Wireless communication device

• US 8,019,285 B2
• Filed: 02/22/2007
• Issued: 09/13/2011
• Est. Priority Date: 09/29/2006
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakamura, Tadashi
• Primary Examiner(s): Urban; Edward
• Assistant Examiner(s): HANIDU, GANIYU A
• Application Number:
  US11/709,250
• Publication Number:
  US 20080079634A1
• Time in Patent Office: 1,664 Days
• Field of Search: 455/63.4, 455/66.1, 455/67.11, 455/562.1, 455/276.1, 455295-296, 455/303, 455306-307, 375/324, 375/148, 342/378, 342/383
• US Class Current: 455/63.4
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

A wireless communication device which permits reduction in the scale of circuitry as well as in the power consumption. The wireless communication device includes an array of antennas, an adaptive array searcher, and a data demodulator. The adaptive array searcher detects the phase difference between the antennas and estimates the direction of arrival of received radio waves. The data demodulator demodulates the radio signal received by the antennas. The adaptive array searcher shares part of circuitry with a calibrator which performs calibration by correcting the phase difference caused between antenna channels in the wireless communication device, and thus has a calibration function incorporated therein.

Claims

1. A wireless communication device using an adaptive array antenna to perform wireless communication, comprising:

an array of antennas to receive a plurality of radio waves;

a reference signal generator to generate a reference signal;

a reference signal coupler, coupled to the array of antennas, to combine the reference signal with received radio wave signals of the individual antennas;

a plurality of matched filters, coupled to the reference signal coupler, to demodulate the received radio wave signals and the reference signals combined therewith;

a plurality of first multipliers, coupled to outputs of the matched filters, to multiply the demodulated radio wave signals and demodulated reference signals by a plurality of first weighting coefficients, respectively;

a plurality of second multipliers, coupled to the first multipliers in series, to further multiply the demodulated radio wave signals and demodulated reference signals by a plurality of second weighting coefficients, respectively;

a calibrator, coupled to the matched filters via the first multipliers, to detect first phase differences between the demodulated reference signals, and provide the first multipliers with the first weighting coefficients calculated from the detected first phase differences, so as to correct different phase characteristics of circuitry that processes the received radio wave signals; and

an adaptive array searcher, coupled to the second multipliers, to detect second phase differences between the demodulated radio wave signals, estimate a direction of arrival of the received radio waves from the detected second phase differences, and provide the second multipliers with the second weighting coefficients calculated from the estimated direction of arrival.

2. The wireless communication device according to claim 1, wherein the adaptive array searcher and the calibrator share a phase difference detector to detect the first phase differences and the second phase differences.

3. The wireless communication device according to claim 1, wherein the adaptive array searcher and the calibrator share an in-phase combiner and a timing calculator, and

the in-phase combiner and the timing calculator carry out both of:

a first process necessary for estimating the direction of arrival, the first process comprising performing in-phase combination of the demodulated radio wave signals and calculating despreading timing for user data based on a signal obtained by the in-phase combination; and

a second process necessary for correcting the different phase characteristics, the second process comprising performing in-phase combination of the demodulated reference signals and calculating despreading timing for the reference signals based on a signal obtained by the in-phase combination.