Radio apparatus and adaptive array processing method

• US 7,423,961 B2
• Filed: 10/11/2002
• Issued: 09/09/2008
• Est. Priority Date: 10/17/2001
• Status: Expired due to Fees

• Current Assignee: Nagaoka University of Technology, Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: National University Corporation Hokkaido University, Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Doi, Yoshiharu, Ohgane, Takeo, Ogawa, Yasutaka
• Primary Examiner(s): Nguyen; Steven H. D.
• Application Number:
  US10/492,351
• Publication Number:
  US 20040246889A1
• Time in Patent Office: 2,160 Days
• Field of Search: None
• US Class Current: 370/210
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/0897 using beamforming per multi-path, e.g. to cope with different directions of arrival [DOA] at different multi-paths
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

A correlator detects arriving timings of a desired wave and an interfering wave from a signal transmitted by the OFDM scheme. A reception response vector estimator estimates a first response vector for a signal arriving within a guard interval section from the head arriving wave and a second response vector for a signal arriving after the guard interval section from the head arriving wave out of the desired wave, and also a third response vector for a signal arriving within the guard interval section from the head arriving wave and a fourth response vector for a signal arriving after the guard interval section from the head arriving wave out of the interfering wave. An adaptive array block provides a weight vector based on a result of Fourier transform on the first to fourth response vectors.

Claims

1. A radio apparatus to transmit and receive a signal transmitted with a guard interval section added to each valid symbol section by an orthogonal frequency division communication scheme employing a plurality of carriers, comprising:

an array antenna including a plurality of antennas,

arrival timing detection means for detecting an arriving timing of a desired wave from signals received by said array antenna,

reception response vector estimation means for estimating a first response vector for a signal arriving within said guard interval section from a head arriving wave out of said desired wave, and a second response vector for a signal arriving after said guard interval section from the head arriving wave out of said desired wave,

first Fourier transform means for applying Fourier transform on said first and second response vectors to extract components for respective ones of said plurality of carriers,

second Fourier transform means for applying Fourier transform on reception signals from said array antenna to extract components for respective carriers of reception signals of respective ones of said antenna, and

adaptive array processing means provided for respective ones of said plurality of carriers, each adaptive array processing means receiving a component of a corresponding carrier from said second Fourier transform means among components for carriers of reception signals for respective ones of said antennas for extracting the component of the corresponding carrier in said desired wave,

wherein said adaptive array processing means provides a weight vector used to extract said component of the corresponding carrier based components for corresponding carriers of at least said first and second response vectors from said first Fourier transform means.

2. The radio apparatus according to claim 1, wherein said arriving timing detection means detects said desired wave in accordance with a cross correlation between said reception signal prior to Fourier transform in said second Fourier transform means and a reference signal including a training signal component corresponding to said plurality of carriers exceeding a predetermined threshold value, for every said antenna.

3. The radio apparatus according to claim 1, wherein said reception response vector estimation means sets a response level to 0 in said first and second response vectors at a time other than said arriving timing detected by said arriving timing detection means.

4. The radio apparatus according to claim 1, wherein said adaptive array processing means provides a weight vector used to extract said desired wave for said corresponding carrier by a correlation matrix for each said carrier, provided based on components for corresponding carriers of said first and second response vectors.

5. The radio apparatus according to claim 1, wherein

said arriving timing detection means detects an arriving timing of n (n:

natural number, n≧

1) interfering waves from a signal received from said array antenna,

said reception response vector estimation means estimates third to (2n+1)th response vectors for signals arriving within said guard interval section from each head arriving wave for each of said n interfering waves, and fourth to (2n+2)th response vectors for respective signals arriving after said guard interval section from each said head arriving wave for each of said n interfering waves,

said first Fourier transform means applies Fourier transform on said third to (2n+2)th response vectors to extract a component for each of said plurality of carriers, and

said adaptive array processing means provides a weight vector used to extract said component of the corresponding carrier based on components for corresponding carriers of said first to (2n+2)th response vectors from said first Fourier transform means.

6. The radio apparatus according to claim 5, wherein said arriving timing detection means detects said desired wave and said interfering wave in accordance with a cross correlation between said reception signal prior to Fourier transform in said second Fourier transform means and a reference signal including training signal component corresponding to said plurality of carriers exceeding a predetermined threshold value, for every said antenna.

7. The radio apparatus according to claim 5, wherein said reception response vector estimation means sets a response level to 0 in said first to (2n+2)th response vectors at a time other than said arriving timing detected by said arriving timing detection means.

8. The radio apparatus according to claim 5, wherein said adaptive array processing means provides a weight vector used to extract said desired wave for said corresponding carrier by a correlation matrix for each said carrier, provided based on components for corresponding carriers of said first to (2n+2)th response vectors.

9. The radio apparatus according to claim 8, wherein said adaptive array processing means provides a weight vector used to extract said interfering wave for said corresponding carrier by a correlation matrix for each said carrier.

10. The radio apparatus according to claim 5, wherein said reception response vector estimation means estimates said first to (2n+2)th response vectors by an MMSE method.

11. An adaptive array processing method to extract a signal transmitted with a guard interval section added to each valid symbol section by an orthogonal frequency division communication scheme employing a plurality of carriers for every component corresponding to said plurality of carriers by an adaptive array processing, said method comprising the steps of:

detecting an arriving timing of at least a desired wave from signals received by an array antenna including a plurality of antennas, estimating a first response vector for a signal arriving within said guard interval section from a head arriving wave out of said desired wave, and a second response vector for a signal arriving after said guard interval section from the head arriving wave out of said desired wave,

applying Fourier transform on said first and second response vectors to extract components for respective ones of said plurality of carriers,

providing a weight vector used to separate by adaptive array processing a component corresponding to said carrier for a desired wave, based on components for carriers of at least said first and second response vectors,

applying Fourier transform on reception signals from said array antennas to extract carrier components of reception signals for respective ones of said antennas, and

multiplying said weight vector by said carrier component of a reception signal for each said antenna to extract the component of said corresponding carrier for said desired wave.

12. The adaptive array processing method according to claim 11, wherein said step of detecting an arriving timing further includes the steps of detecting an arriving timing of at least one interfering wave,

further comprising the steps of estimating a third response vector for a signal arriving within said guard interval section from the head arriving wave out of said interfering wave, and a fourth response vector for a signal arriving after said guard interval section from the head arriving wave out of said interfering wave, and

applying Fourier transform on said third and fourth response vectors to extract components for respective ones of said plurality of carriers,

wherein said step of providing a weight vector provides said weight vector based on components for carriers of said first to fourth response vectors.