Method and apparatus for antenna control in a communications network

• US 6,400,317 B2
• Filed: 02/02/2001
• Issued: 06/04/2002
• Est. Priority Date: 09/21/1998
• Status: Expired due to Term

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Riley, Daniel Innis, Hoffmann, John Erich, Nelson, Jr., George Rodney, Proctor, Jr., James Arthur, Rouphael, Antoine J.
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/776,397
• Publication Number:
  US 20010022557A1
• Time in Patent Office: 487 Days
• Field of Search: 342/81, 342/367, 342/368, 342/373
• 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 for increasing the 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 signal control component to provide a weight to the signal transmitted from each element. The weight for each antenna element is adjusted to achieve optimum reception during, for example, an idle mode when a pilot signal is received. The weight values cause the antenna array to create a beam former 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 and intercell interference are greatly reduced. The weights are adjusted at the transmitting site in accord with signal quality metric information determined at the receiving site. The signal quality metric information is returned to the transmitting site where the optimum signal quality metric is determined. The weights at the transmitting site are then set to provide the antenna directional angle represented by the optimum signal quality metric.

Claims

1. A method for optimizing the directional angle of an antenna of a first transceiver for communicating with a second transceiver, said method comprising the steps of:

(a) establishing a directional angle for the antenna at the first transceiver;

(b) transmitting a known signal from the first transceiver to the second transceiver;

(c) receiving the known signal at the second transceiver;

(d) at the second transceiver, determining a signal quality metric of the known signal;

(e) repeating the steps (a) through (d) wherein a different antenna directional angle is established for each execution of the step (a) and therefore a different signal quality metric is determined for each execution of the step (d);

(f) providing to the first transceiver information representative of the signal quality metrics determined at each execution of the step (d); and

(g) determining an optimum directional angle for the antenna at the first transceiver based on the signal quality metric values determined at each execution of the step (d).

2. The method of claim 1 wherein the first transceiver is in a standby state during which no information is communicated between the first and the second transceivers.

3. The method of claim 2 wherein the known signal is a pilot signal.

4. The method of claim 1 wherein the first transceiver is in an active state during which information signals are transmitted and received thereby, and wherein the known signal is transmitted during periods when no information signal is being transmitted from the first transceiver to the second transceiver.

5. The method of claim 1 wherein the step (f) includes providing the signal quality metric information.

6. The method of claim 1 wherein the step (f) includes providing information related to the difference between the determined signal quality metric and a predetermined threshold value therefor.

7. The method of claim 1 wherein the repetitions of the steps (a) through (d) continue for a predetermined time.

8. The method of claim 1 wherein the repetitions of the steps (a) through (d) continue until a plurality of signal quality metrics for a like plurality of antenna directional angles have been determined.

9. The method of claim 1 wherein the antenna of the first transceiver comprises a plurality of antenna elements and a like plurality of signal control components for adjusting the signal weights for each one of the plurality of antenna elements to establish directional angles for the antenna at the step (a).

10. The method of claim 1 wherein the signal weights are associated with the signal amplitude.

11. The method of claim 1 wherein the signal weights are associated with the signal phase.

12. The method of claim 1 wherein the signal quality metric is the signal to noise ratio.

13. The method of claim 1 wherein the signal quality metric is selected from among the ratio of the signal energy to the interference, the ratio of the signal energy to the thermal noise and the ratio of the signal energy to the sum of the interference and the thermal noise.

14. The method of claim 1 wherein the first transceiver comprises a subscriber unit from among a plurality of subscriber units operative in a wireless communication network and wherein the second transceiver comprises a base station for communicating with the plurality of subscriber unit.

15. A method for optimizing the directional angle of a subscriber unit in a wireless communications system for communicating with a base station, said method comprising the steps of:

(a) during an idle state, establishing a directional angle for an antenna of the subscriber unit;

(b) transmitting a known signal from the subscriber unit to the base station;

(c) receiving the known signal at an antenna of the base station;

(d) at the base station, determining a signal quality metric of the known signal;

(e) repeating the steps (a) through (d) wherein a different antenna directional angle is established for each execution of the step (a), and therefore a different signal quality metric is determined for each execution of the step (d);

(f) providing information from the base station to the subscriber unit, wherein the information is representative of the signal quality metric of the known signal to the subscriber unit for each execution of the step (d); and

(g) determining an optimum directional angle for the antenna at the subscriber unit based on the signal quality metrics for each execution of the step (d).

16. A wireless communications system for communicating between a first transceiver and a second transceiver, said wireless communications system comprising:

at the first transceiver, a plurality of antenna elements for transmitting and receiving a composite beam;

a like plurality of weight control components at the first transceiver, each respectively coupled to one of said plurality of antenna elements;

said plurality of weight control components operable to establish a directional antenna angle at the first transceiver for communicating with the second transceiver;

a transmitter at the first transceiver for transmitting a signal to the second transceiver;

a receiver at the second transceiver for determining a signal quality metric of the received signal;

a module at the second transceiver for providing the signal quality metric information to the first transceiver;

wherein said plurality of weight control components are responsive to the signal quality metric information for establishing an optimal antenna directional angle at the first transceiver for communicating with the second transceiver.

17. The wireless communications system of claim 16 wherein the weight control components are phase shifters for imparting phase shift to the signal input thereto.

18. The wireless communications system of claim 16 wherein the weight control components impart a weight to the signal input thereto and wherein the weight is associated with the signal amplitude, the signal phase or the signal amplitude and phase.

19. The wireless communications system of claim 16 wherein a predetermined number of the plurality of antenna elements are active elements and the remainder of the plurality of the antenna elements are parasitic elements.

20. The wireless communications system of claim 16 wherein the optimal configuration for the weight control components maximizes the signal power to interference ratio.

21. The wireless communications system of claim 16 wherein the optimal configuration for the weight control components minimizes the bit error rate.

22. The wireless communications system of claim 16 wherein the optimal configuration for the weight control components maximizes the received power.

23. The wireless communications system of claim 16 wherein the optimal configuration of the weight control components for a signal transmitted from the first transceiver to the second transceiver in the wireless communications system reduces emissions in a direction of other transceivers not intended to receive the signal.

24. The wireless communications system of claim 16 wherein the first transceiver is a subscriber unit and wherein the second transceiver is a base station for communicating with a plurality of subscriber units in the wireless communications system, and wherein the optimal configuration for the weight control components for a signal transmitted from said subscriber unit reduces interfering emissions at other ones of said plurality of subscriber units not intended to receive the signal.

25. An antenna apparatus for use with a first transceiver operative in a wireless communications system, for communicating with a second transceiver operative in the wireless communication system, said antenna apparatus comprising:

a plurality of antenna elements for transmitting and receiving a composite beam;

a like plurality of weight control components, each respectively coupled to one of said plurality of antenna elements; and

each one of said plurality of weight control components controllable for imparting a weight to the signal at the associated antenna element and thereby establishing a directional antenna angle at the first transceiver for communicating with the second transceiver;

wherein the first transceiver transmits a signal to the second transceiver at the directional antenna angle;

wherein the second transceiver receives the signal and determines a signal quality metric associated therewith;

wherein the signal quality metric is returned to the first transceiver; and

wherein said plurality of weight control components are responsive to the signal quality metric for establishing the directional antenna angle.

26. The antenna apparatus of claim 25, wherein the first transceiver is a one of a plurality of subscriber units and wherein the second transceiver is one of a plurality of base stations, each of the plurality of base stations for bi-directionally communicating with the plurality of subscriber units, wherein the optimal configuration for the weight control components of the subscriber unit creates a directional receiving antenna to optimally detect a signal sent from an intended base station and to suppress signals received from other than the intended base station.

27. The antenna apparatus of claim 26, wherein the optimal configuration for the weight control components of the subscriber unit creates a directional transmitting antenna to optimally transmit a signal to the intended base station and to reduce interfering emissions at other than the intended base station.

28. The apparatus of claim 25 wherein the plurality of antenna elements includes first, second, third, fourth, and fifth antenna elements, and wherein the plurality of weight control components includes first, second, third, fourth, and fifth weight control components, each respectively coupled to the first, second, third, forth and fifth antenna elements.

29. The antenna apparatus of claim 28, wherein the first, second, third, and fourth antenna elements are positioned at locations corresponding to the corners of a rectangle, and the fifth antenna element is positioned at a location corresponding approximately to the center of the rectangle.

30. The antenna apparatus of claim 25 wherein the adjustment of the weight control components occurs when the subscriber unit is in an idle state.

31. The antenna apparatus of claim 25 wherein the adjustment of the weight control components occurs when the subscriber unit is in an active state.

32. The antenna apparatus of claim 25 further comprising a summation network coupled to the plurality of the weight control components, in a transmit mode, said summation network providing a signal to each of the weight control components for transmission from the first transceiver via the plurality of antenna elements, and in a receive mode, said summation network receiving and combining the signals from each of the weight control components via the plurality of antenna elements into a received signal.

33. The antenna apparatus of claim 25 wherein the plurality of antenna elements comprises a first plurality of parasitic elements and at least one active element, wherein the weight is imparted to the signal associated with each of the first plurality of parasitic elements for producing a parasitic signal in response thereto, wherein the parasitic signal is radiated from each of the first plurality of parasitic elements and combined at the at least one active element.