System and method for improving polarization matching on a cellular communication forward link

• US 20030162566A1
• Filed: 02/27/2003
• Published: 08/28/2003
• Est. Priority Date: 05/05/2000
• Status: Active Grant

• Current Assignee: Celletra Ltd. (Unity Wireless Corp.)
• Original Assignee: Celletra Ltd. (Unity Wireless Corp.)
• Inventors: Levy, David, Shapira, Joseph
• Granted Patent: US 7,113,748 B2
• Time in Patent Office: Days
• US Class Current: 455/561
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

The present invention provides a method of controlling a plurality of beam patterns radiated by a base station in a wireless communication system. The method includes receiving at least one signal from a mobile station at the base station, determining estimated attributes of the at least one signal received by the base station. Smoothed versions of the estimated attributes are calculated in accordance with a predetermined set of criteria are calculated. A set of weighted signal parameters are generated to describe a polarization state of the at least one signal received from the mobile station. The generated weighed signal parameters are applied to a signal transmitted by the base station such that the transmitted signal substantially matches the polarization state of the at least one signal from the mobile station.

Claims

1. A method of controlling a plurality of beam patterns radiated by a base station in a wireless communication system, comprising:

receiving at least one signal from a mobile station at the base station;

determining estimated attributes of said at least one signal received by the base station;

calculating smoothed versions of said estimated attributes according to a predetermined set of criteria;

generating a set of weighted signal parameters according to said smoothed versions to describe a polarization state of said at least one signal; and

applying said weighted signal parameters to modify a signal transmitted by said base station such that said transmitted signal substantially matches said polarization state of said at least one signal.

2. The method of claim 1, further comprising setting a default polarization state of transmit elements in the base station.

3. The method of claim 2, wherein said default polarization state is vertical.

4. The method of claim 1, wherein the base station is configured for a TDMA wireless communication system and said weighted signal parameters are applied directly to said transmitted signal for each mobile station.

5. The method of claim 1, wherein the base station is configured for CDMA wireless communication system and said weighted signal parameters are applied digitally at a baseband frequency of said CDMA wireless communication system.

6. The method of claim 1, wherein said estimated attributes include at least amplitude and phase information of said at least one signal.

7. The method of claim 1, wherein said determining is performed by a microprocessor.

8. An apparatus, in a wireless communication system, for controlling a plurality of beam patterns radiated by a base station to match the polarization of beam patterns radiated by at least one mobile station, comprising:

an attribute estimation unit configured to process at least one signal received by the base station;

a data smoothing mechanism coupled to said attribute estimation unit, said data smoothing mechanism configured to calculate smoothed versions of said estimated attributes in accordance with a predetermined set of criteria; and

a normalized weight generator to generate weighted signal parameters according to the smoothed versions, the weighted signal parameters being applied to said at least one signal to achieve polarization matching.

9. The apparatus according to claim 8, wherein said attribute estimation unit produces a set of estimated attributes, including at least an amplitude and phase value of said at least one signal.

10. The apparatus according to claim 8, further comprising:

a quadrant detector configured to determine a sign of said phase value; and

a filtering unit configured to filter out short term variations in said at least one signal based on said estimated attributes,

wherein said normalized weight generator is coupled to said quadrant detector and said filtering unit.