JP5767137B2 - Receiving apparatus and receiving method - Google Patents

Description

  The present invention relates to a receiving apparatus and a receiving method.

  In recent years, the depletion of frequency resources has become a problem due to the widespread use of various wireless communication systems, and studies on superposition transmission techniques that improve frequency utilization efficiency by sharing frequencies with a plurality of wireless signals are underway.

FIG. 6 is a conceptual diagram illustrating an example of combining wireless communication systems that share a frequency band. In the figure, two wireless LAN (Local Area Network) systems with different frequency channels are shown. The wireless communication system shown in the figure includes wireless LAN base stations 91a and 91b and a receiving device 92a. The wireless LAN base station 91a communicates using the frequency band of the channel CH1 that is the center frequency fa. The wireless LAN base station 91b communicates using the frequency band of the channel CH5 having the center frequency fb (fa <fb).
The receiving device 92a is arranged at a position where the wireless signals of both the wireless LAN base stations 91a and 91b reach, and receives a signal in which the wireless signal of the center frequency fa and the wireless signal of the center frequency fb partially interfere with each other. .

Another example of sharing frequency bands with each other is a combination of a wireless LAN system, Bluetooth (registered trademark), and WiMAX (registered trademark), and systems of different wireless systems may share frequencies. .
Thus, for example, when the wireless LAN base station 91a is a communication target, the transmission frequency band of the desired wave having the center frequency fa and the transmission frequency band of the interference wave from the wireless LAN base station 91b having the center frequency fb Partially overlap (interfere). In other wireless communication in which such frequency sharing is performed, the receiving device 92a can detect the presence of an interference wave that overlaps the transmission frequency band of the desired wave in order to efficiently perform error correction and improve frequency use efficiency. It is necessary to detect accurately (Patent Document 1).

  In general, when there is an interference wave, the communication characteristics are remarkably deteriorated, but a technique for realizing accurate transmission by decoding distributed FEC (Forward Error Correction) blocks while suppressing the influence of this interference. Has been studied (Non-Patent Document 1). Specifically, before demodulating the desired wave, a filtering process is performed on a frequency component in which an interference wave is present in the received signal in an RF (Radio Frequency: radio frequency band) stage or an IF (Intermediate Frequency: intermediate frequency band) stage. Alternatively, the frequency component is weighted in the baseband so that the influence of the interference wave is suppressed and demodulated and decoded.

  In addition, a technique for detecting a frequency band in which an interference wave exists has been studied (Non-Patent Document 2). Specifically, in the technique described in Non-Patent Document 1, provisional demodulation decoding is performed by changing the filtering band or the weighting band on a trial basis, and the predetermined band, for example, the filtering band that minimizes the error rate or The weighting band is identified as the frequency band where the interference wave exists. In this case, it is possible to detect the interference band while performing desired wave communication.

JP 2007-282120 A

Masuno and Sugiyama, “Effects of improving frequency utilization efficiency by multi-carrier superimposed transmission”, Shingaku Techniques, vol. 108, no. 188, RCS2008-67, pp. 85-90, August 2008 Otsuki, Masuno, Sugiyama, “Interference wave detection method based on error rate using initial likelihood mask”, IEICE Tech. 111, no. 180, RCS 2011-119, pp. 45-49, August 2011

  However, in order to detect a frequency band in which an interference wave exists (hereinafter referred to as an interference band), it is necessary to repeatedly perform a filtering process, a weighting process, and the like for each of a plurality of combinations that determine a frequency and a frequency width. . Therefore, there is a problem that the amount of calculation required to detect the interference band becomes enormous and it takes time to detect the interference band.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a receiving apparatus and a receiving method capable of receiving a desired wave while reducing the amount of calculation required for detecting an interference band. There is.

  In order to solve the above problem, the present invention provides a signal in which a desired wave transmitted by using a multi-carrier superposition transmission method and a interference wave that interferes with the desired wave are superimposed on a signal modulated by an equal power modulation method. A reference signal in which a randomly generated bit string is modulated by the equal power modulation method, and a transmission path indicating characteristics of a transmission path between the transmission source of the desired wave and the own apparatus A reference signal generation unit that generates a reception reference signal from a coefficient, and calculates error power by subtracting power of the reception reference signal from power of the received signal for each subcarrier, and based on the calculated error power An interference band detection unit that detects an interference band that is a frequency band in which an interference wave exists in the frequency band of the desired wave, and a band suppression unit that suppresses and outputs the signal in the interference band detected by the interference band detection unit. And vessels, is a receiving apparatus characterized by comprising a decoder to obtain the received bit sequence by decoding a signal output from the band suppressor.

  In the present invention described above, the interference band detection unit may determine, for each subcarrier, whether or not the error power is greater than or equal to a predetermined threshold, and error power greater than or equal to the threshold. It is characterized by identifying that an interference wave exists in the frequency band of the subcarrier having

  Further, the present invention is the above-described invention, wherein the interference band detection unit detects a subcarrier having a low frequency from the error power of a subcarrier having a high frequency between adjacent subcarriers in the frequency band of the desired wave. Calculating a first deviation amount obtained by subtracting the error power, and a second deviation amount obtained by subtracting the error power of a subcarrier having a high frequency from the error power of a subcarrier having a low frequency; Is a frequency band equal to or higher than a subcarrier frequency at which the deviation amount is equal to or greater than a predetermined threshold, and a frequency band equal to or lower than the subcarrier frequency at which the second deviation amount is equal to or greater than the threshold is defined as an interference band. It is characterized by identifying.

  In addition, in order to solve the above problem, the present invention superimposes a desired wave, which is a signal modulated by an equal power modulation method, transmitted using a multicarrier superimposed transmission method and an interference wave that interferes with the desired wave. A reception method performed by a receiving device that receives a received signal, a reference signal in which a randomly generated bit string is modulated by the equal power modulation method, and a transmission path between the transmission source of the desired wave and the own device A reference signal generation step of generating a received reference signal from a transmission path coefficient indicating the characteristics of the received signal, and calculating an error power by subtracting the power of the received reference signal from the received signal power for each subcarrier. An interference band detecting step for detecting an interference band, which is a frequency band in which an interference wave exists in the frequency band of the desired wave, based on the error power, and a detection in the interference band detecting step. A reception method characterized in that it has to the band suppression step of signal suppression to the output of the interference band was, and a decoding step of obtaining a received bit sequence by decoding a signal output in the band suppression step.

  Further, the present invention provides the above-described invention, wherein in the interference band detection step, for each subcarrier, it is determined whether or not the error power is greater than or equal to a predetermined threshold, and the error power greater than or equal to the threshold. It is characterized by identifying that an interference wave exists in the frequency band of the subcarrier having

  Further, the present invention is the above-described invention, wherein, in the interference band detecting step, the subcarriers having a low frequency are subtracted from the error power of the subcarrier having a high frequency between adjacent subcarriers in the frequency band of the desired wave. Calculating a first deviation amount obtained by subtracting the error power, and a second deviation amount obtained by subtracting the error power of a subcarrier having a high frequency from the error power of a subcarrier having a low frequency; Is a frequency band equal to or higher than a subcarrier frequency at which the deviation amount is equal to or greater than a predetermined threshold, and a frequency band equal to or lower than the subcarrier frequency at which the second deviation amount is equal to or greater than the threshold is defined as an interference band. It is characterized by identifying.

  According to the present invention, the interference between the power of the received reference signal generated from the randomly generated bit string and the power of the received signal can be obtained without changing the subcarrier for suppressing the signal and trying to detect the interference band. A band can be detected. Therefore, it is not necessary to demodulate and decode the received bit string from the received signal, encode and modulate the received bit string, and further generate distortion in the transmission path to generate a received replica signal. This makes it possible to receive the desired wave.

It is a schematic block diagram which shows the structure of the receiver 1 in 1st Embodiment. It is a schematic block diagram which shows the structure of the interference band detection part 30 in the same embodiment. It is the schematic which shows the detection method of the interference band in the embodiment. It is a flowchart which shows the reception process which the receiver 1 in the embodiment performs. It is the schematic which shows the detection method of the interference band in 2nd Embodiment. It is a conceptual diagram which shows an example which combines the radio | wireless communications system which shares a frequency band.

  Hereinafter, a receiving apparatus and a receiving method in each embodiment according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic block diagram illustrating the configuration of the receiving device 1 according to the first embodiment. The receiving device 1 includes a desired wave that is transmitted by using a multicarrier superimposed transmission method and a interference wave that interferes with the desired wave, by transmitting a signal modulated by the transmitting device that communicates with the own device by the equal power modulation method. Receives a signal superimposed on the transmission path. The receiving device 1 detects an interference band for a desired wave included in the received signal. Here, the equal power modulation scheme refers to a digital modulation scheme in which a bit string is modulated into a plurality of symbols, and the amplitude is constant and each symbol is identified by a phase difference. For example, BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), and the like are equal power modulation schemes.
Further, the receiving apparatus 1 obtains a received bit string by suppressing the interference band detected in the received signal and performing demodulation and decoding. In the following description, a case where a signal transmitted using an OFDM (Orthogonal Frequency Division Multiplexing) transmission system is received as an example of a multicarrier superimposed transmission system will be described.

  As shown in the figure, the receiving apparatus 1 includes an antenna 11, a filter 12, an OFDM demodulator 13, a transmission path estimator 14, an amplitude and phase distortion corrector 15, a demodulator 16, a zero substitution device 17, and a parallel-serial converter 18. , FEC decoder 19, permutation subcarrier setting unit 20, signal buffer 21, and interference band detection unit 30.

The filter 12 suppresses components other than the frequency band in which a desired wave including a signal that is a target of demodulation decoding of the received signal received via the antenna 11 exists, and removes the component of the frequency band. Output signal including. As the filter 12, for example, a band pass filter may be used.
The OFDM demodulator 13 performs FFT on the signal output from the filter 12, performs (Fast Fourier Transform), converts the signal in the time domain to the signal in the frequency domain, and outputs a signal for each subcarrier. Is demodulated.
The transmission path estimator 14 uses the signal of each subcarrier demodulated by the OFDM demodulator 13 to determine the characteristics of the transmission path (changes in amplitude, phase, etc.) between the transmission apparatus and the own apparatus for each subcarrier. Estimate the indicated channel coefficient. For example, the transmission path estimator 14 estimates a transmission path coefficient by applying a known technique to a known pattern (for example, a pilot signal or a training signal) included in each subcarrier signal.

The amplitude / phase distortion corrector 15 corrects amplitude and phase distortion generated in the transmission path with respect to the signal of each subcarrier using the transmission path coefficient of each subcarrier estimated by the transmission path estimator 14.
The demodulator 16 performs demodulation corresponding to the modulation scheme used in the transmission apparatus for each subcarrier signal corrected by the amplitude phase distortion corrector 15. The demodulator 16 outputs the signal of each subcarrier obtained by the demodulation to the zero substitution unit 17. Note that demodulation used in the demodulator 16 is demodulation corresponding to the above-described equal power modulation method.

The zero permutation unit 17 replaces the subcarrier signal designated by the permutation subcarrier setting unit 20 among the demodulated signals of each subcarrier input from the demodulator 16 with “0” and converts the subcarrier signal to the parallel-serial converter 18. Output. Of the demodulated signals of each subcarrier input from the demodulator 16, the zero replacer 17 outputs a signal of a subcarrier not designated by the replacement subcarrier setter 20 to the parallel-serial converter 18. The zero replacer 17 may be other than the one that replaces the signal with “0” as long as it suppresses the signal of the subcarrier designated by the replacement subcarrier setter 20.
The parallel / serial converter 18 performs parallel-serial conversion on the signal sequence input from the zero substitution unit 17, converts the signal sequence into one signal sequence, and outputs the signal sequence to the FEC decoder 19.

The FEC decoder 19 restores the received bit string by performing error correction decoding on the signal string input from the parallel-serial converter 18. The FEC decoder 19 outputs the restored received bit string to an upper device (not shown) or the like.
Based on the suppression band information input from interference band detector 30, replacement subcarrier setter 20 selects a subcarrier that replaces the signal demodulated by demodulator 16 with "0" in zero replacer 17. The substitution subcarrier setting unit 20 controls the zero substitution unit 17 by outputting information indicating the selected subcarrier to the zero substitution unit 17.
The signal buffer 21 receives a signal in the frequency band of the desired wave that has passed through the filter 12 and stores the input signal. The signal buffer 21 outputs signals to the interference band detection unit 30 in the order of input.

  The interference band detector 30 receives the signal output from the filter 12 and the transmission path coefficient estimated by the transmission path estimator 14. The interference band detection unit 30 detects an interference band in the frequency band of the desired wave based on the input signal or the like. Moreover, the interference band detection unit 30 outputs suppression band information indicating a subcarrier corresponding to the detected interference band to the replacement subcarrier setting unit 20.

  FIG. 2 is a schematic block diagram showing the configuration of the interference band detection unit 30 in the present embodiment. As shown in the figure, the interference band detection unit 30 includes a reference signal generation unit 31, power calculators 32 and 34, a subtractor 35, an interference band detector 36, and an averager 37.

  The reference signal generation unit 31 includes a PN (Pseudorandom Noise) sequence generator 311, a serial-parallel converter 312, a modulator 313, an amplitude distortion adder 314, and an OFDM modulator 315.

The PN sequence generator 311 generates a PN sequence that is a random bit sequence, and outputs the generated PN sequence to the serial-parallel converter 312.
The serial-parallel converter 312 performs serial-parallel conversion on the PN sequence input from the PN sequence generator 311 and converts it into a plurality of bit strings corresponding to the number of subcarriers used in communication between the transmission device and the own device. The data is converted and output to the modulator 313.
The modulator 313 modulates each of the plurality of bit strings input from the serial / parallel converter 312 using the same modulation scheme as that used in the transmission apparatus. Modulator 313 outputs a signal corresponding to each subcarrier obtained by modulating a plurality of bit strings to amplitude distortion adder 314.

The amplitude distortion adder 314 uses the transmission path coefficient of each subcarrier estimated by the transmission path estimator 14 and is equivalent to a change in amplitude generated in the transmission path with respect to each subcarrier signal input from the modulator 313. A change in amplitude (distortion) is given. The amplitude distortion adder 314 outputs the signal of each subcarrier to which distortion is added to the OFDM modulator 315.
The OFDM modulator 315 performs an IFFT (Inverse Fast Fourier Transform) on the signal of each subcarrier input from the amplitude distortion adder 314 to convert the signal in the frequency domain into a signal in the time domain. Thus, a reception reference signal is generated. The OFDM modulator 315 outputs the generated received reference signal to the power calculator 32.

Since the reference signal generation unit 31 has the above-described configuration, the reception corresponding to the signal when the signal (desired wave) transmitted from the transmission apparatus is received by the own apparatus without performing demodulation decoding of the reception signal is received. Generate a reference signal. In communication between the transmission device and the reception device 1, as long as the equal power modulation method is used, the power of each subcarrier of the desired wave and the power of each subcarrier of the received reference signal are always the same.
Note that the reference signal generation unit 31 stores the reference signal calculated in advance instead of the configuration for generating the reception reference signal from the PN sequence, and gives distortion in the transmission path to the stored reference signal. A reception reference signal may be generated.

The power calculator 32 calculates the power in each subcarrier of the received reference signal input from the reference signal generation unit 31. The power calculator 32 outputs a signal indicating the calculated power value of each subcarrier to the subtractor 35.
The power calculator 34 calculates the power in each subcarrier of the signal stored in the signal buffer 21. The power calculator 34 outputs a signal indicating the calculated power value of each subcarrier to the subtractor 35.
The subtractor 35 subtracts the power of the reference signal calculated by the power calculator 32 from the power of the signal calculated by the power calculator 34 (signal corresponding to the received signal) for each subcarrier to calculate error power. . The subtractor 35 outputs a signal indicating the calculated error power of each subcarrier to the interference band detector 36.

  The interference band detector 36 determines whether or not an interference wave exists for each subcarrier based on a signal indicating the error power of each subcarrier input from the subtractor 35 and a predetermined power threshold. By performing the above, the interference band is detected. The interference band detector 36 outputs information indicating the detected interference band to the averager 37. Here, the power threshold value is determined based on the result of actual measurement or simulation and the reception performance of the own device (receiving device 1). The reception performance of the receiver 1 is determined by, for example, the symbol determination performance in the demodulator 16, the modulation method and coding rate used in communication, the estimation accuracy of the transmission path coefficient in the transmission path estimator 14, and the like.

  The averager 37 averages information input from the interference band detector 36 over a plurality of symbols (or packets). The averager 37 determines whether or not an interference wave exists in each subcarrier based on the averaged information, and outputs suppression band information indicating the determination result to the replacement subcarrier setting unit 20. Here, the averaging of the information performed by the averager 37 is performed by, for example, calculating the number of times that the interference band detector 36 detects the interference wave over a plurality of symbols (or packets) for each subcarrier. Is identified as an interference wave in a subcarrier that exceeds a predetermined number of times (for example, a majority). Further, instead of the majority, it may be identified that the interference wave exists in the subcarrier exceeding the average number of times that the interference wave is detected in each subcarrier.

Here, an interference band detection method performed by the interference band detector 36 will be described.
FIG. 3 is a schematic diagram showing an interference band detection method in the present embodiment. In the figure, the horizontal axis represents frequency and the vertical axis represents error power. As shown in the figure, the interference band detector 36 has an interference wave in a frequency band (subcarrier) corresponding to the error power value when the error power value input from the subtractor 35 is equal to or greater than the power threshold. Identified as an interference band.

FIG. 4 is a flowchart illustrating a reception process performed by the reception device 1 according to this embodiment.
In the receiving device 1, when the reception process is started, the reference signal generation unit 31 generates a reception reference signal from the PN sequence (step S101).
Each of the power calculators 32 and 34 calculates the power of the received signal and the power of the received reference signal, and the subtractor 35 subtracts the power of the received reference signal from the power value of the received signal for each subcarrier to obtain an error power. Is calculated (step S102).
The interference band detector 36 detects an interference band based on the error power (step S103), and the averager 37 detects zero based on the interference band detected by the interference band detector 36 over a plurality of symbols (or packets). A suppression band indicating a frequency band (subcarrier) in which the signal is suppressed in the replacer 17 is identified (step S104).
The averager 37 outputs suppression band information indicating the identified suppression band to the replacement subcarrier setting unit 20. Replacement subcarrier setting unit 20 sets a subcarrier indicated by the suppression band information as a replacement subcarrier (step S105).
Thereafter, the zero replacer 17 replaces the signal of the subcarrier set as the replacement subcarrier with “0”. The receiving device 1 obtains a received bit string from the received signal through the respective processes from the filter 12 to the FEC decoder 19.

As described above, the receiving apparatus 1 according to the present embodiment calculates the error power by subtracting the power of each subcarrier of the received reference signal from the power of each subcarrier included in the received signal. The reason why the error power occurs is that there is an interference wave superimposed on the desired wave, and there is an error between the received reference signal and the received signal of the desired wave due to the estimation error of the channel coefficient in the interference wave band. There are things to do. In any case, the interference band detector 36 identifies that there is an interference wave in a frequency band in which the error power exceeds a certain value (power threshold) because there is an interference wave with respect to the desired wave. Can do.
That is, the receiving apparatus 1 performs a process of generating a received replica signal from a received bit string obtained by demodulating and decoding the received signal, a process of detecting an interference band by suppressing the signal of each subcarrier by the zero replacer 17, and the like. Since the interference band can be identified without performing repeated trials, the desired wave can be received while reducing the amount of calculation in the identification of the interference band.
In addition, since the generation of the reception reference signal does not require a process for demodulating and decoding the received bit string from the received signal and a process for generating a received replica signal from the received bit string, the amount of calculation can be further reduced.

(Second Embodiment)
In the first embodiment, the configuration in which the interference band detector 36 detects the interference wave by comparing the force threshold with the error power calculated by the subtractor 35 has been described. In the second embodiment, the deviation amount Δpwr of error power between adjacent subcarriers is used as a criterion. The case where the subcarrier numbers in the desired wave are SC1, SC2, SC3,.

FIG. 5 is a schematic diagram illustrating an interference band detection method according to the second embodiment. In the figure, the horizontal axis represents frequency (subcarrier), and the vertical axis represents error power.
First, the interference band detector 36 shifts the error power between adjacent subcarriers Δpwr (SC k → SC k + 1) (k = 1, 2,...) From the lower frequency toward the higher frequency. , 6) are measured in order (Process A). That is, the deviation amount Δpwr (SC k → SC k + 1) is calculated by subtracting the error power of the low-frequency subcarrier (SC k + 1) from the error power of the high-frequency subcarrier (SC k + 1).
In the example shown in FIG. 5, error power deviation amount Δpwr (SC1 → SC2) between subcarrier SC1 and subcarrier SC2 and error power deviation amount Δpwr (SC2 → SC3) between subcarrier SC2 and subcarrier SC3. ) Etc. are almost zero. On the other hand, the deviation amount Δpwr (SC3 → SC4) of the error power between the subcarrier SC3 and the subcarrier SC4 is a large value. Further, deviation amount Δpwr (SC5 → SC6) of error power between subcarrier SC5 and subcarrier SC6 is a negative value.

Subsequently, the interference band detector 36 shifts the error power deviation Δpwr (SC k → SC k−1) (k = 7, 6) in the adjacent subcarriers from the higher frequency toward the lower frequency. ,..., 2) are measured in order (Process B). That is, the deviation amount Δpwr (SC k → SC k−1) is calculated by subtracting the error power of the high frequency subcarrier (SC k−1) from the error power of the low frequency subcarrier (SC k).
In the example shown in FIG. 5, the deviation amount Δpwr (SC6 → SC5) of the error power between the subcarrier SC6 and the subcarrier SC5 becomes a large value, and the deviation amount Δpwr of the error power between the subcarrier SC4 and the subcarrier SC3 ( SC4 → SC3) is a negative value.

  After performing the processing A and the processing B, the interference band detector 36 determines that there is an interference wave at the frequency in the measurement direction when the deviation amount Δpwr is equal to or larger than a predetermined detection threshold. In the example shown in FIG. 5, it is determined from the result of process A that an interference wave exists in a frequency band equal to or higher than the frequency of subcarrier SC4, and from the result of process B, an interference wave exists in a frequency band equal to or lower than the frequency of subcarrier SC5. judge. The interference band detector 36 combines the determination based on the result of the process A and the determination based on the result of the process B to generate an “interference wave in a frequency band higher than the frequency of the subcarrier SC4 and lower than the frequency of the subcarrier SC5. Is present. "

  Further, for example, in process A, the displacement amount Δpwr (SC2 → SC3) and the displacement amount Δpwr (SC6 → SC7) are equal to or larger than the detection threshold value, and in process B, the displacement amount Δpwr (SC4 → SC3) is above the detection threshold value. In this case, the interference band detector 36 identifies that “an interference wave exists in a frequency band equal to or higher than the frequency of the subcarrier SC3 and equal to or lower than the frequency of the subcarrier SC4 and a frequency band equal to or higher than the frequency of the subcarrier SC7”. .

As described above, in this embodiment, the interference band detector 36 detects the interference band and uses the deviation amount Δpwr of the error amplitude in the adjacent subcarrier. Thereby, even when white noise having a high level is included in the frequency band of the desired wave in the received signal, the interference band can be identified without being affected by the white noise.
Also in the second embodiment, similarly to the first embodiment, a process of generating a received replica signal from a received bit string obtained by demodulating and decoding the received signal, and a signal of each subcarrier by the zero permuter 17 Since the interference band can be identified without trying to repeat the process of detecting the interference band by suppressing the interference band, it is possible to receive the desired wave while reducing the amount of calculation in the identification of the interference band. .

  Note that a program for realizing the function of the receiving device 1 in the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to perform reception processing. You may go. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The band suppressor described in the present invention corresponds to the zero replacer 17 in each of the above-described embodiments. The first deviation amount described in the present invention corresponds to the deviation amount Δpwr calculated in the process A in the second embodiment described above. The second displacement amount described in the present invention corresponds to the displacement amount Δpwr calculated in the process B in the second embodiment described above.

  DESCRIPTION OF SYMBOLS 1 ... Receiver, 11 ... Antenna, 12 ... Filter, 13 ... OFDM demodulator, 14 ... Transmission path estimator, 15 ... Amplitude phase distortion corrector, 16 ... Demodulator, 17 ... Zero substitution device, 18 ... Parallel-serial conversion 19 ... FEC decoder 20 ... substitution subcarrier setter 21 ... signal buffer 30 ... interference band detector 31 ... reference signal generator 32 ... power calculator 34 ... power calculator 35 ... subtract , 36 ... interference band detector, 37 ... averager, 91a ... wireless LAN base station, 91b ... wireless LAN base station, 92a ... receiving device, 311 ... PN sequence generator, 312 ... serial-parallel converter, 313 ... Modulator, 314 ... Amplitude distortion applicator, 315 ... OFDM modulator

Claims (4)

A receiving apparatus that receives a signal in which a desired wave transmitted by using a multicarrier superimposed transmission method and a signal modulated by an equal power modulation method and an interference wave that interferes with the desired wave are superimposed,
A reception reference signal is generated from a reference signal in which a bit string generated at random is modulated by the equal power modulation method and a transmission path coefficient indicating a characteristic of a transmission path between the transmission source of the desired wave and the own apparatus. A reference signal generator;
For each subcarrier, calculate the error power by subtracting the power of the received reference signal from the power of the received signal, and based on the calculated error power, a frequency band in which an interference wave exists in the frequency band of the desired wave An interference band detector for detecting an interference band of
An averaging unit that averages the interference band detected by the interference band detection unit over a predetermined period, and identifies an interference band in which an interference wave exists from the obtained average value;
A band suppressor that suppresses and outputs a signal in the interference band identified by the averaging unit ;
And a decoder for decoding a signal output from the band suppressor to obtain a received bit string. A receiving apparatus that receives a signal in which a desired wave transmitted by using a multicarrier superimposed transmission method and a signal modulated by an equal power modulation method and an interference wave that interferes with the desired wave are superimposed,
A reception reference signal is generated from a reference signal in which a bit string generated at random is modulated by the equal power modulation method and a transmission path coefficient indicating a characteristic of a transmission path between the transmission source of the desired wave and the own apparatus. A reference signal generator;
For each subcarrier, calculate the error power by subtracting the power of the received reference signal from the power of the received signal, and based on the calculated error power, a frequency band in which an interference wave exists in the frequency band of the desired wave An interference band detector for detecting an interference band of
A band suppressor that suppresses and outputs an interference band signal detected by the interference band detector;
A decoder for decoding a signal output from the band suppressor to obtain a received bit string;
Comprising
The interference band detector is
A first deviation amount obtained by subtracting the error power of a subcarrier having a low frequency from the error power of a subcarrier having a high frequency between adjacent subcarriers in the frequency band of the desired wave, and a subcarrier having a low frequency A second deviation amount obtained by subtracting the error power of the subcarrier having a high frequency from the error power;
A frequency band equal to or higher than a subcarrier frequency at which the first deviation amount is equal to or greater than a predetermined threshold, and a frequency band equal to or lower than a subcarrier frequency at which the second deviation amount is equal to or greater than the threshold. A receiver characterized by being identified as an interference band. A reception method performed by a receiving device that receives a signal in which a desired wave transmitted by using a multicarrier superimposed transmission method and a signal modulated by an equal power modulation method and an interference wave that interferes with the desired wave are superimposed. ,
A reception reference signal is generated from a reference signal in which a bit string generated at random is modulated by the equal power modulation method and a transmission path coefficient indicating a characteristic of a transmission path between the transmission source of the desired wave and the own apparatus. A reference signal generation step;
For each subcarrier, calculate the error power by subtracting the power of the received reference signal from the power of the received signal, and based on the calculated error power, a frequency band in which an interference wave exists in the frequency band of the desired wave An interference band detecting step of detecting an interference band of
An averaging step of averaging the interference band detected in the interference band detecting step over a predetermined period and identifying an interference band in which an interference wave exists from the obtained average value;
A band suppression step of suppressing and outputting the signal of the interference band identified in the averaging step;
And a decoding step of obtaining a received bit string by decoding the signal output in the band suppressing step. A reception method performed by a receiving device that receives a signal in which a desired wave transmitted by using a multicarrier superimposed transmission method and a signal modulated by an equal power modulation method and an interference wave that interferes with the desired wave are superimposed. ,
A reception reference signal is generated from a reference signal in which a bit string generated at random is modulated by the equal power modulation method and a transmission path coefficient indicating a characteristic of a transmission path between the transmission source of the desired wave and the own apparatus. A reference signal generation step;
For each subcarrier, calculate the error power by subtracting the power of the received reference signal from the power of the received signal, and based on the calculated error power, a frequency band in which an interference wave exists in the frequency band of the desired wave An interference band detecting step of detecting an interference band of
A band suppression step of suppressing and outputting the signal of the interference band detected in the interference band detection step;
A decoding step of decoding the signal output in the band suppression step to obtain a received bit string;
Have
In the interference band detection step,
A first deviation amount obtained by subtracting the error power of a subcarrier having a low frequency from the error power of a subcarrier having a high frequency between adjacent subcarriers in the frequency band of the desired wave, and a subcarrier having a low frequency A second deviation amount obtained by subtracting the error power of the subcarrier having a high frequency from the error power;
A frequency band equal to or higher than a subcarrier frequency at which the first deviation amount is equal to or greater than a predetermined threshold, and a frequency band equal to or lower than a subcarrier frequency at which the second deviation amount is equal to or greater than the threshold. A receiving method characterized by identifying an interference band.

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