Method of secure WLAN communication

• US 20070155353A1
• Filed: 12/29/2005
• Published: 07/05/2007
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: Celeno Communications (Israel) Ltd.
• Original Assignee: Celeno Communications (Israel) Ltd.
• Inventors: Shapira, Nir, Rozen, Gilad
• Granted Patent: US 7,656,965 B2
• Time in Patent Office: Days
• US Class Current: 455/273
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0246 with factorisation
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

Some demonstrative embodiments of the invention include a method device and/or system of secure communication in a wireless network using a spatial division multiple access transmission scheme. The method, according to some demonstrative embodiments may include generating a set of N spatial channels to be transmitted, using a set of N respective antennas, to a set of K destination stations, by applying at least one precoding matrix to a set of inputs including K transmissions intended to the K destination stations, respectively, and one or more dither sequences, wherein the precoding matrix includes K beamforming vectors based on channel state information of the K stations, respectively, and one or more additional vectors orthogonal to the beamforming vectors. Other embodiments are described and claimed.

Claims

1. A method of secure communication in a wireless network using a spatial division multiple access transmission scheme, the method comprising:

generating a set of N spatial channels to be transmitted, using a set of N respective antennas, to a set of K destination stations, by applying at least one precoding matrix to a set of inputs including K transmissions intended to said K destination stations, respectively, and one or more dither sequences,

wherein said precoding matrix includes K beamforming vectors based on channel state information of said K stations, respectively, and one or more additional vectors orthogonal to said beamforming vectors.

2. The method of claim 1, wherein said one or more dither sequences comprise N-K dither sequences, and wherein said one or more additional vectors comprise N-K additional vectors.

3. The method of claim 1 comprising determining one or more of said beamforming vectors based on one or more transmissions received from said K stations.

4. The method of claim 3, wherein determining one or more of said beamforming vectors comprises determining one or more of said beamforming vectors based a transmission selected from the group consisting of an acknowledge transmission and a clear-to-send transmission.

5. The method of claim 3 comprising:

transmitting K null-data frames to said K destination stations, respectively;

receiving K acknowledge frames from said K destination stations, respectively; and

determining said K beamforming vectors based on said K acknowledge frames, respectively.

6. The method of claim 1 comprising determining one or more of said beamforming vectors based on a maximum ratio combining algorithm.

7. The method of claim 1 comprising determining one or more of said additional vectors based on a householder transform algorithm.

8. The method of claim 1, wherein applying said at least one precoding matrix comprises applying a set of F preceding matrices corresponding to a set of F transmission frequencies.

9. The method of claim 1 comprising:

allocating transmission power to said N channels such that the power to be received by each of said K destination stations is not greater, by more than a predefined power margin, than a minimum power required for reception at a desired quality of service.

10. The method of claim 9 comprising:

determining a residual power corresponding to a difference between first and second values of a quality of service parameter, said first value resulting from allocating a predetermined transmission power to K channels of said N channels, and said second value corresponding to said desired quality of service; and

allocating to said K channels transmission power corresponding to a difference between said predetermined transmission power and said residual power.

11. An apparatus to securely communicate in a wireless network using a spatial division multiple access transmission scheme, the apparatus comprising:

a precoder to generate a set of N spatial channels to be transmitted, using a set of N respective antennas, to a set of K destination stations, by applying at least one precoding matrix to a set of inputs including K transmissions intended to said K destination stations, respectively, and one or more dither sequences,

wherein said preceding matrix includes K beamforming vectors based on channel state information of said k stations, respectively, and one or more additional vectors orthogonal to said beamforming vectors.

12. The apparatus of claim 11, wherein said one or more dither sequences comprise N-K dither sequences, and wherein said one or more additional vectors comprise N-K additional vectors.

13. The apparatus of claim 11 comprising a vector calculator to determine one or more of said beamforming vectors based on one or more transmissions received from said K stations.

14. The apparatus of claim 13, wherein the one or more transmissions received from said K stations comprise a transmission selected from the group consisting of an acknowledge transmission and a clear-to-send transmission.

15. The apparatus of claim 13, wherein said vector calculator is able to determine one or more of said beamforming vectors based on a maximum ratio combining algorithm.

16. The apparatus of claim 13, wherein said vector calculator is able to determine one or more of said additional vectors based on a householder transform algorithm.

17. The apparatus of claim 11, wherein said at least one precoding matrix comprises a set of F preceding matrices corresponding to a set of F transmission frequencies.

18. The apparatus of claim 11 comprising:

a power allocator to allocate transmission power to said N channels such that the power to be received by each of said K destination stations is not greater, by more than a predefined power margin, than a minimum power required for reception at a desired quality of service.

19. The apparatus of claim 18, wherein said power allocator is able to:

determine a residual power corresponding to a difference between first and second values of a quality of service parameter, said first value resulting from allocating a predetermined transmission power to K channels of said N channels, and said second value corresponding to said desired quality of service; and

allocate to said K channels transmission power corresponding to a difference between said predetermined transmission power and said residual power.

21. The system of claim 18, wherein said one or more dither sequences comprise N-K dither sequences, and wherein said one or more additional vectors comprise N-K additional vectors.

22. The system of claim 18, wherein said access point is able to determine one or more of said beamforming vectors based on one or more transmissions received from said K stations.

24. The system of claim 18, wherein said access point is able to determine one or more of said beamforming vectors based on a maximum ratio combining algorithm.

25. The system of claim 18, wherein said access point is able to determine one or more of said additional vectors based on a householder transform algorithm.

26. The system of claim 18, wherein said at least one preceding matrix comprises a set of F precoding matrices corresponding to a set of F transmission frequencies.

27. The system of claim 18, wherein said access point is able to allocate transmission power to said N channels such that the power to be received by each of said K destination stations is not greater, by more than a predefined power margin, than a minimum power required for reception at a desired quality of service.

28. The system of claim 27, wherein said access point is able to:

determine a residual power corresponding to a difference between first and second values of a quality of service parameter, said first value resulting from allocating a predetermined transmission power to K channels of said N channels, and said second value corresponding to said desired quality of service; and

allocate to said K channels transmission power corresponding to a difference between said predetermined transmission power and said residual power.

20. A system of secure communication in a wireless network using a spatial division multiple access transmission scheme, the system comprising:

a plurality of stations;

an access point to generate a set of N spatial channels to be transmitted, using a set of N respective antennas, to a set of K destination stations of said plurality of stations, by applying at least one precoding matrix to a set of inputs including K transmissions intended to said K destination stations, respectively, and one or more dither sequences,

wherein said preceding matrix includes K beamforming vectors based on channel state information of said K stations, respectively, and one or more additional vectors orthogonal to said beamforming vectors.

23. The system of claim 20, wherein the one or more transmissions received from said K stations comprise a transmission selected from the group consisting of an acknowledge transmission and a clear-to-send transmission.