Receiver and reception method with channel estimation using smoothing and decimation fast fourier transform (FFT)

• US 7,512,184 B2
• Filed: 08/05/2004
• Issued: 03/31/2009
• Est. Priority Date: 08/19/2003
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuki, Mitsuhiro
• Primary Examiner(s): Torres; Juan A
• Application Number:
  US10/911,597
• Publication Number:
  US 20050069047A1
• Time in Patent Office: 1,699 Days
• Field of Search: 375/260, 370/208
• US Class Current: 375/260
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

A receiver performs an inverse Fast Fourier Transform (FFT) on a plurality of carriers to receive an Orthogonal Frequency Division Multiplexing (OFDM) signal to be transmitted by converting a signal along a frequency-domain into a signal along a time-domain. The receiver includes a frequency response acquisition section configured to acquire a frequency response from the received OFDM signal. The receiver also includes a smoothing section configured to produce a smoothed frequency response from the frequency response, a decimation section configured to decimate a number of points from the smoothed frequency response to produce a decimated frequency response including points corresponding to a path that is reached first, and a time response acquisition section configured to acquire a time response from the decimated frequency response including the points corresponding to the path that is reached first.

Claims

1. A receiver comprising:

a frequency response acquisition section configured to acquire a frequency response having a first number of points from a received Orthogonal Frequency Division Multiplexing (OFDM) signal;

a smoothing section configured to produce a smoothed frequency response from said frequency response;

a decimation section configured to decimate points from said smoothed frequency response to produce a decimated frequency response including a second number of points corresponding to a path that is reached first; and

a time response acquisition section configured to acquire a channel characteristic of a time response from said decimated frequency response including the second number of points corresponding to the path that is reached first, wherein an ordinary data reception is performed using the frequency response having the first number of points, and the first number of points used in the ordinary data reception is greater than the second number of points used in the acquisition of the channel characteristic of the time response.

3. The receiver according to claim 1 or 2,

wherein said time response acquisition section further comprises an inverse Fast Fourier Transform (FFT) to convert a signal along a frequency-domain into a signal along a time-domain.

4. The receiver according to claim 1 or 2, further comprising:

a ranging section configured to perform ranging based on the estimated channel characteristics of the acquired time response.

5. The receiver according to claim 1,

wherein said smoothing section and said decimation section perform smoothing and decimation processes so that said time response acquisition section extracts a time response approximate to 0 on a time-domain.

2. A receiver comprising:

a frequency response acquisition section configured to acquire a frequency response having a first number of points from a received signal;

a smoothing section configured to produce a smoothed frequency response from said frequency response;

a decimation section configured to decimate points from said smoothed frequency response to produce a decimated frequency response including a second number of points;

a time response acquisition section configured to acquire a channel characteristic of a time response from said decimated frequency response including the second number of points; and

said smoothing section and said decimation section are further configured to respectively smooth and decimate so that said time response acquired by said time response acquisition section includes a time response of approximately 0 in the time domain, an ordinary data reception is performed using the frequency response having the first number of points, and the first number of points used in the ordinary data reception is greater than the second number of points used in the acquisition of the channel characteristic of the time response.

6. A reception method comprising steps of:

acquiring, by a frequency response acquisition section, a frequency response having a first number of points from a received Orthogonal Frequency Division Multiplexing (OFDM) signal;

smoothing said frequency response to produce a smoothed frequency response;

decimating points from said smoothed frequency response to produce a decimated frequency response including a second number of points corresponding to a path that is reached first;

acquiring a channel characteristic of a time response from said decimated frequency response including the second number of points corresponding to the path that is reached first; and

performing an ordinary data reception using the frequency response having the first number of points, the first number of points used in the performing the ordinary data reception being greater than the second number of points used in the acquiring the channel characteristic of the time response.

8. The reception method according to claim 6 or 7,

wherein said acquiring the time response step performs an inverse Fast Fourier Transform (FFT) to convert a signal along a frequency-domain into a signal along a time-domain.

9. The reception method according to claim 6 or 7, further comprising:

performing ranging based on the estimate channel characteristics of the acquired time response.

10. The reception method according to claim 6,

wherein said smoothing step and said decimation step perform smoothing and decimation processes so that said acquiring the time response step extracts a time response approximate to 0 on a time-domain.

7. A reception method comprising steps of:

acquiring, by a frequency response acquisition section, a frequency response having a first number of points from a received signal;

smoothing said frequency response to produce a smoothed frequency response;

decimating points from said smoothed frequency response to produce a decimated frequency response including a second number of points;

acquiring a channel characteristic of a time response from said decimated frequency response including the second number of points;

said smoothing and said decimating respectively smooth and decimate so that said acquiring the time response step includes acquiring a time response of approximately 0 in the time domain; and

performing an ordinary data reception using the frequency response having the first number of points, the first number of points used in the performing the ordinary data reception being greater than the second number of points used in the acquiring the channel characteristic of the time response.

11. A receiver which performs an inverse Fast Fourier Transform (FFT) on a plurality of carriers to receive an Orthogonal Frequency Division Multiplexing (OFDM) signal to be transmitted by converting a signal along a frequency-domain into a signal along a time-domain, said receiver comprising:

frequency response acquisition means for acquiring a frequency response having a first number of points from the received OFDM signal;

smoothing means for smoothing said frequency response;

decimation means for decimating points from said smoothed frequency response to produce a decimated frequency response including a second number of points; and

time response acquisition means for acquiring a channel characteristic of a time response for the decimated frequency response including the second number of points,

wherein said smoothing means and said decimation means perform smoothing and decimation processes so that said time response acquisition means extracts a time response approximate to 0 on a time-domain, an ordinary data reception is performed using the frequency response having the first number of points, and the first number of points used in the ordinary data reception is greater than the second number of points used in the acquisition of the channel characteristic of the time response.

12. A receiver in a wireless communication system in which a channel estimation value is found as a frequency response having a first number of points, said receiver comprising:

smoothing means for smoothing said frequency response;

decimation means for decimating the number of points for said smoothed frequency response to produce a decimated frequency response including a second number of points; and

time response acquisition means for acquiring a channel characteristic of a time response from the decimated frequency response including the second number of points,

wherein said smoothing means and said decimation means perform smoothing and decimation processes so that said time response acquisition means extracts a time response approximate to 0 on a time-domain, an ordinary data reception is performed using the frequency response having the first number of points, and the first number of points used in the ordinary data reception is greater than the second number of points used in the acquiring of the channel characteristic of the time response.

13. A reception method for performing an inverse Fast Fourier Transform (FFT) on a plurality of carriers to receive an Orthogonal Frequency Division Multiplexing (OFDM) signal to be transmitted by converting a signal along a frequency-domain into a signal along a time-domain, said method comprising the steps of:

acquiring, by a frequency response acquisition section, a frequency response having a first number of points from the received OFDM signal;

smoothing said frequency response;

decimating points for said smoothed frequency response to produce a decimated frequency response including a second number of points; and

acquiring a channel characteristic of a time response from the decimated frequency response including the second number of points,

wherein said smoothing step and said decimation step perform smoothing and decimation processes so that said acquiring step acquires a time response approximate to 0 on a time-domain, an ordinary data reception is performed using the frequency response having the first number of points, and the first number of points used in the performing the ordinary data reception is greater than the second number of points used in the acquiring the channel characteristic of the time response.

14. A reception method for receiving wireless signals in a wireless communication system in which a channel estimation value is found as a frequency response having a first number of points, said method comprising the steps of:

smoothing, by a smoothing section, said frequency response;

decimating points for said smoothed frequency response to produce a decimated frequency response including a second number of points; and

acquiring a channel characteristic of a time response from the decimated frequency response including the second number of points,

wherein said smoothing step and said decimation step perform smoothing and decimation processes so that said acquiring step acquires a time response approximate to 0 on a time-domain, an ordinary data reception is performed using the frequency response having the first number of points, and the first number of points used in the performing the ordinary data reception is greater than the second number of points used in the acquiring the channel characteristic of the time response.