JP2018007056A - Radio communication system, radio transmission device and radio reception device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate a phase error without being influenced by interferences from an adjacent symbol and an adjacent subcarrier of a pilot signal in a radio communication system to which FBMC/OQAM is applied.SOLUTION: A radio transmission device comprises control means for inserting a null subcarrier consisting of a null signal between a pilot subcarrier consisting of a known signal and a data subcarrier consisting of a data signal in a frequency domain, cancelling an interference from a data subcarrier that is adjacent in the frequency domain, to the pilot subcarrier in the frequency domain, and limiting an interference component included in a pilot signal received in a radio reception device onto to an interference component caused by a symbol that is adjacent in a time domain. The radio reception device comprises phase error estimation means for generating a pilot signal including an interference component caused by a known adjacent symbol, as a reference signal, comparing the generated reference signal with the received pilot signal and estimating a phase error while taking the interference from the adjacent symbol into account.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a radio communication system, a radio transmission apparatus, and a radio reception apparatus that perform phase error estimation using a pilot signal in a radio communication system based on an FBMC (Filter Bank Multi-Carrier) transmission method to which OQAM (Offset QAM) is applied. .

  In the next-generation wireless communication system, the use of a high frequency band is attracting attention in order to accommodate increasing data traffic. In addition, various services and applications are expected to spread. For this reason, a next-generation wireless communication system is required to have a flexible transmission system that can support a wide range of frequencies and various applications. The FBMC (Filter Bank Multi-Carrier) transmission system, which is attracting attention as a transmission system with such flexibility, is a multicarrier transmission system characterized by performing filter processing for each subcarrier using a filter bank. is there. Furthermore, in the FBMC transmission system, it has been proposed to apply OQAM (Offset QAM) in order to have a high data rate (Non-patent Document 1). Hereinafter, the FBMC transmission method to which OQAM is applied is denoted as FBMC / OQAM, and the FBMC transmission method to which OQAM is not applied is denoted as FBMC / QAM.

FIG. 1 shows the concept of FBMC / OQAM.
In FIG. 1, by applying OQAM, the real part and the imaginary part of the complex constellation modulation symbols are alternately arranged in the time domain with a shift of ½ symbol period. In the frequency domain, the real part and the imaginary part are alternately arranged. With such an arrangement, OFDM has complex orthogonality, whereas FBMC / OQAM has only orthogonality between real parts and between imaginary parts. That is, in FBMC / OQAM, real parts and imaginary parts do not interfere with each other, but adjacent signals (adjacent subcarriers) in the frequency domain do not orthogonally interfere with each other, and adjacent signals (adjacent symbols) in the time domain are also orthogonal. Does not interfere (Non-Patent Document 2). The arrows in FIG. 1 indicate that signals that are not orthogonal to the desired signal interfere.

  On the other hand, in the high frequency band, the influence of the phase error due to the frequency error of the local oscillator is large, and there is a problem that the characteristics deteriorate when the FBMC transmission method is used. In order to efficiently use the high frequency band, Reducing characteristic deterioration due to phase error is an important issue. As a typical technique for reducing characteristic deterioration due to a phase error, there is a technique for estimating a phase error using a pilot signal and performing phase error compensation. The phase error estimated by this method is characterized by giving a phase variation equal to all subcarriers in a symbol. From such characteristics, the phase error received by each pilot signal in the symbol is obtained, and the average is obtained to estimate the phase error. Since the phase error fluctuates over time, estimation accuracy can be improved by estimating each phase symbol.

  Examples of the pilot signal insertion method include a method of inserting pilot symbols in the time domain, a method of inserting pilot subcarriers in the frequency domain, and a method of inserting pilot signals in a scattered type in the time and frequency domains. Among these, the method of inserting pilot symbols and the method of inserting pilot signals in a scattered type include symbols in which pilot signals are not inserted, and cannot follow time-varying phase errors and accurately estimate phase errors. Can not. Therefore, a method of inserting pilot subcarriers in the frequency domain is suitable for tracking and estimating time-varying phase errors.

  FIG. 2 shows a configuration of a wireless communication system to which conventional FBMC / OQAM is applied.

  FIG. 2 (1) shows the configuration of the wireless transmission apparatus, a modulation signal generation unit 11 that performs coding processing and modulation processing on the generated data signal, a pilot generation unit 12 that generates a pilot signal from a known signal, A pilot insertion unit 13 that inserts the pilot signal output from the pilot generation unit 12 into the output signal of the modulation signal generation unit 11, an OQAM modulation unit 16 that performs OQAM modulation processing on the output signal of the pilot insertion unit 13, and an OQAM modulation unit The IFFT unit 17 performs inverse Fourier transform on the 16 output signals, and the filter processing unit 18 performs filter processing on the output signal of the IFFT unit 17.

  FIG. 2 (2) shows the configuration of the wireless receiving device, a filter processing unit 21 that performs a filtering process on the received signal, an FFT unit 22 that Fourier-transforms the output signal of the filter processing unit 21, and an output signal of the FFT unit 22 A phase that estimates a phase error by using a pilot separation unit 23 that outputs a pilot subcarrier and a data subcarrier separately, and a known signal shared by the radio transmission / reception apparatus and a pilot signal separated by the pilot separation unit 23 An error estimator 25, a phase error compensator 26 for compensating the phase error of the data signal separated by the pilot separator 23 using the estimated phase error output from the phase error estimator 25, and an output of the phase error compensator OQAM demodulation unit 27 that performs OQAM demodulation processing on the signal, and modulation signal restoration that performs demodulation processing and decoding processing on the output signal of OQAM demodulation unit 27 The unit 28 is configured.

M. Bellanger et al., "FBMC Physical Layer: A Primer," June 2010. T. Yoon et al., "Pilot Structure for High Data Rate in OFDM / OQAM-IOTA System," IEEE Vehicular Technology Conference, VTC 2008-Fall, Sept. 2008.

  In a radio communication system to which FBMC / OQAM is applied, a pilot signal receives interference from adjacent symbols in the time domain and receives interference from adjacent subcarriers in the frequency domain. This makes it difficult to accurately estimate the phase error.

  Therefore, in a wireless communication system to which FBMC / OQAM is applied, one or more pilot signals are inserted into all symbols, and the phase error is accurately estimated without being affected by interference components from adjacent symbols and adjacent subcarriers. A possible pilot signal processing method is required.

  The present invention accurately estimates a phase error without being affected by interference components from adjacent symbols and subcarriers when performing phase error estimation using a pilot signal in a wireless communication system to which FBMC / OQAM is applied. An object of the present invention is to provide a wireless communication system, a wireless transmission device, and a wireless reception device.

  The present invention relates to a wireless communication system in which wireless communication is performed between a wireless transmission device and a wireless reception device using an FBMC / OQAM transmission system. The wireless transmission device includes pilot subcarriers and data signals that are known signals in the frequency domain. Is inserted in the pilot signal received by the radio receiver, by inserting a null subcarrier consisting of a null signal between the data subcarrier consisting of and removing interference from adjacent data subcarriers in the frequency domain to the pilot subcarrier. And a radio reception apparatus generates a pilot signal including an interference component due to a known adjacent symbol as a reference signal, and receives the generated reference signal and the received reference signal. Compared to the pilot signal A phase error estimating means for estimating a phase error in consideration of.

  A radio transmission apparatus of a radio communication system of the present invention generates a modulation signal generation unit that performs encoding processing and modulation processing on a generated data signal, a pilot generation unit that generates a pilot signal from a known signal, and generates a null signal A pilot generator that inserts a pilot subcarrier consisting of a pilot signal into a data subcarrier consisting of a data signal, and further inserts a null subcarrier consisting of a null signal between the pilot subcarrier and the data subcarrier. A null insertion unit, an OQAM modulation unit that performs OQAM modulation processing on the output signal of the null insertion unit, an IFFT unit that performs inverse Fourier transform on the output signal of the OQAM modulation unit, and a filter processing unit that performs filter processing on the output signal of the IFFT unit By inserting null subcarriers, adjacent in the frequency domain To eliminate interference to the pilot subcarrier from the data subcarriers.

  A radio reception apparatus of a radio communication system according to the present invention includes a filter processing unit that performs a filtering process on a received signal, an FFT unit that performs Fourier transform on the output signal of the filter processing unit, and an output signal of the FFT unit that is converted into a pilot subcarrier and a data sub A pilot separation unit that separates a carrier and a null subcarrier and outputs a pilot signal and a data signal; a reference signal generation unit that generates a pilot signal including an interference component of a known adjacent symbol as a reference signal; and a reference signal and a pilot The phase error estimation unit that compares the pilot signal separated by the separation unit and estimates the phase error in consideration of interference from adjacent symbols included in the pilot signal of the received signal, and is output from the phase error estimation unit Compensating for the phase error of the data signal separated by the pilot separation unit using the estimated phase error Comprising an error compensating unit, and OQAM demodulator for performing OQAM demodulation processing on an output signal of the phase error compensation unit, a modulation signal restoration unit which performs demodulation and decoding on the output signal of the OQAM demodulator.

  In the radio reception apparatus of the radio communication system of the present invention, the reference signal generation unit inserts a signal sequence in which a known signal is inserted into a subcarrier into which a pilot subcarrier is inserted and a null subcarrier is inserted into other subcarriers. In this configuration, the signal sequence is subjected to OQAM modulation, inverse Fourier transform, transmission-side filter processing, reception-side filter processing, and Fourier transform, and interference signals due to known adjacent symbols are estimated to generate a reference signal.

  In the radio communication system to which the FBMC / OQAM of the present invention is applied, the interference component included in the pilot signal is limited to only the known signal, so that the phase error is accurately estimated on the receiving side using the pilot signal. As a result, the phase error estimation accuracy is greatly improved and the phase error compensation effect is improved as compared with the case where the conventional method is applied. Thereby, it is possible to reduce the degradation of the error rate characteristic and improve the system throughput.

It is a figure which shows the concept of FBMC / OQAM. It is a figure which shows the structure of the radio | wireless communications system to which the conventional FBMC / OQAM is applied. It is a figure which shows the Example structure of the radio | wireless communications system to which FBMC / OQAM of this invention is applied. It is a figure which shows the simulation result explaining the effect of this invention.

  The radio transmission apparatus of the radio communication system according to the present invention is characterized in that a null subcarrier is inserted between a pilot subcarrier and a data subcarrier in the frequency domain. As a result, interference from the data subcarrier to the pilot subcarrier can be removed, and the interference component included in the pilot signal detected by the radio reception apparatus is limited to only those due to adjacent symbols. Here, since the signal of the symbol adjacent in the time domain in the pilot subcarrier is known, the radio receiving apparatus can easily estimate the interference component remaining in the pilot signal.

  A feature of the wireless receiver of the wireless communication system of the present invention is that a known signal is used to generate a pilot signal including an interference component due to an adjacent symbol as a reference signal, the reference signal is compared with the received pilot signal, The phase error is estimated in consideration of interference from adjacent symbols.

Hereinafter, the configuration of an embodiment of the wireless communication system will be described.
FIG. 3 shows an embodiment of a radio communication system to which the FBMC / OQAM of the present invention is applied.
FIG. 3 (1) shows the configuration of the wireless transmission apparatus, which includes a modulation signal generation unit 11, a pilot generation unit 12, a pilot insertion unit 13, a null generation unit 14, a null insertion unit 15, an OQAM modulation unit 16, an IFFT unit 17, and a filter. The processing unit 18 is configured. The pilot insertion unit 13 and the null insertion unit 15 may be integrated.

  The modulation signal generation unit 11 performs encoding processing and modulation processing of an input data signal. In this encoding process, encoding may be performed at an arbitrary encoding rate using an arbitrary encoding method such as a convolutional code or a turbo code. Further, QAM modulation is generally used for the modulation processing, and modulation may be performed with an arbitrary multilevel number. The pilot generation unit 12 performs BPSK modulation after giving an arbitrary phase rotation to the known signal, and generates a pilot signal. The modulation signal output from the modulation signal generation unit 11 and the pilot signal output from the pilot generation unit 12 are input to the pilot insertion unit 13.

  The pilot insertion unit 13 inserts pilot subcarriers made up of pilot signals into one or more predetermined subcarriers of a modulated signal shared between transmitting and receiving apparatuses in the frequency domain. The output of pilot insertion unit 13 is input to null insertion unit 15. On the other hand, the null generation unit 14 generates and outputs a null signal. Here, the null signal is a signal located at the origin on the IQ plane. Null insertion section 15 inserts a null subcarrier consisting of a null signal output from null generation section 14 between a pilot subcarrier output from pilot insertion section 13 and a data subcarrier in the frequency domain. The output of the null insertion unit 15 is input to the OQAM modulation unit 16.

  The OQAM modulation unit 16 separates the input pilot subcarrier, data subcarrier, and null subcarrier complex signals into a real part and an imaginary part, respectively, and alternately arranges them with a shift of 1/2 symbol in the time domain. In addition, the real part and the imaginary part are also applied in the frequency domain by alternately applying the modulation that places the real part in half symbols ahead and the modulation that places the imaginary part in half symbols ahead for each subcarrier. Place them alternately. The signal subjected to the OQAM modulation process by the OQAM modulation unit 16 is input to the IFFT unit 17. The IFFT unit 17 performs inverse Fourier transform on the input signal and inputs it to the filter processing unit 18. The filter processing unit 18 performs a filter process for each subcarrier in the frequency domain, and performs a process equivalent to parallel / serial conversion (converting a parallel signal composed of a plurality of sequences into a serial signal). I do. In FBMC / OQAM, the polyphase configuration of the synthesis filter bank is applied to the filter processing unit 18. The filter is a prototype filter having the same frequency characteristics as the low-pass filter (PHYDYAS, “D5-1: Prototype filter and structure optimization,” January 2009.).

Here, a processing example of the null insertion unit 15 is shown. When pilot subcarriers are inserted into k = n (1 ≦ n ≦ M−2), where the total number of subcarriers is M and the subcarrier index is k (0 ≦ k ≦ M−1), k = n−1 and k = Null subcarrier is inserted into n + 1. Also, when inserting pilot subcarriers at the end of data subcarriers (k = 0, k = M−1), null subcarriers are inserted only at k = 1 and k = M−2. By sharing the subcarrier into which the pilot signal is inserted between the transmitting and receiving apparatuses, in the radio receiving apparatus, the nth subcarrier is the pilot subcarrier, the n−1 and n + 1th subcarriers are the null subcarriers, and the others By using the subcarrier as the data subcarrier, the pilot subcarrier, the data subcarrier, and the null subcarrier can be accurately separated, and the pilot subcarrier and the data subcarrier can be extracted. Similarly, when a plurality of m pilot subcarriers are inserted, pilot subcarriers are assigned to k = n ₁ , n ₂ ,..., N _m on the transmission side, k = n ₁ ± 1, n ₂ ± 1,. _A null subcarrier is inserted into _m ± 1, and the radio receiving apparatus separates a pilot subcarrier, a null subcarrier, and a data subcarrier, and performs phase error estimation for each symbol using a pilot subcarrier signal.

  Also, when inserting pilot subcarriers into two or more consecutive subcarriers, null subcarriers are inserted only into two subcarriers positioned between both ends of the continuous pilot subcarrier and the data subcarrier. Although adjacent pilot subcarrier signals interfere with each other, each pilot subcarrier signal is a known signal, and therefore the interference component can be easily estimated by the radio reception apparatus.

  FIG. 3 (2) shows the configuration of the radio receiving apparatus, and includes a filter processing unit 21, an FFT unit 22, a pilot separation unit 23, a reference signal generation unit 24, a phase error estimation unit 25, a phase error compensation unit 26, and an OQAM demodulation unit 27. The modulation signal restoration unit 28 is configured.

  The filter processing unit 21 performs processing equivalent to performing filter processing for each subcarrier after serially / parallel-converting an incoming reception signal (converting a serial signal into a parallel signal composed of a plurality of sequences). The filter processing unit 21 is applied with a polyphase configuration of an analysis filter bank that is paired with the filter processing unit 18 of the wireless transmission device. The filter used is also paired with the prototype filter applied in the wireless transmission device.

  The output signal of the filter processing unit 21 is Fourier-transformed by the FFT unit 22 and input to the pilot separation unit 23. The pilot demultiplexing unit 23 demultiplexes the output signal of the FFT unit 22 into a pilot subcarrier, a data subcarrier, and a null subcarrier based on information on the pilot subcarrier insertion location shared between the transmitting and receiving apparatuses. Is input to the phase error estimating unit 25, and the data signal is input to the phase error compensating unit 26.

  On the other hand, the reference signal generation unit 24 inserts a known signal into a subcarrier into which a pilot subcarrier is inserted, and uses a null subcarrier as a subcarrier other than the known signal and pilot subcarrier information. An inserted signal sequence is generated, and OQAM modulation, inverse Fourier transform, transmission side filter processing, reception side filter processing, and Fourier transform are performed on the signal sequence, so that interference components received from adjacent symbols by the inserted pilot subcarriers can be obtained. The considered pilot signal is generated as a reference signal and output. The phase error estimator 25 receives the pilot signal output from the pilot separator 23 and the reference signal output from the reference signal generator 24, and compares these signals to obtain the phase received by each pilot signal. The error is estimated and output as an estimated phase error. When a plurality of pilot signals are inserted in the same symbol, an average of phase errors received by the pilot signals in the same symbol is obtained and output as an estimated phase error.

  The phase error compensator 26 receives the data signal separated by the pilot separator 23 and the estimated phase error output from the phase error estimator 25, compensates for the phase error of the data signal for each symbol, and is an OQAM demodulator 27. To enter. The OQAM demodulator 27 performs OQAM demodulation on the input data signal for each subcarrier. At this time, OQAM demodulation processing corresponding to the modulation processing performed by the transmitting-side OQAM modulation unit 16 is performed on each subcarrier based on information on the pilot subcarrier insertion location. The output signal of the OQAM demodulator 27 is input to the modulation signal restoration unit 28. The modulation signal restoration unit 28 performs a decoding / demodulation process corresponding to the encoding / modulation performed by the modulation signal generation unit 11 on the transmission side to restore the data signal.

  The radio communication system of the present invention constituted by the radio transmission apparatus and radio reception apparatus described above can be applied to a fixed communication system and a mobile communication system using radio.

  The pilot signal processing method according to the present invention can also be applied to phase error estimation in MIMO (Multi-Input Multi-Output) transmission in which wireless communication is performed using a plurality of antennas.

  In addition, since the effect of the pilot signal processing method according to the present invention does not depend on the used frequency, it can be applied to any frequency band used in a radio communication system including a high frequency band. Further, the pilot signal processing between the radio transmitting and receiving apparatuses of the present invention can be used for phase error estimation regardless of the occupied bandwidth.

  The pilot signal processing method in the present invention can also be applied to FBMC / QAM not applying OQAM, and multicarrier transmission such as OFDM. In this case, when the pilot generator 12 generates the pilot signal, it is not necessary to give any phase rotation to the known signal. Further, when applied to an FBMC / QAM system, the OQAM modulation unit 16 of the wireless transmission device and the OQAM demodulation unit 27 of the wireless reception device shown in FIG. 3 are not necessary, and the pilot subcarrier and the null subcarrier are not subjected to OQAM processing. Use. Further, the filter processing unit 18 and the filter processing unit 21 use filters suitable for FBMC / OAM signal formation. Further, when applied to an OFDM system, the OQAM modulation unit 16 and the filter processing unit 18 of the wireless transmission device and the OQAM demodulation unit 27 and the filter processing unit 21 of the wireless reception device are unnecessary, and the pilot subcarrier and the null subcarrier are OQAM. Used without processing and filtering.

  Moreover, when the transmission characteristic of the frequency in which the pilot subcarrier is inserted deteriorates due to frequency selective fading, the subcarrier into which the pilot subcarrier is inserted may be changed. In that case, a subcarrier into which a pilot signal is newly inserted is notified to the radio reception apparatus using a symbol immediately before the pilot subcarrier insertion position is changed. At this time, in the subcarrier insertion position notification symbol, null insertion section 15 of the radio transmission apparatus inserts a null signal into a subcarrier into which a pilot signal is newly inserted. Since the data signal of the notification symbol does not interfere with the next symbol by inserting the null signal, the pilot signal can be accurately restored in the radio reception apparatus. In the radio reception apparatus, after receiving the notification of the change in the insertion position of the pilot subcarrier, the reference signal generation unit 24 generates a reference signal in a new pilot subcarrier arrangement.

  Further, although the phase error can be accurately estimated using the pilot signal on the receiving side by the pilot signal processing method according to the present invention, it can also be used for channel estimation.

FIG. 4 shows simulation results illustrating the effects of the present invention.
The simulation parameters are convolutional code and Viterbi decoding at a coding rate of 3/4 for encoding and decoding, 64QAM for modulation / demodulation, subcarrier spacing of 312.5 kHz, and phase error level of -90 dBc / Hz with 1 MHz offset. The propagation environment is additive white Gaussian noise (AWGN), the number of transmission subcarriers is 60, the number of data subcarriers is 56, the number of pilot subcarriers is 4, and the method of the present invention is data subcarriers. 48, 4 pilot subcarriers, and 8 null subcarriers.

At Eb / No = 20 dB, the conventional method has BER = 0.41, and the inventive method has BER = 2.8 × 10 ⁻⁴ . From this result, assuming that the transmission time of a 1500-byte data packet is 224 μs, and the control signal is 146 μs per packet, the throughput is estimated to be 4.8 × 10 ⁻¹² Mbps, the inventive method is 32 Mbps, and FBMC / OQAM As a result of using the inventive method in the wireless communication system to which the error rate is applied, it is understood that the accuracy of the phase error is improved and the compensation effect of the phase error is improved, so that the deterioration of the error rate characteristic is reduced and the system throughput is improved. . This tendency becomes more prominent as the packet length is longer.

DESCRIPTION OF SYMBOLS 11 Modulation signal generation part 12 Pilot generation part 13 Pilot insertion part 14 Null generation part 15 Null insertion part 16 OQAM modulation part 17 IFFT part 18 Filter processing part 21 Filter processing part 22 FFT part 23 Pilot separation part 24 Reference signal generation part 25 Phase Error estimation unit 26 Phase error compensation unit 27 OQAM demodulation unit 28 Modulated signal restoration unit

Claims (4)

In a wireless communication system in which wireless communication is performed between a wireless transmission device and a wireless reception device by an FBMC (Filter Bank Multi-Carrier) transmission method using OQAM (Offset QAM), the wireless transmission device is known in the frequency domain. A null subcarrier consisting of a null signal is inserted between a pilot subcarrier consisting of a signal and a data subcarrier consisting of a data signal, and interference from the adjacent data subcarrier to the pilot subcarrier in the frequency domain is removed, Control means for making interference components included in pilot signals received by the radio reception apparatus only due to symbols adjacent in the time domain;
The radio reception apparatus generates a pilot signal including an interference component due to a known adjacent symbol as a reference signal, compares the generated reference signal with the received pilot signal, and takes a phase error in consideration of interference from adjacent symbols A wireless communication system comprising phase error estimating means for estimating The wireless transmission device of the wireless communication system according to claim 1,
A modulation signal generation unit that performs encoding processing and modulation processing on the generated data signal;
A pilot generator for generating a pilot signal from a known signal;
A null generator for generating a null signal;
A pilot / null insertion unit that inserts a pilot subcarrier consisting of the pilot signal into a data subcarrier consisting of the data signal, and further inserts a null subcarrier consisting of the null signal between the pilot subcarrier and the data subcarrier. When,
An OQAM modulation unit that performs OQAM modulation processing on the output signal of the null insertion unit;
An IFFT unit that performs inverse Fourier transform on the output signal of the OQAM modulation unit;
A filter processing unit that performs a filter process on the output signal of the IFFT unit,
By inserting the null subcarrier, interference from adjacent data subcarriers to pilot subcarriers in the frequency domain is removed. In the radio | wireless receiver of the radio | wireless communications system of Claim 1,
A filter processing unit that performs a filtering process on the received signal;
An FFT unit for Fourier transforming the output signal of the filter processing unit;
A pilot separation unit that separates an output signal of the FFT unit into a pilot subcarrier, a data subcarrier, and a null subcarrier, and outputs a pilot signal and a data signal;
A reference signal generation unit that generates a pilot signal including an interference component due to a known adjacent symbol as a reference signal;
A phase error estimation unit that compares the reference signal with the pilot signal separated by the pilot separation unit and estimates phase error in consideration of interference from adjacent symbols included in the pilot signal of the reception signal; ,
A phase error compensator that compensates for a phase error of the data signal separated by the pilot separator using the estimated phase error output from the phase error estimator;
An OQAM demodulation unit that performs OQAM demodulation processing on the output signal of the phase error compensation unit;
A radio reception apparatus comprising: a modulation signal restoration unit that performs demodulation processing and decoding processing on an output signal of the OQAM demodulation unit. In the radio | wireless receiver of the radio | wireless communications system of Claim 3,
The reference signal generation unit generates a signal sequence in which the known signal is inserted into a subcarrier into which the pilot subcarrier is inserted, and a null subcarrier is inserted into other subcarriers, and OQAM modulation is performed on the signal sequence. A radio receiving apparatus that performs inverse Fourier transform, transmission-side filter processing, reception-side filter processing, and Fourier transform to estimate an interference component due to the known adjacent symbol and generate the reference signal .

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