Receiver and reception method

• US 20050069047A1
• Filed: 08/05/2004
• Published: 03/31/2005
• Est. Priority Date: 08/19/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuki, Mitsuhiro
• Granted Patent: US 7,512,184 B2
• Time in Patent Office: Days
• 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

It is aimed at performing an inverse FFT for ranging and efficiently estimating channel characteristics of a time response. It is highly possible that the UWB standardization adopts OFDM systems. A transmission estimation section inevitably acquires estimation values for a frequency region. The ranging is a representative feature of the UWB and requires channel estimation values for time response. For this reason, an inverse FFT needs to be performed for conversion. Frequency region smoothing means is used for time response limitation to prevent additional large FFTs from being provided for the ranging. It is therefore possible to acquire time responses using fewer FFT points than for ordinary data reception.

Claims

1. A receiver which performs an inverse FFT on a plurality of carriers to receive an 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 from a received OFDM signal;

smoothing means for smoothing said frequency response;

decimation means for decimating the number of points for said smoothed frequency response; and

time response acquisition means for acquiring a time response for the number of points decimated from said frequency response.

3. The receiver according to claim 1 or 2,

wherein said time response acquisition means comprises an inverse 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 the steps of:

channel characteristic estimation means for estimating channel characteristics of a time-domain response; and

ranging means for performing ranging based on a channel characteristic estimation value of a time-domain response.

5. The receiver according to claim 1 or 2,

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.

2. A receiver in a wireless communication system in which a channel estimation value is found as a frequency response, said receiver comprising:

smoothing means for smoothing said frequency response;

decimation means for decimating the number of points for said smoothed frequency response; and

time response acquisition means for acquiring a time response for the number of points decimated from said frequency response.

6. A reception method for performing an inverse FFT on a plurality of carriers to receive an 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 a frequency response from a received OFDM signal;

smoothing said frequency response;

decimating the number of points for said smoothed frequency response; and

acquiring a time response for the number of points decimated from said frequency response.

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

wherein said time response acquisition step performs an inverse 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,

estimating channel characteristics of a time-domain response;

and

performing ranging based on a channel characteristic estimation value of a time-domain response.

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

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

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

smoothing said frequency response;

decimating the number of points for said smoothed frequency response; and

acquiring a time response for the number of points decimated from said frequency response.