Method and apparatus for adapting antenna array to reduce adaptation time while increasing array performance

• US 6,473,036 B2
• Filed: 02/02/2001
• Issued: 10/29/2002
• 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: Proctor, Jr., James Arthur
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/776,558
• Publication Number:
  US 20010020915A1
• Time in Patent Office: 634 Days
• Field of Search: 342/367, 342/368, 342/372, 342/373, 455/422, 455/426
• US Class Current: 342/372
• 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 that can increase capacity in a cellular communication system is disclosed. The antenna operates in conjunction with a mobile subscriber unit and comprises a plurality of antenna elements, each coupled to a respective weight control component to provide a weight to the signal transmitted from (or received by) 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 antenna array creates 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 in a coarse and a fine mode. In the coarse mode all the weight control components are jointly adjusted or changed so that the antenna beam scans through a predetermined sector of a circle until a signal quality metric of the received signal is optimized. The coarse adjustment mode is followed by a fine adjustment mode during which the weights of are independently adjusted to further optimize the signal quality metric.

Claims

1. An antenna apparatus for use with a receiver in a wireless communication system, said antenna apparatus comprising:

a plurality of antenna elements for receiving a composite beam;

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

said plurality of weight control components operable in a first mode for jointly adjusting at least two of said plurality of weight control components and operable in a second mode for independently adjusting each one of said plurality of weight control components to form the composite beam.

42. The antenna apparatus of claim 1 wherein the adjustment of the weight control components in the first mode comprises assigning predetermined values to the weight control components based on the desired beam position.

2. An antenna apparatus for use with a transmitter in a wireless communication system, said antenna apparatus comprising:

a plurality of antenna elements for transmitting a composite beam;

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

said plurality of weight control components operable in a first mode for jointly adjusting at least two of said plurality of weight control components and operable in a second mode for independently adjusting each one of said plurality of weight control components to form the composite beam.

3. An antenna apparatus for use with a transceiver in a 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

said plurality of weight control components operable in a first mode for jointly adjusting at least two of said plurality of weight control components and operable in a second mode for independently adjusting each one of said plurality of weight control components to form the composite beam.

4. The antenna apparatus of claim 3 wherein the weight control components are phase shifters for imparting phase shift to the signal input thereto.

5. The antenna apparatus of claim 3 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.

6. The antenna apparatus of claim 3 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.

7. The antenna apparatus of claim 3 wherein the optimal configuration for the weight control components maximizes the signal power to interference ratio.

8. The antenna apparatus of claim 3 wherein the optimal configuration for the weight control components minimizes the bit error rate.

9. The antenna apparatus of claim 3 wherein the optimal configuration for the weight control components maximizes the received power.

10. The antenna apparatus of claim 3, wherein the optimal configuration of the weight control components for a signal transmitted from a first transceiver to a second transceiver in the wireless communication system reduces interfering emissions at other transceivers not intended to receive the signal.

11. The antenna apparatus of claim 3 wherein the transceiver is a subscriber unit for communicating with a base station having bi-directional communications capabilities 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.

12. An antenna apparatus for use with a subscriber unit operative in a 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

said plurality of weight control components operable in a first mode for jointly adjusting at least two of said plurality of weight control components and operable in a second mode for independently adjusting each one of said plurality of weight control components to form the composite beam.

13. The antenna apparatus of claim 12, wherein the wireless communications system further comprises a plurality of base stations, each of said plurality of base stations for bi-directionally communicating with a 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 the direction of an intended base station and to suppress signals received from a direction other than the direction of the intended base station.

14. The antenna apparatus of claim 12, wherein the wireless communications system further comprises a plurality of base stations, each of said plurality of base stations for bi-directionally communicating with a plurality of subscriber units, 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 emissions in directions other than the direction of the intended base station.

15. The apparatus of claim 12 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.

16. The antenna apparatus of claim 15, 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.

17. The antenna apparatus of claim 12 wherein the adjustment of the weight control components occurs when the subscriber unit is in an idle state.

18. The antenna apparatus of claim 17 wherein the adjustments occurring in the first mode and the second mode are made so as to maximize a signal quality metric of a received pilot signal received when the subscriber unit is in the idle state.

19. The antenna apparatus of claim 12 wherein the adjustment of the weight control components occurs when the subscriber unit is in an active state.

20. The antenna apparatus of claim 12 wherein the weight control components are jointly adjustable in the first mode and independently adjustable in the second mode to optimize the signal received at the antenna elements by reducing the interference caused by signals that are not transmitted from the intended base station.

21. The antenna apparatus of claim 12 wherein the weight control components are jointly adjustable in the first mode and independently adjustable in the second mode to optimize the signal transmitted to a selected base station via the antenna elements by reducing the interference caused to other base stations.

22. The antenna apparatus of claim 12 further comprising a summation network coupled to the weight control components, the summation network providing the respective reverse link signals from the subscriber unit to each of the weight control components for transmission from the subscriber unit, and the summation network receiving and combining the respective forward link signals from each of the weight control components into one received forward link signal.

23. The antenna apparatus of claim 12 in which multiple subscriber units transmit code division multiple access signals on a common carrier frequency.

24. The antenna apparatus of claim 22 wherein the code division multiple access signals are transmitted within a cell, each cell containing a base station and a plurality of mobile subscriber units, each mobile subscriber unit having an antenna apparatus.

25. The antenna apparatus of claim 12 wherein a plurality of subscriber units and at least one base station comprise a system for providing wireless communications between said plurality of subscribers and said base station using spread spectrum signaling on a common carrier frequency within a defined transmission region.

26. The antenna apparatus of claim 12 wherein the subscriber unit includes a computer.

34. The method of claim 26 wherein the steps (d) and (f) include adjusting the amplitude, phase or the amplitude and the phase imparted to the output signal from the plurality of antenna elements.

35. The method of claim 26 including a plurality of transceivers, wherein said plurality of transceivers comprises a first plurality of subscriber units and a second plurality of base stations, wherein the step (a) is executed at the beginning a communication session between a subscriber unit from among said first plurality of subscriber units and a base station from among said second plurality of base stations.

36. The method of claim 26 wherein the optimum value of the signal quality metric exceeds a predetermined value.

27. A method for setting optimal weight control component arrangements for a plurality of antenna elements of a transceiver, the method comprising the steps of:

(a) detecting a received pilot signal at each of the plurality of antenna elements;

(b) combining the received pilot signal detected at each of the plurality of antenna elements to produce a combined received pilot signal;

(c) determining a signal quality metric for the combined received pilot signal;

(d) jointly adjusting the weight control components associated with at least two of the plurality of antenna elements in the subscriber unit in response to the signal quality metric of the received pilot signal;

(e) repeating the step (d) until an optimum signal quality metric is achieved;

(f) independently adjusting the weight control components in response to the signal quality metric of the received signal; and

(g) repeating the step (e) until the determined signal quality metric of the combined received pilot signal reaches an optimum value.

28. The method of claim 27 wherein the signal quality metric is the ratio of received signal energy to interference.

29. The method of claim 27 wherein the signal quality metric is the ratio of received signal energy to thermal noise.

30. The method of claim 27 wherein the signal quality metric is received signal power.

31. The method of claim 27 wherein each weight control component includes a phase shifter.

32. The method of claim 27 wherein each weight control component includes an amplifier and a phase shifter.

33. The method of claim 27 wherein each weight control component includes an electromagnetic coupler.

37. A method for optimizing a signal transmitted from or received by a transceiver, said transceiver comprising a plurality of antenna elements and a like plurality of weight control components for configuring the weight of the signal transmitted or received by the antenna elements, said method comprising the steps of:

(a) detecting a received signal at each of the plurality of antenna elements;

(b) combining the received signal detected at each of the plurality of antenna elements to produce a combined received signal;

(c) determining a signal quality metric for the combined received signal;

(d) jointly adjusting the weight control component associated with at least two of the plurality of antenna elements in response to the signal quality metric of the combined received signal to optimize the signal quality metric; and

(e) independently adjusting the signal control components in response to the signal quality metric of the combined received signal to further optimize the signal quality metric.

38. An antenna apparatus for use with a transceiver in a wireless communications system, said antenna apparatus comprising:

at least one active antenna element;

a plurality of parasitic antenna elements;

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

a controller for controlling each one of said plurality of weight control components to produce a parasitic signal in response to the received signal at each one of the plurality of parasitic antenna elements, wherein said controller adjusts the plurality of weight control components in a first mode for jointly adjusting at least two of said plurality of weight control components and further adjusts the weight control components in a second mode for independently adjusting each one of said plurality of weight control components.

wherein the parasitic signal is radiated from each one of the plurality of the parasitic antenna elements; and

wherein a composite signal is formed at said active element by combining the plurality of parasitic signals.

39. The antenna apparatus of claim 38, wherein each one of the plurality of weight control components includes a phase shifter.

40. The antenna apparatus of claim 38, wherein each one of the plurality of weight control components imposes a weight value on the received signal, wherein the weight value affects one of the characteristics of the received signal selected from among phase, amplitude, and amplitude and phase.

41. The antenna apparatus of claim 38, wherein each one of the plurality of weight control components includes a predetermined impedance.