ENABLING COEXISTENCE BETWEEN WIRELESS NETWORKS

• US 20120082070A1
• Filed: 06/14/2011
• Published: 04/05/2012
• Est. Priority Date: 10/01/2010
• Status: Active Grant

• Current Assignee: Clearwire Ip Holdings LLC (Deutsche Telekom AG)
• Original Assignee: Clear Wireless LLC (Deutsche Telekom AG)
• Inventors: XU, Yang, GELBMAN, Peter, SAVA, Herkole, HART, Michael
• Granted Patent: US 8,908,571 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0028 Formatting
• CPC Class Codes: H04L 1/0035 evaluation of received explicit signalling
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range

Abstract

Systems and methods for detecting and mitigating interference between from a first wireless time division duplex (TDD) communications device and a second wireless TDD communications device includes processing quality-indicator reports received from the first TDD device to determine if reception at the first TDD device has experienced interference from the second TDD device. Such interference at the first TDD device may indicate that the first TDD device may also cause interference to reception at the second TDD device. Accordingly, to mitigate the possible interference from the first TDD device, an uplink configuration of the first TDD base station may be adjusted. The adjustment of the uplink configuration may include configuring reception of data packets at the first TDD base station from the first TDD device in accordance with an interference-free time interval, an unprotected time interval, or a specific portion of an associated frequency band.

Claims

1. A method of detecting and mitigating interference between a first wireless time division duplex (TDD) communications device operational with a first TDD base station and a second TDD device operational with a second TDD base station, the method comprising:

processing, using a processor operatively associated with the first TDD base station, quality-indicator reports received from the first TDD device indicating a reception quality of one or more TDD data packets at the first TDD device, wherein the processing indicates whether the reception at the first TDD device has experienced interference from the second TDD device; and

responsive to a determination that the reception at the first TDD device has experienced interference from the second TDD device, adjusting, using the processor, an uplink configuration of the first TDD base station to mitigate interference caused by the first TDD device to the second TDD device.

2. The method of claim 1, wherein a determination of interference caused by the first TDD device to the second TDD device is based on the determination that the reception at the first TDD device has experienced interference from the second TDD device.

3. The method of claim 2, wherein a frame start timing associated with the first TDD base station is synchronized with a frame start timing associated with the second TDD base station.

4. The method of claim 3, wherein the frame start timings of the first TDD base station and the second TDD base station is based on a common time reference source, wherein the common time reference source comprises a Global Positioning System (GPS) or a device configured to operate in accordance with the IEEE 1588 standard.

5. The method of claim 3, wherein the first TDD base station and the second TDD base station are associated with different frame configurations.

6. The method of claim 1, further comprising, adjusting, using the processor, a downlink configuration of the first TDD base station to mitigate interference from the second TDD device, responsive to a determination that the reception at the first TDD device has experienced interference from the second TDD device.

7. The method of claim 1, further comprising determining an interference-free time interval based on a frame configuration associated with the first TDD base station and a frame configuration associated with the second TDD base station,

wherein said adjusting the uplink configuration of the first TDD base station is based on the interference-free time interval.

8. The method of claim 7, wherein said adjusting the uplink configuration of the first TDD base station comprises configuring an uplink operation of the first TDD base station such that the first TDD base station receives TDD data packets from the first TDD device during the interference-free time interval.

9. The method of claim 1, further comprising determining an unprotected time interval based on a frame configuration associated with the first TDD base station and a frame configuration associated with the second TDD base station,

wherein said adjusting the uplink configuration of the first TDD base station is based on the unprotected time interval.

10. The method of claim 9, wherein said adjusting the uplink configuration of the first TDD base station comprises configuring an uplink operation of the first TDD base station such that the first TDD base station does not receive TDD data packets from the first TDD device during the unprotected time interval.

11. The method of claim 1, wherein at least one of the first TDD base station or the second TDD base station comprises a WiMAX base station, and at least one of the first TDD device or the second TDD device comprises a WiMAX device.

12. The method of claim 1, wherein at least one of the first TDD base station or the second TDD base station comprises an LTE base station, and at least one of the first TDD device or the second TDD device comprises an LTE device.

13. The method of claim 1, further comprising periodically receiving the quality-indicator reports from the first TDD device, wherein a period of receiving the quality-indicator reports is selectable, and

wherein said processing the quality-indicator reports comprises determining an actual quality-indicator report pattern for a set of periodically-received quality-indicator reports, the actual quality-indicator report pattern indicating whether the reception at the first TDD device has experienced interference from the second TDD device.

14. The method of claim 13, further comprising:

determining, using the processor, an expected quality-indicator report pattern based on a frame configuration associated with the first TDD base station and a frame configuration associated with the second TDD base station; and

correlating, using the processor, the actual quality-indicator report pattern with the expected quality-indicator report pattern to determine whether the reception at the first TDD device has experienced interference from the second TDD device.

15. The method of claim 14, wherein said correlating comprises:

calculating a correlation value representing a correlation between the expected quality-indicator report pattern and the actual quality-indicator report pattern; and

comparing the calculated correlation value with a predetermined threshold value to determine whether the reception at the first TDD device has experienced interference from the second TDD device.

27. The method of claim 1, wherein a frequency band associated with at least one of the first TDD base station and the second TDD base station includes a first portion and a second portion, wherein the first portion of the frequency band includes one or more frequencies on which the reception at the first TDD device experiences interference from the second TDD device,

wherein said adjusting the uplink configuration of the first TDD base station comprises configuring an uplink operation of the first TDD base station such that the first TDD base station receives TDD data packets from the first TDD device using a frequency from the second portion of the frequency band.

28. The method of claim 27, wherein the quality-indicator reports include information to identify the first portion of the frequency band.

16. An apparatus capable of operating in a wireless network, and detecting and mitigating interference between a first time division duplex (TDD) communications device and a second TDD device, the apparatus comprising:

a transceiver configured to exchange TDD data packets with the first TDD device;

a memory device configured to store quality-indicator reports indicating a reception quality of one or more TDD data packets received at the first TDD device;

a channel-quality module configured to process the quality-indicator reports, wherein the processing of the quality-indicator reports indicate whether the first TDD device has experienced interference from the second TDD device; and

a configuration-adjustment module configured to adjust an uplink configuration of the transceiver to mitigate interference caused by the first TDD device to the second TDD device, responsive to a determination that the first TDD device has experienced interference from the second TDD device.

17. The apparatus of claim 16, wherein a determination of interference caused by the first TDD device to the second TDD device is based on the determination that the reception at the first TDD device has experienced interference from the second TDD device.

18. The apparatus of claim 17, wherein a frame start timing associated with the first TDD base station is synchronized with a frame start timing associated with the second TDD base station.

19. The apparatus of claim 18, wherein the frame start timings of the first TDD base station and the second TDD base station is based on a common time reference source, wherein the common time reference source comprises a Global Positioning System (GPS) or a device configured to operate in accordance with the IEEE 1588 standard.

20. The apparatus of claim 19, wherein the first TDD base station and the second TDD base station are associated with different frame configurations.

21. The apparatus of claim 16, wherein the configuration-adjustment module is further configured to adjust a downlink configuration of the first TDD base station to mitigate interference from the second TDD device, responsive to a determination that the reception at the first TDD device has experienced interference from the second TDD device.

22. The apparatus of claim 16, further comprising a clean-slot module to determine an interference-free time interval based on a frame configuration associated with the first TDD base station and a frame configuration associated with the second TDD base station,

wherein the configuration-adjustment module is configured to adjust the uplink configuration of the first TDD base station based on the interference-free time interval.

23. The apparatus of claim 22, wherein the configuration-adjustment module, to adjust the uplink configuration of the first TDD base station, is adapted to configure an uplink operation of the first TDD base station such that the first TDD base station receives TDD data packets from the first TDD device during the interference-free time interval.

24. The apparatus of claim 16, further comprising a clean-slot module to determine an unprotected time interval based on a frame configuration associated with the first TDD base station and a frame configuration associated with the second TDD base station,

wherein the configuration-adjustment module is configured to adjust the uplink configuration of the first TDD base station based on the unprotected time interval.

25. The apparatus of claim 24, wherein the configuration-adjustment module, to adjust the uplink configuration of the first TDD base station, is adapted to configure an uplink operation of the first TDD base station such that the first TDD base station does not receive TDD data packets from the first TDD device during the unprotected time interval.

26. A non-transitory computer-readable medium comprising computer-readable instructions physically embodied thereon which, when executed by a processor associated with in a base station capable of operating in wireless network, cause the processor to carry out the functions of detecting and mitigating interference between a first wireless time division duplex (TDD) communications device operational with a first TDD base station and a second TDD device operational with a second TDD base station, the functions comprising:

processing quality-indicator reports received from the first TDD device indicating a reception quality of one or more TDD data packets at the first TDD device, wherein the processing indicates whether the reception at the first TDD device has experienced interference from the second TDD device; and

responsive to a determination that the reception at the first TDD device has experienced interference from the second TDD device, adjusting, using the processor, an uplink configuration of the first TDD base station to mitigate interference caused by the first TDD device to the second TDD device.