WO2012114769A1

WO2012114769A1 - Channel estimation device and channel estimation method

Info

Publication number: WO2012114769A1
Application number: PCT/JP2012/001288
Authority: WO
Inventors: 孝宜田中
Original assignee: 京セラ株式会社
Priority date: 2011-02-25
Filing date: 2012-02-24
Publication date: 2012-08-30

Abstract

A reference signal replica generator (1) generates a replica of a reference signal. A complex divider (2) performs complex division on a reception signal using the replica of the reference signal, and calculates a channel response estimation value. An IDFT unit (3) performs a conversion to a time-region channel response estimation value. A window function multiplier (4) multiplies a window function by a channel response estimation value of a desired wave signal after the IDFT process. A DFT unit (5) performs a conversion to a frequency-region channel response estimation value. A sample corrector (6) calculates replacement data from the channel response estimation value calculated in the complex divider (2). A sample replacement unit (7) replaces, with the replacement data calculated by the sample corrector (6), data in the high band portion and the low band portion on both ends of the frequency band to which data for the channel response estimation value outputted by the DFT unit (5) is assigned.

Description

Channel estimation apparatus and channel estimation method

Cross-reference to related applications

The present application includes Japanese Patent Application No. 2011-39346 (filed on Feb. 25, 2011), Japanese Patent Application No. 2011-39347 (filed on Feb. 25, 2011), and Japanese Patent Application No. 2011-39348. The benefit of the priority of (filed on Feb. 25, 2011) is claimed and all of these are incorporated herein by reference.

The present invention relates to a channel estimation device and a channel estimation method for a receiver of a multicarrier transmission system.

In a multicarrier transmission system, a reference signal is inserted into a transmission signal at a certain interval on the transmitter side, and a channel estimation device on the receiver side performs complex division on the received signal by a replica of the reference signal to change the state of the propagation path. Channel estimation is performed. Further, since the estimated channel response value is affected by noise having a period higher than the sample period of multicarrier transmission, the channel estimation apparatus converts the channel response value into time domain data by IDFT (Inverse Discrete Fourier Transform) processing. After the conversion and noise suppression, the frequency domain data is restored by DFT (Discrete Fourier Transform) processing.

FIG. 1 is a diagram showing a configuration of a general channel estimation apparatus. In FIG. 1, a reference signal replica generation unit 21 generates a replica of a reference signal inserted into a transmission signal on the transmitter side. The complex division unit 22 calculates a channel response estimated value by performing complex division on the received signal by a replica of the reference signal. FIG. 2 shows channel response estimation values after complex division. The IDFT unit 23 converts the frequency domain channel response estimation value calculated by the complex division unit 22 into a time domain channel response estimation value by IDFT processing. FIG. 3 shows the channel response estimation value after the IDFT processing. As shown in FIG. 3, the window function multiplier 24 multiplies the channel response estimation value of the desired wave signal by a window function (which may be a rectangular window or another window). The DFT unit 25 converts the channel response estimated value multiplied by the window function into a frequency domain channel response estimated value by DFT processing. FIG. 4 shows channel response estimation values after DFT processing. As described above, by multiplying the channel response estimation value of the desired wave signal by the window function, it is possible to reduce the influence of noise having a period higher than the sample period of multicarrier transmission.

An OFDM receiver that further includes a window function selection unit that selects a window function based on the estimated propagation path state, and in which the extraction unit extracts a demodulated symbol by multiplying the reception signal by the window function is known. (See Patent Document 1).

JP 2007-066788 A

However, in an actual system, since the number of points of IFFT / FFT processing used for transmission / reception is not equal to the number of subcarriers used for data transmission / reception, a window function is added to the channel response estimation value as shown in FIG. When multiplying, the desired wave signal component (effective delay wave component) is also removed in fact. Therefore, in the channel estimation using the IDFT / DFT processing described above, as shown in FIG. 6, after the DFT processing, distortion is caused in the high frequency region and the low frequency region at both ends of the frequency band to which the data of the channel response estimation value is allocated. As a result, the channel response estimation accuracy decreases.

Further, in the channel estimation using the IDFT / DFT processing described above, as shown in FIG. 7, when there is noise within the window function target time, the estimation accuracy of the channel response decreases due to the influence. In particular, as shown in FIG. 8, when the signal level of a desired wave with a delay of zero is high (when the desired wave protrudes from the window function target time due to the delay), the IFFT / FFT processing is performed. Since the number of points and the number of subcarriers used for data transmission / reception are not equal, the information on the return of the impulse response (right end in the figure) disappears completely by multiplying the window function. Estimation accuracy decreases.

The present invention has been made in view of such problems, and an object of the present invention is to provide a channel estimation apparatus and a channel estimation method capable of improving the accuracy of channel response estimation.

A first aspect of the present invention is a channel estimation apparatus that calculates a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal to estimate a state of a propagation path. An IDFT unit for converting the channel response estimation value calculated by the complex division into a time domain channel response estimation value by IDFT processing, and multiplying the channel response estimation value of the desired wave signal after the IDFT processing by a window function A window function multiplication unit that performs multiplication, a DFT unit that converts the channel response estimated value multiplied by the window function into a frequency domain channel response estimated value by DFT processing, and a channel response estimated value calculated by the complex division Sample correction unit for calculating data, and frequency band to which channel response estimation data output from the DFT unit is assigned The data of high-frequency part and the low part of the both ends, and a sample replacement unit for replacing at the replacement data to which the sample corrector is calculated.

In the first aspect of the present invention, the sample correction unit has a number of replacement points from the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned. It is preferable to extract data and use the extracted data as the replacement data.

In the first aspect of the present invention, the sample correction unit has a number of replacement points from the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned. It is preferable that data is extracted and an average value of the extracted data is used as the replacement data.

In the first aspect of the present invention, the sample correction unit has a number of replacement points from the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned. It is preferable that data is extracted, an average value of the extracted data is calculated, and data obtained by multiplying the calculated average value by a forgetting factor is used as the replacement data.

A second aspect of the present invention is a channel estimation method for estimating a channel state by calculating a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal. The channel response estimated value calculated by the complex division is converted into a time domain channel response estimated value by IDFT processing, and the channel response estimated value of the desired wave signal after the IDFT processing is multiplied by a window function. A step of converting a channel response estimation value multiplied by the window function into a frequency domain channel response estimation value by DFT processing, and a step of calculating replacement data from the channel response estimation value calculated by the complex division And a high-frequency part and a low-frequency part at both ends of the frequency band to which data of channel response estimation values after DFT processing is assigned The data, including the step of replacing in the replacement data.

According to a third aspect of the present invention, there is provided a channel estimation apparatus that calculates a channel response estimated value by performing complex division on a received signal into which a reference signal is inserted by a replica of the reference signal to estimate a channel state. An IDFT unit that converts the channel response estimated value calculated by the complex division into a time domain channel response estimated value by IDFT processing, and a maximum of channel response estimated values after the IDFT processing within a predetermined range. A peak search unit that searches for impulse components of a level, a window slide unit that derives a window function of several samples before and after the sample point of the impulse component of the maximum level specified by the peak search unit, and a window slide unit that derives the window function A window function multiplier for multiplying the estimated channel function by the channel response estimation value after the IDFT processing, and a channel multiplied by the window function The answer estimates, and a DFT section for converting the channel response estimate in the frequency domain by DFT process.

In the third aspect of the present invention, it is preferable that the preceding and following samples be variable from the bandwidth of the multicarrier transmission system, the CP length, and the distance between the transmitter and the receiver.

According to a fourth aspect of the present invention, there is provided a channel estimation method for estimating a channel state by calculating a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal. A channel response estimated value calculated by the complex division is converted into a time domain channel response estimated value by IDFT processing, and the channel response estimated value after the IDFT processing has a maximum level within a predetermined range. A step of searching for impulse components, a step of deriving a window function of several samples before and after the sample point of the impulse component of the maximum level specified by the search, and the derived window function as a channel after the IDFT processing A step of multiplying the response estimation value, and a channel response estimation value multiplied by the window function by means of DFT processing. And converting the the channel response estimate.

According to a fifth aspect of the present invention, there is provided a channel estimation apparatus that calculates a channel response estimation value by performing complex division on a received signal into which a reference signal is inserted by a replica of the reference signal to estimate a channel state. An IDFT unit that converts the channel response estimated value calculated by the complex division into a time domain channel response estimated value by IDFT processing, and a maximum of channel response estimated values after the IDFT processing within a predetermined range. A peak search unit that searches for impulse components of a level, a window slide unit that derives a window function of several samples before and after the sample point of the impulse component of the maximum level specified by the peak search unit, and a window slide unit that derives the window function A window function multiplier for multiplying the estimated channel function by the channel response estimation value after the IDFT processing, and a channel multiplied by the window function The DFT unit that converts the estimated answer value into the frequency domain channel response estimated value by DFT processing, the sample correction unit that calculates replacement data from the channel response estimated value calculated by the complex division, and the DFT unit A sample replacement unit that replaces the data of the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value is assigned with the replacement data calculated by the sample correction unit.

In the fifth aspect of the present invention, it is preferable that the preceding and following samples be variable from the bandwidth of the multicarrier transmission system, the CP length, and the distance between the transmitter and the receiver.

5th aspect of this invention WHEREIN: The said sample correction | amendment part is the number of replacement points from the high frequency part and the low frequency part of the both ends of the frequency band to which the data of the channel response estimated value calculated by the said complex division are allocated. It is preferable to extract data and use the extracted data as the replacement data.

5th aspect of this invention WHEREIN: The said sample correction | amendment part is the number of replacement points from the high frequency part and the low frequency part of the both ends of the frequency band to which the data of the channel response estimated value calculated by the said complex division are allocated. It is preferable that data is extracted and an average value of the extracted data is used as the replacement data.

5th aspect of this invention WHEREIN: The said sample correction | amendment part is the number of replacement points from the high frequency part and the low frequency part of the both ends of the frequency band to which the data of the channel response estimated value calculated by the said complex division are allocated. It is preferable that data is extracted, an average value of the extracted data is calculated, and data obtained by multiplying the calculated average value by a forgetting factor is used as the replacement data.

A sixth aspect of the present invention is a channel estimation method for estimating a channel state by calculating a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal. A channel response estimated value calculated by the complex division is converted into a time domain channel response estimated value by IDFT processing, and the channel response estimated value after the IDFT processing has a maximum level within a predetermined range. A step of searching for impulse components, a step of deriving a window function of several samples before and after the sample point of the impulse component of the maximum level specified by the search, and the derived window function as a channel after the IDFT processing A step of multiplying the response estimation value, and a channel response estimation value multiplied by the window function by means of DFT processing. A channel response estimation value, a step of calculating replacement data from the channel response estimation value calculated by the complex division, and a channel response estimation value data after DFT processing at both ends of the frequency band to which the data is assigned. Replacing the data of the high frequency part and the low frequency part with the replacement data.

The inventions according to the first and second aspects can eliminate the distortion generated in the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value is assigned. Can be improved.

In the inventions according to the third and fourth aspects, since the window function can be derived so that unnecessary noise components are not mixed within the window function target time, the estimation accuracy of the channel response can be improved.

The inventions according to the fifth and sixth aspects can eliminate the distortion occurring in the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value is assigned. Can be improved.
In the inventions according to the fifth and sixth aspects, since the window function can be derived so that unnecessary noise components are not mixed within the window function target time, the estimation accuracy of the channel response can be improved.

It is a figure which shows the structure of a general channel estimation apparatus. It is a figure which shows the channel response estimated value after complex division. It is a figure which shows the channel response estimated value after IDFT process. It is a figure which shows the channel response estimated value after a DFT process. It is a figure explaining that a desired wave signal component will also be removed when multiplying a channel response estimated value by a window function. It is a figure explaining that distortion arises in the high frequency part and low frequency part of the frequency band both ends where the data of a channel response estimated value are allocated. It is a figure which shows the channel response estimated value after IDFT process when there exists noise in window function object time. It is a figure explaining that the return information of an impulse response disappears completely by multiplying by a window function. It is a figure which shows the structure of the base station receiver in the multicarrier transmission system where the channel estimation apparatus of this invention is used. It is a block diagram of the channel estimation apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the channel response estimated value output from the complex division part. It is a figure which shows the channel response estimated value output from a sample replacement part. It is a block diagram of the channel estimation apparatus which concerns on the 2nd Embodiment of this invention. It is a figure explaining derivation of a peak search and a window function. It is a figure explaining derivation of a peak search and a window function. It is a block diagram of the channel estimation apparatus which concerns on the 3rd Embodiment of this invention.

Embodiments of the present invention will be described with reference to the drawings. FIG. 9 is a diagram showing a configuration of a base station receiver in a multicarrier transmission system (for example, OFDM) in which the channel estimation apparatus of the present invention is used, and shows an example of two antennas. The base station receiver shown in FIG. 9 receives signals at radio receiving sections 11-1 and 11-2, and analog / digital converts received signals at A / D converting sections 12-1 and 12-2. CP removing sections 13-1 and 13-2 remove CP (Cyclic Prefix) from the digitally converted received signal. The FFT units 14-1 and 14-2 perform fast Fourier transform (FFT) on the received signal after CP removal. The received signals output from the FFT units 14-1 and 14-2 are divided into two, one being input to the channel estimation units 15-1 and 15-2 and the other being input to the channel equalization unit 16. Channel estimation units (channel estimation devices) 15-1 and 15-2 estimate channel responses from received signals output from FFT units 14-1 and 14-2 using reference signal replicas. Channel equalization unit 16 performs channel equalization on the received signals output from FFT units 14-1 and 14-2 using the channel responses estimated by channel estimation units 15-1 and 15-2. . The subcarrier demapping unit 17 demaps the signal after channel equalization. The demodulator 18 demodulates the demapped signal and calculates received data.

FIG. 10 is a block diagram of the channel estimation apparatus according to the first embodiment of the present invention. The channel estimation apparatus according to the first embodiment performs high-frequency correction at both ends of the band in order to eliminate distortion in the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation values shown in FIG. It replaces the values of the band part and the low band part with the channel response estimation value calculated by complex division.

The channel estimation apparatus according to the first embodiment includes a reference signal replica generation unit 1, a complex division unit 2, an IDFT unit 3, a window function multiplication unit 4, a DFT unit 5, a sample correction unit 6, and a sample And a replacement unit 7. The reference signal replica generation unit 1 generates a replica of the reference signal inserted into the transmission signal on the transmitter side. The complex division unit 2 calculates a channel response estimated value by performing complex division on the received signal by a replica of the reference signal. The IDFT unit 3 converts the frequency domain channel response estimation value calculated by the complex division unit 2 into a time domain channel response estimation value by IDFT processing. The window function multiplication unit 4 multiplies the channel response estimation value of the desired wave signal after the IDFT processing by a window function (which may be a rectangular window or another window). The DFT unit 5 converts the channel response estimated value multiplied by the window function into a frequency domain channel response estimated value by DFT processing. The sample correction unit 6 calculates replacement data from the channel response estimation value calculated by the complex division unit 2. The sample replacement unit 7 replaces the data of the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value output from the DFT unit 5 is assigned with the replacement data calculated by the sample correction unit 6. .

FIG. 11 is a diagram illustrating the channel response estimation value output from the complex division unit. The sample correction unit 6 extracts channel response estimation values corresponding to the number of replacement points from the high-frequency part and the low-frequency part at both ends of the data allocation band from the channel response estimation values output from the complex division part 2 and To do. The sample replacement unit 7 replaces the data having distortion in the high frequency part and the low frequency part at both ends of the data allocation band shown in FIG. 6 with the replacement data. FIG. 12 is a diagram illustrating channel response estimation values output from the sample replacement unit. The sample replacement unit 7 can output channel response estimation values having no distortion in the high frequency part and the low frequency part at both ends of the data allocation band.

The sample correction unit 6 calculates replacement data from the channel response estimation value calculated by the complex division unit 2 by the following method. The number of points is variable from the system bandwidth and the allocation data bandwidth. The first method is a method of extracting data for the number of replacement points from the high frequency part and low frequency part at both ends of the data allocation band, and using the data as replacement data as it is. The second method is a method of extracting data for the number of replacement points from the high frequency part and the low frequency part at both ends of the data allocation band, obtaining an average value for each, and using the data as replacement data. In the third method, data obtained by multiplying the average value obtained by the second method by a forgetting factor is used as replacement data.

For example, the number of points is 3, the output of the sample replacement unit 7 is y '(0), y' (1), y '(2), and the output of the complex division unit 2 is y (0), y (1), y (2) If the forgetting factor is 0 <α ≦ 1, when the replacement data is calculated by the first method, the output of the sample replacement unit 7 is

When the replacement data is calculated by the second method, the output of the sample replacement unit 7 is

When the replacement data is calculated by the third method, the output of the sample replacement unit 7 is

It becomes.

As described above, the channel estimation apparatus according to the first embodiment of the present invention eliminates the distortion that occurs in the high-frequency part and the low-frequency part at both ends of the frequency band to which the channel response estimation value data is assigned. Therefore, the estimation accuracy of the channel response can be improved.

FIG. 13 is a configuration diagram of a channel estimation apparatus according to the second embodiment of the present invention. As shown in FIG. 7, the channel estimation apparatus according to the second embodiment reduces the estimation accuracy of the channel response due to the influence when there is noise within the window function target time, as shown in FIG. In order to deal with the problem that the accuracy of channel response estimation is reduced due to the disappearance of the impulse response aliasing (right end in the figure) by the multiplication of the window function, The impulse component (desired wave delay wave) having the strongest level is specified, and several samples before and after that are multiplied by a window function.

The channel estimation apparatus according to the second embodiment includes a reference signal replica generation unit 1, a complex division unit 2, an IDFT unit 3, a window function multiplication unit 4, a DFT unit 5, a peak search unit 8, a window And a slide portion 9. The reference signal replica generation unit 1 generates a replica of the reference signal inserted into the transmission signal on the transmitter side. The complex division unit 2 calculates a channel response estimated value by performing complex division on the received signal by a replica of the reference signal. The IDFT unit 3 converts the frequency domain channel response estimation value calculated by the complex division unit 2 into a time domain channel response estimation value by IDFT processing. The peak search unit 8 searches for the impulse component (desired delay wave) having the maximum level within a predetermined range from the channel response estimated value output from the IDFT unit 3. Here, the predetermined range is variable, but it is generally assumed that the predetermined range is the CP length. The window slide unit 9 derives a window function (a rectangular window or other window) of several samples from the sample point of the impulse component of the maximum level specified by the peak search unit 8. The number of samples before and after at this time is variable from the bandwidth of the multicarrier transmission system, the CP length, the distance between the transmitter and the receiver, and the like. The window function multiplication unit 4 multiplies the window function derived from the window slide unit 9 by the channel response estimation value output from the IDFT unit 3. The DFT unit 5 converts the channel response estimated value multiplied by the window function into a frequency domain channel response estimated value by DFT processing.

FIG. 14 shows a case where there is noise within the window function target time, the peak search unit 8 searches for a maximum level impulse component within a predetermined range, and the window slide unit 9 specifies the maximum level specified by the peak search unit 8. The window function of several samples before and after is derived from the sample point of the impulse component (the window function target time is slid slightly to the right as shown in FIG. 14), and the calculated window function is subjected to the IDFT processing by the window function multiplication unit 4 It is a figure which shows the case where it applies to the channel response estimated value. FIG. 15 shows that when there is information on the return of the impulse response (the right end in the figure), the peak search unit 8 searches for the maximum level impulse component within a predetermined range, and the window slide unit 9 causes the peak search unit 8 to A window function of several samples is derived from the sample point of the identified impulse component of the maximum level (the window function target time is set at the left end in the figure and the right end in the figure as shown in FIG. 15), and the calculated window function is It is a figure which shows the case where it applies to the channel response estimated value after an IDFT process by the function multiplication part 4. FIG.

As described above, the channel estimation apparatus according to the second embodiment of the present invention can derive the window function so that unnecessary noise components do not coexist within the window function target time, so that the estimation accuracy of the channel response Can be improved.

FIG. 16 is a configuration diagram of a channel estimation apparatus according to the third embodiment of the present invention. The channel estimation apparatus according to the third embodiment is a combination of the channel estimation apparatus according to the first embodiment and the channel estimation apparatus according to the second embodiment. The channel estimation apparatus according to the third embodiment includes a reference signal replica generation unit 1, a complex division unit 2, an IDFT unit 3, a window function multiplication unit 4, a DFT unit 5, a sample correction unit 6, and a sample A replacement unit 7, a peak search unit 8, and a window slide unit 9 are provided.

The reference signal replica generation unit 1 generates a replica of the reference signal inserted into the transmission signal on the transmitter side. The complex division unit 2 calculates a channel response estimated value by performing complex division on the received signal by a replica of the reference signal. The IDFT unit 3 converts the channel response estimated value in the frequency domain calculated by the complex division unit 2 into time domain data by IDFT processing. The peak search unit 8 searches for the impulse component (desired delay wave) having the maximum level within a predetermined range from the channel response estimated value output from the IDFT unit 3. The window slide unit 9 derives a window function (a rectangular window or other window) of several samples from the sample point of the impulse component of the maximum level specified by the peak search unit 8. The window function multiplication unit 4 multiplies the window function derived from the window slide unit 9 by the channel response estimation value output from the IDFT unit 3. The DFT unit 5 converts the channel response estimated value multiplied by the window function into a frequency domain channel response estimated value by DFT processing. The sample correction unit 6 calculates replacement data from the channel response estimation value calculated by the complex division unit 2. The sample replacement unit 7 replaces the data of the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value output from the DFT unit 5 is assigned with the replacement data calculated by the sample correction unit 6. .

Since the channel estimation apparatus according to the third embodiment of the present invention can eliminate distortion occurring in the high-frequency part and the low-frequency part at both ends of the frequency band to which channel response estimation value data is assigned, Response estimation accuracy can be improved.
Also, the channel estimation apparatus according to the third embodiment of the present invention can derive a window function so that unnecessary noise components do not coexist within the window function target time, thereby improving channel response estimation accuracy. be able to.

1, 21 Reference signal

replica generation unit

2, 22

Complex division unit

3, 23

IDFT unit

4, 24 Window

function multiplication unit

5, 25 DFT unit 6 Sample correction unit 7 Sample replacement unit 8 Peak search unit 9 Window slide unit 11-1 , 11-2 Radio reception unit 12-1, 12-2 A / D conversion unit 13-1, 13-2 CP removal unit 14-1, 14-2 FFT unit 15-1, 15-2 Channel estimation unit 16 channels Equalization unit 17 Subcarrier demapping unit 18 Demodulation unit

Claims

A channel estimation apparatus that calculates a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal to estimate a state of a propagation path,
An IDFT unit that converts the channel response estimated value calculated by the complex division into a time domain channel response estimated value by IDFT processing;
A window function multiplier for multiplying a channel response estimated value of the desired wave signal after the IDFT processing by a window function;
A DFT unit that converts the channel response estimation value multiplied by the window function into a frequency domain channel response estimation value by DFT processing;
A sample correction unit for calculating replacement data from the channel response estimation value calculated by the complex division;
A sample replacement unit that replaces the data of the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value output from the DFT unit is assigned, with the replacement data calculated by the sample correction unit;
A channel estimation apparatus comprising:
The sample correction unit extracts data corresponding to the number of replacement points from the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned, and extracts the extracted data The channel estimation apparatus according to claim 1, wherein the replacement data is used as the replacement data.
The sample correction unit extracts data corresponding to the number of replacement points from the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned, and the extracted data The channel estimation apparatus according to claim 1, wherein an average value is used as the replacement data.
The sample correction unit extracts data corresponding to the number of replacement points from the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned, and the extracted data The channel estimation apparatus according to claim 1, wherein an average value is calculated, and data obtained by multiplying the calculated average value by a forgetting factor is used as the replacement data.
A channel estimation method for estimating a channel state by calculating a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal,
Converting the channel response estimate calculated by the complex division into a time domain channel response estimate by IDFT processing;
Multiplying the channel response estimate of the desired wave signal after the IDFT processing by a window function;
Transforming the channel response estimate multiplied by the window function into a frequency domain channel response estimate by DFT processing;
Calculating replacement data from the channel response estimate calculated by the complex division;
Replacing the data of the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value after the DFT processing is assigned, with the replacement data;
A channel estimation method comprising:
A channel estimation apparatus that calculates a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal to estimate a state of a propagation path,
An IDFT unit that converts the channel response estimated value calculated by the complex division into a time domain channel response estimated value by IDFT processing;
A peak search unit for searching for a maximum level impulse component within a predetermined range of the channel response estimation value after the IDFT processing;
A window slide part for deriving a window function of several samples before and after the sample point of the impulse component of the maximum level specified in the peak search part;
A window function multiplication unit that multiplies the window function derived by the window slide unit by the channel response estimation value after the IDFT processing;
A DFT unit that converts the channel response estimation value multiplied by the window function into a frequency domain channel response estimation value by DFT processing;
A channel estimation apparatus comprising:
The channel estimation apparatus according to claim 6, wherein the number of samples before and after is variable from a bandwidth of a multicarrier transmission system, a CP length, and a distance between a transmitter and a receiver.
A channel estimation method for estimating a channel state by calculating a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal,
Converting the channel response estimate calculated by the complex division into a time domain channel response estimate by IDFT processing;
Searching for a maximum level impulse component within a predetermined range of the channel response estimation value after the IDFT processing;
Deriving a window function of several samples before and after the sample point of the impulse component of the maximum level specified in the search;
Multiplying the derived window function by the channel response estimate after the IDFT processing;
Transforming the channel response estimate multiplied by the window function into a frequency domain channel response estimate by DFT processing;
A channel estimation method comprising:
A channel estimation apparatus that calculates a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal to estimate a state of a propagation path,
An IDFT unit that converts the channel response estimated value calculated by the complex division into a time domain channel response estimated value by IDFT processing;
A peak search unit for searching for a maximum level impulse component within a predetermined range of the channel response estimation value after the IDFT processing;
A window slide part for deriving a window function of several samples before and after the sample point of the impulse component of the maximum level specified in the peak search part;
A window function multiplication unit that multiplies the window function derived by the window slide unit by the channel response estimation value after the IDFT processing;
A DFT unit that converts the channel response estimation value multiplied by the window function into a frequency domain channel response estimation value by DFT processing;
A sample correction unit for calculating replacement data from the channel response estimation value calculated by the complex division;
A sample replacement unit that replaces the data of the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value output from the DFT unit is assigned, with the replacement data calculated by the sample correction unit;
A channel estimation apparatus comprising:
10. The channel estimation apparatus according to claim 9, wherein the number of samples before and after is variable from a bandwidth of a multicarrier transmission system, a CP length, and a distance between a transmitter and a receiver.
The sample correction unit extracts data corresponding to the number of replacement points from the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned, and extracts the extracted data The channel estimation apparatus according to claim 9, wherein the replacement data is used as the replacement data.
The sample correction unit extracts data corresponding to the number of replacement points from the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned, and the extracted data The channel estimation apparatus according to claim 9, wherein an average value is used as the replacement data.
The sample correction unit extracts data corresponding to the number of replacement points from the high frequency part and the low frequency part at both ends of the frequency band to which the data of the channel response estimation value calculated by the complex division is assigned, and the extracted data The channel estimation apparatus according to claim 9, wherein an average value is calculated, and data obtained by multiplying the calculated average value by a forgetting factor is used as the replacement data.
A channel estimation method for estimating a channel state by calculating a channel response estimated value by complex-dividing a received signal into which a reference signal is inserted by a replica of the reference signal,
Converting the channel response estimate calculated by the complex division into a time domain channel response estimate by IDFT processing;
Searching for a maximum level impulse component within a predetermined range of the channel response estimation value after the IDFT processing;
Deriving a window function of several samples before and after the sample point of the impulse component of the maximum level specified in the search;
Multiplying the derived window function by the channel response estimate after the IDFT processing;
Transforming the channel response estimate multiplied by the window function into a frequency domain channel response estimate by DFT processing;
Calculating replacement data from the channel response estimate calculated by the complex division;
Replacing the data of the high-frequency part and the low-frequency part at both ends of the frequency band to which the data of the channel response estimation value after the DFT processing is assigned, with the replacement data;
A channel estimation method comprising: