JP4728597B2 - Array antenna communication device - Google Patents

Description

  The present invention relates to a communication apparatus using an array antenna whose antenna directivity is determined by a plurality of antennas.

  In wireless communication, adaptive array antenna receivers that change the directivity adaptively according to radio wave conditions are widely used. In this receiving apparatus, when a desired wave and an interference wave arrive from different directions, the directivity is formed in the direction of the desired wave, and the antenna directivity is controlled so as to form a null in the direction of the interference wave. The desired wave-to-interference ratio of the received signal can be maintained at the best value. Further, since the antenna exhibits the same directivity in transmission and reception, an adaptive array antenna transmission / reception device can be configured by using the directivity formed by the reception device also in the transmission device.

  FIG. 10 shows a general conventional configuration of the adaptive array antenna receiver 3. Signals received by the respective antennas 10 are amplified by the receiver 12 and converted into an intermediate frequency band, and then input to the receiving unit 64. The receiving unit 64 includes a weight coefficient multiplier 18, an adder 20, and an orthogonal demodulator 22. The signal input to the receiving unit 64 is adjusted in amplitude and phase by the weight coefficient multiplier 18 based on the weight coefficient calculated by the weight coefficient calculating unit 66 and is synthesized by the adder 20. The adder 20 outputs a received combined signal that is the combined signal. The received composite signal is converted into a baseband signal by the quadrature demodulator 22 and output from the receiver 64. In general, a baseband signal is composed of a plurality of channels. For convenience of explanation, FIG. 10 shows a single signal line, and the same applies to the following explanation. The reception composite signal output from the reception unit 64 is input to the data demodulation unit 70. The data demodulator 70 extracts the received data signal and the frame synchronization signal from the received combined signal and outputs them.

  The data demodulator 70 includes a symbol synchronizer 28 and a data extractor 26. The symbol synchronizer 28 detects a symbol period from the received composite signal, and the data extractor 26 extracts data based on the detected symbol period. To do. Here, the symbol period is a period in which a set of values that can be taken by the I channel signal and the Q channel signal appears in the case of a QPSK signal, for example, and is a period in which digital information predetermined by the system, that is, a symbol is obtained. Say.

  The data demodulator 70 is further provided with a frame period detector 62, which generates a frame synchronization signal based on the demodulated data signal. Here, the frame period refers to a data string composed of a plurality of symbols of a predetermined number in the system, that is, a period in which a frame appears. A reference signal, which is a signal for enabling adaptive operation of the adaptive array antenna, is attached to the beginning of each frame of the received composite signal or a predetermined symbol position, and the reference signal appears every frame period. This is shown in FIG. 11 (a).

The weight coefficient calculation unit 66 is an error that is a difference between the reference signal given at a predetermined position in the frame of the received combined signal and the reference signal stored in advance in the reference signal generation unit 68 of the weight coefficient calculation unit 66. calculates the signal by the subtractor 48, calculates the weight coefficient based on the received signal S _a which is separately received from the error and a plurality of antennas 10. As algorithms for calculating such weight coefficients, there are an RLS algorithm, an LMS algorithm, and the like, which are executed by the adaptive algorithm execution unit 38. In general, the received signal S _A is often used for an adaptive algorithm after being converted into a baseband signal by the orthogonal demodulator 22.

  When the adaptive algorithm is executed, the reference signal generator 68 receives a frame synchronization signal from the data demodulator 70, and outputs a reference signal stored by itself at a timing according to this. Therefore, before the weight coefficient is calculated, the data demodulator 70 must detect the frame period and establish frame synchronization. Until the frame synchronization is established, the weight coefficient calculation unit 66 outputs an initial weight coefficient determined in advance as a fixed constant. FIG. 11B to FIG. 11D show an operation process in which symbol synchronization is established, weight coefficient calculation is performed after frame synchronization is established, and weight coefficients in the array antenna are determined.

  As described above, in order to converge to the steady operation of the adaptive array antenna in which the weight coefficient is calculated for each frame period and the antenna directivity is adaptively determined, frame synchronization is established and attached to a predetermined position in the frame. It must be possible to take out a reference signal that has been stored and compare it with a reference signal stored by itself. However, frame synchronization is not established when the adaptive array antenna receiver starts up or when the reception condition deteriorates and deviates from the normal operation, and the adaptive array antenna communication apparatus operates with directivity determined by the initial weight coefficient. To do. At this time, depending on the reception situation, such as the presence of a high level interference wave, it is difficult to detect the symbol period and frame period of the desired wave, and it is impossible to converge to a steady operation. In order to avoid such a problem, it is necessary to separately provide means for quickly and surely establishing synchronization and enabling the adaptive array antenna receiving apparatus to be brought into a steady operation.

  Japanese Patent No. 3075983 discloses a first adaptive algorithm that does not require synchronization establishment, and synchronization establishment for obtaining a reference signal from a received signal, but has a relatively large fading and multipath suppression effect. A receiving apparatus with an adaptive antenna that can perform adaptive processing even in a state in which synchronization establishment is difficult by combining with the adaptive algorithm is disclosed.

Japanese Patent No. 3075983

  The receiving apparatus with an adaptive antenna disclosed in Japanese Patent No. 3075983 performs synchronization establishment by executing a first adaptive algorithm that does not require synchronization establishment, obtains a reference signal, and based on this reference signal The second adaptive algorithm is configured to be executed. As a result, even when it is difficult to establish synchronization due to fading or multipath, stable operation of the adaptive array antenna can be performed. However, this configuration requires two types of adaptive processing systems, which complicates the configuration and operation, and is disadvantageous in terms of design cost and manufacturing cost.

  An adaptive algorithm that obtains a reference signal from a received signal and compares it with a reference signal stored by itself has a greater interference wave suppression effect in a steady operation than an adaptive algorithm that does not compare reference signals. Therefore, once convergence to steady operation is achieved, sufficient reception performance should be ensured without using other adaptive algorithms.

  Therefore, as long as there is a simple means to establish synchronization, obtain a reference signal, and lead to a steady state, sufficient reception performance can be ensured without the need for an additional adaptive processing system. It is possible to realize an adaptive array antenna receiving apparatus capable of performing the above.

  The present invention has been made for such a problem, and provides an adaptive array antenna communication apparatus that enables frame synchronization to be obtained only by a single adaptive algorithm to obtain a reference signal.

The present invention includes a plurality of antennas, a main receiver that changes the amplitude and phase of the signals received by each of the plurality of antennas, combines the signals with the changed amplitude and phase, and outputs a combined signal; An array antenna communication apparatus that extracts received data from a main received composite signal output by the main receiver, and a weight coefficient calculator that calculates and outputs a weight coefficient that changes the amplitude and phase of the signal; Sub-reception for changing the amplitude and phase of the signal received by each of the antennas based on the weight coefficient output from the weight coefficient calculation unit, combining the signals with the changed amplitude and phase, and outputting the combined signal And the weight coefficient calculation unit stores a reference signal and outputs a reference signal, and a difference between the main received synthesized signal and the reference signal output by the reference signal generation unit Is calculated as a main reception error, and an error calculation unit that calculates a difference between a sub-reception combined signal output from the sub-reception unit and a reference signal output from the reference signal generation unit as a sub-reception error, and the reference signal generation unit outputs The convergence evaluation of the sub-reception error is performed for a plurality of error calculation timings of the reference signal to be transmitted and the sub-reception combined signal, and the convergence is evaluated based on the convergence evaluation for each error calculation timing. An error convergence determination unit that generates an estimation timing signal for a reference signal, and performs update calculation of a weight coefficient based on the sub-reception error corresponding to each error calculation timing, and the error convergence determination unit performs the estimation timing After executing synchronization establishment mode processing for generating a signal, the reference signal is generated based on the timing indicated by the estimated timing signal. A steady operation mode process is performed in which a weight coefficient update calculation is performed based on the main reception error obtained according to the reference signal output from the generation unit, and the weight coefficient calculation unit includes the weight coefficient calculation unit. When executing the steady operation mode processing, the amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output by the weight coefficient calculation unit, and the amplitude and phase are changed. The main received combined signal is output based on a signal, and the array antenna communication apparatus further includes a transmission unit that generates a transmission signal, and the amplitude from which the main receiving unit outputs the main received combined signal The amplitude and phase of the transmission signal are changed based on the amount of phase change, and the transmission signal with the amplitude and phase changed is transmitted from each antenna .

The array antenna communication apparatus according to the present invention further includes a sub-weight coefficient output unit that is provided separately from the weight coefficient calculation unit and outputs a weight coefficient separately from the weight coefficient calculation unit. When the weight coefficient calculation unit executes the synchronization establishment mode process, the amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output by the sub weight coefficient output unit. It is preferable to output the main reception composite signal based on the signal whose amplitude and phase are changed. Moreover, in the array antenna communication apparatus according to the present invention, the sub-weight coefficient output unit acquires a signal received by each of the plurality of antennas, and the signal-to-noise ratio of the main received combined signal is maximized. As described above, it is preferable to calculate and output a weight coefficient based on the acquired signal. The array antenna communication apparatus according to the present invention further includes a data demodulator that generates and outputs a frame synchronization signal indicating a frame synchronization timing of the main received composite signal, and the data demodulator includes the weight coefficient calculator. When executing the steady operation mode process, the frame synchronization signal is generated based on the main received composite signal and the estimated timing signal, and the reference signal generation unit is configured so that the weight coefficient calculation unit is the steady operation mode process. It is preferable to output the reference signal based on the timing indicated by the frame synchronization signal.

In addition, the present invention provides a main receiver that outputs a synthesized signal by changing the amplitude and phase of a plurality of antennas and signals received by each of the plurality of antennas, combining the signals with the changed amplitude and phase. A weight coefficient calculation unit that calculates and outputs a weight coefficient that changes the amplitude and phase of the signal in an array antenna communication device that extracts received data from the main received combined signal output by the main receiver . The amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output from the weight coefficient calculation unit, and the signals whose amplitude and phase are changed are combined and the combined signal is output. and a sub receiver, wherein the weight coefficient calculation unit, a reference signal generator for storing the reference signal output, said main receiving combined signal and the reference signal the reference signal generating unit outputs Differences determined as the main receiving error, the a error calculator for determining the difference as a sub reception error between the reference signal sub-receiving composite signal sub receiving unit outputs said reference signal generating unit outputs, the reference signal generator The sub- reception error convergence evaluation is performed for a plurality of error calculation timings of the reference signal output from the sub- reception combined signal, and the main reception combined signal is determined based on the convergence evaluation for each error calculation timing. An error convergence determination unit that generates an estimated timing signal for the included reference signal, and performs update calculation of a weight coefficient based on the sub- reception error according to each error calculation timing, and the error convergence determination unit After executing the synchronization establishment mode process for generating the estimated timing signal, the reference is performed based on the timing indicated by the estimated timing signal. Updating calculation of the weight coefficient based on the main reception error obtained in response to the reference signal outputted from the signal generating unit, perform the steady operation mode process, the main receiving unit, the weight coefficient calculation unit When executing the steady operation mode processing, the amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output by the weight coefficient calculation unit, and the amplitude and phase are changed. The main received composite signal is output based on the received signal .

Further, in the array antenna communication apparatus according to the present invention, the error convergence determination unit converges each of a plurality of reference signals having different output timings when the weight coefficient calculation unit executes the synchronization establishment mode process. It is preferable to perform the sex evaluation by parallel calculation processing. Moreover, in the array antenna communication apparatus according to the present invention, the sub-receiving unit includes a storage unit that stores a signal received by each antenna, and a plurality of reception timings that are different from a signal stored in the storage unit. A cut-out unit that acquires a signal for each antenna, and when the weight coefficient calculation unit executes the synchronization establishment mode process, reception timing differs based on the signal acquired for each antenna by the cut-out unit It is preferable to output a plurality of the sub-reception combined signals .

In the array antenna communication apparatus according to the present invention, the weight coefficient calculation unit calculates a weight coefficient according to an algorithm based on a signal received by each of the plurality of antennas and whose amplitude and phase are not changed by the weight coefficient. It is preferable to do.

ADVANTAGE OF THE INVENTION According to this invention, the adaptive array antenna communication apparatus which can establish the frame synchronization for acquiring a reference signal only with a single adaptive algorithm can be comprised. In addition, as long as synchronization is not established, as an embodiment , a weight coefficient is calculated by maximum ratio combining, and the antenna is operated as an array antenna in which directivity is formed based on this weight coefficient. In addition, an adaptive array antenna communication apparatus excellent in adaptive controllability of antenna directivity can be configured.

  A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of an adaptive array antenna receiving apparatus 1 that enables frame synchronization establishment for obtaining a reference signal using only a single adaptive algorithm. The adaptive array antenna receiving apparatus 1 is for establishing frame synchronization from the start-up operation to the steady operation, or until the reception condition deteriorates and the normal operation recovers from the state deviating from the steady operation. It operates in the synchronization establishment mode. In the synchronization establishment mode, the switch 44 is connected to the a side, and in the steady operation mode, the switch 44 is connected to the b side.

  FIG. 2 shows the connection state in the synchronization establishment mode. First, operations of the main receiver 14 and the data demodulator 24 will be described. Signals received by the respective antennas 10 are amplified by the receiver 12 and converted into an intermediate frequency band, and then input to the main receiver 14. The main receiver 14 includes a weight coefficient multiplier 18, an adder 20, and an orthogonal demodulator 22. The signal input to the main receiver 14 is adjusted in amplitude and phase by the weight coefficient multiplier 18 based on the weight coefficient calculated by the initial weight coefficient calculator 16 and is synthesized by the adder 20. The adder 20 outputs a main received combined signal that is the combined signal. The main received composite signal is converted into a baseband signal by the quadrature demodulator 22 and output from the main receiver 14. The main received composite signal output from the main receiver 14 is input to the data demodulator 24. The data demodulator 24 extracts the received data signal and the frame synchronization signal from the main received composite signal and outputs them. In the synchronization establishment mode, this received data signal is used as a system received signal and input to a signal processing unit (not shown) of the receiving apparatus.

  The data demodulator 24 includes a symbol synchronizer 28 and a data extractor 26. The symbol synchronizer 28 detects a symbol period from the received combined signal, and the data extractor 26 extracts data based on the detected symbol period. To do. The data demodulator 24 further includes a frame period estimator 30 that estimates a frame period based on the received data signal and outputs a frame synchronization signal. A reference signal, which is a signal for enabling adaptive operation of the adaptive array antenna, is attached to a predetermined position of each frame of the received composite signal, and the reference signal appears every frame period.

  The initial weight coefficient calculation unit 16 gives some weight coefficient to the main reception unit 14 in the synchronization establishment mode. Here, there is no particular limitation, and an arbitrary weight coefficient predetermined by the system is output.

  On the other hand, the signals received by the respective antennas 10, converted to the intermediate frequency band by the receiver 12 and amplified are also input to the quadrature demodulator 22. The signal converted into the baseband signal by the quadrature demodulator 22 is input to the sub receiver 34. The sub receiver 34 includes a weight coefficient multiplier 18 and an adder 20. The signal input to the sub-receiving unit 34 is adjusted in amplitude and phase based on the weight coefficient calculated by the weight coefficient calculating unit 36 and is synthesized by the adder 20. The adder 20 is the synthesized signal. A sub-reception composite signal is output. The sub reception composite signal output from the sub reception unit 34 is input to the weight coefficient calculation unit 36.

  In the present embodiment, the main receiving unit 14 is configured to perform quadrature demodulation after generating the main received combined signal, but may be configured to perform quadrature demodulation before generating the main received combined signal. is there. In this case, the quadrature demodulator 22 is arranged in front of the weight coefficient multiplier 18 of the main receiver 14 or in the adder 20. Similarly, the sub-receiving unit 34 can be configured such that the signal input to the sub-receiving unit 34 is a signal before being subjected to quadrature demodulation, and the quadrature demodulator 22 is placed before or after the adder 20. is there.

Next, the operation of the weight coefficient calculation unit 36, which is a characteristic component of the present invention, will be described. The weight coefficient calculation unit 36 includes a frame synchronization timing determination unit 40 and an adaptive algorithm execution unit 38. The frame synchronization timing determination unit 40 has an error between the reference signal included in the sub-reception combined signal input from the sub-reception unit 34 and the reference signal stored in advance in the reference signal generation unit 42 by the frame synchronization timing determination unit 40. Find e. Adaptive algorithm execution unit 38, and the weight coefficients that are currently output, calculates a new weighting factor based on the error e and the signal S _A received separately by each of the antenna 10. At this time, it is preferable that the sub-reception combined signal y is further input to the adaptive algorithm execution unit 38 and the error e and the amplitude of the received signal S _A are normalized based on the amplitude of the sub-reception combined signal y. . One calculation step of the algorithm is performed for each symbol period when symbols are extracted from the main received composite signal. Therefore, the adaptive algorithm execution unit 38 receives a sample clock signal for sampling a symbol from the system, and performs a calculation step for each symbol period based on the sample clock signal. Further, the supplied sample clock signal is required to operate together with the frame synchronization timing determination unit 40 described later. Further, as the adaptive algorithm, it is preferable to use an RLS algorithm, an LMS algorithm, or the like.

  When both symbol synchronization and frame synchronization are established, the error e converges to 0 with the execution of the adaptive algorithm. However, except for the case where symbol synchronization and frame synchronization are established, the frame synchronization timing determination unit 40 cannot recognize the frame period of the sub-reception combined signal, so the sub-reception combining input from the sub-reception unit 34 The reference signal included in the signal does not match the timing of the reference signal stored in advance by the frame synchronization timing determination unit 40, and the error e does not converge to a sufficiently small value. FIG. 3 shows this situation, and compares the convergence status when there is no frame synchronization timing shift, when there is 1 frame + 1 symbol shift, and when 1 frame-1 symbol shift. From this, it can be seen that a difference appears in the convergence state between the state where the symbol synchronization and the frame synchronization are established and the state where the symbol synchronization and the frame synchronization are not established over time of about several symbols. In the present invention, the frame synchronization timing is determined by actively utilizing the difference in the convergence state.

  FIG. 4 shows the configuration of the frame synchronization timing determination unit 40. When the frame synchronization timing determination unit 40 calculates the error e, the reference signal stored in the reference signal generation unit 42 is output with a predetermined timing. For this reason, the reference signal generator 42 is supplied with the sample clock signal. The reference signal generation unit 42 outputs a reference signal stored by itself at a plurality of timings based on the sample clock signal. FIG. 5 shows such a situation. Here, it is assumed that the reference signal is output at eight timings from the estimation timing A to the estimation timing H. Further, the symbols are oversampled four times, and the estimated timing A to the estimated timing H are output with a timing difference of one sample from each other. The frame is composed of 8 symbols from S0 to S7, that is, 32 samples from C0 to C31, and the reference signal is composed of 3 symbols from the head of the frame, S0, S1, and S3.

The weight coefficient calculation unit 36 executes the adaptive algorithm at the timing from the estimation timing A to the estimation timing H, and the frame synchronization timing determination unit 40 obtains an error for each step of the algorithm with respect to each estimation timing. Error calculated by taking the difference between the sub-received composite signal by the subtractor 48, in this _{case, E (e A, e B} , e C, e D, e E, e F, e G, e H) It is expressed as Along with the execution of the algorithm, the error convergence determination unit 46 performs convergence determination for each of e _A to e _H , and outputs a signal indicating the estimated timing corresponding to the error in which convergence is observed. In the example of FIG. 5, it is assumed that the convergence is determined with 8 samples (2 symbols), and it is determined that the error e _H has converged when the adaptive algorithm is executed at the estimation timing H.

  In addition, since the frame synchronization timing determination unit 40 is configured by a DSP to be described later, error calculation for a plurality of types of estimation timing can be performed by parallel calculation processing. The specific operation of this parallel calculation process will be described below.

The weight coefficient calculation unit 36 first executes an adaptive algorithm based on the estimated timing A. The error convergence determination unit determines whether e _A has converged to a sufficiently small value after a sufficient number of steps have elapsed to determine convergence. Next, the weight coefficient calculation unit 36 executes the adaptive algorithm based on the estimated timing B one sample after the execution of the adaptive algorithm based on the estimated timing A has started. This timing is determined based on the sample clock signal. The error convergence determination unit 46 determines whether or not e _B has converged to a sufficiently small value after a sufficient number of steps has elapsed to determine convergence. If the number of steps for determining the number of steps and the convergence of the e _B to determine the convergence of the e _A are equal, the convergence judgment of e _B after one sample convergence judgment e _A has been performed ends To do. That begins the execution of the adaptive algorithm based on the estimated timing B, until the convergence determination of e _A is completed, and the process according to the convergence determination processing and e _B according to the convergence determination of e _A It is done in parallel. Similarly, the execution of the adaptive algorithm based on each estimation timing is started every time one sample passes in the order from the estimation timing C to the estimation timing H, and each calculation processing time is shifted by a time corresponding to one sample. Perform parallel computing. The error convergence determination unit outputs a signal indicating an estimation timing corresponding to an error in which convergence is observed. In the example of FIG. 5, the convergence is determined every time one sample elapses in the order of e _A , e _B , e _C , e _D , e _E , e _F , e _G , and e _H is determined to be converged. A signal indicating the estimated timing H is output.

  In a state where the error has converged, the weight coefficient calculation unit 36 should output a weight coefficient that forms an antenna directivity adapted to the incoming direction of the received wave. Therefore, after convergence, the frame period is estimated according to the estimation timing at which the error is converged, the adaptive algorithm is executed, and the weight coefficient is updated.

  The error convergence determination unit 46 inputs a signal indicating the estimation timing to the frame period estimation unit 30 of the data demodulation unit 24, and the frame period estimation unit 30 is sufficient to perform an adaptive algorithm based on the received data and the signal. A frame period is estimated with high accuracy and a frame synchronization signal is output. The frame synchronization signal is input to a reference signal generation unit 42 of the frame synchronization timing determination unit 40, and the reference signal generation unit 42 outputs a reference signal stored by itself based on the input frame synchronization signal after error convergence.

  When the timing estimation in the frame synchronization timing determination unit 40 is performed by parallel calculation processing, the calculation capability of the DSP, such as the calculation speed and memory capacity, must be sufficient to perform the parallel calculation processing. . However, in the case where there is a restriction on the calculation capability, it is possible to take out data from the received signal and store it in the storage device, and use the stored data to perform timing estimation by a single calculation process.

  The configuration of the adaptive array antenna receiving apparatus 1 in that case is shown in FIG. However, this figure is drawn by extracting the connection state in the synchronization establishment mode. A difference from the configuration of FIG. 2 is that a storage unit 50 and a cutout unit 52 are provided in front of the sub-reception unit 34. With respect to the configuration in which the connection state in the synchronization establishment mode and the connection state in the steady operation mode are selected by a switch, the storage unit 50 and the cutout unit 52 may be placed in front of the sub reception unit 34 in FIG. In this configuration, data for two frames of the received signal output from the receiver 12 and orthogonally demodulated by the orthogonal demodulator 22 is stored in the storage unit 50. Here, two frames are used because even if two frames of data are extracted regardless of the frame synchronization timing, they always contain one frame of continuous data including a reference signal. is there. The cutout unit 52 cuts out received data for 8 samples used for timing estimation from the stored received data and inputs the cut data to the weight coefficient multiplier 18. The weight coefficient multiplier 18 adjusts the amplitude and phase of the signal represented by the extracted reception data, based on the weight coefficient output at each step of the adaptive algorithm. Adder 20 combines the reception data output from weight multiplier 18 and outputs a sub-reception combined signal. FIG. 7 shows the sub-reception combined signal. Here, it is assumed that data from the estimation timing A to the estimation timing D is cut out at intervals of one sample.

  Here, the reference signal stored in the reference signal generation unit 42 is not necessarily output based on the sample clock unlike the case of using the configuration of FIG. This is because the relative timing between the reference signal in the two-frame data of the sub-reception combined signal cut out and combined with the reference signal stored in the reference signal generation unit 42 is the same as the time when the storage unit 50 stores the data. This is because the data is grasped from the position in the data for two frames.

  The weight coefficient calculation unit 36 executes the adaptive algorithm using the cut data from the estimation timing A to the estimation timing D and the reference signal stored in the reference signal generation unit 42. The reception data cut out by the cutout unit 52 is not subjected to amplitude and phase adjustment, but the sub-reception combined signal is generated based on the weight coefficient updated at each step of the algorithm. The convergence of the error e can be determined as it is performed.

The frame synchronization timing determination unit 40 performs convergence determination of the error E (e _A , e _B , e _C , e _D ) for each estimation timing. The operation for determining the convergence of the error is the same as that using the configuration of FIG. The error convergence determination unit 46 outputs a signal indicating an estimation timing corresponding to the converged error. The estimated timing is calculated from the time when the storage unit 50 stores the data for two frames and the position of the estimated timing data in the data for two frames. In the example of FIG. 7, it is assumed that the convergence determination is performed with 8 samples, and it is determined that the error has converged when the adaptive algorithm is executed at the estimation timing D.

  The error convergence determination unit 46 included in the frame synchronization timing determination unit 42 inputs a signal indicating the estimation timing to the frame period estimation unit 30 of the data demodulation unit 24. The frame period estimation unit 30 is based on the received data and the signal. The frame period is estimated with sufficient accuracy to perform the adaptive algorithm, and a frame synchronization signal is output. The subsequent operation is the same as that in the case of using the configuration of FIG.

The above is the operation in the synchronization establishment mode. The synchronization establishment mode ends when a signal indicating the estimation timing is input from the frame cycle timing determination unit 40 to the frame cycle estimation unit 30 of the data demodulation unit 24 and the frame cycle estimation unit 30 outputs the frame synchronization signal. At the same time, the switch 44 in FIG. 1 is connected to the b side and switches to the steady operation mode. That is, the weight coefficient output from the weight coefficient calculation unit 36 is supplied to the main reception unit 14, and the main reception composite signal is supplied to the frame synchronization timing determination unit 40. In the steady operation mode, an error e is obtained from the reference signal included in the main received composite signal and the reference signal stored in the reference signal generation unit 42 included in the frame synchronization timing determination unit 40, and the currently output weight coefficient and , _A new weight coefficient is calculated based on the error e and the signal S _A separately received by each antenna 10. The reference signal generation unit 42 outputs a reference signal stored by itself at a timing based on the frame synchronization signal output by the frame period estimation unit 30. In the steady operation mode, the sub receiver 34 and the initial weight coefficient calculator 16 are inactive, and the operation load of the DSP is almost the same as that of the conventional configuration of FIG.

  In the above, it is assumed that, in principle, synchronization is established through the synchronization establishment mode before operating in the steady operation mode. However, when there is no interfering wave, synchronization may be established by a single operation of the frame period estimation unit 30 in a sufficiently short time without using the synchronization establishment mode. Even in such a case, passing through the synchronization establishment mode is wasteful of processing, and it is preferable to provide operation means for avoiding this. Therefore, before starting the operation in the synchronization establishment mode, or by performing a parallel operation process with the synchronization establishment mode, the single operation priority determination for determining whether to give priority to the synchronization establishment by the single operation of the frame period estimation unit 30 Is preferable.

  In the independent operation priority determination, the frame synchronization timing determination unit 40 is supplied with the frame synchronization signal in the initial state output from the frame period estimation unit 30 in the connection state of the synchronization establishment mode. The frame synchronization timing determination unit 40 generates a reference signal stored by the reference signal generation unit 42 based on the frame synchronization signal, and calculates an error e from the sub-reception combined signal. The weight coefficient calculation unit 36 executes an adaptive algorithm based on the error e and the frame synchronization signal in the initial state, and when the error e is converged, priority is given to establishment of synchronization by the single operation of the frame period estimation unit 30. To do.

  If it is determined by the single operation priority determination that priority is given to the establishment of synchronization by the single operation of the frame cycle estimation unit 30, after the determination, an adaptive algorithm is executed according to the frame synchronization signal output by the frame cycle estimation unit 30, and the weight coefficient Will be updated.

In the first embodiment of the present invention, the main reception unit 14 is configured to operate based on the weight coefficient output from the initial weight coefficient calculation unit 16 in the synchronization establishment mode. Further, the initial weight coefficient is an arbitrary weight coefficient predetermined by the system, and the value is not particularly limited. However, it is preferable to obtain a weight coefficient that reduces the influence of the interference wave as much as possible even in the synchronization establishment mode. Thus, the initial weight coefficient calculation unit 16 using the maximum ratio synthesis weight coefficient calculation unit 54 to which weight coefficient calculation by maximum ratio synthesis is applied is the second embodiment, and its configuration is shown in FIG. When the maximum ratio combined weight coefficient calculation unit 54 calculates weight coefficients, signals received by the plurality of antennas 10 are separately required. In FIG. 8, this signal is denoted as S _B. The maximum ratio combining is to calculate a weight coefficient so that the signal-to-noise ratio of the combined signal output from the main receiving unit 14 is maximized based on the received signal S _B and can be realized by a known algorithm. .

  Next, a third embodiment will be described with reference to FIG. In this configuration, an adaptive array antenna transmission / reception device 2 is configured by adding a transmission unit 58 including a modulator and an amplifier for modulating transmission data to the adaptive array antenna reception device 1 in the second embodiment. Due to the reciprocity of antenna characteristics, the antenna exhibits the same directivity in transmission and reception. Therefore, the weight coefficient determined by operating as an adaptive array antenna receiving apparatus can be used as it is when operating as an adaptive array antenna transmitting apparatus.

  In FIG. 9, the antenna 10 is connected to the transceiver 56. The transceiver 56 includes a receiver and a transmitter, and either operation is selected according to transmission / reception. When the operation as a receiver is selected, the signal received from the antenna 10 and input to the transceiver 56 is amplified and converted into an intermediate frequency band, and then input to the weight coefficient multiplier 18. When the operation as the transmitter is selected, the signal output from the weight coefficient multiplier 18 and input to the transceiver 56 is converted into a radio frequency band, amplified, and transmitted from the antenna 10. The weight coefficient multiplier 18 used here can perform weight coefficient multiplication on a bidirectional signal. Connection with the transmission / reception unit is performed by a transmission / reception changeover switch 60.

  Each circuit of the adaptive array antenna receiving apparatus 1 and the adaptive array antenna transmitting / receiving apparatus 2 according to the present invention can be constituted by a digital circuit. The digital circuit outputs the input digital signal as a digital signal after performing arithmetic processing on the binary number represented by the digital signal. The arithmetic processing results in addition, subtraction, digit shift, etc. of the binary number. Is done. Although it is theoretically possible to configure the binary arithmetic processing by associating a logic circuit for each calculation step, it is preferable to configure the arithmetic processing by a DSP (Digital Signal Processor) because the circuit scale increases. It is. The DSP includes a circuit that performs basic arithmetic processing that operates according to a program created in advance. It has a high-speed multiply-accumulate arithmetic unit composed of a multiplier and an adder / subtracter, and is configured to execute various instructions for each calculation step. A program is necessary to operate the DSP, and a program corresponding to the operation of each circuit is created by a known technique.

  When each circuit is configured by a DSP, for example, a signal indicating an estimation timing, an error, or the like does not need to be generated as an actual signal. However, the conceptual diagram that actually configures the logic circuit and shows the timing of signals that would be obtained when these signals are actually generated is used as an operation timing chart in the design by the DSP. Then, each circuit configured by the DSP performs a calculation process so as to realize an operation exactly the same as an operation that would be performed if it configured a logic circuit and operated based on the timing chart.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. For example, the number of oversamples and the frame length of the signals shown in FIG. 5 and FIG. Further, the algorithm used in the adaptive algorithm execution unit 38 is not limited to the RLS algorithm, the LMS algorithm, or the like, and obtains an error between the reference signal included in the received signal and the reference signal stored in the adaptive array antenna receiving apparatus. Of course, any application is applicable.

It is a figure which shows the structure of an adaptive array antenna receiver. It is a figure which shows the connection state at the time of the synchronization establishment mode of an adaptive array antenna receiver. It is a figure which shows the convergence property of the error of an adaptive algorithm. It is a figure which shows the structure of the frame synchronization timing determination part which performs a parallel calculation process. It is a figure which shows a mode that a frame synchronization timing determination part outputs the reference signal which self memorize | stores in several timings. It is a figure which shows the connection state at the time of the synchronization establishment mode of the adaptive array antenna receiver which performs a single calculation process. It is a figure which shows a mode that a frame-synchronization timing determination part cuts out estimated timing data from the sub-reception synthetic | combination signal memorize | stored in the memory | storage part. It is a figure which shows the structure of the adaptive array antenna receiver which applied the weight coefficient calculation by maximum ratio synthesis | combination to calculation of an initial weight coefficient. It is a figure which shows the structure of an adaptive array antenna transmission / reception apparatus. It is a figure which shows the general conventional structure of an adaptive array antenna receiver. It is a figure which shows the operation | movement process of an adaptive array antenna receiver.

Explanation of symbols

  1, 3 Adaptive Array Antenna Receiver, 2 Adaptive Array Antenna Transmitter / Receiver, 10 Antenna, 12 Receiver, 14 Main Receiver, 16 Initial Weight Coefficient Calculator, 18 Weight Coefficient Multiplier, 20 Adder, 22 Quadrature Demodulator, 24,70 data demodulation unit, 26 data extraction unit, 28 symbol synchronization unit, 30 frame period estimation unit, 34 sub-reception unit, 36,66 weight coefficient calculation unit, 38 adaptive algorithm execution unit, 40 frame synchronization timing determination unit, 42 , 68 Reference signal generation unit, 44 switch, 46 Error convergence determination unit, 48 Subtractor, 50 Storage unit, 54 Maximum ratio combined weight coefficient calculation unit, 56 Transmitter / receiver, 58 Transmitter, 60 Transmission / reception changeover switch, 62 Frame period detection Part, 64 receiving part.

Claims (8)

Multiple antennas,
A main receiver that changes the amplitude and phase of the signal received by each of the plurality of antennas, synthesizes the signal with the changed amplitude and phase, and outputs the synthesized signal;
In the array antenna communication apparatus that extracts the reception data from the main reception composite signal output by the main reception unit,
A weight coefficient calculator that calculates and outputs a weight coefficient that changes the amplitude and phase of the signal;
The amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output from the weight coefficient calculation unit, and the signals whose amplitude and phase are changed are combined and the combined signal is output. A sub-reception unit;
With
The weight coefficient calculation unit
A reference signal generator for storing and outputting a reference signal;
A difference between the main reception combined signal and the reference signal output from the reference signal generation unit is obtained as a main reception error, and a sub reception reception signal output from the sub reception unit and a reference signal output from the reference signal generation unit An error calculation unit for obtaining a difference as a sub-reception error;
Convergence evaluation of the sub-reception error is performed for a plurality of error calculation timings of the reference signal output by the reference signal generation unit and the sub-reception combined signal, and based on the convergence evaluation for each error calculation timing, An error convergence determination unit that generates an estimated timing signal for a reference signal included in the main received combined signal;
With
After performing the synchronization establishment mode process of performing the update calculation of the weight coefficient based on the sub reception error according to each error calculation timing and generating the estimated timing signal by the error convergence determination unit,
Performing a steady operation mode process for performing a weight coefficient update calculation based on the main reception error obtained according to the reference signal output from the reference signal generation unit based on the timing indicated by the estimated timing signal;
The main receiver is
When the weight coefficient calculation unit executes the steady operation mode process, the amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output by the weight coefficient calculation unit, Based on the signal whose amplitude and phase are changed, the main received composite signal is output,
The array antenna communication device further includes:
A transmission unit for generating a transmission signal;
The main reception unit changes the amplitude and phase of the transmission signal based on the amplitude and phase variation from which the main reception composite signal is output, and the transmission signal with the amplitude and phase changed is transmitted to each antenna. An array antenna communication apparatus, wherein The array antenna communication apparatus according to claim 1,
A sub-weight coefficient output unit that is provided separately from the weight coefficient calculation unit and outputs a weight coefficient separately from the weight coefficient calculation unit;
The main receiver is
When the weight coefficient calculation unit executes the synchronization establishment mode process, the amplitude and phase of the signal received by each of the plurality of antennas is changed based on the weight coefficient output by the sub weight coefficient output unit, An array antenna communication apparatus that outputs the main reception composite signal based on a signal whose amplitude and phase are changed. The array antenna communication apparatus according to claim 2,
The sub-weight coefficient output unit is
A signal received by each of the plurality of antennas is acquired, and a weight coefficient is calculated and output based on the acquired signal so that a signal-to-noise ratio of the main received combined signal is maximized. Array antenna communication device. In the array antenna communication apparatus according to any one of claims 1 to 3,
A data demodulator that generates and outputs a frame synchronization signal indicating a frame synchronization timing of the main reception composite signal;
The data demodulator
When the weight coefficient calculation unit executes the steady operation mode processing, the frame synchronization signal is generated based on the main received synthesized signal and the estimated timing signal,
The reference signal generator is
The array antenna communication apparatus, wherein when the weight coefficient calculation unit executes the steady operation mode process, a reference signal is output based on a timing indicated by the frame synchronization signal. Multiple antennas,
A main receiver that changes the amplitude and phase of the signal received by each of the plurality of antennas, synthesizes the signal with the changed amplitude and phase, and outputs the synthesized signal ;
In the array antenna communication apparatus that extracts the reception data from the main reception composite signal output by the main reception unit,
A weight coefficient calculator that calculates and outputs a weight coefficient that changes the amplitude and phase of the signal;
The amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output from the weight coefficient calculation unit, and the signals whose amplitude and phase are changed are combined and the combined signal is output. A sub-reception unit ;
With
The weight coefficient calculation unit
A reference signal generator for storing and outputting a reference signal;
A difference between the main reception combined signal and the reference signal output from the reference signal generation unit is obtained as a main reception error, and a sub reception reception signal output from the sub reception unit and a reference signal output from the reference signal generation unit An error calculation unit for obtaining a difference as a sub- reception error;
Convergence evaluation of the sub- reception error is performed for a plurality of error calculation timings of the reference signal output by the reference signal generation unit and the sub- reception combined signal, and based on the convergence evaluation for each error calculation timing, An error convergence determination unit that generates an estimated timing signal for a reference signal included in the main received combined signal;
With
After performing the synchronization establishment mode process of performing the update calculation of the weight coefficient based on the sub reception error according to each error calculation timing and generating the estimated timing signal by the error convergence determination unit,
Performing a steady operation mode process for performing a weight coefficient update calculation based on the main reception error obtained according to the reference signal output from the reference signal generation unit based on the timing indicated by the estimated timing signal ;
The main receiver is
When the weight coefficient calculation unit executes the steady operation mode process, the amplitude and phase of the signal received by each of the plurality of antennas are changed based on the weight coefficient output by the weight coefficient calculation unit, An array antenna communication apparatus for outputting the main reception composite signal based on a signal whose amplitude and phase are changed . The array antenna communication apparatus according to any one of claims 1 to 5,
The error convergence determination unit
The array antenna communication apparatus, wherein when the weight coefficient calculation unit executes the synchronization establishment mode process, the convergence evaluation for each of a plurality of reference signals having different output timings is executed by a parallel calculation process. The array antenna communication apparatus according to any one of claims 1 to 5 ,
The sub receiver is
A storage unit for storing a signal received by each antenna;
A cutout unit that acquires a plurality of signals having different reception timings from the signals stored in the storage unit for each antenna;
With
When the weight coefficient calculation unit executes the synchronization establishment mode process, a plurality of the sub-reception combined signals having different reception timings are output based on the signals acquired for each antenna by the clipping unit. Array antenna communication device. In the array antenna communication apparatus according to any one of claims 1 to 7 ,
The weight coefficient calculation unit
An array antenna communication apparatus, wherein a weighting factor is calculated according to an algorithm based on a signal received by each of the plurality of antennas and whose amplitude and phase are not changed by the weighting factor.

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