System and method for preambles in a wireless communications network

• US 9,071,489 B2
• Filed: 10/25/2012
• Issued: 06/30/2015
• Est. Priority Date: 12/07/2011
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Suh, Junghoon, Li, Yunbo, Au, Kwok Shum, Aboul-Magd, Osama, Sun, Sheng
• Primary Examiner(s): Mui, Gary
• Application Number:
  US13/660,934
• Publication Number:
  US 20130148644A1
• Time in Patent Office: 978 Days
• Field of Search: 370/328, 370/338, 370/474
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• 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: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method for transmitting a frame includes generating an omni portion of the frame, the omni portion including a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field, the non-beamformed long training field configured to be transmitted through one of multiple antennas and multiple streams. The method also includes generating a multi-stream portion of the frame, the multi-stream portion including a data field and a multi-stream long training field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field. The method further includes applying a beamforming indicator to the signal field of the omni portion, and transmitting the frame.

Claims

1. A method for transmitting a frame, the method comprises:

generating, by an access point, an omni portion of the frame, the omni portion including a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field, the non-beamformed long training field configured to be transmitted through one of multiple antennas and one of multiple streams;

generating, by the access point, a multi-stream portion of the frame, the multi-stream portion including a data field and a multi-stream long training field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field;

applying, by the access point, a beamforming indicator to the signal field of the omni portion, wherein applying the beamforming indicator comprises setting a status indicator in the signal field, wherein the status indicator is set to a first value when the multi-stream portion is beamformed, and wherein the status indicator is set to a second value when the multi-stream portion is not beamformed; and

transmitting, by the access point, the frame.

2. The method of claim 1, wherein the multi-stream portion is located after the omni portion.

3. The method of claim 1, wherein the status indicator is a one or more bit long indicator.

4. The method of claim 1, wherein applying the beamforming indicator comprises using signal intensity at different axes of a representation of a modulation symbol of a subset of the signal field to apply the beamforming indicator.

5. The method of claim 1, wherein applying the beamforming indicator comprises modulating a subset of the signal field.

6. The method of claim 5, wherein the subset of the signal field is modulated using a first modulation technique if the multi-stream portion is beamformed, and wherein the subset of the signal field is modulated using a second modulation technique if the multi-stream portion is not beamformed.

7. The method of claim 6, wherein the first modulation technique is binary phase shift keying, and wherein the second modulation technique is quadrature binary phase shift keying.

8. The method of claim 1, wherein the multi-stream portion is transmitted through multiple antennas and multiple streams.

9. The method of claim 1, wherein the frame is an IEEE 802.11ah frame.

10. A method for receiving a frame, the method comprising:

receiving, by a station, an omni portion of the frame, the omni portion includes a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field;

determining, by the station, a beamform status of a multi-stream portion of the frame;

receiving, by the station, the multi-stream portion of the frame, the multi-stream portion including a multi-stream long training field and a data field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field; and

decoding, by the station, the multi-stream portion of the frame using a technique commensurate with the beamform status of the multi-stream portion of the frame.

11. The method of claim 10, wherein determining the beamform status comprises examining a status indicator located in the signal field of the omni portion.

12. The method of claim 11, wherein the status indicator is set to a first value if the multi-stream portion is beamformed, and wherein the status indicator is set to a second value if the multi-stream portion is not beamformed.

13. The method of claim 10, wherein determining the beamform status comprises examining signal intensity of a subset of the signal field of the omni portion.

14. The method of claim 13, wherein examining the signal intensity comprises determining a modulation technique used for the subset of the signal field.

15. The method of claim 14, wherein the multi-stream portion is beamformed if the subset of the signal field is modulated using a first modulation technique, and wherein the multi-stream portion is non-beamformed if the subset of the signal field is modulated using a second modulation technique.

16. The method of claim 15, wherein the first modulation technique is binary phase shift keying, and wherein the second modulation technique is quadrature binary phase shift keying.

17. A transmitting device comprising:

a processor configured to;

generate an omni portion of a frame, the omni portion including a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field, the non-beamformed long training field to be transmitted through one of multiple antennas and one of multiple streams,

generate a multi-stream portion of the frame, the multi-stream portion including a data field and a multi-stream long training field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field, and

apply a beamforming indicator to the signal field of the omni portion, wherein the processor configured to apply the beamforming indicator comprises the processor configured to set a status indicator in the signal field, wherein the status indicator is set to a first value when the multi-stream portion is beamformed, and wherein the status indicator is set to a second value when the multi-stream portion is not beamformed; and

a transmitter operatively coupled to the processor, the transmitter configured to transmit the frame.

18. The transmitting device of claim 17, wherein the processor is configured to use signal intensity at different axes of a representation of a modulation symbol of a subset of the signal field to apply the beamforming indicator.

19. The transmitting device of claim 17, wherein the processor is configured to modulate a subset of the signal field.

20. The transmitting device of claim 19, wherein the subset of the signal field is modulated using a first modulation technique if the multi-stream portion is beamformed, and wherein the subset of the signal field is modulated using a second modulation technique if the multi-stream portion is not beamformed.

21. The transmitting device of claim 20, wherein the first modulation technique is binary phase shift keying, and wherein the second modulation technique is quadrature binary phase shift keying.

22. The transmitting device of claim 17, wherein the transmitting device is an IEEE 802.11ah access point.

23. The transmitting device of claim 17, wherein the multi-stream portion is located after the omni portion.

24. The transmitting device of claim 17, wherein the status indicator is a one or more bit long indicator.

25. The transmitting device of claim 17, wherein transmitter is configured to transmit the multi-stream portion through multiple antennas and multiple streams.

26. A receiving device comprising:

a receiver configured to receive an omni portion of a frame, the omni portion includes a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field, and to receive a multi-stream portion of the frame, the multi-stream portion including a multi-stream long training field and a data field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field; and

a processor operatively coupled to the receiver, the processor configured to determine a beamform status of the multi-stream portion of the frame, and to decode the multi-stream portion of the frame using a technique commensurate with the beamform status of the multi-stream portion of the frame.

27. The receiving device of claim 26, wherein the processor is configured to examine a status indicator located in the signal field of the omni portion.

28. The receiving device of claim 26, wherein the processor is configured to examine signal intensity of a subset of the signal field of the omni portion.

29. The receiving device of claim 28, wherein the processor is configured to determine a modulation technique used for the subset of the signal field.

30. The receiving device of claim 26, wherein the receiving device is an IEEE 802.11ah station.