JP2003249910A - Signal receiving method, communication method and communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a bit error rate of transmission information which is caused when the peak power of a multicarrier modulation signal obtained by multiplexing a carrier subjected to quadrature amplitude phase modulation is compressed in a time domain without significantly increasing data throughput. <P>SOLUTION: A signal received by a receiving side is Fourier-transformed in a fast Fourier transformer 143 and then equalized by an equalizer 144. The distortion of the signal is thereby removed, and the signal with transmission line distortion removed is subjected to amplitude expansion as it is in a frequency domain according to a predetermined expansion amount. As a result, a bit error rate of transmission information can be easily reduced without depending upon a transmission line characteristics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Orthogonal Frequency Division Multiplexing in a digital information transmission system.
quency Division Multiplexing (OFDM) modulation system, etc., and peak-to-average power ratio (Pe
The present invention relates to a signal processing method for compressing an ak-to-average power ratio (PAPR) and, more particularly, to a signal receiving method in a receiving device under a transmission path condition in which signal distortion exists.

[0002]

2. Description of the Related Art In a communication technique using a carrier wave, a method of transmitting data by modulating the amplitude, phase or frequency of one carrier is called a single carrier modulation method. On the other hand, a method of combining a plurality of carriers whose amplitudes or phases are modulated into a transmission signal is called a multi-carrier modulation method. When the transmission rates are the same, the multi-carrier modulation method has the characteristic that it is less susceptible to the reflected waves generated in the communication path because the multi-carrier modulation method can transmit the data in a time that is several times the number of carriers.

In recent years, the OFDM modulation method has attracted attention as a digital modulation method that is resistant to noise, which is a problem in a digital transmission system, and is not easily affected by multipaths in a transmission line, and 16QAM (Quadrature Amplitude Modula).
is a frequency division multiplex modulation system with high frequency utilization efficiency, which transmits information using a plurality of orthogonally modulated carrier waves subjected to quadrature amplitude phase modulation.

Since this OFDM modulation system has high frequency utilization efficiency, a high information transmission rate can be realized even if the symbol frequency is set low by adding a guard interval to the symbol. Therefore, even when compared with other modulation methods, it is possible to avoid the influence of delayed waves due to multipath without lowering the transmission rate. That is,
On the receiving side, the original transmission data is obtained by detecting the amplitude and phase of each carrier by removing the guard interval from the received symbol and performing demodulation processing.

However, not only the OFDM method but also the multi-carrier modulation method combines a plurality of carriers to form a transmission signal. Therefore, if the phases of a large number of carriers are aligned at a certain point, the effective value of the amplitude of the transmission signal is obtained. On the other hand, there is a problem of having a very large peak. Therefore, the ratio of the peak power to the average power (PAPR) also becomes large, and when the PAPR is large, the amplifier with the maximum power must be used as the transmission amplifier, which increases the cost of the transmission amplifier. Further, there is a problem that the dynamic range of the digital processing circuit used for signal processing of transmission and reception must be increased.

Although many methods of compressing the peak power of a transmission signal have been proposed, some restrictions such as a method of limiting the arrangement of transmission data are provided. There is also a method of directly compressing a signal in the time domain without limiting the transmission data, but in that case, it is necessary to perform decompression processing on the receiving side.

According to Japanese Patent Laid-Open No. 7-143098, the OFDM modulated wave from the inverse FFT circuit is limited by a level limiter to clip a large amplitude, but the receiving side does not expand the signal and the error correction code is used. Since the information is assured by the above, it is necessary to use an error correction code that is strong to some extent, and the effective transmission rate of the information is reduced.

Further, in JP-A-2000-324082, a function (polynomial) is applied to an OFDM modulated wave.
The peak power is suppressed by multiplying by and the expansion is performed on the receiving side by multiplying by the reciprocal of the function (polynomial).
However, for example, when a power line is used as a transmission line, the actual power line has a large distortion in the transmission line, the restoration is insufficient by the conventional method, and a data error occurs, which is not practical.

[0009]

As described above, it is required to suppress PAPR in the multi-carrier modulation method. However, when the peak value is compressed in the time domain as a PAPR suppressing method, an error may occur in transmission information. Is high. Therefore, it is necessary to expand the signal on the receiving side to restore the peak value.

However, since the signal waveform is distorted on the transmission line, when the expansion is performed in the time domain before the equalization processing for removing the distortion, only the compressed part of the signal is subjected to the amplitude before compression. The desired decompression result of decompressing the peak value is not obtained. Therefore, it is highly possible that an error in the transmission information caused by compressing the peak value remains. Further, when the signal equalization processing is performed before expansion, high-speed communication becomes difficult due to an increase in FFT calculation amount and the like.

In view of these problems, it is an object of the present invention to provide effective means for reducing errors in transmission information caused by signal compression.

[0012]

Since the amplitude of a signal in which carriers of respective frequencies are multiplexed is compressed, it is highly possible that the amplitude of each carrier is also compressed. Therefore, in the present invention, the error of the transmission information of each carrier, that is, the bit error rate is reduced by expanding the amplitude of each carrier in the frequency domain. In order to realize such a function, the present invention is configured as follows, for example. After the signal compressed in the time domain is transmitted, it is received by the receiver, analog / digital converted, and then Fourier transformed, and the frequency characteristics are equalized by performing the inverse calculation of the transmission path characteristics estimated from the pilot signal. To be done. The received signal from which the distortion in the transmission path has been removed is amplitude-expanded as it is in the frequency domain. The amount of expansion at the time of expansion can be obtained by simulating the same circuit. In other words, by expanding the amplitude in the frequency domain, the inverse Fourier transform calculation for returning to the time domain and expanding the amplitude becomes unnecessary,
High-speed signal processing can be realized.

That is, the signal receiving method of the present invention compresses a multi-carrier modulated transmission signal in the time domain and Fourier-transforms the received signal, equalizes the Fourier-transformed signal in the frequency domain, and equalizes the equalized signal. With respect to, the amplitude of the signal is expanded. According to the present invention, the amount of expansion at the time of amplitude expansion is determined to be the amount of expansion that reduces the bit error rate of the transmission information compared to the case where amplitude expansion is not performed, and the PAP of the signal encoded in 256QAM is determined.
The expansion amount for a signal compressed so that the maximum value of R is 9.0 or less and 7.1 or more is -31 dB of the amplitude of the received signal.
Do the following: PA of signal encoded in 256QAM
The expansion amount for a signal compressed so that the maximum PR value is less than 7.1 is set to -23 dB or less of the amplitude of the received signal, and the maximum PAPR value of the signal encoded in 64QAM is set to 5.8 or less. The amount of expansion of the compressed signal to be -19 dB or less of the amplitude of the received signal, 16Q
The expansion amount for a signal compressed so that the maximum value of PAPR of an AM-encoded signal is 4.2 or less is set to -12 dB or less of the amplitude of a received signal, and each carrier is separately expanded during amplitude expansion. Stretching with an amount is the preferred embodiment. The communication method of the present invention compresses the signal amplitude of a multi-carrier modulated signal in the time domain and transmits the signal,
The transmission signal is received by any one of these signal receiving methods.

Further, the signal receiving apparatus of the present invention comprises Fourier transform means for Fourier transforming the received signal transmitted by compressing the multicarrier modulated transmission signal in the time domain, and equalizing the Fourier transformed signal in the frequency domain. And a decompression unit for decompressing the amplitude of the equalized signal with respect to the equalized signal. A communication apparatus of the present invention comprises a signal transmitting apparatus that compresses a signal amplitude of a multicarrier modulated signal in a time domain and transmits the compressed signal, and this signal receiving apparatus as an apparatus that receives the transmitted signal. Is characterized by.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a communication system which is a preferred embodiment of the present invention. As shown in FIG. 1, in the communication system of the present embodiment, a plurality of communication devices 1a, 1b, 1c
Are connected via a power line 2 and each communication device 1
A, 1b, 1c, ... Send and receive data to and from each other by superimposing a signal on the power line 2. That is, the communication device of this embodiment is a power line carrier device that transmits and receives data by power line carrier. The communication devices 1a, 1b, 1c ...
Have the same device configuration and their operation is also the same.

The case of transmitting data from the communication device 1a to the communication device 1b will be described below. First, the transmission data to be transmitted to the communication device 1b is the OFDM of the communication device 1a.
It is input to the modulator 10. In the OFDM modulator 10, the input transmission data is input to the mapping 101, and the mapping 101 converts the input transmission data to 0, 1
Convert a pattern to complex data. This complex number data becomes the amplitude data of each carrier.

The obtained complex number data is input to an inverse fast Fourier transformer (IFFT) 102 and subjected to an inverse fast Fourier transform to generate a modulated signal in the time domain. In this embodiment, the inverse fast Fourier transform is used to combine a plurality of carriers having different amplitudes and frequencies.

The complex number signal obtained by the inverse fast Fourier transform by the IFFT 102 is input to the quadrature modulator 103. The quadrature modulator 103 converts the input complex number signal into a real number signal and outputs it. The real number signal output from the quadrature modulator 103 is input to the compressor 104, and the compressor 104 performs amplitude compression of the input signal according to a preset compression condition, and outputs the compressed signal.
The compression method and the compression condition used at this time are arbitrary as long as the signal is directly compressed in the time domain.

When a multi-carrier modulation system such as an OFDM modulation system is used, the input signal (called the original signal) of the compressor 104 is pulsed as shown in FIG. The change in the amplitude causes the waveform to have a point with a large amplitude. FIG. 2A shows the waveform of the original signal when random data is given as the transmission data, where the vertical axis is the amplitude and the horizontal axis is the time. Figure 2 (b)
Is an example of a signal constellation diagram (constellation) in the frequency domain when 16QAM modulation is used, and the vertical axis represents Q.
The axis and the horizontal axis are shown by the I axis, and the signal point position A ₁ is shown. When the original signal shown in FIG. 2A is compressed by the compressor 104, a waveform with a compressed peak as shown in FIG. 3A is output. FIG. 3B shows the constellation of the signal shown in FIG. Here, the plurality of signals at the signal point position A ₁ in FIG. 2B have spread into the signal point position A ₂ as shown by the broken line in FIG. 3B. By compressing such a large amplitude, the peak power can be reduced, and the ratio of the peak power to the average power (PAPR) is significantly reduced, but due to the influence, the position of the signal point is distorted from the original position. It will be.

The signal output from the compressor 104 is input to a digital / analog converter (D / A) 105, and D
/ A105 converts the input signal from a digital signal into an analog signal and outputs it. The signal output from the D / A 105 is the OFDM output from the OFDM modulator 10.
It is input to the amplifier 11 as a modulation signal. The amplifier 11 amplifies the input OFDM modulated signal with a preset amplification factor so that the average power of the OFDM modulated signal becomes power that enables communication even in a noise environment, and the OFDM modulated signal amplified by the amplifier 11 is sent to the coupler 12. Is entered. The combiner 12 superimposes the input OFDM modulated signal on the power line 2.

The OFDM modulated signal superimposed on the power line 2 is received by the communication device 1b. The communication device 1b takes in the signal output to the communication device 1b among the signals superimposed on the power line 2. The signal captured by the coupler 12 is input to a BPF (bandpass filter) 13, and the BPF 13 outputs only a signal in the frequency range approved by the Radio Law. The signal output from this BPF 13 is input to the OFDM demodulator 14.

The signal input to the OFDM demodulator 14 is input to the analog / digital converter (A / D) 141,
The A / D 141 converts the input signal from an analog signal into a digital signal and outputs it. The signal output from the A / D 141 is input to the quadrature demodulator 142, and the quadrature demodulator 1
42 converts the input signal from a real number signal to a complex number signal. The complex number signal obtained by the quadrature demodulator 142 is input to a fast Fourier transformer (FFT) 143,
A signal in the frequency domain is generated by the fast Fourier transform. The waveform of the transmission signal in the time domain before the fast Fourier transform is shown in FIG. 4A, and the constellation of the transmission signal in the frequency domain after the fast Fourier transform is shown in FIG. 4B. As can be seen by comparing FIG. 4 (b) with FIG. 3 (b), it can be seen that the signal is significantly distorted by the transmission path distortion.

The signal obtained by the FFT 143 is input to the equalizer 144, and the transmission line distortion is removed by performing equalization by inverse calculation of the transmission line characteristic estimated from the pilot signal in advance. FIG. 5 shows a signal constellation after equalization. As a result of such equalization, it can be seen that FIG. 5 shows almost the same constellation as FIG.

After this, inverse fast Fourier transform is performed to return to the time domain, then amplitude expansion is performed, and further fast Fourier transform is performed to return to the frequency domain, whereby the amplitude before compression is expanded. However, there is a problem that the processing speed does not improve because the processing of the fast Fourier transform operation and the inverse fast Fourier transform operation becomes enormous. In the present embodiment, such a situation does not occur, so that the expansion of the compressed signal is performed. However, the transmission speed does not decrease.

The output signal from which the transmission line distortion has been removed by the equalizer 144 is input to the expander 145 and amplitude expanded. By thus extending the amplitude, the bit error rate of the transmission data is improved and the effective transmission rate is increased.
The decompression method at this time will be described later.

The signal obtained by the decompressor 145 is input to the demapping 146, and the demapping 146 converts the input signal from complex number data into 0, 1 pattern data. This data is the received data. In this way, data communication is performed from the communication device 1a to the communication device 1b.

Here, a method of determining the amount of expansion of the amplitude in the expander 145 will be described. If the amount of expansion is reduced, the possibility that an error will occur due to expansion is small, but the effect of restoration to the original signal point position is also small. For example,
If decompression is not performed at all, no new error may occur, but no restoration effect will be obtained. On the contrary, as the expansion amount increases, the restoration effect increases, but the possibility of a new error increases.

FIG. 6 is a schematic diagram when amplitude expansion is performed in the frequency domain. The arrow i indicates that distortion caused by compression can be decoded into the original signal point, and the arrow ii indicates that
i indicates amplitude extension. By setting the expansion amount of the amplitude to an appropriate value in this way, the signal point is decoded to the desired signal point position.

FIG. 7 is a diagram showing the relationship between the expansion amount and the bit error rate of transmission information when the same expansion amount is used for all carriers by simulating the configuration of FIG. 1 by simulation. In FIG. 7, it can be seen that if the expansion amount is set between C ₁ and C ₄ and the expansion is performed, the bit error rate is reduced as compared with the case without expansion. Further, in order to minimize the bit error rate of transmission information, it is desirable to set the expansion amount between C ₂ and C ₃ .

The present invention is not limited to the above embodiment, and other embodiments are possible. For example, the power line 2 in FIG. 1 may be a general subscriber telephone line.

Next, a second embodiment of the present invention will be described. Gray coding is performed when random data is given as input data in the communication system shown in the first embodiment.
PA of OFDM signal in which carriers subjected to quadrature amplitude phase modulation of 56QAM are multiplexed into 48 carriers per symbol
The distribution of the number of symbols for PR is as shown in FIG. 8, for example. Here, the total number of symbols in the distribution shown in FIG.
And the average PAPR of signals with such a distribution is about 1.
It is 0.2. In general, the amplitude of such an OFDM signal is evaluated in a compressor 104 for the relationship between the compression rate and the bit error rate. For example, the maximum value of PAPR is 9.0 or less and 7.
The distribution of the number of symbols with respect to PAPR of a signal compressed to 1 or more is as shown in FIG. The average PAPR of the distribution shown in FIG. 9 is about 7.3.

FIG. 10 shows a simulation result of the bit error rate with respect to the expansion amount when the signal thus compressed is transmitted. It should be noted that FIG. 10 shows the bit error rate when the error correction by the error correction code is not performed. Here, the amplitude before expansion is x ₁ , the amplitude after expansion is x ₂ , and the expansion amount k
[DB] is defined by the equation (1).

K = 20Log ₁₀ ((x ₂ −x ₁ ) / x ₁ ) ... (1) From FIG. 10, the bit error rate when the expansion amount is −34 dB is about 1.9 × 10 ^{−3, which} is the most bit. Since the error rate is low,
It is desirable to set the extension amount to -34 dB, but -3
If the expansion amount is 1 dB or less, the bit error rate is reduced, so the expansion amount may be set to -31 dB or less.

The distribution of the number of symbols for the PAPR of a signal compressed so that the maximum value of PAPR is less than 7.1 is as shown in FIG. The average PAPR of the distribution shown in FIG. 11 is about 5.7. FIG. 12 shows the simulation result of the bit error rate with respect to the expansion amount defined by the equation (1) when the signal thus compressed is transmitted.
Note that FIG. 12 shows the bit error rate when the error correction by the error correction code is not performed.

From FIG. 12, the bit error rate is about 1.2 × 10 ^-2 when the expansion amount is -31 dB, which is the lowest bit error rate. Therefore, it is desirable to set the expansion amount to -31 dB. If the expansion amount is 23 dB or less, the bit error rate is reduced, so the expansion amount may be set to -23 dB or less.

Next, the case where 64QAM modulation is used will be described. O multiplexed with carriers modulated to 64QAM
The distribution of the number of symbols for the PAPR of the signal obtained by compressing the FDM signal so that the maximum value of PAPR is 5.8 or less is as shown in FIG. 13, for example. The average PAPR of the distribution shown in FIG. 13 is about 4.4. FIG. 14 shows a simulation result of the bit error rate with respect to the expansion amount defined by the equation (1) when the signal thus compressed is transmitted. Note that FIG. 14 shows the bit error rate when the error correction by the error correction code is not performed.

From FIG. 14, the bit error rate is about 1.0 × 10 ⁻³ when the expansion amount is −30 dB, which is the lowest bit error rate. Therefore, it is desirable to set the expansion amount to −30 dB. If the expansion amount is 19 dB or less, the bit error rate is reduced, so the expansion amount may be set to -19 dB or less.

Next, the case where 16QAM modulation is used will be described. O multiplexed carrier modulated in 16QAM
The distribution of the number of symbols for the PAPR of the signal obtained by compressing the FDM signal so that the maximum value of PAPR is 4.2 or less is as shown in FIG. The average PAPR of the distribution shown in FIG. 15 is about 3.0. FIG. 16 shows a simulation result of the bit error rate with respect to the expansion amount defined by the equation (1) when the signal thus compressed is transmitted. Note that FIG. 16 shows the bit error rate when the error correction by the error correction code is not performed.

From FIG. 16, the extension amounts are −18 dB and −20.
Since the bit error rate is 0, which is the lowest in the case of dB, it is desirable to set the expansion amount from -18 dB to -20 dB, but if the expansion amount is -12 dB or less, the bit error rate will be reduced. Therefore, the extension amount is −
It may be set to 12 dB or less.

Next, a third embodiment of the present invention will be described. In the second embodiment, the extension amount is defined by the equation (1), but other definition methods are possible. For example, in the formula (1), the expansion amount is represented by a relative amount with respect to the amplitude of the carrier wave, but the expansion amount can be defined by an absolute amount that does not depend on the amplitude. In other words, if the extension amount is 0.05, the amplitude is 0.
The carrier 2 amplitude is extended to 0.25 and the amplitude is 0.25.
It is also possible to use a method of uniformly expanding the amplitudes of all the carriers by 0.1, such as expanding the amplitudes of all the carriers to 0.3. Next, as a fourth embodiment of the present invention, an example of a communication system, which is different from the first embodiment, will be described. The basic configuration of this embodiment is the same as that of FIG. 1 described above, but in this embodiment, the expansion amount used in the expander 145 uses different values for each carrier. In the first embodiment, since the same amount of expansion is applied to all carriers, only an average restoration effect can be obtained.
Since the influence of compression does not occur equally on each carrier of the signal compressed in 4, but the influence of each is different,
By applying different expansion amounts for each carrier, it is possible to further enhance the restoration effect to the original signal point position.

[0042]

As is apparent from the above description, in the signal receiving method of the frequency division multiplex modulation system of the present invention, when the peak power is compressed in the time domain in the communication by the multicarrier modulation system, the receiving side By performing equalization processing of the signal in the frequency domain and then correcting the signal compression, it is possible to reduce the data error rate and improve the communication reliability without depending on the frequency characteristic of the transmission path. it can. Further, since the data processing is easy, it is possible to compress / decompress the signal only by slightly increasing the data processing amount compared to the case where the compression / decompression is not performed, and it is possible to speed up the signal processing. Especially when applied to power line carrier communication using a power line, since the transmission line distortion due to the power line, that is, the amplitude and the phase of the communication signal (transmission signal) greatly change, the effect of the present invention is remarkable, and the invention value is great. is there.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a communication system which is a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram of an example of an OFDM signal before compression and an example of a constellation of a signal before compression according to the first embodiment.

FIG. 3 is an explanatory diagram of an example of an OFDM signal after compression and an example of a constellation of a signal after compression regarding the first embodiment.

FIG. 4 is an explanatory diagram of an example of an OFDM signal after transmission and an example of a constellation of a signal after transmission according to the first embodiment.

FIG. 5 is an explanatory diagram of an example of a constellation of a signal after equalization in the first example.

FIG. 6 is a schematic diagram of amplitude expansion in the frequency domain for the first embodiment.

FIG. 7 is a diagram showing a simulation result of an expansion amount and a bit error rate regarding the first embodiment.

FIG. 8 is a diagram illustrating P of an OFDM signal before compression according to the second embodiment.
It is a figure which shows the distribution example of the number of symbols with respect to APR.

FIG. 9 relates to the second embodiment, P of the OFDM signal after compression
It is a figure which shows the distribution example of the number of symbols with respect to APR.

FIG. 10 is a diagram showing an example of simulation of an expansion amount and a bit error rate in the second example.

FIG. 11 is a diagram showing a distribution example of the number of symbols with respect to PAPR of a compressed OFDM signal according to the second embodiment.

FIG. 12 is a diagram showing an example of simulation of an expansion amount and a bit error rate in the second example.

FIG. 13 is a diagram showing a distribution example of the number of symbols with respect to PAPR of a compressed OFDM signal according to the second embodiment.

FIG. 14 is a diagram showing an example of simulation of an expansion amount and a bit error rate in the second example.

FIG. 15 is a diagram showing a distribution example of the number of symbols with respect to PAPR of an OFDM signal after compression according to the second embodiment.

FIG. 16 is a diagram showing an example of simulation of an expansion amount and a bit error rate in the second example.

[Explanation of symbols]

1a, 1b, 1c ... communication device, 2 ... power line, 10 ... OFD
M modulator, 11 ... Amplifier, 12 ... Combiner, 13 ... Band pass filter, 14 ... OFDM demodulator, 101 ... Mapping, 102 ... Inverse Fourier transform, 103 ... Quadrature modulator, 104 ... Compressor, 105 ... Digital / Analog converter, 141 ... Analog / digital converter, 142 ... Quadrature demodulator, 143 ... Fourier converter, 144 ... Equalizer, 1
45 ... Expander, 146 ... Demapping.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshikazu Ishii             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Setsuo Arita             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. F term (reference) 5K022 AA02 AA16 AA34 DD01 DD13                       DD18 DD19 DD23 DD33 DD34                 5K046 BB05 DD18 EE37 PS00

Claims (10)

[Claims] 1. A multicarrier-modulated transmission signal is compressed in the time domain and transmitted, and the received signal is Fourier transformed, and the Fourier transformed signal is equalized in the frequency domain.
A signal receiving method, which comprises expanding the amplitude of the equalized signal. 2. A Fourier transform means for Fourier transforming a received signal transmitted by compressing a multicarrier modulated transmission signal in the time domain, an equalization means for equalizing the Fourier transformed signal in the frequency domain, and the equalized means. And a decompression unit that decompresses the amplitude of the signal. 3. The signal receiving method according to claim 1, wherein the amount of expansion at the time of amplitude expansion is determined to be an amount of expansion that reduces the bit error rate of transmission information as compared with the case where amplitude expansion is not performed. 4. The expansion amount for a signal compressed so that the maximum value of PAPR of a 256QAM-encoded signal is 9.0 or less and 7.1 or more is set to −31 dB or less of the amplitude of the received signal. A signal receiving method characterized by the above. 5. The expansion amount for a signal compressed so that the maximum value of PAPR of a signal encoded in 256QAM is less than 7.1, according to claim 1, which is -23d of the amplitude of the received signal.
A signal receiving method characterized in that it is B or less. 6. The expansion amount for a signal compressed according to claim 1 so that the maximum value of PAPR of a signal encoded in 64QAM is 5.8 or less is -19d of an amplitude of a received signal.
A signal receiving method characterized in that it is B or less. 7. The expansion amount for a signal compressed so that the maximum value of PAPR of a 16QAM-encoded signal is 4.2 or less according to claim 1, the received signal amplitude being −12d.
A signal receiving method characterized in that it is B or less. 8. The signal receiving method according to claim 1, wherein the expansion is performed by using different expansion amounts for each carrier when expanding the amplitude. 9. A multi-carrier modulated signal is transmitted with its signal amplitude compressed in the time domain, and this transmitted signal is transmitted.
Alternatively, a communication method comprising receiving by the method according to any one of claims 3 to 8. 10. A signal transmitting apparatus for compressing the signal amplitude of a multi-carrier modulated signal in the time domain and transmitting the compressed signal, and a signal receiving apparatus according to claim 2 as an apparatus for receiving the transmitted signal. And a communication device.