Antenna adaptation in a time division duplexing system

• US 7,308,285 B2
• Filed: 05/07/2003
• Issued: 12/11/2007
• Est. Priority Date: 05/07/2002
• Status: Expired due to Fees

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Nelson, George Rodney Jr., Proctor, James A. Jr., Regnier, John A.
• Primary Examiner(s): Vuong, Quochien B.
• Application Number:
  US10/434,437
• Publication Number:
  US 20040147287A1
• Time in Patent Office: 1,679 Days
• Field of Search: 455/67.11, 455/73, 455/78, 455/83, 455/450, 455/452.1, 455/453, 455/561, 455/562.1, 455/269, 455/272
• US Class Current: 455/562.1
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/18 TPC being performed according to specific parameters
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A technique for steering a directional antenna such as may be used with User Equipment (UE) in a wireless communication system. Optimum angle settings for the directional antenna are determined as different values for an uplink and downlink; that is for simple reception and simple transmission. Thus, rather than determine compromised directions that are picked in an attempt to optimize transmission and reception with the same directional setting, directional settings may be optimized independently. The invention is of particular use in a Time Division Duplex (TDD) system where transmit and receive functions can be operating independently at different times. In further aspects, an optimum direction is determined by estimating an interference signal power which is detected from signals emanating from adjacent base stations (access points) and determining a directional setting that minimizes interference to adjacent cells based upon such measurements. A further level of sophistication in antenna angle setting, is to monitor the loading of adjacent cell sites base stations and turning interference and determine the settings accordingly to minimize interference to such heavily loaded neighbors. Further aspects of the invention adapts to acquisition modes that accommodate the directional setting in active use of the system.

Claims

1. A method for setting a direction for an antenna in a wireless communication system having both uplink and downlink communication channels, the method comprising the steps of:

setting the antenna to a candidate setting;

measuring a metric associated with utilization of the antenna at the candidate setting;

determining an optimum setting based upon such metrics measured for at least two candidate settings; and

using different metrics for determining the optimum setting for the uplink and downlink communication channels.

2. A method as in claim 1 wherein different optimum settings are determined for the uplink and downlink channels.

3. A method as in claim 1 wherein the candidate settings include an omnidirectional setting.

4. A method as in claim 1 wherein an optimum setting for the antenna in an uplink channel is determined from a metric measured from a signal received on a downlink channel.

5. A method as in claim 1 wherein multiple metric measurements are averaged before determining the optimum setting.

6. A method as in claim 1 wherein the metric is taken from a received pilot channel signal.

7. A method as in claim 1 wherein the metric is taken from a received data payload signal.

8. A method as in claim 1 wherein the system is a Time Division Duplex (TDD) system, and the uplink and downlink channels are time slotted.

9. A method as in claim 8 wherein the metric is taken during inactive time slots.

10. A method as in claim 8 wherein active time slots are scheduled in advance.

11. A method as in claim 10 wherein active time slots are scheduled by a central base station.

12. A method as in claim 8 wherein metrics for the antenna candidate settings are measured during unused time slots.

13. A method as in claim 8 additionally comprising the step of:

storing optimum positions determined for different time slots as needed, in synchronization with active time slot assignments.

14. A method as in claim 13 additionally comprising the step of:

reading at the stored optimum settings.

15. A method for dynamically determining a steering direction of an antenna in a wireless system comprising:

providing a transmission quality metric applicable to describe a quality measure of a wireless signal;

applying the quality metric to a current steering position of the antenna;

repointing the antenna to a trial steering position;

reapplying the quality metric to the trial steering position;

comparing the quality metrics of the current and trial steering positions;

repeating the repointing by incrementally selecting a new trial steering position;

selecting a best steering position by comparing each of the incremented trial steering positions;

determining an active time slot sequence, the active time slots employed for transmission of data;

identifying a frame offset in the sequence of the active time slots;

determining non-occupied time slots in the sequence based on a frame offset; and

transmitting information in directional non-active time slots.

16. A method as in claim 15 wherein the directional information is indicative of a plurality of the candidate settings.

17. A method as in claim 16 further comprising the step of:

computing an optimum setting from the directional information transmitted for a plurality of candidate directions.

18. A method for setting a direction for an antenna in a wireless communication system having both uplink and downlink communication channels, the system being a Time Division Duplex (TDD) system, and the uplink and downlink channels are time slotted, the method comprising the steps of:

setting the antenna to a candidate setting;

measuring a metric associated with utilization of the antenna at the candidate setting;

determining an optimum setting based upon such metrics measured for at least two candidate settings;

using different metrics for determining the optimum setting for the uplink and downlink communication channels;

determining an active time slot sequence, the active time slots employed for transmission of data;

identifying a frame offset in the sequence of the active time slots;

determining non-occupied time slots in the sequence based on a frame offset; and

transmitting information in directional non-active time slots.