SPATIAL DIVISION MULTIPLE ACCESS WIRELESS COMMUNICATION SYSTEM

• US 20100103893A1
• Filed: 08/11/2009
• Published: 04/29/2010
• Est. Priority Date: 10/29/2008
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Xia, Pengfei, Ngo, Chiu, Yong, Su-Khiong
• Application Number:
  US12/539,515
• Publication Number:
  US 20100103893A1
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

A method and system for wireless communication in a network of wireless devices, is disclosed. The network includes multiple stations (STAs) and an access point (AP). Each wireless device includes plural antennas. In one embodiment, multiple stations accessing the access point at the same time using a spatial division multiple access (SDMA) protocol. The SDMA protocol involves performing an iterative antenna training process for obtaining principle singular vectors for beamforming communication over a wireless channel without explicit knowledge of the channel.

Claims

1. A communication method in a network of wireless devices including multiple stations (STAs) and an access point (AP), each wireless device including plural antennas, the method comprising:

multiple stations accessing the access point at the same time using a spatial division multiple access (SDMA) protocol; and

the SDMA protocol including performing an iterative antenna training process for obtaining principle singular vectors for beamforming communication over a wireless channel without explicit knowledge of the channel.

2. The method of claim 1 wherein:

the wireless network comprises a 60 GHz Millimeter Wave wireless network; and

the iterative antenna training process comprises acquiring antenna beamforming vectors for the stations accessing the access point using iterative beamforming.

3. The method of claim 2 wherein the iterative antenna training process further comprises:

performing power iterations to estimate the beamforming vectors for the stations and the access point.

4. The method of claim 3 wherein the iterative antenna training process further comprises:

performing similar power iteration processes in estimating the beamforming vectors for the stations and the access point.

5. The method of claim 4 wherein the iterative antenna training process further comprises:

the stations transmitting training sequences to the access point at the same time using orthogonal spreading sequences for each station to reduce interference, by repeating destination beamforming vector training and source beamforming vector training multiple times, such that in each iteration step;

a normalized beamforming vector t is used for transmission to train a destination beamforming vector, and a normalized beamforming vector outcome r is used for transmission to train a source beamforming vector, and a normalized beamforming vector outcome t is used in the next iteration for transmission to train destination beamforming vector.

6. The method of claim 5 wherein the iterative antenna training process further comprises repeating STA-side antenna training and AP-side antenna training steps multiple times, such that:

normalized interim transmit beamforming vectors v, w obtained in each iteration for the first and second stations, respectively, are used in AP-side antenna training step in a next step; and

normalized interim receive beamforming vectors u₁, u₂ obtained in each iteration step for the first and second stations, respectively, are used in STA-side antenna training in a next iteration step.

7. The method of claim 6 wherein each iteration step includes:

transmitting a vector t in a given time slot includes sending a predetermined pseudo random sequence spatially spread by vector t, and transmitting a vector r in a given time slot includes sending a predetermined pseudo random sequence spatially spread by vector r.

8. The method of claim 7 wherein:

a first transmitting station includes an N-element antenna array, and a second transmitting station includes an M-element antenna array, and an AP includes a K-element antenna array;

a training step includes station side training by;

repeatedly transmitting from a first radio frequency (RF) chain of an AP the same initial receive beamforming vector u₁ for a first station for N consecutive channel time slots, while each time slot is spread by a pseudo random spreading sequence p₁;

repeatedly transmitting from a second RF chain of an AP the same initial receive beamforming vector u₂ for a second station for M consecutive channel time slots, while each time slot is spread by a pseudo random spreading sequence p₂, wherein p₂ is essentially orthogonal to p₁;

the first station using I_N as a receive beamforming vector over N time slots, while performing de-spreading using p₁;

the second station using I_M as a receive beamforming vector over M channel time slots, while performing de-spreading using p₂; and

collecting the received samples, and estimating transmit beamforming vectors v, w for first and second stations, respectively.

9. The method of claim 8 wherein:

v=H′

₁(u₁⊕

u₂)+noise,

w=H′

₂(u₁⊕

u₂)+noise.

10. The method of claim 7 wherein a training step includes AP-side training by:

repeatedly transmitting the same normalized vector v over K channel time slots from the first station while each time slot is spread by a pseudo random sequence q₁;

repeatedly transmitting the same normalized vector w over K channel time slots from the second station while each time slot is spread by a pseudo random sequence q₂, that is essentially orthogonal to q₁;

in a first RF chain of the AP using I_K as the receive beamforming vector over K time slots while de-spreading using q₁;

in a second RF chain of the AP using J_K as the receive beamforming vector over K time slots while de-spreading using q₂, wherein J_K is selected as an orthogonal matrix such that each column of J_K is orthogonal to the corresponding column of I_K;

collecting and rearranging samples for estimating vectors u₁, u₂; and

using the normalized beamforming vectors u₁, u₂ in the next iteration of station-side antenna training

11. The method of claim 10 wherein:

u₁=H₁v+interference+noise,

u₂=H₂w+interference+noise.

12. A wireless communication system, comprising:

a wireless network of plural wireless devices including plural stations (STAs) and an access point (AP), each wireless device including plural antennas; and

the multiple stations accessing the access point at the same time using a spatial division multiple access (SDMA) protocol, the SDMA protocol including performing an iterative antenna training process involving the stations and the access point, for obtaining principle singular vectors for beamforming communication over a wireless channel without explicit knowledge of the channel.

13. The system of claim 12 wherein:

the wireless network comprises a 60 GHz Millimeter Wave wireless network; and

the stations and the access point are configured for iterative antenna training by acquiring antenna beamforming vectors for the stations accessing the access point using beamforming.

14. The system of claim 13 wherein the stations and the access point are configured for iterative antenna training using power iterations to estimate the beamforming vectors for the stations and the access point.

15. The system of claim 14 wherein the stations and the access point are configured for performing similar power iteration processes in estimating the beamforming vectors for the stations and the access point.

16. The system of claim 15 wherein the stations and the access point are configured for iterative antenna training such that:

the stations transmit training sequences to the access point at the same time using orthogonal spreading sequences for each station to reduce interference, by repeating destination beamforming vector training and source beamforming vector training multiple times, such that in each iteration step;

a normalized beamforming vector t is used for transmission to train a destination beamforming vector, and a normalized beamforming vector outcome r is used in a next step for transmission source beamforming vector training, and a normalized beamforming vector outcome t is used in the next iteration for transmission destination beamforming vector training.

17. The system of claim 15 wherein the stations and the access point are configured for iterative antenna training, comprising repeating STA-side antenna training and AP-side antenna training multiple times, such that:

normalized interim transmit beamforming vectors v, w obtained in each iteration for the first and second stations, respectively, are used in AP-side antenna training in a next step; and

normalized interim receive beamforming vectors u₁, u₂ obtained in each iteration for the first and second stations, respectively, are used in STA-side antenna training in a next iteration.

18. The system of claim 17 wherein in each iteration, transmitting a vector t in a given time slot includes sending a predetermined pseudo random sequence spatially spread by vector t, and transmitting a vector r in a given time slot includes sending a predetermined pseudo random sequence spatially spread by vector r.

19. A wireless station (STA), comprising:

a radio frequency (RF) chain and plural antennas, configured for access to an access point (AP) in a wireless network at the same time as another wireless device, using a spatial division multiple access (SDMA) protocol; and

antenna training logic configured for performing an iterative antenna training process for obtaining principle singular vectors for beamforming communication over a wireless channel without explicit knowledge of the channel.

20. The wireless station of claim 19 wherein the wireless network comprises a 60 GHz Millimeter Wave wireless network, and the antenna training logic is configured for iterative antenna training by estimating antenna beamforming vectors for accessing the access point using beamforming.

21. The wireless station of claim 20 wherein the antenna training logic is configured for power iterations by repeating STA-side antenna training in cooperation with an AP-side antenna training, such that:

a normalized interim transmit beamforming vector obtained in each iteration for the wireless station is used in AP-side antenna training in a next iteration; and

a normalized interim receive beamforming vector obtained in each iteration for the wireless station is used in STA-side antenna training

22. A wireless access point (AP), comprising:

multiple radio frequency (RF) chains and multiple antennas, configured for access by multiple wireless stations (STAs) at the same time in a wireless network, using a spatial division multiple access (SDMA) protocol; and

antenna training logic configured for performing an iterative antenna training process for obtaining principle singular vectors for beamforming communication over a wireless channel without explicit knowledge of the channel.

23. The wireless access point of claim 22 wherein the wireless network comprises a 60 GHz Millimeter Wave wireless network, and the antenna training logic is configured for iterative antenna training by estimating antenna beamforming vectors using transceiver beamforming power iterations by repeating AP-side antenna training in cooperation with an STA-side antenna training, such that:

a normalized interim transmit beamforming vector obtained in each iteration for each wireless station is used in AP-side antenna training in a next iteration; and

a normalized interim receive beamforming vector obtained in each iteration for each wireless station is used in STA-side antenna training

24. The wireless access point of claim 23, wherein the STAs transmit training sequences to the AP at the same time using orthogonal spreading sequences for each STA to reduce interference, by repeating destination beamforming vector training and source beamforming vector training multiple times, such that in each iteration step:

a normalized beamforming vector outcome r is used in a next step for transmission source beamforming vector training, and a normalized beamforming vector outcome t is used in the next iteration for transmission destination beamforming vector training

25. The wireless access point of claim 24 wherein the antenna training logic is configured such that each iteration comprises transmitting a vector t in a given time slot by sending a predetermined pseudo random sequence spatially spread by vector t, and transmitting a vector r in a given time slot by sending a predetermined pseudo random sequence spatially spread by vector r.