LTF design for WLAN system

• US 20160119047A1
• Filed: 10/28/2015
• Published: 04/28/2016
• Est. Priority Date: 10/28/2014
• Status: Active Grant

• Current Assignee: Atlas Global Technologies LLC (Acacia Research Corporation)
• Original Assignee: Newracom Inc.
• Inventors: Lee, Daewon
• Granted Patent: US 9,893,784 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

In an example of wireless multi-user communication, a station may generate a frame and provide the frame for transmission to multiple stations. The frame may include a long training field (LTF) portion and a data portion. The LTF portion and the data portion may be associated with a plurality of tones. Each group of the plurality of tones in the data portion may be associated with a respective steering matrix. Each group of the plurality of tones in the data portion may include two or more tones of the plurality of tones. One or more of the multiple stations may receive the frame and process the frame. Other methods, apparatus, and computer-readable media are also disclosed.

Claims

1. A method for a transmitting apparatus to transmit a frame, the method comprising:

generating a frame, the frame comprising a long training field (LTF) portion and a data portion which are associated with a plurality of tones, wherein each group of the plurality of tones in the data portion is associated with a respective steering matrix, and each group of the plurality of tones in the data portion comprises two or more tones of the plurality of tones; and

providing the frame for transmission.

2. The method of claim 1, wherein a training sequence is allocated to every other tone of the plurality of tones in the LTF portion for a spatial stream.

3. The method of claim 1, wherein the LTF portion is a compressed LTF portion.

4. The method of claim 1, wherein the two or more tones of the plurality of tones in the data portion comprise consecutive tones.

5. The method of claim 1, wherein the two or more tones of the plurality of tones in the data portion comprise an integer multiple of two tones.

6. The method of claim 1, wherein each group of the plurality of tones in the data portion is associated with a respective cyclic shift value.

7. The method of claim 1, wherein the LTF portion comprises a first frequency region allocated for a first station and a second frequency region allocated for a second station.

8. The method of claim 7, wherein a number of space-time streams (STSs) associated with the first station is different from a number of STSs associated with the second station.

9. The method of claim 1, wherein an Orthogonal Frequency Division Multiplexing (OFDM) symbol of the LTF portion has a duration of 6.4 μ

s excluding any cyclic prefix (CP) duration.

10. The method of claim 1, wherein the frame further comprises an omni-directional portion.

11. The method of claim 10, wherein the omni-directional portion comprises legacy header fields, a repeated legacy signal (R-L-SIG) field, and one or more high efficiency signal (HE-SIG) fields.

12. The method of claim 1, wherein the frame comprises a beamformed portion, wherein the beamformed portion comprises a high efficiency short training field (HE-STF), an HE-LTF, and an HE data field, and wherein the HE-LTF is the LTF portion.

13. The method of claim 1, wherein tones in the LTF portion, except every other tone of the plurality of tones in the LTF portion, are null tones.

14. A method for a receiving apparatus to receive a frame, the method comprising:

receiving a frame, the frame comprising a long training field (LTF) portion and a data portion which are associated with a plurality of tones, wherein each group of the plurality of tones in the data portion is associated with a respective steering matrix, and each group of the plurality of tones in the data portion comprises two or more tones of the plurality of tones;

processing the LTF portion; and

processing the data portion.

15. The method of claim 14, wherein a training sequence is allocated to every other tone of the plurality of tones in the LTF portion for a spatial stream.

16. The method of claim 14, wherein the LTF portion is a compressed LTF portion.

17. The method of claim 14, wherein the two or more tones of the plurality of tones in the data portion comprise consecutive tones.

18. The method of claim 14, wherein the two or more tones of the plurality of tones in the data portion comprise an integer multiple of two tones.

19. The method of claim 14, wherein each group of the plurality of tones in the data portion is associated with a respective cyclic shift value.

20. The method of claim 14, wherein processing the LTF portion comprises estimating a channel based on the LTF portion, and processing the data portion comprises decoding data based on the estimated channel.