Adaptive antenna for use in wireless communication systems

• US 20070210977A1
• Filed: 05/08/2007
• Published: 09/13/2007
• Est. Priority Date: 09/21/1998
• Status: Active Grant

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Chiang, Bing, Snyder, Christopher, Proctor, James, Gainey, Kenneth, Gothard, Griffin, Wood, Douglas, Keel, Alton, Richeson, Joe
• Granted Patent: US 7,528,789 B2
• Time in Patent Office: Days
• US Class Current: 343/835
• CPC Class Codes: H01Q 1/241 used in mobile communications, e.g. GSM H01Q1/247, H01Q1/248 take precedence
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 19/26 the primary active element being end-fed and elongated
• CPC Class Codes: H01Q 19/32 the primary active element being end-fed and elongated
• 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 3/2611 Means for null steering; Adaptive interference nulling
• CPC Class Codes: H01Q 3/446 the radiating element being at the centre of one or more rings of auxiliary elements

Abstract

An antenna apparatus, which can increase capacity in a cellular communication system or Wireless Local Area Network (WLAN), such as an 802.11 network, operates in conjunction with a mobile subscriber unit or client station. At least one antenna element is active and located within multiple passive antenna elements. The passive antenna elements are coupled to selectable impedance components for phase control of re-radiated RF signals. Various techniques for determining the phase of each antenna element are supported to enable the antenna apparatus to direct an antenna beam pattern toward a base station or access point with maximum gain, and, consequently, maximum signal-to-noise ratio. By directionally receiving and transmitting signals, multipath fading is greatly reduced as well as intercell interference.

Claims

1. A method for providing a wireless transmit receive unit (WRTU), including a directional antenna apparatus having one or more antenna elements, directional reception of radio signals in a wireless communication system comprising:

independently adjusting each of a plurality of phase shifters to affect directionality of received radio signals, each one of said phase shifters coupled to one of said antenna elements; and

receiving said radio signals originating from the direction of a transmitting base station, wherein the radio signals transmitted from a different direction are rejected.

2. The method of claim 1, wherein each of said received signals at each of said antenna elements out of phase with each other.

3. The method of claim 2, further comprising phase shifting each of said received signals by said plurality of said phase shifters.

4. The method of claim 1, further comprising determining an optimal phase setting for each of the antenna elements based on an optimized reception of a current pilot signal.

5. The method of claim 4, wherein said determining step comprises:

a) selecting one of a plurality of phase settings;

b) reading a pre-calculated phase value for each antenna element;

c) applying each of said phase values to the respective phase shifter; and

d) repeating steps a-c for each selected phase setting.

6. The method of claim 5, further comprising selecting a phase setting that resulted in a best recover response.

7. The method of claim 6, wherein said best recover response is measured by a maximum signal to noise ratio.

8. The method of claim 4, wherein said determining step comprises:

individually varying a phase value of one of the plurality of phase shifters while a phase value of other phase shifters remains constant;

selecting a phase value of the one of the plurality of phase shifters with a best response for said phase shifter; and

repeating the above steps for each of said other phase shifters.

9. The method of claim 8, wherein each of the best response phase values for each phase shifter is applied to each respective phase shifter.

10. The method of claim 8, further comprising:

applying the selected best phase value to the one of the plurality of phase shifters; and

said one of the plurality of phase shifters remaining constant at said selected best phase value when the other phase shifters best phase value are being selected.

11. A wireless receive transmit unit (WRTU), including a directional antenna apparatus for providing directional reception of radio signals in a wireless communication system, comprising:

said directional antenna apparatus comprising;

a plurality of antenna elements; and

a plurality of phase shifters wherein each phase shifter is coupled to a respective one of said antenna elements;

the plurality of phase shifters being configured such that they can be, independently adjusted to affect the directionality of said received radio signals;

said directional antenna apparatus receiving said radio signals originating from the direction of a transmitting base station, wherein radio signals received from a different direction are rejected.

12. The WRTU of claim 11 wherein said radio signal received at each of said antenna elements is out of phase with each other.

13. The WRTU of claim 11, wherein said antenna apparatus further comprises a processor for determining an optimal phase setting for each of the antenna elements.

14. The WRTU of claim 13, wherein the optimal phase setting is applied to said phase shifters.