JP2007235407A - Adaptive equalizer and communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adaptive equalizer which realizes a sufficient channel estimating speed and accuracy in the adaptive equalization in a frequency range. <P>SOLUTION: The adaptive equalizer 3 for compensating the distortion of received signals in a frequency range using the overlap saving method comprises a latter-half block saver 6 which destructs the former-half overlap series every M point block, to output other series about PS-converted signals after conversion of the output signals of the equalizer 3 in the time domain; a block memory 7 for holding the other series to output in the next equalizing process; a coupler 8 for coupling an output series from the block memory 7 with the other series; an error calculator 9 for calculating the error series, based on a reference series and coupling series; and a tap coefficient estimator 12 for estimating the tap coefficient, based on an error series converted in the frequency domain and the received signal in the frequency range after SP-converting the error series. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication apparatus that operates in a communication environment that may be affected by frequency selective fading, and more particularly to an adaptive equalizer and communication apparatus that compensate for distortion of a received signal in the frequency domain. is there.

  Hereinafter, a conventional equalizer in the frequency domain will be described. In mobile communication, a multipath transmission path is formed by reflected, diffracted, and scattered waves, and the transmission waveform is affected by frequency selective fading.

  As a technique for overcoming the influence of the frequency selective fading, in recent years, an adaptive equalization method in the frequency domain has attracted attention, and an adaptation method using an overlap preserving method as one method of the adaptive equalization method in the frequency domain. An equalization technique has been proposed (see Non-Patent Document 1 below). In order to perform equalization processing, it is necessary to know transmission path information in advance, or to estimate the transmission path by some process, and in particular, an equalizer having a function for estimating the transmission path is applied. It is called a chemical.

  Next, a conventional adaptive equalizer will be described. The adaptive equalizer includes an equalizer and a transmission path (tap coefficient) estimator. The equalizer is a filter that performs equalization processing using the tap coefficient estimated in the transmission path estimation processing. Also, the transmission path estimator converts the sequence in the frequency domain before being input to the equalizer, and the error sequence between the sequence after converting the output of the adaptive filter into the time domain and the reference sequence into the frequency domain. The transmission path is estimated based on the series. The reference sequence means a known signal sequence or a signal sequence for determining a signal after adaptive filter output.

  Also, when the overlap preserving method is used, serial / parallel conversion is performed to overlap the equalizer input signal with L (L is a natural number) points, and then converted into the frequency domain to perform transmission path estimation processing. Equalization is performed using the tap coefficients estimated in step (1). The equalized output is converted into the time domain, and after parallel / serial conversion, the overlapped L point data series is discarded, and the remaining data series becomes equalized output.

  Further, generally, when using the above overlap storage method, as an error sequence used for estimation of tap coefficients, a remaining data sequence that is an output of an adaptive equalizer, a reference sequence corresponding to the remaining data sequence, and An error is calculated from the above, and an L-point extension corresponding to an overlap is performed by 0 interpolation, and then a frequency-converted sequence is used.

S. Haykin, “Adaptive Filter Theory”, fourth edition, Prentice-Hall, 2002.Chapter 7.3

  However, in the method using the conventional overlap preservation method, the number of error series calculation points is calculated from the discarded number of overlaps with respect to the set number of tap coefficient series points. The discard point is supplemented by interpolation. Therefore, compared with other methods (for example, the method of adding a cyclic prefix: “D.Falconer, SLAriyavisitakul, A. Benyamin-Seeyar and B. Eidson,“ Frequency Domain Equalization for Single-Carrier Broadband Wireless Systems, ”IEEE Commun. .Mag., Vol. 40, pp. 58-66, Apr. 2002.)), there was a problem that the tap coefficient estimation speed decreased.

  The present invention has been made in view of the above, and an object of the present invention is to obtain an adaptive equalizer and a communication device that achieve a good channel estimation speed and channel estimation accuracy in frequency domain adaptive equalization. To do.

  In order to solve the above-described problems and achieve the object, the adaptive equalizer according to the present invention performs L (L is a natural number: M>) in units of M (M is a natural number) point blocks with respect to a received signal in the time domain. L) SP conversion is performed while performing point overlap, and then the signal after SP conversion is converted into the frequency domain, and the equalizer uses the tap coefficient estimated in the predetermined transmission path estimation process, 1 is an adaptive equalizer that compensates for distortion of the received signal, for example, a first conversion means for converting the output signal of the equalizer into the time domain and further performing PS conversion on each time domain signal Among the output series of the first conversion means, discard the temporally old L point overlap series for each M point block, and output other series; output from the output means; A delay unit that holds the sequence and outputs it at the next equalization process, a coupling unit that combines the output sequence of the delay unit and the output sequence of the output unit, a reference sequence and the sequence after the combination An error calculation means for calculating an error sequence based on the error conversion means, a second conversion means for performing SP conversion on the error series and converting the signal after SP conversion into the frequency domain, an error sequence in the frequency domain, and Tap coefficient estimating means for estimating the tap coefficient based on the received signal converted into the frequency domain.

  According to the present invention, since an error sequence can be calculated without using zero interpolation, a better transmission path estimation speed and transmission path estimation accuracy can be realized as compared with the prior art.

  Embodiments of an adaptive equalizer and a communication apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of an adaptive equalizer according to the present invention, in which an SP converter 1, a frequency domain converter 2, an equalizer 3, a time domain converter 4, and a PS converter are illustrated. 5, second half block storage unit 6, block memory 7, combination unit 8, error calculation unit 9, SP converter 10, frequency domain converter 11, tap coefficient estimation unit 12, determination unit 13, It is equipped with. FIG. 2 is a diagram showing an example of a frame format used by the adaptive equalizer, which is composed of training blocks,..., Data blocks,. Also good).

  Here, the training block is known data in advance. As the data, in addition to the PN (pseudo noise) sequence, a CAZAC (Constant Amplitude Zero Auto-Correlation) sequence signal such as a Chu sequence or Frank-Zadoff sequence ("D.Falconer, SLAriyavisitakul, A. Benyamin-Seeyar and B. Eidson," Frequency Domain Equalization for Single-Carrier Broadband Wireless Systems "IEEE Commun. Mag., Vol. 40, pp. 58 -66, Apr. 2002 "). These sequences have the property that the frequency spectrum has a constant amplitude spectrum.

  Next, the operation of the adaptive equalizer according to the first embodiment configured as described above will be described. First, a signal obtained by converting a modulated input signal such as phase modulation or amplitude modulation into a baseband digital complex signal by a predetermined reception process is input to the SP converter 1. Here, for the sake of simplicity, the received signal sequence is 1-times oversampling, but can be easily expanded even with K-times oversampling (K is a natural number).

  The SP conversion unit 1 performs serial / parallel conversion processing for parallelizing signals input in series on the time axis. Here, as shown in FIG. 2, when M points are SP-converted in one equalization process (M is a natural number), the SP conversion for the second equalization process is performed from the point shifted by L points. SP conversion is performed only for points (L is a natural number). That is, SP conversion is performed while performing L point overlap. Here, as an example, a case of 50% overlap where M = 2L is assumed.

  The frequency domain converter 2 converts the block of 2L points, which is the output of the SP converter 1, from the time domain to the frequency domain. Then, the training block converted into the frequency domain is output to the equalizer 3 and the tap coefficient estimation unit 12. Here, Fourier transform is used for the conversion to the frequency domain, and DFT (Discrete Fourier Transform) or FFT (Fast Fourier Transform) is used for the Fourier transform processing. The same applies to the subsequent Fourier transform processing.

  In the equalizer 3, complex multiplication is performed for each frequency element component between the output of the frequency domain converter 2 and the output of the tap coefficient estimator 12 to correct the frequency characteristics. The training block of 2L points after the complex multiplication is output to the time domain converter 4.

  The time domain converter 4 converts the frequency domain training block of 2L points into the time domain. The inverse Fourier transform is used for the conversion to the time domain, and IDFT or IFFT is used for the inverse Fourier transform process. The same applies to the subsequent inverse Fourier transform processing. Then, the training sequence converted into the time domain is output to the PS converter 5.

  The PS converter 5 converts a data series that is a parallel signal into a serial signal. Then, the signal converted into the serial signal is output to the latter half block storage unit 6 and the error calculation unit 9.

  The latter half block storage unit 6 discards the old L point data in the M-point training sequence in the time domain subjected to PS conversion, and outputs the new L point data in time. The stored L-point time domain data is output to the block memory 7, the combining unit 8, and the determination unit 13. The determiner 13 performs a determination process corresponding to the modulation method on the data series whose distortion has been compensated by the above process.

  In the block memory 7, the output of the latter half block storage unit 6 is stored in the memory and is output to the combining unit 8 in the next equalization process. As shown in FIG. 3, the combining unit 8 combines the output of the second half block storage unit 6 and the data series stored in the block memory 7. At this time, the L-point data series output from the block memory 7 is used as the first half series, the L-point data series output from the second-half block storage unit 6 is combined as the second half data series, and the 2L point data series is combined. create.

  In the error calculation unit 9, in the equalization process where the number of equalization repetitions is the initial N times (N is a natural number), a 2L point data series that is the output of the PS converter 5 and a known 2L point reference signal An error sequence is calculated using the sequence. Here, the number of times that the tap coefficient estimation algorithm estimates the tap coefficient with a certain degree of accuracy is set to N, for example, smaller than the number of training blocks. The calculation method of the error series is calculated by a method determined by an algorithm used in the tap coefficient estimation unit 12 described later. The calculated error series signal is output to the SP converter 10.

  Further, in the equalization process with the number of repetitions larger than the initial N times, an error sequence is calculated using a 2L point data sequence that is the output of the combining unit 8 and a 2L point reference signal sequence that is known in advance. . Similarly, the error sequence calculation method is calculated by a method determined by an algorithm used in the tap coefficient estimation unit 12.

  The SP conversion unit 10 performs serial / parallel conversion processing for parallelizing signals input in series on the time axis. And it outputs to the frequency domain converter 11.

  The frequency domain converter 11 converts the data sequence of 2L points, which is the output of the SP converter 10, from the time domain to the frequency domain. Then, the data sequence of 2L points converted into the frequency domain is output to the tap coefficient estimation unit 12.

  The tap coefficient estimator 12 uses the 2 L point frequency domain received signal that is the output of the frequency domain converter 2 and the 2 L point frequency domain error sequence signal that is the output of the frequency domain converter 11, and Estimate the tap coefficient. As the tap coefficient estimation method, for example, other well-known algorithms such as an LMS (Least Mean Square) algorithm, an RLS (Recursive Least Squares) algorithm, and a CMA (Constant Modulus Algorithm) are used. The tap coefficient series estimated by the above algorithm is output to the equalizer 3.

  The tap coefficient estimator 12 estimates the tap coefficient series by the above process when receiving the training series, but does not perform the estimation process and finally estimates when receiving the data series. Hold the tap coefficient. At the time of data sequence reception, the data sequence is equalized using the held tap coefficient sequence.

  As described above, in the present embodiment, a series obtained by combining the L point data series output from the second half block storage unit 6 and the L point block data series stored in the block memory 7 is used. Thus, error calculation was performed. As a result, an error sequence can be calculated from a 2L point data sequence without using 0 interpolation, so that a better transmission path estimation speed and transmission path estimation accuracy can be realized as compared with the prior art. In addition, it is possible to obtain a highly accurate equalized signal with a small number of training blocks.

  In the present embodiment, not limited to the above processing, for example, even when a tap coefficient estimation algorithm in another frequency domain is used, by using the above error sequence calculation method, Good transmission path estimation speed and transmission path estimation accuracy can be realized. Even if the overlap interval is changed (M = 2L is not set), it can be realized by combining the output sequences of the memory blocks corresponding to the discarded sequences in the combining unit, and the error sequence as described above. By using this calculation method, it is possible to realize good transmission path estimation speed and transmission path estimation accuracy.

Embodiment 2. FIG.
FIG. 4 is a diagram showing a configuration example of the adaptive equalizer according to the second embodiment of the present invention. This adaptive equalizer has the block memory 14 and the coupling unit 15 added to the configuration of the first embodiment described above. , The signal selection unit 16 is added. It should be noted that the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Here, processing different from that of the first embodiment will be described.

  First, the determiner 13 performs a determination process corresponding to the modulation method on the L-point data series whose distortion has been compensated. The determined data series is output from the adaptive equalizer according to the present embodiment, and is also output to the block memory 14 and the combining unit 15.

  In the block memory 14, the output of the determiner 13 is stored in the memory and is output to the combining unit 15 in the next equalization process. The combining unit 15 combines the output of the determination unit 13 of the current data series and the data series stored in the block memory 14. At this time, the L-point data series output from the block memory 14 is combined as the first half series, and the L-point data series output from the determiner 13 is combined as the second half data series to create a 2L-point data series. .

  The signal selection unit 16 is a selector that selects either a known reference signal sequence or the output of the combining unit 15. When receiving a training block, a known 2L point reference signal sequence is selected, and when receiving a data block, a 2L point determination sequence created by the combining unit 15 is selected. When the training series and the data series are input in the same 2L point block (first half L point: training series, second half L point: data series), the signal selection unit 16 selects the output series of the combining unit 15. .

  In the initial N times of equalization processing, the error calculation unit 9 calculates an error sequence from the 2L point data sequence output from the PS converter 5 and the output from the signal selection unit 16. Here, N is set to the number of times the tap coefficient estimation algorithm estimates the tap coefficient with a certain degree of accuracy. The error sequence calculation method is calculated by a method determined by an algorithm used in the tap coefficient estimation unit 12. The calculated error series signal is output to the SP converter 10.

  Further, in the equalization process exceeding the initial N times, an error sequence is calculated from the 2L point data sequence output from the combining unit 8 and the output from the signal selection unit 16. Similarly, the error sequence calculation method is calculated by a method determined by an algorithm used in the tap coefficient estimation unit 12.

  In the first embodiment described above, the tap coefficient sequence is estimated when the training sequence is received, and the estimation process is not performed when the data sequence starts to be received. The tap coefficient estimation unit 12 estimates the tap coefficient series by the above process regardless of the reception of the training series and the data series.

  As described above, in the present embodiment, the L point data series output from the determiner 13 and the L point data judgment series stored in the block memory 14 are combined when the data series is received. The error was calculated using the series. This makes it possible to perform highly accurate equalization processing on a data series that has passed through a time-varying transmission line.

Embodiment 3 FIG.
FIG. 5 is a diagram illustrating an example of a frame format according to the third embodiment. Here, frames are formed in the order of a training block, a data block, a training block, a data block, and so on.

  The configuration of the adaptive equalizer of the third embodiment is the same as that of the first embodiment and the second embodiment described above, and therefore the same reference numerals are given and description thereof is omitted.

  Thus, in this embodiment, the training series and the data series are alternately set. Thereby, in the training sequence, a known reference sequence can be used for error calculation. Therefore, since the reference sequence can be used for calculating the error sequence at regular intervals, it is possible to perform an even more accurate equalization process on the data block received after passing through the time-varying transmission path.

Embodiment 4 FIG.
FIG. 6 is a diagram illustrating a configuration example of a receiving apparatus according to the present invention using the adaptive equalizer according to any one of the first to third embodiments, and includes a receiving antenna 50, a quasi-synchronous detection unit 51, and an automatic gain control unit. (AGC: Automatic Gain Control) 52, Bit Timing Recovery Unit (BTR) 53, Slot Synchronization Unit 54, Automatic Frequency Control Unit (AFC) 55, Embodiment 1, 2, or 3 The adaptive equalizer 56 of FIG.

  Here, the operation of the receiving apparatus of this embodiment will be described. First, a signal received by the receiving antenna 50 is output to the quasi-synchronous detection unit 51. In the quasi-synchronous detection 51, analog / digital conversion is performed on the received signal at a predetermined sampling rate, and a baseband signal is output. Here, the subsequent baseband signals have complex values.

  Further, the quasi-synchronous detection unit 51 performs gain correction of the received baseband signal based on an output control signal of the AGC 52 described later. The result is output to AGC 52 and BTR 53.

  The AGC 52 calculates the power of the received baseband signal, executes a control algorithm that converts the obtained power value into a preset value, and outputs a gain control signal to the quasi-synchronous detection unit 51.

  In the BTR 53, the timing of the Nyquist point is estimated from the baseband signal. Then, a reproduction baseband signal that is a baseband signal that is resampled at a speed several times the symbol speed in synchronization with the estimated timing of the Nyquist point is generated. The BTR 53 outputs the generated reproduction baseband signal to the slot synchronization unit 54 and the AFC 55.

  The slot synchronization unit 54 performs a correlation operation between the reproduction baseband signal that is the output signal of the BTR 53 and the known training sequence. Then, a slot synchronization pulse is generated at a timing when the correlation value obtained by the correlation calculation exceeds a preset threshold value. The generated slot synchronization pulse signal is output to the AFC 55, the adaptive equalizer 56, and the determiner 13.

  In the AFC 55, a frequency deviation is calculated from a phase rotation amount of a certain section in the reproduction baseband signal, and a phase rotation is applied to the reproduction baseband signal so as to cancel the calculated frequency deviation, thereby correcting the frequency deviation. Here, the AFC 55 uses the slot synchronization pulse output from the slot synchronization unit 54 as a reference timing, and takes into account the processing delay that is recognized in advance. Remove components. Thereby, highly accurate frequency deviation estimation is performed.

  The adaptive equalizer 56 performs any of the operations described in the first to third embodiments, and performs adaptive equalization processing on the reproduction baseband signal that has been subjected to gain correction and frequency deviation correction. Here, the adaptive equalizer 56 adjusts the processing timing of the known sequence and the data sequence from the slot synchronization pulse (reference timing) output from the slot synchronization unit 54 and the processing delay amount recognized in advance.

  The determiner 13 performs a determination process corresponding to the modulation method on the data series whose distortion has been compensated by the adaptive equalization process.

  As described above, in the present embodiment, before performing the adaptive equalization processing shown in the first to third embodiments, a high-precision equalization signal is obtained by performing gain correction and frequency correction based on the synchronization pulse. And the output of the determiner 13 can obtain demodulated data of higher quality.

Embodiment 5 FIG.
FIG. 7 is a diagram illustrating a configuration example of the receiving apparatus according to the fifth embodiment. Compared to the configuration of the fourth embodiment, an initial carrier regenerator (CR: Carrier Recovery) is provided between the AFC 55 and the adaptive equalizer 56. 58 is added. In addition, about the structure similar to Embodiment 1-4 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first to fourth embodiments will be described.

  The baseband signal whose frequency deviation is corrected by the AFC 55 is output to the initial CR 58. In the initial CR 58, the carrier phase is estimated from the training sequence that is a known sequence using the slot synchronization pulse signal, and phase correction is performed on the baseband signal by the estimated carrier phase error. The baseband signal subjected to the phase correction is output to the adaptive equalizer 56.

  Thus, in the present embodiment, carrier phase correction is added before performing adaptive equalization processing. As a result, the adaptive equalizer 56 can output a highly accurate equalized signal with a small number of training blocks, and the output of the data determination unit 13 can obtain demodulated data of higher quality. Become.

Embodiment 6 FIG.
FIG. 8 is a diagram illustrating a configuration example of the receiving apparatus according to the sixth embodiment. As an example, a carrier regenerator (CR: Carrier) is provided between the adaptive equalizer 56 and the determiner 13 with respect to the fifth embodiment. Recovery) 59 is added. In addition, about the structure similar to the above-mentioned Embodiment 1-5, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, processing different from the first to fifth embodiments will be described.

  In the present embodiment, the data equalized by the adaptive equalizer 58 is output to the CR 59. In CR59, a carrier phase is estimated from a training sequence that is a known sequence, and phase correction is performed on the baseband signal by an error of the estimated carrier phase. The baseband signal subjected to the phase correction is output to the determiner 13.

  Thus, in this embodiment, carrier phase correction processing is performed between the adaptive equalizer 56 and the determiner 13. As a result, it is possible to perform a more accurate equalization process for the data series that has passed through the time-varying transmission line, and the output of the determiner 13 can obtain higher-quality demodulated data. It becomes.

  As described above, the adaptive equalizer according to the present invention is useful for a communication apparatus that operates in a communication environment that may be affected by frequency selective fading, and particularly compensates for distortion of a received signal in the frequency domain. Suitable for you.

It is a figure which shows the structural example of Embodiment 1 of the adaptive equalizer concerning this invention. It is a figure which shows an example of the frame format which an adaptive equalizer uses. It is a figure which shows the joint process by a coupling part. It is a figure which shows the structural example of Embodiment 2 of the adaptive equalizer concerning this invention. FIG. 10 is a diagram illustrating an example of a frame format according to the third embodiment. FIG. 11 is a diagram illustrating a configuration example of a receiving device according to a fourth embodiment. FIG. 10 is a diagram illustrating a configuration example of a receiving device according to a fifth embodiment. FIG. 20 is a diagram illustrating a configuration example of a receiving device according to a sixth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 SP converter 2 Frequency domain converter 3 Equalizer 4 Time domain converter 5 PS converter 6 Second half block preservation | save part 7 Block memory 8 Coupling part 9 Error calculation part 10 SP converter 11 Frequency domain converter 12 Tap coefficient estimation Unit 13 determination unit 14 block memory 15 coupling unit 16 signal selection unit 50 reception antenna 51 quasi-synchronous detection unit 52 automatic gain control unit (AGC)
53-bit timing playback unit (BTR)
54 Slot synchronization section 55 Automatic frequency control section (AFC)
56 Adaptive equalizer 58 Initial carrier regenerator (CR)
59 Carrier regenerator (CR)

Claims (11)

SP conversion (serial / parallel conversion) is performed while performing L (L is a natural number: M> L) point overlap for the received signal in the time domain with M (M is a natural number) point block unit, and then after SP conversion An adaptive equalizer that compensates for distortion of the received signal in the frequency domain using the tap coefficient estimated in a predetermined transmission path estimation process,
First conversion means for converting the output signal of the equalizer into the time domain, and further performing PS conversion (parallel / serial conversion) on each time domain signal;
Out of the output series of the first conversion means, output means for discarding the temporally old L point overlap series for each M point block and outputting other series;
A delay unit that holds the sequence output from the output unit and outputs the next equalization process;
Combining means for combining the output series of the delay means and the output series of the output means;
Error calculating means for calculating an error sequence based on a reference sequence and the combined sequence;
Second conversion means for performing SP conversion on the error series, and further converting the signal after SP conversion into a frequency domain;
Tap coefficient estimating means for estimating the tap coefficient based on the error sequence in the frequency domain and the received signal converted into the frequency domain;
An adaptive equalizer comprising: And determining means for determining a sequence output from the output means in accordance with a modulation method,
The adaptive equalizer according to claim 1, further comprising: A post-determination delay unit that holds the sequence output from the determination unit and outputs the next equalization process;
A post-determination combining unit that combines the output sequence of the post-determination delay unit and the output sequence of the determination unit;
A signal sequence selection means for selecting the reference sequence if the current received signal is a known sequence;
With
3. The adaptive equalization according to claim 2, wherein the error calculation unit calculates an error sequence based on the signal sequence selected by the signal sequence selection unit and the sequence combined by the combining unit. vessel.   In the initial N times (N is a natural number) equalization process, the error calculation means calculates an error series based on the reference series and the output series of the first conversion means. The adaptive equalizer according to claim 1, wherein an error sequence is calculated based on a reference sequence and a sequence after being combined by the combining unit.   In the initial N times (N is a natural number) equalization process, the error calculation unit calculates an error sequence based on the signal sequence selected by the signal sequence selection unit and the output sequence of the first conversion unit. 4. After the initial N times, the error sequence is calculated based on the signal sequence selected by the signal sequence selection unit and the sequence combined by the combining unit. Generator.   The adaptive equalization according to any one of claims 1 to 5, wherein the received signal is a signal in which a plurality of known sequences are arranged and then a single or a plurality of data sequences are arranged. vessel.   6. The adaptive equalizer according to claim 1, wherein the received signal is a signal in which a known sequence and a data sequence are alternately arranged. The adaptive equalizer according to any one of claims 1 to 7,
A communication apparatus comprising: Furthermore, a synchronization pulse generating means for performing a correlation operation between the baseband signal synchronized with the timing of the Nyquist point and the known sequence, and generating a synchronization pulse signal based on the obtained correlation value,
With
The frequency deviation of the baseband signal is corrected using the synchronization pulse signal, and then the adaptive equalizer performs an adaptive equalization process on the signal after the frequency deviation correction using the synchronization pulse signal. The communication apparatus according to claim 8. Furthermore, a synchronization pulse generating means for performing a correlation operation between the baseband signal synchronized with the timing of the Nyquist point and the known sequence, and generating a synchronization pulse signal based on the obtained correlation value,
With
Using the synchronization pulse signal, the frequency deviation of the baseband signal is corrected, and further, phase correction is performed based on the carrier phase estimated from the signal after the frequency deviation correction, and then the adaptive equalizer, The communication apparatus according to claim 8, wherein adaptive equalization processing is performed on the phase-corrected signal using the synchronization pulse signal. The adaptive equalizer uses a sequence output from the output unit to estimate a carrier phase, and based on the estimated carrier phase, a phase correction unit that performs phase correction of the sequence output from the output unit;
Further comprising
The communication apparatus according to claim 9 or 10, wherein the phase correction unit determines a series after phase correction.

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