight calculating means for calculating antenna weight based on the reception outputs of a plurality of antennas;
Control means for controlling the antenna directivity of the transmission signal based on the antenna weight;
In a wireless communication device comprising:
Receiving level measuring means for measuring information related to received intensity for each of the received signals of each antenna;
Noise increasing means for increasing the noise intensity of each received signal in accordance with information on the received intensity of the received signal of each antenna;
Including
The antenna weight calculation means calculates an antenna weight based on each received signal whose noise intensity has been increased.
A wireless communication apparatus. The wireless communication device according to claim 1,
The noise raising means is
Means for generating noise;
Increasing the noise intensity of each received signal by adding the noise to each received signal;
A wireless communication apparatus. The wireless communication apparatus according to claim 1 or 2,
The information regarding the reception strength of the reception signal is the reception strength of the reception signal.
A wireless communication apparatus. The wireless communication apparatus according to claim 1 or 2,
The information regarding the reception strength of the received signal is a signal-to-interference noise ratio of the received signal.
A wireless communication apparatus. In the radio | wireless communication apparatus of any one of Claim 1 or 4,
Signal-to-interference noise ratio correction amount determining means for determining a signal-to-interference noise ratio correction amount according to the reception intensity of each antenna;
A transmission signal transmission power determining means for determining a transmission power or a modulation scheme of the transmission signal based on the received signal added with the noise and the signal-to-interference noise ratio correction amount;
A wireless communication apparatus, further comprising: A reception level measuring step for measuring information on reception intensity for each of the reception signals of the plurality of antennas;
A noise increasing step for increasing the noise intensity of each received signal according to information on the received intensity of the received signal of each antenna;
An antenna weight calculating step for calculating an antenna weight based on each received signal whose noise intensity has been increased; and
A control step of controlling the antenna directivity of the transmission signal based on the antenna weight;
Including a transmission power control method.

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