JP2007043617A - Ofdm communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an OFDM communication apparatus performing phase correction upon the data subcarrier of an OFDM symbol in which a phase rotation amount θ is detected, without adding any memory for temporarily holding the data subcarrier until the phase rotation amount θ is detected. <P>SOLUTION: The receiving part of an OFDM communication apparatus comprises: an FFT circuit 72; a subcarrier rearrangement circuit 2 which outputs four pilot subcarriers output from the FFT circuit 72 and outputs 48 data subcarriers output from the FFT circuit 72 thereafter in a predetermined arrangement order; a phase tracking circuit 3 which corrects phases of the 48 data subcarriers on the basis of the four pilot subcarriers; and a decoder 75 which obtains an original data stream before encoding by demodulating and decoding the 48 data sub-carriers phase-corrected by the phase tracking circuit 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an OFDM communication apparatus, and more particularly to phase tracking of data subcarriers obtained by performing a fast Fourier transform on a received OFDM signal.

FIG. 7 is a diagram illustrating an example of a receiving unit of an OFDM communication apparatus according to the related art.
The receiving unit 70 of the OFDM communication apparatus shown in FIG. 7 includes an AFC (Automatic Frequency Control) circuit 71 that corrects a carrier frequency error of a received OFDM (Orthogonal Frequency Division Multiplexing) signal including a preamble and one or more OFDM symbols. And by performing a fast Fourier transform on the OFDM signal output from the AFC circuit 71, among the 52 subcarriers (of “−26” to “+26”) having different frequencies of “−26” to “+26”, respectively. “−21”, “−7”, “+7”, and “+21” are pilot subcarriers (subcarriers corresponding to “0 (DC)” are not used to avoid deterioration due to DC components)) FFT that outputs data including (Fast Fourier Transform) circuit 72, subcarrier rearrangement circuit 73 for outputting 52 subcarriers in the order of “−26” to “+26” out of the data output from FFT circuit 72, and subcarrier reconfiguration A channel equalization circuit 74 that corrects channel distortion of the phase and amplitude of each subcarrier by performing channel equalization on each subcarrier output from the placement circuit 73, and is output from the channel equalization circuit 74. Of the 52 subcarriers, four pilot subcarriers are used to determine the phase rotation amount, and the remaining 48 data subcarriers among the 52 subcarriers are determined based on the obtained phase rotation amount. Phase tracking circuit 75 for correcting the phase, and 48 data subcarriers phase-corrected by the phase tracking circuit 75 are demodulated and decoded. It is constituted by a decoder 76 to obtain the data string of the code before the original by Rukoto. It is assumed that the OFDM signal input to the AFC circuit 71 is converted to a baseband signal by multiplication with an output signal of a local oscillator provided in an RF (Radio Frequency) unit or the like.

  The phase tracking circuit 75 extracts four pilot subcarriers from each subcarrier output from the channel equalization circuit 74 and outputs the remaining 48 data subcarriers. 77, a phase rotation amount detection circuit 78 for detecting the phase rotation amount of the four pilot subcarriers extracted by the pilot / subcarrier extraction circuit 77, and a phase rotation amount detected by the phase rotation amount detection circuit 78. And a phase correction circuit 79 for correcting the phases of 48 data subcarriers output from the pilot subcarrier extraction circuit 77.

  For example, the decoder 76 demodulates the 48 data subcarriers based on the phase and amplitude of the 48 data subcarriers after the phase correction, and demodulates the 48 data subcarriers. A deinterleave circuit that rearranges the subsequent data sequence in the order of the original data, a decoding circuit that decodes the rearranged data sequence, and the like.

  FIG. 8A shows a constellation (hereinafter referred to as an IQ constellation) of an I (In-phase) component (horizontal axis) and a Q (Quadrature-phase) component (vertical axis) of a subcarrier when there is no phase rotation. FIG. Further, FIG. 8B is a diagram showing an I-Q constellation of subcarriers when there is phase rotation. FIG. 8C is a diagram showing an IQ constellation of subcarriers before phase correction. FIG. 8D is a diagram showing an IQ constellation of subcarriers after phase correction. In each IQ constellation shown in FIGS. 8A to 8D, black circles indicate data subcarriers. Also, in each IQ constellation shown in FIGS. 8A to 8C, the black triangles indicate pilot subcarriers. In the IQ constellation shown in FIG. 8D, the white circles indicate the corrected data subcarriers. In addition, it is assumed that the data subcarriers shown in each IQ constellation shown in FIGS. 8A to 8D are modulated by QPSK (Quadrature Phase Shift Keying).

  For example, when the received OFDM signal is converted into a baseband signal, the subcarrier is subtracted due to phase noise generated due to unstable operation of a local oscillator that outputs a signal to be multiplied by the OFDM signal or residual carrier frequency error generated in the AFC circuit 71. When the phase of the carrier rotates, as shown in FIG. 8B, the phase of the pilot subcarrier and the phase of the data subcarrier rotate by θ than the phase shown in FIG.

  As described above, when the phase of the data subcarrier is rotated, it is necessary to correct the phase of the data subcarrier based on the pilot subcarrier as described above (for example, refer to Patent Document 1). .

First, the pilot / subcarrier extraction circuit 77 extracts a pilot / subcarrier from the subcarriers output from the channel equalization circuit 74.
Next, the phase rotation amount detection circuit 78 detects the phase rotation amount θ of the pilot / subcarrier extracted by the pilot / subcarrier extraction circuit 77 as shown in FIG. 8B or 8C. .

Then, based on the phase rotation amount θ detected by the phase rotation amount detection circuit 78, the phase correction circuit 79 reversely rotates the phase of the data subcarrier by θ as shown in FIG.
As a result, the phase of the data subcarrier can be corrected, so that decoding errors can be reduced.

  However, normally, four pilot subcarriers are arranged at “−21”, “−7”, “+7”, and “+21”, respectively, and the subcarrier rearrangement circuit 73 performs “−26” to “−26”. Since it is output in the order of “+26”, it takes time to extract all pilot subcarriers. Therefore, in the case of performing phase correction by extracting all pilot subcarriers, when the phase rotation amount θ is detected by the phase rotation amount detection circuit 78, the subcarrier of the next OFDM symbol is sent to the phase tracking circuit 75. In such a case, the detected phase rotation amount θ cannot be used for the data subcarrier of the OFDM symbol in which the phase rotation amount θ is detected, and the data of the next OFDM symbol -Phase correction is not performed accurately because it can only be used for subcarriers. Therefore, there is a problem that decoding errors may increase.

In order to solve this problem, for example, a configuration in which the data subcarrier is temporarily held in the memory until the phase rotation amount θ is detected can be considered.
JP 2003-229829 A

  However, as described above, the configuration in which the data subcarrier is temporarily held in the memory until the phase rotation amount θ is detected is that the data subcarrier is temporarily stored until the phase rotation amount θ is detected. Since a memory to be held is separately required, there is a problem that the circuit scale is increased and the data subcarrier is held for a certain time (for example, 1 OFDM symbol length (4 μs) or more), so that the signal processing time is increased.

  Therefore, in the present invention, the phase rotation amount θ is detected by using the detected phase rotation amount θ without adding a memory for temporarily holding data subcarriers until the phase rotation amount θ is detected. An object of the present invention is to provide an OFDM communication apparatus capable of correcting the phase of a data subcarrier of an OFDM symbol in which the quantity θ is detected.

In order to solve the above problems, the present invention adopts the following configuration.
That is, the ODFM communication apparatus of the present invention demodulates the plurality of data subcarriers based on the phase and amplitude of the plurality of data subcarriers obtained by performing fast Fourier transform on the received OFDM signal. An OFDM communication apparatus that performs fast Fourier transform on a received OFDM signal to output the plurality of data subcarriers and a plurality of pilot subcarriers, and outputs from the FFT circuit The plurality of pilot subcarriers are output from the FFT circuit, and then the plurality of data subcarriers are output in a predetermined arrangement order, and the subcarrier rearrangement circuit outputs the subcarrier rearrangement circuit. The subcarrier relocation circuit based on a plurality of pilot subcarriers; Characterized in that it comprises a phase tracking circuit for correcting the respective phases of said plurality of data sub-carriers to be outputted.

  As described above, since a plurality of pilot subcarriers are output and then a plurality of data subcarriers are output, a plurality of pilot subcarriers are input to the phase tracking circuit before the data subcarriers. Is done. As a result, the detection of the phase rotation amount θ can be detected quickly, and the phase of the data subcarrier of the OFDM symbol in which the phase rotation amount θ is detected is detected using the detected phase rotation amount θ. Can do. Further, since it is not necessary to add a memory for temporarily holding data subcarriers until the phase rotation amount θ is detected, the circuit scale and signal processing time are not increased.

  The subcarrier rearrangement circuit may be configured to output the plurality of data subcarriers after a lapse of a predetermined time after outputting the plurality of pilot subcarriers.

Thereby, the phase rotation amount of the pilot subcarrier can be detected more accurately, and the accuracy of the phase correction of the data subcarrier can be improved.
The predetermined time may be a time taken to detect the phase rotation amount of the plurality of pilot subcarriers used for correcting each phase of the plurality of data subcarriers.

  As a result, since the phase of the data subcarrier can be corrected after the detection of the phase rotation amount is completed, the phase correction can be performed using the accurate phase rotation amount, and the accuracy of the phase correction is increased. be able to.

  According to the present invention, the detected phase rotation amount θ is used without adding a memory for temporarily holding data subcarriers until the phase rotation amount θ is detected. The phase of the data subcarrier of the OFDM symbol in which the quantity θ is detected can be corrected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a receiving unit of an OFDM communication apparatus according to an embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same structure as the structure shown in FIG. In addition, the OFDM communication apparatus of this embodiment is assumed to be compliant with the IEEE 802.11a / g OFDM communication scheme.

  The receiving unit 1 shown in FIG. 1 outputs the AFC circuit 71, the FFT circuit 72, and four pilot subcarriers output from the FFT circuit 72, and then outputs 48 data output from the FFT circuit 72. Subcarrier rearrangement circuit 2 that outputs subcarriers in a predetermined arrangement order (arrangement order of 48 data subcarriers before modulation on the transmission side), and each output from subcarrier rearrangement circuit 2 The channel equalization circuit 74 that performs channel equalization on the subcarrier, the phase tracking circuit 3 that corrects the phase of 48 data subcarriers output from the channel equalization circuit 74, and the phase tracking circuit 3 And a decoder 76 that obtains the original data sequence before encoding by demodulating and decoding the corrected 48 data subcarriers.

  The phase tracking circuit 3 includes a pilot / subcarrier extraction circuit 4 that extracts four pilot subcarriers from the subcarriers output from the channel equalization circuit 74 and outputs 48 data subcarriers; Based on the phase rotation amount detection circuit 78 for detecting the phase rotation amount θ of the four pilot subcarriers extracted by the pilot / subcarrier extraction circuit 4, and the phase rotation amount θ detected by the phase rotation amount detection circuit 78. And a phase correction circuit 79 that corrects the phase of 48 data subcarriers output from the pilot / subcarrier extraction circuit 4.

  A feature of the receiving unit 1 of the OFDM communication apparatus according to the present embodiment is that the subcarrier rearrangement circuit 2 outputs four pilot subcarriers and then outputs 48 data subcarriers. It is.

  The pilot / subcarrier extraction circuit 4 includes a counter that counts each time a subcarrier is input and resets when the count number reaches 52, and the counter count number of the input subcarriers is 1 to 4. The corresponding subcarrier may be determined to be a pilot subcarrier.

  As described above, the receiving unit 1 of the OFDM communication apparatus of the present embodiment is configured to output four pilot subcarriers and then output 48 data subcarriers. Four pilot subcarriers are input to the phase tracking circuit 3 before the subcarriers. As a result, the four pilot subcarriers are arranged at “−21”, “−7”, “+7”, and “+21”, respectively, as in the past, and the subcarrier rearrangement circuit 73 outputs “− 26 ”to“ +26 ”, the detection of the phase rotation amount θ by the phase rotation amount detection circuit 78 can be detected earlier, so that the detected phase rotation amount θ can be used. The phase of the data subcarrier of the OFDM symbol in which the phase rotation amount θ is detected can be corrected. Further, since it is not necessary to add a memory for temporarily holding data subcarriers until the phase rotation amount θ is detected, the circuit scale and signal processing time are not increased.

  Another feature of the receiving unit 1 of the OFDM communication apparatus according to the present embodiment is that the output timing of the data subcarrier after the pilot subcarrier is output from the subcarrier rearrangement circuit 2 is adjusted. It is.

  FIG. 2A is a timing chart showing the subcarrier output timing and the phase rotation amount θ detection time in each circuit of the receiving unit 70 of the OFDM communication apparatus according to the prior art shown in FIG. FIG. 2B is a timing chart showing subcarrier output timing and phase rotation amount θ detection time in each circuit of the receiving unit 1 of the OFDM communication apparatus of this embodiment. In FIGS. 2A and 2B, the horizontal direction indicates time.

  In the OFDM communication apparatus according to the prior art, as shown in FIG. 2A, 52 subcarriers serially output from the subcarrier rearrangement circuit 73 are “−26”, “−25”, “−” 24 ”,...,“ −1 ”,“ +1 ”,...,“ +24 ”,“ +25 ”,“ +26 ”. Specifically, four pilot subcarriers are arranged at “−21”, “−7”, “+7”, and “+21”, respectively, and the subcarrier rearrangement circuit 73 performs “−26” to “−26”. Are output in the order of “+26”. Therefore, it takes time until all of the pilot subcarriers are output from the pilot / subcarrier extraction circuit 77, and when the detection of the phase rotation amount θ by the phase rotation amount detection circuit 78 ends, the next ODFM symbol has already been output. Each subcarrier is output from the channel equalization circuit 74. Therefore, in the receiving unit 70 shown in FIG. 7, the detected phase rotation amount θ cannot be used for the data subcarrier of the OFDM symbol in which the phase rotation amount θ is detected, and is used as the data subcarrier of the next OFDM symbol. On the other hand, phase correction cannot be performed accurately because it must be used.

  On the other hand, in the OFDM communication apparatus of the present embodiment, as shown in FIG. 2 (b), the subcarrier rearrangement circuit 2 outputs four pilot subcarriers, and then the remaining 48 data · Subcarriers are represented by “−26”, “−25”, “−24”, “−23”, “−22”, “−20”, “−19”,..., “−8”, “−” 6 ", ...," -1 "," +1 ", ...," +6 "," +8 ", ...," +19 "," +20 "," +22 "," +23 "," +24 " ”,“ +25 ”,“ +26 ”. Therefore, since the phase rotation amount θ can be detected early by the phase rotation amount detection circuit 78, the detected phase rotation amount θ is used to detect the data subcarrier of the OFDM symbol from which the phase rotation amount θ is detected. Phase correction can be performed.

  Further, as shown in FIG. 2B, the subcarrier rearrangement circuit 2 outputs the remaining four 48 sub-carriers after the time required to detect the phase rotation amount θ after outputting four pilot subcarriers. Data subcarriers are output. The subcarrier rearrangement circuit 2 is configured to continue outputting “+21” after outputting “+21” which is a pilot subcarrier until “−26” which is a data subcarrier is output. Also good.

  As described above, the time elapsed for detecting the phase rotation amount θ is obtained from the output timing of the 48 data subcarriers output after the four pilot subcarriers are output from the subcarrier rearrangement circuit 2. By doing so, it is possible to perform phase correction using an accurate phase rotation amount θ, and to improve the accuracy of phase correction. The output timing of the 48 data subcarriers output from the subcarrier rearrangement circuit 2 may be after a predetermined time has elapsed since the extraction of the four pilot subcarriers. In this configuration, the phase rotation amount θ of the pilot subcarriers is more accurate than the configuration in which 48 data subcarriers are output immediately after outputting at least four pilot subcarriers. And the accuracy of the phase correction of the data subcarrier can be improved.

  2B, each of the subcarrier rearrangement circuit 2 provided in the reception unit 1, the channel equalization circuit 74 provided in the reception unit 1, and the phase correction circuit 79 provided in the reception unit 1. It is assumed that the signal processing time per subcarrier is set to be short so as to recover the loss for the predetermined time.

  FIG. 3A is a diagram showing an IQ constellation of data subcarriers after a phase correction simulation is performed by the receiving unit 70 of the OFDM communication apparatus according to the related art shown in FIG. FIG. 3B is a diagram showing an IQ constellation of data subcarriers after a phase correction simulation is performed by the receiving unit 1 of the OFDM communication apparatus of the present embodiment.

  In the OFDM communication apparatus according to the prior art, as shown in FIG. 3A, each data subcarrier whose phase has been corrected by the receiving unit 70 has not been subjected to accurate phase correction. Even the phase rotation is large.

  On the other hand, in the OFDM communication apparatus of the present embodiment, as shown in FIG. 3B, each data subcarrier whose phase is corrected by the receiving unit 1 is almost accurately phase-corrected. Data subcarrier is not phase rotated too much. In this manner, each data subcarrier shown in FIG. 3B is more accurately phase-corrected than each data subcarrier shown in FIG. be able to.

Next, an example of the subcarrier rearrangement circuit 2 will be described.
FIG. 4 is a diagram illustrating an example of the subcarrier rearrangement circuit 2. In addition, the same code | symbol is attached | subjected to the same structure as the structure shown in FIG.

As shown in FIG. 4, the subcarrier rearrangement circuit 2 includes a RAM 40, for example.
First, 64 pieces of data corresponding to one OFDM symbol output serially from the FFT circuit 72 are written in the RAM 40 based on a predetermined write address. Next, 52 data corresponding to the subcarriers among the 64 data written in the RAM 40 are read from the RAM 40 based on a predetermined read address. As described above, the read address of the RAM 40 is set so that the arrangement order of the 52 subcarriers read from the RAM 40 is the same as the arrangement order of the 52 subcarriers before modulation on the transmission side. Shall.

  FIG. 5A is a diagram illustrating an example of a data table in which the write address of the RAM 40 is recorded. FIG. 5B shows an example of the RAM 40 after the subcarrier is written.

  The data table 50 shown in FIG. 5A includes 64 data (52 data corresponding to 52 subcarriers “−26” to “+26”, DC, and DC) output serially from the FFT circuit 72. 64 write addresses 0-63 respectively corresponding to the 64 storage areas of the RAM 40 are recorded so that 11 data indicating 0) are stored in the 64 storage areas of the RAM 40, respectively. Note that the 64 write addresses are in the output order of the 64 data output from the FFT circuit 72 (“0 (DC)”, “+1”, “+2”, “+3”,..., “+24”). , "+25", "+26", 0, ..., 0, "-1", "-2", "-3", ..., "-24", "-25", "-26" ) Are recorded in the data table 50 in the order in which they are stored in the storage areas corresponding to the addresses 0 to 63 of the RAM 40, respectively.

  Thereby, for example, when the subcarrier “0 (DC)” is output from the FFT circuit 72, the subcarrier “0 (DC)” is based on the write address 0 of the data table 50 shown in FIG. When the subcarrier “+1” is output from the FFT circuit 72, the subcarrier “+1” is stored in the data table in the storage area corresponding to the address 0 of the RAM 40 shown in FIG. When the subcarrier “+2” is output from the FFT circuit 72 based on the write address 1 of 50 and stored in the storage area corresponding to the address 1 of the RAM 40, the subcarrier “+2” is stored in the data table 50. Is stored in the storage area corresponding to the address 2 of the RAM 40 based on the write address 2. The same applies hereinafter.

  FIG. 6A is a diagram showing an example of a data table in which read addresses of the RAM constituting the subcarrier rearrangement circuit 73 according to the prior art are recorded. FIG. 6B is a diagram illustrating an example of a data table in which read addresses of the RAM 40 configuring the subcarrier rearrangement circuit 2 of the present embodiment are recorded. It is assumed that 52 subcarriers are recorded in the order of arrangement shown in FIG. 5B in the RAM constituting the subcarrier rearrangement circuit 73 according to the prior art or the RAM (RAM 40) of the present invention. .

  As shown in FIG. 6A, the data table 60 includes 52 read addresses 1 to 26 and 38 to 63, 38, 39, 40,..., 63, 1,. They are recorded in the order of 25 and 26. As a result, when subcarriers are read out using the read addresses of the data table 60 in the order of arrangement, 52 subcarriers recorded in the RAM constituting the subcarrier rearrangement circuit 73 according to the prior art are “−26”. ”, To“ +26 ”.

  On the other hand, in the data table 61 shown in FIG. 6B, 52 read addresses are 43, 57, 7, 21, 38, 39, 40, 41, 42, 44, 45,. ,..., 19, 20, 22, 23, 24, 25, 26 are recorded in the order of arrangement. As a result, when subcarriers are read out using the read addresses of the data table 61 in order, four pilot subcarriers out of the 52 subcarriers recorded in the RAM 40 are read out first and the remaining subcarriers are read out. Forty-eight data subcarriers can be read.

In addition, although the OFDM communication apparatus of the said embodiment is a structure provided with the receiving part 1, you may provide further the transmission part for transmitting an OFDM signal to the OFDM communication apparatus of this embodiment.
In the OFDM communication apparatus of the above-described embodiment, the data subcarrier is modulated by QPSK. However, the data subcarrier modulation method is BPSK (Binary Phase Shift Keying), 8PSK (Octuple Phase), in addition to QPSK. Shift Keying), 16QAM (16-position Quadrature Amplitude Modulation), 64QAM (64-position Quadrature Amplitude Modulation), 128QAM (128-position Quadrature Amplified)

  Further, in the OFDM communication apparatus of the above embodiment, when reading the subcarriers from the RAM 40, the pilot subcarriers are read first, and then 52 read addresses are recorded in the data table so that the data subcarriers can be read. However, when the subcarriers are read from the RAM 40, the pilot subcarriers may be read first, and then 52 write addresses may be stored in the data table so that the data subcarriers can be read. .

It is a figure which shows the receiving part of the OFDM communication apparatus of embodiment of this invention. (A) is a timing chart which shows the output timing of the subcarrier in each circuit of the receiving part of the OFDM communication apparatus based on a prior art, and the detection time of phase rotation amount (theta). (B) is a timing chart showing the output timing of the subcarrier and the detection time of the phase rotation amount θ in each circuit of the receiving unit of the OFDM communication apparatus of this embodiment. (A) is a figure which shows the IQ constellation of the subcarrier after performing phase correction in the receiving part of the OFDM communication apparatus based on a prior art. (B) is a figure which shows the IQ constellation of the subcarrier after carrying out phase correction | amendment by the receiving part of the OFDM communication apparatus of this embodiment. It is a figure which shows an example of a subcarrier rearrangement circuit. (A) is a figure which shows an example of the data table in which the write address of RAM which comprises a subcarrier rearrangement circuit is recorded. (B) is a figure which shows an example of RAM after a subcarrier is written. (A) is a figure which shows an example of the data table in which the read-out address of RAM which comprises the subcarrier rearrangement circuit based on a prior art is recorded. (B) is a figure which shows an example of the data table in which the read-out address of RAM which comprises the subcarrier rearrangement circuit of this embodiment is recorded. It is a figure which shows the receiving part of the OFDM communication apparatus based on a prior art. (A) is a figure which shows IQ constellation of a subcarrier when there is no phase rotation. (B) is a figure which shows IQ constellation of a subcarrier when there exists phase rotation. (C) is a figure which shows the IQ constellation of the subcarrier before phase correction. (D) is a figure which shows the IQ constellation of the subcarrier after phase correction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception part 2 Subcarrier rearrangement circuit 3 Phase tracking circuit 4 Pilot subcarrier extraction circuit 70 Reception part 71 AFC circuit 72 FFT circuit 73 Subcarrier rearrangement circuit 74 Channel equalization circuit 75 Phase tracking circuit 76 Decoder 77 Pilot Subcarrier extraction circuit 78 Phase rotation amount detection circuit 79 Phase correction circuit

Claims (3)

An OFDM communication apparatus that demodulates a plurality of data subcarriers based on phases and amplitudes of a plurality of data subcarriers obtained by performing a fast Fourier transform on a received OFDM signal,
An FFT circuit for outputting the plurality of data subcarriers and a plurality of pilot subcarriers by performing a fast Fourier transform on the received OFDM signal;
A subcarrier rearrangement circuit that outputs the plurality of pilot subcarriers output from the FFT circuit and then outputs the plurality of data subcarriers output from the FFT circuit in a predetermined arrangement order;
A phase tracking circuit for correcting each phase of the plurality of data subcarriers output from the subcarrier rearrangement circuit based on the plurality of pilot subcarriers output from the subcarrier rearrangement circuit;
An OFDM communication apparatus comprising: The OFDM communication apparatus according to claim 1, wherein
The subcarrier rearrangement circuit outputs the plurality of data subcarriers after a predetermined time has elapsed after outputting the plurality of pilot subcarriers.
An OFDM communication apparatus. The OFDM communication apparatus according to claim 2, wherein
The predetermined time is a time taken to detect a phase rotation amount of the plurality of pilot subcarriers used for correcting each phase of the plurality of data subcarriers.
An OFDM communication apparatus.