Interference Cancellation System and Method for Wireless Antenna Configuration

• US 20100178875A1
• Filed: 03/23/2010
• Published: 07/15/2010
• Est. Priority Date: 02/27/2002
• Status: Active Grant

• Current Assignee: Sprint Spectrum LLC (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Oh, Dae-Sik, Hayne, Kristin A., Yarkosky, Mark, Steele, Thomas M.
• Granted Patent: US 8,422,537 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Presently disclosed is a method for reducing interference in a wireless distributed antenna systems. In an embodiment, interference is reduced by selectively placing a first wireless remote unit in a reduced signal interference mode. A controller sends a signal, such as a reverse link power-down signal, to the first remote unit after detecting less than a threshold incoming signal strength at the first remote unit. In an alternative embodiment, the controller requests that a given remote unit switch to the reduced signal interference mode when the controller is receiving signals from a mobile station through at least two different remote units.

Claims

1. A method comprising:

providing a wireless distributed antenna system (WDAS) including a controller and a plurality of WDAS remote units, wherein the WDAS is configured for radio-frequency (RF) communications between the plurality of WDAS remote units and the controller;

the controller detecting that a first remote unit of the plurality of WDAS remote units is receiving less than a threshold level of input signal strength by comparing signal strengths of signals received from the first remote unit and at least one other remote unit; and

in response to the determination that the first remote unit is receiving less than the threshold level of input signal strength, the controller determining to switch the first remote unit to a reduced signal interference mode.

2. The method of claim 1, wherein the reduced signal interference mode comprises a reduced level of RF communication between the controller and the first remote unit.

3. The method of claim 1, further comprising in response to a determination that the first remote unit has completed a communication, the controller determining to switch the first remote unit to a normal mode.

4. The method of claim 3, wherein in response to a determination that the first remote unit has received an origination signal from a mobile station, the controller determining to switch the first remote unit to a normal mode.

5. The method of claim 1, wherein the WDAS is implemented within a building.

6. The method of claim 1, further comprising wirelessly transmitting a signal from the controller to the first remote unit, wherein the signal includes an indication to switch a radio-frequency (RF) reverse-link from the first remote unit to the controller to the reduced signal interference mode.

7. The method of claim 1, further comprising transmitting a message from the controller to the first remote unit, wherein the message is an indication to switch the first remote unit to the reduced signal interference mode.

8. The method of claim 1, wherein switching the first remote unit to a reduced interference mode comprises shutting off reverse-link back-end RF transmission from the first remote unit.

9. The method of claim 1, further comprising in response to detecting that the first remote unit is receiving less than the threshold level of input signal strength, shutting off RF communications between the controller and the first remote unit.

10. The method of claim 1, wherein the RF communications between the plurality of WDAS remote units and the controller operate using a communications mode selected from the group consisting of CDMA, TDMA, GSM, AMPS, 802.11, Bluetooth, and cordless phone transmission.

11. The method of claim 1, wherein detecting that the first remote unit is receiving less than the threshold level of input signal strength comprises detecting that the input signal strength at the first remote unit is functionally zero.

12. The method of claim 1, wherein the first remote unit is a wireless repeater and wherein the reduced interference mode of the first remote unit comprises shutting off a reverse link communication between the first remote unit and the controller.

13. The method of claim 1, further comprising:

selecting a second remote unit for communicating with a mobile station; and

after receiving an indication of a termination of a connection between the mobile station and the second remote unit, wirelessly transmitting a signal from the controller to the first remote unit indicating to switch the first remote unit to a normal mode.

14. The method of claim 1, further comprising the controller determining that there is no detectable mobile station in a coverage area of the first remote unit.

15. The method of claim 1, further comprising in response to a determination that the first remote unit is subsequently receiving more than the threshold level of input signal strength, the controller determining to switch the first remote unit to a normal mode.

16. A system comprising:

a plurality of WDAS remote units;

a wireless distributed antenna system controller (WDASC) configured for radio-frequency (RF) communications with the plurality of WDAS remote units, wherein the controller receives an indication that a mobile station is communicating through at least two remote units of the WDAS by receiving a radio-frequency (RF) message from each of the at least two remote units, wherein the controller selects a first remote unit from the at least two remote units by (i) comparing signal strengths received by the at least two remote units, and (ii) based on the comparison, selecting the first remote unit, wherein the signal strength received by the first remote unit is less than the signal strength received by at least one of the remote units, wherein the controller wirelessly transmits a signal to the first remote unit to provide an indication to switch a radio-frequency (RF) reverse-link from the first remote unit to the controller to a reduced signal interference mode.

17. The system of claim 16, wherein switching the RF reverse-link to a reduced signal interference mode comprises switching off the RF reverse-link.

18. The system of claim 16, wherein the controller selects a second remote unit for continuing communication with the mobile station, wherein the second remote unit is different from the first remote unit.

19. The system of claim 16, wherein the WDASC is configured to communicate with a plurality of remote units over a CDMA radio-frequency (RF) network.

20. The system of claim 16, wherein the WDAS remote units operate within a building.