JP4633600B2 - Wireless communication apparatus and signal processing method thereof - Google Patents

Description

  The present invention relates to a wireless communication apparatus that includes an adaptive array antenna having a plurality of antenna elements and performs communication using the adaptive array antenna, and a signal processing method therefor.

  In general, an adaptive array antenna is used to remove an interference wave (jamming wave) having the same frequency (channel) as that of a desired wave, that is, a co-channel interference, while an adaptive equalizer is used on a time axis. It is used to remove a delayed wave that is delayed in time although it is a desired wave by signal processing, that is, to remove intersymbol interference. For example, Patent Literature 1 is disclosed as a wireless communication device in which these adaptive array antennas and adaptive equalizers are combined.

  By the way, in a transmitter used in a wireless communication apparatus, an adaptive array antenna apparatus has, for example, the configuration shown in FIG. 5, and a plurality of antenna elements 11-1 to 11-K (where K is Array antenna 11 having two or more integers), modulators 12-1 to 12-K connected to antenna elements 11-1 to 11-K, respectively, and array input decomposition section 13. The array input decomposition unit 13 is given an array weight coefficient W (vector) (that is, given array weight coefficients W1 to WK). The array weight coefficients W1 to WK are array weight coefficients generated when a reception signal is received on the receiver side in the wireless communication apparatus.

The input signal Sin input to the array input decomposing unit 13 is multiplied by the array weight coefficients W1 to WK in the array antenna decomposing unit 13, respectively, to become first to K-th multiplied signals. Are respectively supplied to the modulators 12-1 to 12-K. The first to Kth multiplication signals are modulated by the modulators 12-1 to 12-K and transmitted from the antenna elements 11-1 to 11-K as the first to Kth transmission signals X1 to XK. The
JP-A-2001-345744 (pages 5 to 9, FIGS. 1 to 8).

  Here, in the wireless communication device described above, the receiver in the wireless communication device corrects the reception signal by the adaptive equalizer, but in the transmitter of the wireless communication device, the correction amount is used as the reception signal. Since the process of modulating and transmitting from the antenna element without performing addition is performed, it cannot be said that the radio wave propagation path is the same between transmission and reception. In other words, if the radio wave propagation path is not the same at the time of transmission and at the time of reception, unnecessary interference occurs due to the influence of the radio wave propagation environment, resulting in a signal reception error processing result on the reception side and the transmission side. Differences may occur. As a result, between wireless communication devices that communicate with each other, one wireless communication device can receive a transmission signal transmitted from the other wireless communication device, but the other wireless communication device has transmitted from one wireless communication device. There is a problem if it falls into a situation where a transmission signal cannot be received.

  An object of the present invention is to provide a radio communication apparatus and a signal processing method for the radio communication apparatus which can be considered to have the same radio wave propagation path for transmission and reception.

In order to achieve the above object, a wireless communication apparatus according to the present invention includes a transmission processing unit that performs processing for transmitting a signal from the antenna element in the wireless communication apparatus including a plurality of antenna elements, and the antenna. A reception processing unit for processing a signal received by the element, and the reception processing unit corrects the reception signal for each antenna element from the reception signal received by the antenna element. A means for generating a tap coefficient; a means for removing an interference wave from the received signal for each antenna element based on the tap coefficient; and outputting an array equalized signal for the antenna element; and In response, means for generating a weighting factor for each antenna element, multiplying the array equalization signal by the weighting factor, and for each antenna element multiplied by the weighting factor Means for synthesizing an array equalized signal and outputting the synthesized signal; means for generating an adaptive tap coefficient according to the synthesized signal; and an intersymbol interference component inherent in the synthesized signal according to the adaptive tap coefficient The transmission processing unit adaptively equalizes the input signal for transmission based on the adaptive tap coefficient and outputs an adaptive equalized signal, and the adaptive equalization Means for outputting a signal to each of the antenna elements as an array input signal; means for equalizing the array input signal using the tap coefficient and the weighting coefficient to obtain a transmission signal for each antenna element; It is characterized by having .

A signal processing method according to the present invention is a signal processing method in a radio communication apparatus including a plurality of antenna elements, and a tap for correcting the reception signal for each antenna element from a reception signal received by the antenna element. A process of generating a coefficient, a process of removing an interference wave from the received signal for each antenna element based on the tap coefficient, and outputting an array equalized signal for the antenna element, and a process according to the array equalized signal Generating a weighting factor for each antenna element, multiplying the array equalization signal by the weighting factor, and synthesizing the array equalization signal for each antenna element multiplied by the weighting factor, A process of outputting a signal, a process of generating an adaptive tap coefficient according to the composite signal, and a code inherent in the composite signal according to the adaptive tap coefficient. A step of removing an interfering interference component, based on the adaptive tap coefficient, adaptively equalizing an input signal for transmission and outputting an adaptive equalized signal; and Output as an array input signal for each antenna element, and using the tap coefficient and the weight coefficient to equalize the array input signal to obtain a transmission signal for each antenna element. It is characterized by that.

  As described above, in the present invention, when transmitting a transmission signal, the input signal is corrected according to the correction coefficient for correcting the reception signal for each antenna element to obtain a transmission signal. It can be considered that the reception and reception are equal. This also has the effect that there is no difference in signal reception error processing results between the reception side and the transmission side due to unnecessary interference due to the influence of the radio wave propagation environment.

  In the present invention, since the array tap coefficient, the weight coefficient, and the adaptive tap coefficient are used as the correction coefficient on both the receiving side and the transmitting side, the radio wave propagation path can always be regarded as equal in transmission and reception. effective.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a receiver (reception processing unit) 21 used in the wireless communication device 20 according to the embodiment of the present invention.

  In FIG. 1, the receiver 21 includes an array antenna 22 having a plurality of antenna elements 22-1 to 22-K (K is an integer equal to or greater than 2). The first to Kth demodulators 23-1 to 23-K are connected. First to Kth tap coefficient estimators 24-1 to 24-K are connected to output sides of the first to Kth demodulators 23-1 to 23-K, respectively. Array equalizers 25-1 to 25-K (reception array equalization means) are connected. The first to Kth tap coefficients T1 to TK (T1 to TK are vectors: array tap coefficients) generated by the first to Kth tap coefficient estimation units 24-1 to 24-K are The 1st to Kth array equalizers 25-1 to 25-K are provided.

Further, the output sides of the first to Kth array equalizers 25-1 to 25-K are connected to the array weight coefficient estimation unit 26 and also to the array output synthesis unit 27, and the array weight coefficient estimation is performed. The array weighting coefficient W (vector: weighting coefficient) generated by the unit 26 is given to the array output combining unit 27. The output side of the array output combining unit 27 is connected to the tap coefficient estimating unit 28 and also connected to the adaptive equalizer 29, and the tap coefficient T _BB generated by the tap coefficient estimating unit 28 (vector: adaptive tap coefficient). Is provided to the adaptive equalizer 29.

  FIG. 2 is a block diagram showing an example of a transmitter (transmission processing unit) 31 used in the wireless communication apparatus 20 according to the embodiment of the present invention. In FIG. 2, the transmitter 31 includes an array antenna 32 having a plurality of antenna elements 32-1 to 32-K. The antenna elements 32-1 to 32-K are first to K-th modulators 33, respectively. -1 to 33-K. First to Kth array equalizers 34-1 to 34-K (transmission array equalization means) are connected to the input sides of the first to Kth modulators 33-1 to 33-K, respectively. An array input decomposition unit 35 is connected to the input side of the first to Kth array equalizers 34-1 to 34-K. An adaptive equalizer 36 is connected to the input side of the array input decomposition unit 35.

In the transmitter 31, the first to Kth array equalizers 34-1 to 34-K are respectively connected to the first to Kth tap coefficients T1 to TK (each of which is a vector, as shown). The array input decomposition unit 35 is given an array weight coefficient W (a vector is given). The adaptive equalizer 36 is given a tap coefficient T _BB (vector).

  Referring to FIG. 1 again, when the receiver 21 shown in FIG. 1 receives a transmission signal transmitted from another wireless communication device (not shown, having the same configuration as the wireless communication device 20). Will be described. The transmission signal is received by the array antenna 22 as a reception signal. The received signals from the antenna elements 22-1 to 22-K are demodulated by the demodulators 23-1 to 23-K, respectively, and the first to Kth tap coefficient estimators 24 are respectively provided as the first to Kth demodulated signals. -1 to 24-K and the first to Kth array equalizers 25-1 to 25-K.

  The first to Kth tap coefficient estimators 24-1 to 24-K generate first to Kth tap coefficients T1 to TK (each of which is a vector) according to the first to Kth demodulated signals, respectively. (Estimated), the first to Kth tap coefficients T1 to TK are supplied to the first to Kth array equalizers 25-1 to 25-K. The first to Kth array equalizers 25-1 to 25-K equalize the first to Kth demodulated signals according to the first to Kth tap coefficients T1 to TK, respectively. 1st to Kth array equalization signals are output.

The array weight coefficient estimation unit 26 generates an array weight coefficient W in accordance with the first to Kth array equalization signals, and the array output synthesis unit 27, for example, uses the array weight coefficient W (W ₁ to W _K ) and the The 1st to Kth array equalization signals are multiplied, and the multiplication outputs are combined and output as a combined output signal. The tap coefficient estimating unit 28 estimates a tap coefficient T _BB (vector) to be given to the adaptive equalizer 29 according to the combined output signal, and the adaptive equalizer 29 performs adaptive equalization processing according to the tap coefficient T _BB. And output as a receiver output signal Sout.

That is, in the above-described receiver 21, the received signals X1 to XK received by the _first to Kth antenna elements 22-1 to 22- _K are combined to suppress interference components, and an adaptive algorithm is used. A tap coefficient is obtained by an adaptive equalization process typified by a certain LMS (Least Mean Square), and the tap coefficient is added to the time series component of the synthesized output signal from the array output synthesizer 27 to suppress intersymbol interference. ing.

  Next, the operation of the transmitter 31 will be described with reference to FIGS. 3 and 4 together with FIG. FIG. 3 is a block diagram showing the configuration of the first to Kth array equalizers 34-1 to 34-K, and FIG. 4 is a flowchart for explaining the operation of the transmitter 31. As shown in FIG. 3, the first to Kth array equalizers 34-1 to 34-K have the same configuration. Now, paying attention to the first array equalizer 34-1, The first array equalizer 34-1 includes first to Lth delay elements 41-1 to 41-L (L is an integer of 2 or more), and 0th to Lth multipliers 42-0 to 42-L. , And an adder 43.

Now, when the input signal Sin is given to the adaptive equalizer 36, the adaptive equalizer 36 performs adaptive equalization processing on the input signal according to the tap coefficient T _BB (vector), and the adaptive processing input signal (hereinafter simply referred to as input signal). To the array input decomposition unit 35. The array input decomposition unit 35 samples the head of the input signal (step S1) and sets array antenna = 1 (step S2, that is, sets the antenna element 32-1). The array input decomposition unit 35 receives an input of an array weight coefficient W (vector) (W ₁ , W ₂ ,..., W _K ). Thereafter, the number of processes = 1 is set (step S3), and the subsequent processes are performed.

First, the array input signal D ₁ is supplied to the first array equalizer 34-1, (after obtaining the product of the tap coefficient and array weight coefficients (step S4)) After obtaining the equalization coefficient, equalization coefficient and obtains the product of the 1 symbol of the input signal _{D 1} (step S5). If the tap coefficient T ₁ (vector) has {(T ′ _1,1 , T ′ ₁ , ₂ ,..., T ′ _{1, L} )} as vector components, specifically, The 0th multiplier 42-0 multiplies the input signal D ₁ by the tap coefficient T ′ _1,1 and the array weight coefficient W ₁ and outputs the result to the adder 43. The adder 43 sequentially adds the input calculation results (step S6).

Subsequently, it is determined whether or not the number of processings <the number of taps (step S7). If the number of processings <the number of taps, the number of processings + 1 is set (step S8), and the first delay element 41-1 receives an input signal. the D ₁ delay time tau (i.e., tau symbol) is delayed (step S9), and returns to the process of calculating the equalization coefficients in step S4. That is, the multiplication process is performed by the first multiplier 42-1 as in step S5, and the calculation result is output to the adder 43 as in step S6 to perform the addition process.

Then, successively, the input signal _{D 1} by a delay element 41-2 to 41-L of the second to L is delayed, the tap coefficient and array weight in the multiplier 42-2 to 42-L of the second to L multiplying the delay value of the input signal _{D 1} coefficients, and outputs to the adder 43 <in FIG. 3, the second to (L-1) th delay element 41-2 to the 41- (L-1) The second to (L-1) th multipliers 42-2 to 42- (L-1) are not shown>.

  In this way, when the calculation result of the Lth multiplier 42-L is output to the adder 43 and the addition process is performed, the number of processings = the number of taps, and then whether the array antenna <K. It is determined whether or not (step S10). If array antenna <K, the next array antenna (that is, the next antenna element) is set (step S11), and the process returns to step S3.

As a result, in the illustrated example, the input signal D ₁ received by the array input decomposing unit 35 is provided to the second array equalizers 34-2, equalization processing according to the second array equalizers 34-2 Then, each value obtained by multiplying the input signal D ₁ by T ′ _2,1 W ₂ , T ′ _2,2 W ₂ ,..., T ′ _{2, L} W ₂ is added by the adder 43. Similarly, the input signal D ₁ received by the array input decomposing unit 35 is given to the array equalizer 34-K of the K, in the equalization processing by array equalizer 34-K of the K is done Each value obtained by multiplying the input signal D ₁ by T ′ _{K, 1} W _K , T ′ _{K, 2} W _K ,..., T ′ _{K, L} W _K is added by the adder 43.

  In this way, when the processing corresponding to all the antenna elements is completed, it is determined whether or not sample number <number of samples (step S12). If the sample number <the number of samples, the next input signal is sampled by one (step S13), and the process returns to step S2 to continue the processing. On the other hand, when the sample number = the number of samples, the process is terminated.

When the equalization processing by the first to Kth array equalizers 34-1 to 34-K is completed, output signals (first to Kth array equalizers 34-1 to 34-K) are output from the first to Kth array equalizers 34-1 to 34-K. array equalized signal of the K) are respectively provided to the modulator 33-1 to 33-K of the first to K, where it is modulated as a transmission signal X ₁ to X _K of the first to K The signals are output from the antenna elements 32-1 to 32-K (that is, the first to Kth transmission signals are collectively transmitted as transmission signals from the array antenna 32).

  In the above-described embodiment, different array weight coefficients for the antenna elements 32-1 to 32-K and different tap coefficients for the delay taps (delay elements) are accumulated in time series in the input signal, Signal synthesis is performed on the time axis defined by the number L of taps of the array equalizer. In this process, conjugate transposition of an array weight coefficient (complex number) and a tap coefficient (complex number) is performed and added to the input signal as a new coefficient. This process is for reducing the number of operations. The array equalizer does not necessarily have the configuration shown in FIG.

  Further, the processing in the adaptive equalizer, the array input decomposing unit, and the array equalizer is not limited to the communication method and its algorithm, and the processing in the adaptive equalizer, the array input decomposing unit, and the array equalizer is not limited. There is no limit to the order. Then, equalization processing can be performed on any signal in the intermediate frequency band or the baseband band.

  In the process shown in FIG. 4, when one time-series sample of the transmission signal is generated, a delay sample (delay time is 1) is controlled for each antenna element by the array weight coefficient and the number of taps for each antenna element. A sample signal or less is desirable, and the sign of the delay is positive or negative). By multiplying each tap signal multiplied by conjugate transposition and combining each delayed signal, a transmission signal of one sample is obtained. The process is repeated for the length of the transmission signal, that is, the input signal.

  As apparent from the above description, the array tap coefficient, the weight coefficient, and the adaptive tap coefficient are collectively used as the correction coefficient, that is, the tap coefficient estimation units 24-1 to 24-K and the array weight coefficient estimation. Section 26 and tap coefficient estimating section 28 function as correction coefficient calculating means, and array equalizers 25-1 to 25-K, array output combining section 27, and adaptive equalizer 29 function as received signal correcting means. . Further, a transmission equalization step is executed in the array input decomposition unit 35 and the array equalizers 34-1 to 34-K.

  As described above, in this embodiment, the transmission signal is generated using the array tap coefficient, the array weighting coefficient, and the adaptive tap coefficient obtained when receiving the reception signal. Even in the radio wave propagation environment, it is possible to accurately approximate the radio wave propagation environment on the reception side and the transmission side, and it is possible to sufficiently suppress the effects of intersymbol interference and interference waves in multipath fading on both the reception side and the transmission side. is there. Then, one wireless communication device can receive a transmission signal transmitted from the other wireless communication device, but the other wireless communication device reliably avoids a situation in which the transmission signal transmitted from one wireless communication device cannot be received. can do. As a result, data retransmission processing due to reception errors is reduced, which can contribute to effective use of frequencies.

  When transmitting a transmission signal, the input signal is corrected according to the correction coefficient for correcting the reception signal for each antenna element so that it becomes a transmission signal. As a result that can be regarded as equal to each other, it can be applied to various wireless communication apparatuses.

It is a block diagram which shows an example of the reception process part used with the radio | wireless communication apparatus by embodiment of this invention. It is a block diagram which shows an example of the transmission process part used with the radio | wireless communication apparatus by embodiment of this invention. It is a block diagram which shows the structure of the array equalizer used with the transmission process part shown in FIG. It is a flowchart for demonstrating the transmission process in the transmission process part shown in FIG. It is a block diagram which shows the transmitter used with the conventional radio | wireless communication apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Adaptive array antenna apparatus 11, 22, 32 Array antenna 11-1 to 11-K, 22-1 to 22-K, 32-1 to 32-K Antenna element 12-1 to 12-K, 33-1 to 33 -K modulator 13, 35 array input decomposition unit 20 wireless communication device 21 receiver 23-1 to 23-K demodulator 24-1 to 24-K, 28 tap coefficient estimation unit 25-1 to 25-K, 34- 1 to 34-K array equalizer 26 array weight coefficient estimation unit 27 array output combining unit 29, 36 adaptive equalizer 31 transmitter 41-1 to 41-L delay element 42-0 to 42-L multiplier 43 addition vessel

Claims (2)

In a wireless communication device including a plurality of antenna elements ,
A transmission processing unit for executing processing for transmitting a signal from the antenna element; and a reception processing unit for processing a signal received by the antenna element;
The reception processing unit
Means for generating a tap coefficient for correcting the received signal for each antenna element from the received signal received by the antenna element;
Means for removing an interference wave from the received signal for each antenna element based on the tap coefficient and outputting an array equalized signal for the antenna element;
Means for generating a weighting factor for each antenna element in response to the array equalization signal;
Means for multiplying the array equalization signal by the weighting factor, synthesizing the array equalization signal for each antenna element multiplied by the weighting factor, and outputting the combined signal;
Means for generating an adaptive tap coefficient in response to the combined signal;
Means for removing an intersymbol interference component inherent in the combined signal in accordance with the adaptive tap coefficient,
The transmission processing unit
Means for adaptively equalizing an input signal for transmission based on the adaptive tap coefficient and outputting an adaptive equalized signal;
Means for outputting the adaptive equalization signal as an array input signal to each of the antenna elements;
Means for equalizing the array input signal using the tap coefficient and the weighting coefficient to obtain a transmission signal for each antenna element;
Radio communication apparatus characterized by having a. In a signal processing method in a wireless communication apparatus provided with a plurality of antenna elements,
Generating a tap coefficient for correcting the received signal for each antenna element from the received signal received by the antenna element;
Based on the tap coefficient, a process of removing an interference wave from the received signal for each antenna element and outputting an array equalized signal for the antenna element;
Generating a weighting factor for each antenna element according to the array equalization signal;
Multiplying the array equalization signal by the weighting factor, synthesizing the array equalization signal for each antenna element multiplied by the weighting factor, and outputting the combined signal;
Generating an adaptive tap coefficient according to the combined signal;
Removing an intersymbol interference component inherent in the combined signal in accordance with the adaptive tap coefficient,
A process of adaptively equalizing an input signal for transmission based on the adaptive tap coefficient and outputting an adaptive equalized signal;
Outputting the adaptive equalization signal as an array input signal to each of the antenna elements;
Using the tap coefficient and the weight coefficient to equalize the array input signal to obtain a transmission signal for each antenna element;
Including, the signal processing method characterized by.

Images