Weighting factor adjustment in adaptive antenna arrays

• US 8,934,843 B2
• Filed: 10/16/2013
• Issued: 01/13/2015
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Original Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Inventors: Eldering, Charles A.
• Primary Examiner(s): Nguyen, Simon
• Application Number:
  US14/055,447
• Publication Number:
  US 20140045439A1
• Time in Patent Office: 454 Days
• Field of Search: 455/63.2, 455/63.4, 455/67.16, 455/101, 455/562.1
• US Class Current: 455/63.2
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A method of forming an adaptive antenna array includes calculating intra-unit phase relationships between antenna elements of a plurality of access units and measuring inter-unit phase relationships between the access units. An indication of a desired coverage area collectively produced by the plurality of access units is received. A set of weighting factors is determined. Each weighting factor is associated with an individual antenna element in the plurality of access units and the set of weighting factors provide the desired coverage pattern. Phase lock between the plurality of access units is maintained to control the desired coverage pattern.

Claims

1. A method of producing a desired coverage area in a wireless network, the method comprising:

(a) calculating intra-unit phase relationships between antenna elements of a plurality of access units;

(b) measuring inter-unit phase relationships between the plurality of access units;

(c) receiving an indication of the desired coverage area collectively produced by the plurality of access units;

(d) determining a set of weighting factors, wherein each weighting factor is associated with an individual antenna element in the plurality of access units and the set of weighting factors provide the desired coverage pattern; and

(e) maintaining phase lock between the plurality of access units to control the desired coverage pattern.

2. The method of claim 1, wherein each antenna element of a first access unit includes a phase locked loop, and the inter-unit phase relationships are measured by each antenna element of the first access unit by monitoring the signal received from a second access unit.

3. The method of claim 1, further comprising:

(f) adjusting the weighting factors based on testing if the set of weighting factors do not provide the desired coverage pattern.

4. The method of claim 1, wherein the set of weighting factors used in step (d) are determined using an iterative method selected from a group comprising:

Conjugate Gradient Method, Constant Modulus Algorithm, Least Mean Squares Algorithm, Recursive Least Squares Algorithm, and Sample Matrix Inversion Algorithm.

5. The method of claim 1, further comprising:

(f) periodically measuring the inter-unit phase relationships before transmission of data between the access units; and

(g) adjusting an aggregated set of weight factors if the inter-unit phase relationships change in order to maintain the radiation pattern, where the aggregated set of weight factors include the sets of weight factors from step (c).

6. The method of claim 1, wherein the measurement of inter-phase relationships includes a measure of at least one of phase noise and phase drift.

7. The method of claim 6, wherein phase noise and phase drift limit the degree of phase lock between the access units.

8. The method of claim 1, wherein the coverage pattern is a radiation field produced by collective radiation patterns of the plurality of access units.

9. The method of claim 1, wherein at least one of the plurality of access units is a mobile access unit.