WIRELESS COMMUNICATION APPARATUS AND WIRELESS COMMUNICATING METHOD

• US 20100046667A1
• Filed: 11/05/2009
• Published: 02/25/2010
• Est. Priority Date: 05/16/2007
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: TSUTSUI, Masafumi
• Granted Patent: US 8,265,054 B2
• Time in Patent Office: Days
• US Class Current: 375/296
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

A wireless communication apparatus of a base station uses antennas for multiple systems, forms a multi-beam, transmits data to a mobile station, and includes a code book configured to store therein beamforming information; a pre-coder that reads the code book and executes a process of forming a given beam for the data; a control unit that, based on feedback information to correct variations in phase occurring at transmitting circuits respectively corresponding to each of the systems, performs control such that the beamforming information to correct the variations in phase is read from the code book; and a phase correcting unit that corrects a phase of the multi-beam formed by the pre-coder, based on the feedback information and such that relations among the phases of the multi-beam become substantially linear.

Claims

1. A wireless communication apparatus of a base station, using antennas for a plurality of systems, forming a multi-beam, transmitting data to a mobile station, and comprising:

a code book configured to store therein beamforming information;

a pre-coder that reads the code book and executes a process of forming a given beam for the data;

a control unit that, based on feedback information to correct variations in phase occurring at transmitting circuits respectively corresponding to each of the systems, performs control such that the beamforming information to correct the variations in phase is read from the code book; and

a phase correcting unit that corrects a phase of the multi-beam formed by the pre-coder, based on the feedback information and such that relations among the phases of the multi-beam become substantially linear.

2. The wireless communication apparatus according to claim 1, wherein

the feedback information includes a matrix number and a beam number of the code book to correct the variations in phase,

the control unit reads the matrix number and the beam number from the code book, and

the phase correcting unit measures a distribution of the matrix number included in the feedback information and corrects a phase of the multi-beam such that the center of the distribution of the measured matrix number coincides with the position of a given matrix number.

3. The wireless communication apparatus according to claim 1, wherein

the phase correcting unit corrects the phase by a phase unit that is smaller than the phase unit used by the control unit to correct the variations in phase.

4. The wireless communication apparatus according to claim 2, wherein

the phase correcting unit moves, stepwise in given units, the center of the distribution of the measured matrix number.

5. The wireless communication apparatus according to claim 2, wherein

the phase correcting unit measures the distribution by calculating an average value obtained by time-averaging the matrix number.

6. The wireless communication apparatus according to claim 2, wherein

the phase correcting unit measures the distribution by calculating a mode of the matrix number.

7. The wireless communication apparatus according to claim 1, wherein

the transmitting circuits respectively modulate the data using an oscillator specific for each of the systems.

8. The wireless communication apparatus according to claim 1, wherein

the transmitting circuits respectively modulate the data using a common oscillator for the systems.

9. The wireless communication apparatus according to claim 1, wherein

the phase correcting unit measures the distribution of the matrix number by weighting that corresponds to the number of streams of the mobile station that transmits the feedback information.

10. A wireless communication method of a wireless communication apparatus that is at a base station, uses antennas for a plurality of systems, forms a multi-beam, and transmits data to a mobile station, the wireless communication method comprising:

reading a code book configured to store therein beamforming information;

forming a given beam for the data;

performing control, based on feedback information to correct variations in phase occurring at transmitting circuits respectively corresponding to each of the systems, such that the beamforming information to correct the variations in phase is read from the code book; and

correcting a phase of the multi-beam formed at the forming, based on the feedback information and such that relations among the phases of the multi-beam become substantially linear.