JP5437508B1 - Reception device, reception method, and frequency error estimation circuit - Google Patents

Abstract

Even if there are different frequency errors in a plurality of sub-modulation signals, each frequency error is compensated to synthesize a modulation signal without distortion, thereby improving transmission characteristics.
In a receiving apparatus, each sub-modulated signal generated on the transmitting side is frequency-shifted to a discontinuous band, and a received signal transmitted via a different transmission path is processed for each one or a plurality of sub-modulated signals. For each receiving device corresponding to each transmission path, the frequency error is compensated by the signal component in the superposition region extracted while sweeping the frequency of the received signal 1 including one sub-modulated signal 1 and the correlated frequency error estimation circuit. The correlation value with the signal component in the superimposed region of the sub-modulation signal 2 adjacent to the sub-modulation signal 1 among the sub-modulation signals of the received signal 2 is calculated, and reception is performed according to the sweep amount of the reception signal 1 that maximizes this correlation value. And a sweep type frequency error estimation circuit for estimating and compensating for the frequency error of the signal 1.
[Selection] Figure 1

Description

  The present invention relates to a receiving apparatus and a receiving method for receiving a sub-modulated signal transmitted by dividing a frequency band from a transmitting apparatus, and performing demodulation processing by combining the bands. In particular, the present invention relates to a receiving apparatus, a receiving method, and a frequency error estimating circuit corresponding to a form in which a sub-modulated signal is transmitted through a plurality of different transmission paths.

FIG. 8 shows a configuration example of the transmission apparatus.
In FIG. 8, the transmission device includes a modulation circuit 10, a serial-parallel conversion circuit 11, an FFT (Fast Fourier Transform) circuit 12, a transmission filter bank 20, an IFFT (Fast Inverse Fourier Transform) circuit 13, and a parallel-serial conversion circuit 14. The modulation circuit 10 modulates a data signal to be transmitted by a modulation method such as QPSK, and inputs the waveform-shaped modulation signal to the serial-parallel conversion circuit 11. The serial-parallel conversion circuit 11 performs serial-parallel conversion on the modulation signal, performs fast Fourier transform with the FFT circuit 12, converts the signal in the time domain into a signal in the frequency domain, and inputs the signal to the transmission filter bank 20.

The transmission filter bank 20 includes a dividing circuit 21, frequency shifters 22 _{1 to} 22 _N (N is an integer of 2 or more), and an adding circuit 23, and is configured to divide the band of the modulated signal into N. An example in which the modulation signal band is divided into three (N = 3) is shown in FIG.

The dividing circuit 21 of the transmission filter bank 20 multiplies the modulation signal converted into the frequency domain by a division coefficient for dividing the signal band indicated by the broken line in FIG. N sub-modulated signals 1 to N shown in FIG. The frequency shifters 22 _{1 to} 22 _N are distributed and arranged as shown in FIG. 10C by distributing the sub-modulated signals 1 to N in a desired band on the frequency axis and adding them by the adding circuit 23. A sub-modulated signal is generated. The transmission submodulated signal after the dispersion arrangement is converted from a frequency domain signal to a time domain signal by fast inverse Fourier transform in the IFFT circuit 13, and parallel-serial converted by the parallel-serial conversion circuit 14 and output.

FIG. 9 shows a configuration example 1 of the receiving device (see Non-Patent Document 1).
In FIG. 9, the receiving apparatus includes a serial-parallel conversion circuit 31, an FFT circuit 32, a reception filter bank 40, an IFFT circuit 33, a parallel-serial conversion circuit 34, a demodulation circuit 35, a multiplication circuit 36, and a UW type frequency error estimation circuit 50. . The serial / parallel conversion circuit 31 performs serial / parallel conversion on the reception signal input via the multiplication circuit 36, performs fast Fourier transform by the FFT circuit 32, and converts the time domain signal to the frequency domain reception signal to convert the reception filter bank 40. To enter.

The reception filter bank 40 includes a sub modulation signal extraction circuit 41, frequency shifters 42 _{1 to} 42 _N , and an addition circuit 43, and is configured to synthesize a sub modulation signal whose band is divided into N into a modulation signal before division. An example of synthesizing a modulation signal whose band is divided into three (N = 3) is shown in FIG.

The sub-modulation signal extraction circuit 41 of the reception filter bank 40 multiplies the reception signal converted into the frequency domain for each frequency by the division coefficient indicated by the broken line in FIG. The submodulation signals 1 to N are extracted. As shown in FIG. 11 (b), the frequency shifters 42 _{1 to} 42 _N return the received sub-modulated signals 1 to N to the band before being frequency-shifted on the transmission side, and add them by the adder circuit 43. A synthesized modulated signal as shown in 11 (c) is generated. The combined modulated signal is converted from a frequency domain signal to a time domain signal by fast inverse Fourier transform in the IFFT circuit 33, and parallel-serial converted by the parallel-serial conversion circuit 34 and output. The demodulation circuit 35 demodulates the modulation signal output from the parallel / serial conversion circuit 34 and restores the data signal transmitted from the transmission device.

  By using such a transmission device and reception device, each sub-modulation signal generated by dividing the occupied band of the modulation signal can be distributed and arranged at any place on the frequency axis, so that a discontinuous free frequency band, etc. Can be used effectively.

  However, if a frequency error Δf occurs in the received signal, the signal is distorted when the sub-modulated signal transmitted by dividing the band is combined, and the transmission characteristics deteriorate. Therefore, in the UW type frequency error estimation circuit 50 shown in FIG. 9, the frequency error included in the received signal is estimated from the signal input to the demodulation circuit 35 to generate a frequency error compensation value, and the frequency error compensation value is multiplied by the multiplication circuit. A method for improving transmission characteristics by compensating for a frequency error before extracting and synthesizing a sub-modulated signal from the received signal by inputting to 36 and multiplying by the received signal has been proposed (Non-Patent Document 1).

  Here, as shown in FIG. 12, it is assumed that a frame format including a known signal (UW) and a data signal (DATA) is used. In the UW type frequency error estimation circuit 50 shown in FIG. 9, the timing detection circuit 51 detects the UW timing, and the non-modulation circuit 52 demodulates the received signal using a known UW pattern. A non-modulated signal is generated by removing the modulation component. The phase rotation amount detection circuit 53 detects the phase rotation amount of the unmodulated signal with the adjacent symbol, reduces the influence of noise by the loop filter 54 so that the phase rotation amount becomes zero, and then integrates A frequency error compensation value is generated using the circuit 55 and the variable oscillator 56, and the frequency error compensation value is input to the multiplication circuit 36 to compensate for the frequency error of the received signal.

FIG. 13 shows an example of frequency error compensation.
FIG. 13 (a) shows a state in which a frequency error Δf is generated in each sub-modulated signal and the division coefficient band of the received signal. The UW type frequency error estimation circuit 50 generates a frequency error compensation value Δf for compensating for this frequency error Δf by the above procedure, and the multiplication circuit 36 compensates for the frequency error Δf of the received signal, so that FIG. The received signal after frequency error compensation shown in FIG. This is extracted by the respective division coefficients by the sub-modulation signal extraction circuit 41 and is frequency-shifted by the frequency shifters 42 _{1 to} 42 _N to obtain the sub-modulation signal shown in FIG. By synthesizing, a distortion-free modulated signal shown in FIG. 13 (d) is generated.

FIG. 14 shows a configuration example 2 of the receiving apparatus (see Non-Patent Document 2).
In FIG. 14, the receiving apparatus includes a serial-parallel conversion circuit 31, an FFT circuit 32, a reception filter bank 40, an IFFT circuit 33, a parallel-serial conversion circuit 34, a demodulation circuit 35, a multiplication circuit 37, and a correlated frequency error estimation circuit 60. . The serial / parallel conversion circuit 31 performs serial / parallel conversion on the reception signal input via the multiplication circuit 37, performs fast Fourier transform by the FFT circuit 32, converts the signal in the time domain to the reception signal in the frequency domain, and receives the reception filter bank 40. To enter.

  The correlation type frequency error estimation circuit 60 includes a frequency component extraction circuit 61, correlation circuits 62-1 to 62-2, smoothing circuits 63-1 to 63-2, an addition circuit 64, a smoothing circuit 65 between sub-modulation signals, A loop filter 66, an integration circuit 67, and a variable oscillator 68 are included. Correlation frequency error estimation circuit 60 divides and inputs a signal input from FFT circuit 32 to reception filter bank 40, and determines the frequency of the received signal based on the correlation of the submodulation signal components in the overlapping region where adjacent division coefficients overlap. The error is estimated as follows.

As shown in FIG. 15, in the overlap region W _k of adjacent division coefficients k and k + 1, the sub-modulation signals k and k + 1 have the same signal components after division because they are the same signal before division. Therefore, the superimposition area W _k is divided into two, the signal components of the submodulation signal k corresponding to the superposition area W _k are S _k, c and S _k, d, and the signal components of the sub modulation signal k + 1 are S _{k + 1} , Let a and S _{k + 1} , b.

The frequency component extraction circuit 61 inputs the signal components S _k, c and S _{k + 1} , a in the same band to the correlation circuit 62-1, and the signal components S _k, d and S _{k + 1} , a in the same band. b is input to the correlation circuit 62-2. At this time, one of the signal components is input with a complex conjugate (here, S ^* _{k + 1} , a, S ^* _{k + 1} , b). The correlation circuit 62-1 inputs the absolute value or square value of the value obtained by multiplying S _k, c and S ^* _{k + 1} , a as the correlation value to the addition circuit 64 via the smoothing circuit 63-1. . The multiplication circuit 62-2 inputs the absolute value or square value of the value obtained by multiplying S _k, d and S ^* _{k + 1} , b as a correlation value to the addition circuit 64 via the smoothing circuit 63-2. . The adder circuit 64 calculates the difference between the correlation value output from the smoothing circuit 63-1 and the correlation value output from the smoothing circuit 63-2 and inputs the difference to the smoothing circuit 65 between the sub-modulation signals.

When there is no frequency error in the received signal (Δf = 0), as shown in FIGS. 15B _and 15C, the correlation value (A) between the signal components S _k, c and S _{k + 1} , a and the signal The time average value d _k of the difference (A−B) between the correlation values (B) of the components S _k, d and S _{k + 1} , b is zero.

On the other hand, when a frequency error occurs in the received signal (Δf ≠ 0), as shown in FIGS. 16B and 16C, the correlation value (A) between the signal components S _k, c and S _{k + 1} , a. The time average value d _k of the difference (A−B) of the correlation value (B) between the signal components S _k, d and S _{k + 1} , b does not become zero. For example, d _k <0 when Δf> 0, and d _k > 0 when Δf <0.

The smoothing circuit 65 between the sub-modulation signals obtains one or more of the time average values d _k of the difference between the correlation values corresponding to the respective overlapping regions W _k (1 ≦ k <N−1) between the plurality of sub-modulation signals. The selected and smoothed frequency error value D is output. The frequency error value D is multiplied by the loop gain by the loop filter 66, further integrated by the integration circuit 67, and input to the variable oscillator 68, and the frequency error compensation value is generated by controlling the oscillation frequency. Using this frequency error compensation value, the multiplier circuit 37 compensates the frequency error of the received signal so that the frequency error value D becomes 0, and inputs it to the serial-parallel conversion circuit 31.

Abe, Nakahira, Sugiyama, “Experimental Verification of Blind Phase Compensation in Bandwidth Dispersion Transmission”, IEICE Technical Report, Satellite Communications, vol.111, no.336, SAT2011-46, pp.41- 46, December 2011 Abe, Nakahira, Sugiyama, “Proposal of Blind Frequency Synchronization Method for Spectrum Division Adapter”, IEICE Society Conference B-3-1 September 2012 Abe, Yamashita, Kobayashi, "Experimental verification of spectrum-edited band-dispersed transmission", IEICE technical report, satellite communication, vol.110, SAT2010-1, pp.1-6, June 2010

  Here, as shown in FIGS. 17 (a) and 17 (b), the sub-modulated signal after the band dispersion arrangement may be transmitted through a plurality of different transmission paths. For example, it may be transmitted through different repeaters for each band, or the transmission output may be distributed to a plurality using an analog filter and transmitted / received using different antennas. By using a plurality of different transmission paths, it is possible to effectively use vacant frequency bands scattered in different systems, and by using a plurality of antennas, it is possible to reduce the transmission output per antenna and suppress the occurrence of nonlinear distortion. is there.

  In such a case, since each sub-modulated signal passes through a different repeater or undergoes frequency conversion by the RF device, different frequency errors occur depending on the transmission path as shown in FIG.

  The conventional receiving apparatus shown in FIGS. 9 and 14 does not have a configuration capable of individually compensating for different frequency errors for each transmission path, so that frequency errors remain as shown in FIGS. 17 (d) and 17 (e). Extraction, frequency shift, and synthesis are performed as they are, and there is a problem that transmission characteristics deteriorate due to distortion in the synthesized signal.

  Further, assuming that transmission is performed through a plurality of different transmission paths when generating a sub-modulated signal in the transmission device, as shown in FIG. 18, there are m systems using transmission filter banks 20-1 to 20-m. The structure which outputs the transmission signals 1-m of this can be considered. For example, there are a case where the sub-modulated signal is dispersed in frequency bands of two vertical and horizontal polarizations, and a case where transmission is performed using a plurality of antennas.

  In such a case, since a different frequency error occurs for each output system, the synthesized signal is distorted in the conventional receiving apparatus shown in FIGS. 9 and 14 as in the case where a different frequency error occurs for each transmission path. There is a problem that transmission characteristics deteriorate.

  The present invention relates to a receiving apparatus, a receiving method, and a frequency error which can improve the transmission characteristics by compensating for each frequency error and synthesizing a modulated signal without distortion even if there are different frequency errors in a plurality of sub-modulated signals. An object is to provide an estimation circuit.

  According to a first aspect of the present invention, in a transmission filter bank of a transmission device, a sub-modulation signal is generated by dividing a modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and the sub-modulation signals are mutually connected. Frequency shifted to a discontinuous band, transmitted through a different transmission path for each sub-modulation signal, each sub-modulation signal is extracted from the reception signal for each reception filter bank of the receiving device corresponding to each transmission path, In a receiving apparatus of a wireless communication system that demodulates a modulated signal that is synthesized by returning the band of each sub-modulated signal to the band before the frequency shift on the transmitting side, a plurality of sub-modulated signals are provided for each receiving apparatus corresponding to each transmission path. Each of the signal components corresponding to one of the bands obtained by dividing the superposed area, which is a band in which the adjacent sub-modulated signal has the same signal component, is extracted from the received signal, and the correlation value 1 is calculated. A correlation type frequency error estimation circuit which extracts each signal component corresponding to the other band and calculates a correlation value 2 and estimates and compensates the frequency error of the received signal according to the difference between the correlation value 1 and the correlation value 2 Is provided.

  According to a second aspect of the present invention, a transmission filter bank of a transmission device generates a sub-modulation signal obtained by dividing a modulation signal into a plurality of bands having overlapping regions that overlap adjacent division bands on the frequency axis, and the sub-modulation signals are mutually connected. Frequency shifts to a discontinuous band, transmits one or more sub-modulated signals via different transmission paths, and extracts each sub-modulated signal from the received signal for each reception filter bank of the receiving device corresponding to each transmission path In the receiving apparatus of the wireless communication system that demodulates the modulated signal by combining the band of each sub-modulated signal back to the band before the frequency shift on the transmitting side, a plurality of sub-modulations are provided for each receiving apparatus corresponding to each transmission path. A correlation value 1 is calculated by extracting each signal component corresponding to one of the bands obtained by dividing the overlapped area, which is a band in which the adjacent sub-modulated signal has the same signal component, from the received signal including the signal, Correlation frequency for extracting each signal component corresponding to the other band obtained by dividing the band to calculate correlation value 2 and estimating and compensating the frequency error of the received signal according to the difference between correlation value 1 and correlation value 2 For each receiver corresponding to each transmission path, the error estimation circuit, the signal component in the superimposed region extracted while sweeping the frequency of the received signal 1 including one sub-modulated signal 1, and the frequency by the correlated frequency error estimation circuit A correlation value with a signal component in a superposed region of the submodulation signal 2 adjacent to the submodulation signal 1 among the submodulation signals of the reception signal 2 in which the error is compensated is calculated, and the reception signal 1 having the maximum correlation value is calculated. And a sweep-type frequency error estimation circuit that estimates and compensates for the frequency error of the received signal 1 based on the sweep amount.

  According to a third aspect of the present invention, a transmission filter bank of a transmission device generates a sub-modulation signal obtained by dividing a modulation signal into a plurality of bands having overlapping regions that overlap adjacent division bands on the frequency axis, and the sub-modulation signals are mutually connected. Frequency shifted to a discontinuous band, transmitted through a different transmission path for each sub-modulation signal, each sub-modulation signal is extracted from the reception signal for each reception filter bank of the reception device corresponding to each transmission path, In a receiving apparatus of a wireless communication system that demodulates a modulated signal obtained by returning the band of each sub-modulated signal to the band before the frequency shift on the transmitting side, the received signal of one receiving apparatus among the receiving apparatuses corresponding to each transmission path 1 with a frequency error of 1 as a reference, a signal component in a superposition region, which is a band in which the sub-modulation signal adjacent to the reception signal 1 and the adjacent sub-modulation signal have the same signal component, and the reception signal 1 A correlation value with the signal component in the superposed region extracted while sweeping the frequency of the received signal 2 is calculated, and the frequency error 2 of the received signal 2 is changed to the frequency error 1 by the amount of sweep of the received signal 2 at which the correlation value is maximized. A sweep type frequency error estimation circuit for matching the frequency error i + 1 with the frequency error i + 1 of the reception signal i + 1 adjacent to the reception signal i (i is an integer equal to or greater than 2) as in the case of the reception signal 2; And a UW type frequency error estimation circuit that estimates and compensates for the frequency error 1 using the known information of the modulation signal extracted from the plurality of received signals and further frequency-shifted and synthesized.

  The frequency error estimation circuit of the receiving apparatus according to the second aspect of the present invention provides a signal component in the superposition region extracted while sweeping the frequency of the received signal 1 including one sub-modulated signal 1 for each receiving apparatus corresponding to each transmission path. The correlation value with the signal component in the superposed region of the sub-modulation signal 2 adjacent to the sub-modulation signal 1 out of the sub-modulation signals of the reception signal 2 whose frequency error has been compensated by the correlation type frequency error estimation circuit is calculated. In this configuration, the frequency error of the received signal 1 is estimated and compensated by the amount of sweep of the received signal 1 having the maximum value.

  According to a third aspect of the present invention, there is provided a frequency error estimation circuit for a receiving device, wherein the frequency error 1 of the received signal 1 of one receiving device among the receiving devices corresponding to each transmission path is used as a reference, The correlation value with the signal component in the overlapped region extracted while sweeping the frequency of the reception signal 2 adjacent to the reception signal 1 is calculated, and the frequency of the reception signal 2 is calculated based on the sweep amount of the reception signal 2 that maximizes this correlation value. The error 2 is made to coincide with the frequency error 1, and similarly, the frequency error i + 1 of the reception signal i + 1 adjacent to the reception signal i (i is a natural number) is made to coincide with the frequency error 1.

  According to a fourth aspect of the present invention, a transmission filter bank of a transmission device generates a sub-modulation signal obtained by dividing a modulation signal into a plurality of bands having overlapping regions that overlap adjacent division bands on the frequency axis, and the sub-modulation signals are mutually connected. Frequency shifted to a discontinuous band, transmitted through a different transmission path for each sub-modulation signal, each sub-modulation signal is extracted from the reception signal for each reception filter bank of the receiving device corresponding to each transmission path, In a receiving method of a wireless communication system that demodulates a modulated signal that is synthesized by returning the band of each sub-modulated signal to the band before the frequency shift on the transmitting side, a plurality of sub-modulated signals are provided for each receiving device corresponding to each transmission path. Each of the signal components corresponding to one of the bands obtained by dividing the superposed area, which is a band in which the adjacent sub-modulated signal has the same signal component, is extracted from the received signal, and the correlation value 1 is calculated. Correlation frequency error compensation step of extracting each signal component corresponding to the other band and calculating correlation value 2 and estimating and compensating the frequency error of the received signal according to the difference between correlation value 1 and correlation value 2 Have

  In a fifth aspect of the present invention, a transmission filter bank of a transmission device generates a sub-modulation signal obtained by dividing a modulation signal into a plurality of bands having overlapping regions that overlap adjacent division bands on the frequency axis, and the sub-modulation signals are mutually connected. Frequency shifts to a discontinuous band, transmits one or more sub-modulated signals via different transmission paths, and extracts each sub-modulated signal from the received signal for each reception filter bank of the receiving device corresponding to each transmission path In the reception method of the radio communication system that demodulates the modulated signal by combining the band of each sub-modulated signal back to the band before the frequency shift on the transmitting side, a plurality of sub-modulations are provided for each receiving device corresponding to each transmission path. A correlation value 1 is calculated by extracting each signal component corresponding to one of the bands obtained by dividing the overlapped area, which is a band in which the adjacent sub-modulated signal has the same signal component, from the received signal including the signal, Correlation frequency for extracting each signal component corresponding to the other band obtained by dividing the band to calculate correlation value 2 and estimating and compensating the frequency error of the received signal according to the difference between correlation value 1 and correlation value 2 The error compensation step, the signal component in the superposition region extracted while sweeping the frequency of the reception signal 1 including one sub-modulation signal 1 for each reception device corresponding to each transmission path, and the frequency by the correlation type frequency error estimation circuit A correlation value with a signal component in a superposed region of the submodulation signal 2 adjacent to the submodulation signal 1 among the submodulation signals of the reception signal 2 in which the error is compensated is calculated, and the reception signal 1 having the maximum correlation value is calculated. And a sweep type frequency error compensation step for estimating and compensating for the frequency error of the received signal 1 based on the sweep amount.

  According to a sixth aspect of the present invention, a transmission filter bank of a transmission apparatus generates a sub-modulation signal obtained by dividing a modulation signal into a plurality of bands having overlapping regions that overlap adjacent division bands on the frequency axis, and the sub-modulation signals are mutually connected. Frequency shifted to a discontinuous band, transmitted through a different transmission path for each sub-modulation signal, each sub-modulation signal is extracted from the reception signal for each reception filter bank of the reception device corresponding to each transmission path, In a receiving method of a radio communication system that demodulates a modulated signal that is synthesized by returning the band of each sub-modulated signal to the band before frequency shift on the transmitting side, the received signal of one receiving apparatus among the receiving apparatuses corresponding to each transmission path 1 with a frequency error of 1 as a reference, a signal component in a superposition region, which is a band in which the sub-modulation signal adjacent to the reception signal 1 and the adjacent sub-modulation signal have the same signal component, and the reception signal 1 A correlation value with the signal component in the superposed region extracted while sweeping the frequency of the received signal 2 is calculated, and the frequency error 2 of the received signal 2 is changed to the frequency error 1 by the amount of sweep of the received signal 2 at which the correlation value is maximized. A frequency error compensation step 1 and a sweep type frequency error compensation step for matching the frequency error i + 1 of the reception signal i + 1 adjacent to the reception signal i (i is an integer of 2 or more) in the same manner as the reception signal 2 and the frequency error 1 A UW type frequency error compensation step of extracting and subtracting each sub-modulated signal from a plurality of received signals and estimating and compensating for the frequency error 1 using known information of the modulated signal synthesized by frequency shift.

  The present invention reduces the frequency error of a received signal having a plurality of sub-modulated signals using a correlated frequency error estimation circuit corresponding to each transmission path when transmitted through a different transmission path for each of the plurality of sub-modulated signals. By compensating each, it is possible to synthesize a modulated signal without distortion and improve the transmission characteristics.

  The present invention relates to a frequency of a received signal having a plurality of sub-modulated signals using a correlated frequency error estimation circuit corresponding to each transmission path when transmitted through a different transmission path for one or a plurality of sub-modulated signals. By compensating for the error and compensating the frequency error of the received signal having one sub-modulated signal using the sweep type frequency error estimation circuit based on the sub-modulated signal of the received signal whose frequency error is compensated, It is possible to improve the transmission characteristics by synthesizing no modulation signal.

  In the present invention, when each sub-modulated signal is transmitted via a different transmission path, a sweep type frequency error estimation circuit is used for each transmission path, and the frequency error of each received signal is reduced to one received signal. By matching the frequency error and compensating the matched frequency error of each received signal using the UW type frequency error estimation circuit, it is possible to synthesize a modulation signal without distortion and improve the transmission characteristics.

It is a figure which shows the structure of Example 1 of the receiver of this invention. It is a figure which shows the structure of Example 2 of the receiver of this invention. It is a figure which shows the principal part structural example of Example 1 of the receiver of this invention. It is a figure which shows the operation example 1 of the receiver of this invention. It is a figure which shows the operation example 2 of the receiver of this invention. It is a figure explaining the frequency error compensation principle of the received signal 2 in the operation example 2. FIG. It is a figure which shows the operation example 3 of the receiver of this invention. It is a figure which shows the structural example of a transmitter. It is a figure which shows the structural example 1 of a receiver. It is a figure explaining the band division | segmentation in a transmitter. It is a figure explaining the zone | band synthesis | combination in a receiver. It is a figure which shows a frame format. It is a figure explaining the example of frequency error compensation. It is a figure which shows the structural example 2 of a receiver. It is a figure explaining the estimation principle (frequency error (DELTA) f = 0) of a frequency error. It is a figure explaining the estimation principle (frequency error (DELTA) f <> 0) of a frequency error. It is a figure explaining the subject 1 in the conventional receiver. It is a figure which shows the structural example of the transmitter which demonstrates the subject 2 in the conventional receiver.

FIG. 1 shows the configuration of Embodiment 1 of a receiving apparatus of the present invention.
In FIG. 1, the receiving apparatus according to the first embodiment has a configuration in which received signals 1 to m transmitted via an m-sequence transmission path are input in parallel. For example, it is the structure of the receiver corresponding to the transmitter shown in FIG.

  The reception signal i (i is an integer of 1 to m) is input to the reception filter bank 40-i via the multiplication circuit 36-i, the multiplication circuit 37-i, the serial / parallel conversion circuit 31-i, and the FFT circuit 32-i. Then, the signals are converted into one or a plurality of sub-modulation signals, all the sub-modulation signals are added by the addition circuit 43 common to each series, and input to the demodulation circuit 35 via the IFFT circuit 33 and the parallel-serial conversion circuit 34. Further, for each series of the received signal i, a correlation type frequency error estimation circuit 60-i and a sweep type frequency error estimation circuit 70-i for branching and inputting the output of the FFT circuit 32-i are provided, and the switch 69-i Selects the output of the correlation type frequency error estimation circuit 60-i or the sweep type frequency error estimation circuit 70-i and connects it to the multiplication circuit 37-i. One output of the reception filter bank of the adjacent reception signal sequence is also connected to the sweep type frequency error estimation circuit 70-i (details will be described later). Further, a UW type frequency error estimation circuit 50 similar to the conventional configuration of FIG. 9 is provided, and its output is commonly connected to the multiplication circuit 36-i.

FIG. 2 shows the configuration of Embodiment 2 of the receiving apparatus of the present invention.
In FIG. 2, the receiving apparatus according to the second embodiment has a configuration in which received signals transmitted via an m-sequence transmission path are input in a lump. The received signal is branched into m series via the multiplication circuit 36 and connected to the multiplication circuit 37-i, and other configurations are the same as those in the first embodiment.

  FIG. 3 illustrates a configuration example of a main part of the first embodiment of the receiving device according to the embodiment. Here, configuration examples of the correlation type frequency error estimation circuit 60-2 and the sweep type frequency error estimation circuit 70-2 of the series of the received signal 2 are shown.

In FIG. 3, the output of the FFT circuit 32-2 of the series of the received signal 2 is branched and input to the correlation type frequency error estimation circuit 60-2 and the sweep type frequency error estimation circuit 70-2. Further, the sweep type frequency error estimation circuit 70-2 has submodulation signals (submodulation signals adjacent to the submodulation signal of the reception signal 2 out of the submodulation signals output from the reception filter bank 40-1 corresponding to the reception signal 1). The output of the frequency shifter 42 _N ). One of the outputs of the correlation type frequency error estimation circuit 60-2 and the sweep type frequency error estimation circuit 70-2 is selected via the switch 69-2 and input to the multiplication circuit 37-2.

  Similar to the conventional configuration shown in FIGS. 14 to 16, correlated frequency error estimation circuit 60-2 receives a signal input from FFT circuit 32-2 to reception filter bank 40-2 and superimposes adjacent division coefficients overlapping. Based on the correlation between the sub-modulated signal components in the frequency band, the frequency error included in the received signal 2 is estimated to generate a frequency error compensation value, and this frequency error compensation value is input to the multiplication circuit 37-2 to receive the received signal. The sub-modulated signal is extracted after the frequency error of 2 is compensated.

  The sweep type frequency error estimation circuit 70-2 includes a sweeper 71, a frequency component extraction circuit 72, a correlation circuit 73, a smoothing circuit 74, and a maximum value detection circuit 75. The operation of each circuit will be described later.

  Hereinafter, the configuration for compensating the frequency error of the received signal is common to the first embodiment and the second embodiment, and will be described collectively.

(Operation example 1 of receiving apparatus)
FIG. 4 shows an operation example 1 of the receiving apparatus of the present invention.
In FIG. 4, when the frequency error Δf ₁ of the received signal ₁ and the frequency error Δf ₂ of the received signal ₂ are different, the frequency errors are individually compensated by the correlated frequency error estimating circuits 60-1 and 60-2. Thus, extraction, frequency shift, and synthesis of the sub-modulated signals 1 to 4 can be performed in a state where the frequency error between the received signal 1 and the received signal 2 is compensated.

  This operation example 1 corresponds to the case where each received signal includes a plurality of adjacent sub-modulated signals. Among the configurations of FIGS. 1 and 2, sweep type frequency error estimation circuits 70-1 to 70 -m, The UW type frequency error estimation circuit 50 and the multiplication circuits 36-1 to 36-m, 36 are not used, and the switches 69-2 to 69-m select the correlation type frequency error estimation circuits 60-1 to 60-m.

(Operation example 2 of receiving apparatus)
FIG. 5 shows an operation example 2 of the receiving apparatus of the present invention.
In FIG. 5, received signal 1 including a plurality of adjacent submodulated signals 1 to 3 can be compensated by estimating frequency error Δf ₁ using correlated frequency error estimation circuit 60-1. On the other hand, the received signal 2 including one sub-modulated signal 4 cannot be estimated by the correlation type frequency error estimation circuit 61-2. Therefore, the frequency error is estimated by using the sweep type frequency error estimation circuit 70-2. Is compensated by estimating the frequency error Δf ₂ of the received signal 2 on the basis of the sub-modulated signal 3 of the received signal 1 compensated for (details will be described later). Therefore, the sweep type frequency error estimation circuit 70-2 includes the output of the FFT circuit 32-2 corresponding to the reception signal 2 and the sub-modulation signal output from the reception filter bank 40-1 corresponding to the reception signal 1. Of these, the sub-modulation signal (output of the frequency shifter 42 _N ) adjacent to the sub-modulation signal of the reception signal 2 is input.

When received signal 1 includes only one sub-modulated signal and received signal 2 includes a plurality of adjacent sub-modulated signals, sweep type frequency error estimating circuit 70-1 arranged in the series of received signals 1 Is used to estimate and compensate for the frequency error of the received signal 1 on the basis of the submodulation signal of the received signal 2 for which the frequency error has been compensated. Therefore, the sweep type frequency error estimation circuit 70-1 includes the output of the FFT 32-1 corresponding to the reception signal 1 and the sub-modulation signal output from the reception filter bank 40-2 corresponding to the reception signal 2. A sub modulation signal (output of the frequency shifter 42 ₁ ) adjacent to the sub modulation signal of the reception signal 1 is input.

  The same configuration applies to other received signal sequences. Here, a band in which a sub-modulated signal exists is preset for each received signal series, and the reception filter banks 40-1 to 40-m of the receiving apparatus respectively extract the sub-modulated signal in the required band and shift the frequency. It is configured. Further, since the received signal sequence for processing a plurality of adjacent sub-modulated signals and the received signal sequence for processing one sub-modulated signal are also known, the switch 69-i uses the correlated frequency based on the known information. The error estimation circuit 60-i and the sweep type frequency error estimation circuit 70-i are selected and the output is input to the multiplication circuit 37-i. In the case of the received signal 1 and the received signal 2 shown in FIG. 5, the switch 69-1 of the received signal 1 series selects the output of the correlation type frequency error estimation circuit 60-1, and the switch 69- of the received signal 2 series. 2 selects the output of the sweep type frequency error estimation circuit 70-2.

  Here, the principle of frequency error compensation in the sweep type frequency error estimation circuit 70 will be described with reference to FIGS.

As shown in FIG. 6, when the received signal 1 has adjacent submodulated signals 1 to 3 and the received signal 2 has a submodulated signal 4 adjacent to the submodulated signal 3, the frequency error of the received signal 1 is correlated. The frequency error estimation circuit 60-1 compensates the frequency error of the received signal 2 but cannot be compensated by the correlation frequency error estimation circuit 60-2. Therefore, the sweep type frequency error estimation circuit 70-2 is used. The sweep type frequency error estimation circuit 70-2 sweeps the received signal 2 in the frequency domain with reference to the sub-modulated signal 3 of the received signal 1, and the correlation value is maximum in the superposed area W ₃ of the adjacent sub-modulated signals 3 and 4. And the frequency error Δf ₂ of the corresponding received signal ₂ is compensated.

3 and 6, the sweeper 71 of the sweep type frequency error estimation circuit 70-2 sweeps the frequency of the reception signal 2 input from the FFT circuit 32-2 within a predetermined frequency range. The frequency amount to be swept is constant for a predetermined time t. The frequency component extraction circuit 72 includes a signal component r ₁₂ in the superimposition region W ₃ of the sub modulation signal 3 input from the frequency shifter 42 _N of the reception filter bank 40-1 and a superimposition region of the sub modulation signal 4 output from the sweeper 71. The signal component r ₂₁ at W ₃ is extracted and input to the correlation circuit 73. The correlation circuit 73 inputs an absolute value or a squared value obtained by multiplying the complex conjugate of r ₁₂ and r _{21 to} the smoothing circuit 74 as a correlation value, and smoothes all correlation values obtained at the time interval t. And input to the maximum value detection circuit 75. The maximum value detection circuit 75 calculates a sweep amount that maximizes the smoothed correlation value, and outputs the result as a frequency error compensation value. The sweeper 71 sets the sweep amount to 0 when the sweep is completed. The multiplication circuit 37-2 that inputs this frequency error compensation value via the switch 69-2 compensates the frequency error of the received signal so that the frequency error of the received signal 2 becomes 0, and the serial-parallel conversion circuit 31-2. To enter.

  Note that this operation example 2 corresponds to the case where a reception signal including a plurality of adjacent sub-modulation signals and a reception signal including one sub-modulation signal coexist. The frequency error estimation circuit 50 and the multiplication circuits 36-1 to 36-m, 36 are not used.

(Modification of operation example 2 of receiver)
The operation example 2 of the receiving apparatus shows an example in which the frequency error of the reception signal 2 including one sub-modulation signal 4 is estimated using the sweep type frequency error estimation circuit 70-2 in FIG. This is a sub-modulation signal 4 of the received signal 2, when the sub-modulation signal 3 of the reception signal 1 frequency error is compensated adjacent sub modulation signal 4 the correlation value in the overlay region W ₃ is maximum The fact that the sweep amount matches the frequency error of the received signal 2 is used. In this way, if there is a received signal in which the frequency error is compensated, even if there is one sub-modulated signal of the received signal adjacent to the received signal, the frequency error is compensated using the sweep type frequency error estimation circuit. Can be performed sequentially. That is, if the frequency error of one submodulation signal 4 of the reception signal 2 is compensated, the frequency error can be similarly compensated even if there is one submodulation signal of the reception signal 3 adjacent thereto.

  A sweep-type frequency error estimation circuit 70-1 shown in FIG. 1 has a correlated frequency error estimation circuit 60 when the received signal 1 includes one sub-modulated signal and the received signal 2 includes a plurality of adjacent sub-modulated signals. 2 shows a connection relationship for compensating the frequency error of the received signal 1 using the received signal 2 in which the frequency error is compensated. Similarly, when the received signal 1 and the received signal 2 include one sub-modulated signal and the received signal 3 includes a plurality of adjacent sub-modulated signals, the received signal 2 using the received signal 3 compensated for the frequency error is used. And the connection relationship may be made to compensate for the frequency error of the received signal 1 using the received signal 2 that has been compensated for the frequency error.

(Operation example 3 of receiving apparatus)
FIG. 7 shows an operation example 3 of the receiving apparatus of the present invention.
In FIG. 7, when each of the received signals 1 to 3 includes one sub-modulated signal, for example, the received signal 1 is fixed, and the frequency error Δf ₂ of the received signal _{2 is changed} to that of the received signal 1 using a sweep type frequency error estimation circuit. Adjust to the frequency error Δf ₁ . Control for adjusting the frequency error of one received signal to the frequency error of the other received signal is as described with reference to FIG. Next, the frequency error Δf ₃ of the reception signal ₃ is matched with the frequency error Δf ₁ of the reception signal 2 using a sweep type frequency error estimation circuit. In this way, all the frequency errors of the reception signals 2 and 3 can be matched with the frequency error Δf ₁ of the reception signal 1. The reference frequency error may be other than the frequency error Δf ₁ of the received signal 1.

In this state, the sub-modulation signals of the reception signals 1 to 3 are synthesized, and an estimated frequency error compensation value for the common frequency error Δf ₁ of the reception signals 1 to 3 is generated using the UW type frequency error estimation circuit 50. This frequency error compensation value is input to the multiplication circuits 36-1 to 36-3 of the first embodiment or the multiplication circuit 36 of the second embodiment, and sub-modulation signals are extracted and synthesized by compensating for the frequency errors of the received signals 1 to 3. I do.

  This operation example 3 corresponds to the case where all of the received signals 1 to m include one sub-modulated signal, and among the configurations of FIGS. 1 and 2, correlated frequency error estimation circuits 60-1 to 60- m is not used. Further, when the frequency error of the received signal 1 is used as a reference, the sweep type frequency error estimation circuit 70-1 and the switch 69-1 are not used, and the switches 69-2 to 69-m are the sweep type frequency error estimation circuit. 70-2 to 70-m are selected.

  With the configuration of the embodiment described above, signal transmission characteristics can be improved by estimating and compensating for the frequency error of the received signal. Further, since the present invention does not require a special pilot signal or frame format, it is possible to improve the signal transmission characteristics by compensating for the frequency error of the received signal without reducing the transmission efficiency.

  In addition, a configuration for compensating for the phase between the sub-modulation signals may be added before or after the frequency shifter 42 of the reception filter bank 40. As the phase compensation, for example, there are methods shown in Non-Patent Documents 1 and 3. In addition, a phase compensation may be performed at the same time when the division coefficient is multiplied.

  Further, when the overlap filter is used as the reception filter bank 40 for processing the continuous signal, the frequency error estimation value may be calculated from the sub-modulation signals generated in each of the two FFT circuits that perform the overlap addition. . Further, the frequency error estimation value calculated from the sub-modulation signal generated by one FFT circuit may be shared by the two FFT circuits.

DESCRIPTION OF SYMBOLS 10 Modulation circuit 11 Serial / parallel conversion circuit 12 FFT (Fast Fourier transform) circuit 13 IFFT (Fast Fourier transform) circuit 14 Parallel serial conversion circuit 20 Transmission filter bank 21 Dividing circuit 22 Frequency shifter 22
23 adder circuit 31 serial-parallel converter circuit 32 FFT circuit 33 IFFT circuit 34 parallel-serial converter circuit 35 demodulator circuit 36 multiplier circuit 37 multiplier circuit 40 reception filter bank 41 submodulation signal extraction circuit 42 frequency shifter 43 adder circuit 50 UW type frequency error estimation Circuit 51 Timing detection circuit 52 Unmodulation circuit 53 Phase rotation amount detection circuit 54 Loop filter 55 Integration circuit 56 Variable oscillator 60 Correlated frequency error estimation circuit 61 Frequency component extraction circuit 62 Correlation circuit 63 Smoothing circuit 64 Adder circuit 65 Smoothing Circuit 66 Loop filter 67 Integration circuit 68 Variable oscillator 69 Switch (SW)
70 sweep type frequency error estimation circuit 71 sweeper 72 frequency component extraction circuit 73 correlation circuit 74 smoothing circuit 75 maximum value detection circuit

Claims (8)

The transmission filter bank of the transmission device generates a sub-modulation signal obtained by dividing the modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and each sub-modulation signal has a frequency in a discontinuous band. Shift, transmit each sub-modulated signal via a different transmission path, extract each sub-modulated signal from the received signal for each reception filter bank of the receiving device corresponding to each transmission path, and band of each sub-modulated signal In the receiving apparatus of the wireless communication system that demodulates the modulated signal synthesized by returning the signal to the band before the frequency shift on the transmission side,
Each signal corresponding to one band obtained by dividing the overlapped area, which is a band in which adjacent sub-modulated signals have the same signal component, from a received signal including a plurality of sub-modulated signals for each receiving device corresponding to each transmission path The component is extracted to calculate the correlation value 1, the signal component corresponding to the other band obtained by dividing the superimposition zone is extracted to calculate the correlation value 2, and the correlation value 1 and the correlation value 2 are calculated according to the difference between the correlation value 1 and the correlation value 2 A receiving apparatus comprising a correlated frequency error estimation circuit that estimates and compensates for a frequency error of the received signal. The transmission filter bank of the transmission device generates a sub-modulation signal obtained by dividing the modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and each sub-modulation signal has a frequency in a discontinuous band. Shift, transmit each of one or a plurality of sub-modulated signals via different transmission paths, extract each sub-modulated signal from the received signal for each reception filter bank of the receiving apparatus corresponding to each transmission path, and each sub-modulated signal In the receiving apparatus of the wireless communication system that demodulates the modulated signal that is synthesized by returning the band to the band before the frequency shift on the transmission side,
Each signal corresponding to one band obtained by dividing the overlapped area, which is a band in which adjacent sub-modulated signals have the same signal component, from a received signal including a plurality of sub-modulated signals for each receiving device corresponding to each transmission path The component is extracted to calculate the correlation value 1, the signal component corresponding to the other band obtained by dividing the superimposition zone is extracted to calculate the correlation value 2, and the correlation value 1 and the correlation value 2 are calculated according to the difference between the correlation value 1 and the correlation value 2 A correlated frequency error estimation circuit that estimates and compensates for the frequency error of the received signal;
For each receiving device corresponding to each transmission path, a frequency error is generated by the signal component in the superposition region extracted while sweeping the frequency of the received signal 1 including one sub-modulated signal 1 and the correlated frequency error estimation circuit. Of the submodulated signal of the received signal 2 that has been compensated, a correlation value with the signal component in the superposed region of the submodulated signal 2 adjacent to the submodulated signal 1 is calculated. A sweep type frequency error estimation circuit that estimates and compensates for a frequency error of the received signal 1 by a quantity. The transmission filter bank of the transmission device generates a sub-modulation signal obtained by dividing the modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and each sub-modulation signal has a frequency in a discontinuous band. Shift, transmit each sub-modulated signal via a different transmission path, extract each sub-modulated signal from the received signal for each reception filter bank of the receiving apparatus corresponding to each transmission path, and band of each sub-modulated signal In the receiving apparatus of the wireless communication system that demodulates the modulated signal synthesized by returning the signal to the band before the frequency shift on the transmission side,
The sub-modulation signal adjacent to the sub-modulation signal of the reception signal 1 is a band having the same signal component with the frequency error 1 of the reception signal 1 of one reception device among the reception devices corresponding to each transmission path as a reference. A correlation value between the signal component in the superimposition area and the signal component in the superposition area extracted while sweeping the frequency of the reception signal 2 adjacent to the reception signal 1 is calculated, and the sweep of the reception signal 2 having the maximum correlation value is calculated. The frequency error 2 of the received signal 2 is matched with the frequency error 1 according to the amount, and the frequency error i + 1 of the received signal i + 1 adjacent to the received signal i (i is an integer of 2 or more) as in the received signal 2 A sweep-type frequency error estimation circuit for matching with error 1,
A UW type frequency error estimation circuit that extracts each sub-modulation signal from a plurality of reception signals having the frequency error 1, and estimates and compensates for the frequency error 1 using known information of the modulation signal synthesized by the frequency shift. And a receiving device. The frequency error estimation circuit of the receiving device according to claim 2,
For each receiving device corresponding to each transmission path, a frequency error is generated by the signal component in the superposition region extracted while sweeping the frequency of the received signal 1 including one sub-modulated signal 1 and the correlated frequency error estimation circuit. Of the submodulated signal of the received signal 2 that has been compensated, a correlation value with the signal component in the superposed region of the submodulated signal 2 adjacent to the submodulated signal 1 is calculated, and the sweep of the received signal 1 that maximizes this correlation value A frequency error estimation circuit characterized in that the frequency error of the received signal 1 is estimated and compensated by a quantity. The frequency error estimation circuit of the receiving device according to claim 3,
With reference to the frequency error 1 of the received signal 1 of one receiving device among the receiving devices corresponding to each transmission path, the signal component in the superposed region of the received signal 1 and the frequency of the received signal 2 adjacent to the received signal 1 The correlation value with the signal component in the overlapped region extracted while sweeping is calculated, and the frequency error 2 of the received signal 2 is made to coincide with the frequency error 1 by the sweep amount of the received signal 2 at which the correlation value is maximized. A frequency error estimation circuit, wherein the frequency error i + 1 of the received signal i + 1 adjacent to the received signal i is made to coincide with the frequency error 1 in the same manner as the received signal 2. The transmission filter bank of the transmission device generates a sub-modulation signal obtained by dividing the modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and each sub-modulation signal has a frequency in a discontinuous band. Shift, transmit each sub-modulated signal via a different transmission path, extract each sub-modulated signal from the received signal for each reception filter bank of the receiving device corresponding to each transmission path, and band of each sub-modulated signal In the receiving method of the wireless communication system that demodulates the modulated signal synthesized by returning the signal to the band before the frequency shift on the transmission side,
Each signal corresponding to one band obtained by dividing the overlapped area, which is a band in which adjacent sub-modulated signals have the same signal component, from a received signal including a plurality of sub-modulated signals for each receiving device corresponding to each transmission path The component is extracted to calculate the correlation value 1, the signal component corresponding to the other band obtained by dividing the superimposition zone is extracted to calculate the correlation value 2, and the correlation value 1 and the correlation value 2 are calculated according to the difference between the correlation value 1 and the correlation value 2 A reception method comprising a correlated frequency error compensation step for estimating and compensating for a frequency error of the received signal. The transmission filter bank of the transmission device generates a sub-modulation signal obtained by dividing the modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and each sub-modulation signal has a frequency in a discontinuous band. Shift, transmit each of one or a plurality of sub-modulated signals via different transmission paths, extract each sub-modulated signal from the received signal for each reception filter bank of the receiving apparatus corresponding to each transmission path, and each sub-modulated signal In the receiving method of the wireless communication system that demodulates the modulated signal that is synthesized by returning the band to the band before the frequency shift on the transmission side,
Each signal corresponding to one band obtained by dividing the overlapped area, which is a band in which adjacent sub-modulated signals have the same signal component, from a received signal including a plurality of sub-modulated signals for each receiving device corresponding to each transmission path The component is extracted to calculate the correlation value 1, the signal component corresponding to the other band obtained by dividing the superimposition zone is extracted to calculate the correlation value 2, and the correlation value 1 and the correlation value 2 are calculated according to the difference between the correlation value 1 and the correlation value 2 A correlated frequency error compensation step for estimating and compensating for the frequency error of the received signal;
For each receiving device corresponding to each transmission path, a frequency error is generated by the signal component in the superposition region extracted while sweeping the frequency of the received signal 1 including one sub-modulated signal 1 and the correlated frequency error estimation circuit. Of the submodulated signal of the received signal 2 that has been compensated, a correlation value with the signal component in the superposed region of the submodulated signal 2 adjacent to the submodulated signal 1 is calculated, and the sweep of the received signal 1 that maximizes this correlation value And a sweep type frequency error compensation step for estimating and compensating for the frequency error of the received signal 1 according to the quantity. The transmission filter bank of the transmission device generates a sub-modulation signal obtained by dividing the modulation signal into a plurality of bands having overlapping regions where adjacent division bands on the frequency axis overlap, and each sub-modulation signal has a frequency in a discontinuous band. Shift, transmit each sub-modulated signal via a different transmission path, extract each sub-modulated signal from the received signal for each reception filter bank of the receiving apparatus corresponding to each transmission path, and band of each sub-modulated signal In the receiving method of the wireless communication system that demodulates the modulated signal synthesized by returning the signal to the band before the frequency shift on the transmission side,
The sub-modulation signal adjacent to the sub-modulation signal of the reception signal 1 is a band having the same signal component with the frequency error 1 of the reception signal 1 of one reception device among the reception devices corresponding to each transmission path as a reference. A correlation value between the signal component in the superimposition area and the signal component in the superposition area extracted while sweeping the frequency of the reception signal 2 adjacent to the reception signal 1 is calculated, and the sweep of the reception signal 2 having the maximum correlation value is calculated. The frequency error 2 of the received signal 2 is matched with the frequency error 1 according to the amount, and the frequency error i + 1 of the received signal i + 1 adjacent to the received signal i (i is an integer of 2 or more) as in the received signal 2 A sweep type frequency error compensation step to match the error 1;
A UW type frequency error compensation step of extracting each sub-modulation signal from a plurality of received signals having the frequency error 1, and estimating and compensating the frequency error 1 using known information of the modulation signal synthesized by the frequency shift. And a reception method comprising:

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