WLAN DESIGNS FOR SUPPORTING AN OUTDOOR PROPAGATION CHANNEL

• US 20180278308A1
• Filed: 10/22/2015
• Published: 09/27/2018
• Est. Priority Date: 10/24/2014
• Status: Active Application

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Jin, Yuan Sheng, Xi, Fengjun, Xia, Pengfei, Shah, Nirav B., Lou, Hanqing, Olesen, Robert L., Oteri, Oghenekome
• Application Number:
  US15/521,475
• Publication Number:
  US 20180278308A1
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04L 25/0202 Channel estimation
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Systems, methods and instrumentalities are disclosed to enable time domain null-forming. An access point (AP) may be configured to send a channel training request to a station (STA). The AP may be configured to receive a channel training packet in response to the channel training request. The channel training packet may include a legacy long training field (LTF). The AP may estimate the channel. The channel estimation may be computed using the legacy LTF. The AP may compute a null-forming vector using the channel estimation. The AP may use the null-forming vector to precode the entire packet.

Claims

1. An access point for communicating with multiple stations, comprising:

a memory comprising three guard intervals;

a processor comprising executable instructions that cause the access point to;

request information from the multiple stations that is associated with a guard interval, for each station, that comprises one of the three guard intervals;

process received information from the multiple stations that indicates a requested guard interval, for each station, that comprises one of the three guard intervals; and

select, for a multi-user transmission, one of the three guard intervals for communicating with the multiple stations based on the received information.

2. The access point of claim 1, wherein the processor further comprises executable instructions that causes the access point to select, for a single-user communication, one of the three guard intervals for communicating with one of the multiple stations in a single-user communication based on received information from the multiple stations.

3. The access point of claim 1, wherein selecting one of the three guard interval comprises selecting the longest guard interval indicated by the received information.

4. The access point of claim 1, wherein the received information comprises a data field used by each of the multiple stations to indicate the requested guard interval.

5. The access point of claim 1, wherein the request comprises a schedule for each of the multiple stations to provide the received information and the received information is received according to the schedule.

6. The access point of claim 1, wherein the three guard intervals comprise a first, a second, and a third guard interval and the first guard interval is shorter than the second and the third guard intervals, and the second guard interval is shorter than the third guard interval.

7. The access point of claim 1, wherein the executable instructions for requesting information comprise requesting a time domain channel estimate of a frame received by each of the multiple stations.

8. The access point of claim 1, wherein the requested information uses a cyclic prefix discovery frame.

9. (canceled)

10. (canceled)

11. (canceled)

12. (canceled)

13. (canceled)

14. A method for an access point communicating with multiple stations, comprising the access point:

requesting information from the multiple stations that is associated with one of three guard intervals for each station;

processing received information from the multiple stations that indicates a requested guard interval, for each station, that comprises one of the three guard intervals;

selecting for a multi-user transmission, one of the three guard intervals for communicating with the multiple stations based on the received information.

15. The method of claim 14, further comprising selecting, for a single-user communication, one of the three guard intervals for communicating with one of the multiple stations based on received information from the multiple stations.

16. The method of claim 14, wherein selecting one of the three guard interval comprises selecting the longest guard interval indicated by the received information.

17. The method of claim 14, wherein the received information comprises a data field used by each of the multiple stations to indicate the requested guard interval.

18. The method of claim 14, wherein requesting comprises a schedule for each of the multiple stations to provide the received information and the received information is received according to the schedule.

19. (canceled)

20. (canceled)

21. An access point for communicating with one or more stations, comprising:

a memory comprising three guard intervals;

a processor comprising executable instructions that cause the access point to;

select one of the three guard intervals to use for transmissions between the access point and the one or more stations; and

transmit a message to the one or more stations with an indication of the selected guard interval in a message.

22. The access point of claim 21, wherein the processor executable instructions further comprise a request for information from each of the one or more stations that indicates the guard interval for each of the one or more stations to use for downlink transmissions.

23. The access point of claim 21, wherein the three guard intervals to use for transmissions are for downlink transmissions to the one or more stations.

24. The access point of claim 23, wherein the downlink transmission are multi user transmissions.

25. The access point of claim 21, wherein the three guard intervals to use for transmissions are for single user uplink transmissions.