Adaptive CCA and TX power level adjustment for dense deployment of wireless networks

• US 9,820,162 B2
• Filed: 02/09/2016
• Issued: 11/14/2017
• Est. Priority Date: 01/24/2014
• Status: Active Grant

• Current Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Original Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Inventors: Wang, James June-Ming, Liu, Jianhan, Hsu, YungPing, Yu, Ching-Hwa
• Primary Examiner(s): Kincaid, Lester
• Assistant Examiner(s): WANG, WILLIAM Y
• Application Number:
  US15/019,849
• Publication Number:
  US 20160174079A1
• Time in Patent Office: 644 Days
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

A method of spatial re-use with TPC and adaptive CCA is proposed. A spatial re-use station detects spatial re-use information associated with other peer OBSS stations. The spatial re-use information comprises a TX spectral density (power/Hz) and received signal or interference information of each inter-BSS peer station. The spatial re-use STA determines a TX spectral density based on the detected spatial re-use information. The spatial re-use STA then contends the medium for spatial re-use transmission opportunity (TXOP) with an intra-BSS peer station. Finally, the spatial re-use STA starts spatial re-use frame exchange with the intra-BSS peer station using the determined TX spectral density. By adjusting the TX spectral density, the spatial re-use STA adapts its CCA level to spatially reuse the medium without causing collision and interference to OBSS stations and thus increases network throughput.

Claims

1. A method performed by an initiating wireless station, the method comprising:

detecting spatial re-use information associated with one or more detected overlapping basic service set (OBSS) stations engaging an ongoing frame exchange;

determining a transmit (TX) power or power density level and an adjusted clear channel assessment (CCA) level based on the detected spatial re-use information; and

attempting to initiate a spatial re-use frame exchange with a responding wireless station in concurrent with the ongoing frame exchange of the detected OBSS stations.

2. The method of claim 1, wherein the adjusted CCA level is raised to be equal to or above a detected power from each of the one or more detected OBSS stations.

3. The method of claim 1, wherein the detected spatial re-use information comprises a transmit power or power density level signaled by each of the one or more detected OBSS stations for determining a corresponding space loss.

4. The method of claim 1, wherein the detected spatial re-use information comprises a received interference power or power spectral density level signaled by the one or more detected OBSS stations.

5. The method of claim 4, wherein the determined TX power or power density level results a spatial re-use signal arriving at the one or more OBSS stations is below the signaled interference power or power spectral density level of the OBSS stations by a predefined margin.

6. The method of claim 1, wherein the detected spatial re-use information comprises an adjusted clear channel assessment (CCA) level signaled by the one or more detected OBSS stations.

7. The method of claim 6, wherein the determined TX power or power density level results a spatial re-use signal arriving at the one or more OBSS stations is below the signaled adjusted CCA level of the OBSS stations by a predefined margin.

8. The method of claim 1, wherein the detected spatial re-use information comprises a peer received signal strength indicator (RSSI) signaled by the one or more detected OBSS stations.

9. The method of claim 8, wherein the determined TX power or power density level results a spatial re-use signal arriving at the one or more OBSS stations is below the signaled peer received RSSI of the OBSS stations by a predefined margin.

10. The method of claim 1, wherein the detected spatial re-use information comprises a signal bandwidth signaled by the one or more detected OBSS stations, and wherein the detected spatial re-use information is scaled by the signal bandwidth.

11. The method of claim 1, further comprising:

signaling spatial re-use information of the initiating wireless station, the information comprising at least one of a transmit power level, a transmit power density level, a signal bandwidth, a BSS color, a TX/RX ID, a received peer RSSI, a received interference power level, a received interference power spectral density level, an adjusted CCA level, and an excess margin.

12. The method of claim 1, wherein the detected spatial re-use information comprises an excess margin signaled by the one or more detected OBSS stations, and wherein the excess margin is defined as a difference between a link signal to noise ratio (SNR) and a required SNR for the highest modulation and coding scheme (MCS).

13. The method of claim 1, wherein the OBSS stations are legacy stations, and wherein the spatial re-use information is detected based on the received signal power or power spectral density level, a reference transmit power level and an estimated co-channel interference of the legacy stations.

14. The method of claim 1, wherein the OBSS stations applies OFDMA for uplink transmission, and wherein the determined TX power level or power density level is based on an aggregated received interference power level or power spectral density level of the OBSS stations.

15. The method of claim 1, wherein the OBSS stations applies OFDMA for uplink transmission, and wherein the determined TX power level or power density level is based on a maximum received power level or power density level from the OBSS stations.

16. The method of claim 1, wherein the determined TX power decreases by an amount from a reference transmit power level, wherein the adjusted CCA level increases by the same amount, and wherein the adjusted CCA level is between a lower limit and an upper limit.

17. A method performed by a responding wireless station, the method comprising:

detecting spatial re-use information associated with one or more detected overlapping basic service set (OBSS) stations engaging an ongoing frame exchange;

determining a transmit power or power density level based on the detected spatial re-use information; and

engaging in a spatial re-use frame exchange with an initiating wireless station in concurrent with the ongoing frame exchange of the detected OBSS stations.

18. The method of claim 17, wherein the detected spatial re-use information comprising at least one of a transmit power level, a transmit power density level, a signal bandwidth, a BSS color, a TX/RX ID, a received peer RSSI, a received interference power level, a received interference power spectral density level, an adjusted clear channel assessment (CCA) level, and an excess margin.

19. The method of claim 17, wherein the determined TX power or power density level results a spatial re-use signal arriving at the one or more OBSS stations is below the detected interference power or power spectral density level, the detected adjusted CCA level, or the detected peer received RSSI by a predefined margin.

20. The method of claim 17, wherein the responding wireless station sends a response to inhibit the spatial re-use attempt.

21. The method of claim 17, wherein the response comprises a spatial re-use flag in a header of the response.

22. A method performed by an initiating wireless station, comprising:

(a) detecting spatial re-use information associated with overlapping basic service set (OBSS) stations, wherein the spatial re-use information comprises a transmit power level and received signal or interference information of each OBSS station;

(b) determining a transmit power level or power density level and an adjusted clear channel assessment (CCA) level based on the detected spatial re-use information;

(c) contending for a spatial re-use transmission opportunity (TXOP) with a spatial re-use responding station; and

(d) starting spatial re-use frame exchange with the spatial re-use responding station using the transmit power level or power density level determined in (b).

23. The method of claim 22, further comprising:

observing a wireless medium for spatial re-use during a moving window before the detecting in (a), wherein the station updates a database storing the spatial re-use information.

24. The method of claim 22, wherein the spatial re-use information further comprises a BSS color that indicates a BSS ID of the OBSS.

25. The method of claim 22, wherein the spatial re-use information further comprises a remaining TXOP duration, and wherein the spatial re-use TXOP is set to be less than or equal to the remaining TXOP.

26. The method of claim 22, wherein the contending in (c) involves an independent backoff procedure for the spatial re-use TXOP.

27. The method of claim 22, wherein the initiating wireless station sets a spatial re-use inhibit flag in a frame header to inhibit spatial re-use attempts.