Wireless communication device

• US 20080079634A1
• Filed: 02/22/2007
• Published: 04/03/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakamura, Tadashi
• Granted Patent: US 8,019,285 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• 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; and

an adaptive array searcher for detecting a phase difference between the antennas and estimating a direction of arrival of received radio waves,

wherein the adaptive array searcher shares part of circuitry with a calibrator which performs calibration by correcting a phase difference caused between antenna channels in the wireless communication device.

2. The wireless communication device according to claim 1, wherein the adaptive array searcher includes matched filters, the matched filters carrying out both of demodulation of received signals, necessary for estimating the arrival direction, and demodulation of reference signals, necessary for the calibration.

3. The wireless communication device according to claim 1, wherein the adaptive array searcher includes a phase difference detector, the phase difference detector carrying out both of detection of phase difference between the antennas, necessary for estimating the arrival direction, and detection of phase difference of reference signals, necessary for the calibration.

4. The wireless communication device according to claim 1, wherein the adaptive array searcher includes 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 arrival direction, the first process comprising performing in-phase combination of received signals demodulated by matched filters and calculating despreading timing for user data based on a signal obtained by the in-phase combination; and

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

5. The wireless communication device according to claim 1, further comprising a weighting factor setting unit for setting weighting factors used to weight respective outputs of the antennas, wherein the adaptive array searcher generates arrival direction information synchronized with despreading timing for received signals, calculates the weighting factors based on the arrival direction information and a phase difference correction amount derived by the calibration to correct the phase difference between the antenna channels in the wireless communication device, and sends the calculated weighting factors to the weighting factor setting unit.

6. An adaptive array searcher for detecting a phase difference between antennas and estimating a direction of arrival of received radio waves, comprising:

matched filters for carrying out both of demodulation of received user data and demodulation of reference signals which are necessary for performing calibration by correcting a phase difference caused between antenna channels in a wireless communication device and which are used as a basis for the correction; and

a phase difference detector for carrying out both of detection of phase difference between the antennas and detection of phase difference of the reference signals.