Adaptive antenna for use in same frequency networks

• US 20020047800A1
• Filed: 08/28/2001
• Published: 04/25/2002
• Est. Priority Date: 09/21/1998
• Status: Active Grant

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr., Gainey, Kenneth M.
• Granted Patent: US 6,518,920 B2
• Time in Patent Office: Days
• US Class Current: 342/367
• 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: H04B 7/0874 using subgroups of receive antennas

Abstract

An antenna apparatus which can increase capacity in a cellular communication system. The antenna operates in conjunction with a mobile subscriber unit and provides a plurality of antenna elements, each coupled to a respective programmable phase shifter. The phase of each antenna element is programmed for optimum reception during, for example, an idle mode which receives a pilot signal. The antenna array creates a beamformer for signals to be transmitted from the mobile subscriber unit, and a directional receiving array to more optimally detect and receive signals transmitted from the base station. By directionally receiving and transmitting signals, multipath fading is greatly reduced as well as intercell interference. Various techniques for determining the proper phase of each antenna element are accommodated.

Claims

1. In a code division multiple access communications system having a plurality of cells, each cell containing a base station and a plurality of mobile units which may communicate to the base station on the same carrier frequency using different codes, an antenna apparatus for reducing communications interference comprising:

five antenna elements;

five programmable phase shifters each respectively coupled to the five antenna elements;

means for programming the phase shifters to set a phase setting associated with each of the five antenna elements such that signals to be transmitted from the mobile subscriber unit are transmitted more optimally in a direction of an intended receiver base station and such that signals to be received by the mobile subscriber unit are more optimally received from a direction associated with the location of the base station.

2. In a system for providing wireless communications among a plurality of subscribers using spread spectrum signaling for transmission of a plurality of desired traffic signals from a subscriber unit to a base station unit on a common carrier frequency within a defined transmission region, a method for operating a directional antenna array which includes a plurality of antenna elements having programmable phase shifters, the method comprising the steps of:

determining, from a received pilot signal transmitted on a forward link from the base station to the subscriber unit, a set of phase shifts for the antenna array that optimize reception of the pilot signal; and

setting the phase shifts to the optimized set of values during transmission of a forward link traffic signal.