MULTI-USER MIMO RELAY PROTOCOL WITH SELF-INTERFERENCE CANCELLATION

• US 20090221231A1
• Filed: 02/29/2008
• Published: 09/03/2009
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Lingna Holdings Pte LLC (Intellectual Ventures LLC)
• Original Assignee: Hong Kong University of Science and Technology
• Inventors: Weng, Lingfan, Murch, Ross David
• Granted Patent: US 8,457,549 B2
• Time in Patent Office: Days
• US Class Current: 455/15
• CPC Class Codes: H04B 7/15585 by interference cancellation
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Systems and methodologies for employing a multi-user Multiple Input Multiple Output (MIMO) relay protocol with self-interference cancellation in a wireless communication environment are provided herein. Data streams sent between user device(s) and base station(s) can traverse through a relay. Further, a decode and forward protocol can be employed by the relay rather than merely amplifying and forwarding the data streams. Moreover, each user device can listen to and decode data stream(s) sent by other user device(s) to the relay, and these decoded data stream(s) can be utilized for interference cancellation. Further, the user device(s) and the base station(s) can employ self-interference cancellation upon signals received from the relay. According to another example, an adaptive relay power allocation algorithm, which enhances power efficiency, can be leveraged by the relay for transmitting signals to the user device(s) and the base station(s).

Claims

1. A system that employs a multi-user Multiple Input Multiple Output (MIMO) relay protocol with self-interference cancellation in a wireless communication environment, comprising:

a relay that receives data streams via a first channel and a second channel, decodes the received data streams, superimposes the decoded data streams to yield a signal, and transmits the signal simultaneously over the first channel and the second channel;

a base station that transmits a first data stream and a second data stream to the relay and receives the signal from the relay via the first channel, the first data stream and the second data stream being respectively directed to a first user device and a second user device;

the first user device transmits a third data stream to the relay and receives the signal from the relay via the second channel, the third data stream being directed to the base station; and

the second user device transmits a fourth data stream to the relay and receives the signal from the relay via the second channel, the fourth data stream being directed to the base station.

2. The system of claim 1, the base station further comprises an interference cancellation component that utilizes knowledge of the first data stream and the second data stream and knowledge of channel state information of the first channel and the second channel to cancel interference introduced by the first data stream and the second data stream from the received signal.

3. The system of claim 1, the first user device and the second user device each further comprise a respective channel monitoring component that listens to and decodes data stream transmissions of the other user device.

4. The system of claim 3, the first user device and the second user device each further comprise a respective interference monitoring component that cancels interference from the received signal based upon knowledge of the data stream transmitted by the respective user device and the data stream transmissions decoded by the respective channel monitoring component of the respective user device.

5. The system of claim 4, wherein the channel monitoring component of the first user device listens to and decodes the fourth data stream transmitted by the second user device and the interference monitoring component of the first user device cancels interference from the received signal based upon knowledge of the third data stream and the decoded fourth data stream and knowledge of channel state information of the first channel and the second channel.

6. The system of claim 5, wherein the channel monitoring component of the second user device listens to and decodes the third data stream transmitted by the first user device and the interference monitoring component of the second user device cancels interference from the received signal based upon knowledge of the fourth data stream and the decoded third data stream and knowledge of the channel state information of the first channel and the second channel.

7. The system of claim 1, wherein the relay receives the first data stream from the base station and the third data stream from the first user device during a first time slot of a Time Division Duplex (TDD) frame, and the relay receives the second data stream from the base station and the fourth data stream from the second user device during a second time slot of the TDD frame.

8. The system of claim 7, wherein the relay transmits the signal simultaneously to the base station, the first user device, and the second user device during a third time slot of the TDD frame.

9. The system of claim 7, wherein the relay decodes the first data stream and the third data stream during the first time slot utilizing successive interference cancellation and decodes the second data stream and the fourth data stream during the second time slot utilizing successive interference cancellation.

10. The system of claim 7, wherein the relay simultaneously receives the first data stream and the third data stream, and simultaneously receives the second data stream and the fourth data stream.

11. The system of claim 1, wherein the relay transmits the signal over the first channel at a first power level and the second channel at a second power level, the first power level and the second power level being fixed.

12. The system of claim 1, the relay further comprises an adaptive power control component that adaptive allocates power to the first channel and the second channel for transmission of the signal.

13. The system of claim 1, the base station, the first user device, and the second user device each further comprise a respective data stream generation component that yields a data stream for transfer to the relay.

14. A method for operating a relay employing a multi-user MIMO relay protocol with self-interference cancellation, comprising:

decoding a first data stream from a base station and a second data stream from a first user device received simultaneously during a first time slot of a Time Division Duplex (TDD) frame;

decoding a third data stream from the base station and a fourth data stream from a second user device received simultaneously during a second time slot of the TDD frame;

superimposing the first data stream, the second data stream, the third data stream, and the fourth data stream into a common signal; and

transmitting the common signal over a relay to user devices channel and a relay to base station channel during a third time slot of the TDD frame.

15. The method of claim 14, further comprising:

employing successive interference cancellation to decode the first data stream and the second data stream received simultaneously during the first time slot; and

employing successive interference cancellation to decode the third data stream and the fourth data stream received simultaneously during the second time slot.

16. The method of claim 14, wherein the first data stream is directed to the first user device, the second data stream is directed to the base station, the third data stream is directed to the second user device, and the fourth data stream is directed to the base station.

17. The method of claim 14, further comprising adaptively allocating relay power to the relay to user devices channel and the relay to base station channel for transmission of the common signal.

18. The method of claim 14, further comprising transmitting the common signal utilizing fixed power levels for the relay to user devices channel and the relay to base station channel.

19. A system that enables operating a user device in a wireless communication environment, comprising:

means for transmitting a first data stream to a relay during a first time slot of a Time Division Duplex (TDD) frame, the first data stream being intended for a base station;

means for decoding information associated with a second data stream transmitted by a disparate user device to the relay during a second time slot of the TDD frame;

means for receiving a signal from the relay during a third time slot of the TDD frame; and

means for cancelling interference from the received signal utilizing the first data stream and the decoded information associated with the second data stream.

20. The system of claim 19, wherein the relay decodes and forwards the first data stream and the second data stream to the base station as part of the signal sent during the third time slot of the TDD frame.

21. The system of claim 19, further comprising:

means for generating the first data stream;

means for retaining information associated with the first data stream in memory; and

means for retrieving the information associated with the first data stream for interference cancellation.