System and Method for Smart Relay Operation in a Wireless Communications System

• US 20100232345A1
• Filed: 03/10/2010
• Published: 09/16/2010
• Est. Priority Date: 03/12/2009
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wu, Tao, Oteri, Oghenekome, Tsai, Shiau-He, Tang, Yang, Sartori, Philippe
• Granted Patent: US 9,112,575 B2
• Time in Patent Office: Days
• US Class Current: 370/315
• CPC Class Codes: H04B 7/15528 Control of operation parameters of a relay station to exploit the physical medium

Abstract

A system and method for smart relay operation in a wireless communications system is provided. A method for smart relay operations includes receiving, at a smart relay, a transmission from a communications device, the transmission destined for a controller, decoding the transmission, computing a response based on the decoding, and transmitting the response to the controller.

Claims

1. A method for smart relay operations, the method comprising:

receiving, at a smart relay, a transmission from a communications device, the transmission destined for a controller;

decoding the transmission;

computing a response based on the decoding; and

transmitting the response to the controller.

2. The method of claim 1, wherein computing a response comprises:

setting the response to an acknowledgement message if the decoding of the transmission was successful; and

setting the response to a negative acknowledgement message if the decoding of the transmission was not successful.

3. The method of claim 1, wherein the controller also receives the transmission and decodes the transmission, and wherein the transmitting the response occurs before the controller computes its response based on its decoding of the transmission.

4. The method of claim 1, further comprising receiving an indication from the controller, wherein the indication comprises a request to retransmit the transmission to the controller.

5. The method of claim 4, further comprising multiplexing an amplified-and-forwarded transmission from the communications device with a retransmission of the transmission to the controller.

6. The method of claim 5, wherein the multiplexing comprises spatial multiplexing.

7. A method for smart relay operations, the method comprising:

receiving, at a smart relay, a transmission from a controller, the transmission intended for a communications device;

decoding the transmission;

computing a first response based on the decoding;

transmitting the first response to the controller;

receiving a second response transmitted from the communications device to the controller; and

decoding the second response.

8. The method of claim 7, further comprising relaying the transmission to the communications device.

9. The method of claim 7, wherein computing a first response comprises:

setting the first response to an acknowledgement message if the decoding of the transmission was successful; and

setting the first response to a negative acknowledgement message if the decoding of the transmission was not successful.

10. The method of claim 7, further comprising:

receiving a first indication from the controller, wherein the first indication instructs the smart relay to retransmit the transmission to the communications device; and

retransmitting the transmission to the communications device.

11. The method of claim 10, wherein the retransmitting comprises multiplexing an amplified-and-forwarded transmission to the communications device with the retransmitting of the transmission.

12. The method of claim 7, further comprising clearing the transmission from its buffers if the second response indicates that the communications device successfully decoded the transmission.

13. The method of claim 7, further comprising retransmitting the transmission to the communications device if the second response indicates that the communications device unsuccessfully decoded the transmission.

14. The method of claim 7, further comprising:

receiving a second indication from the controller, wherein the second indication indicates that the communications device successfully decoded the transmission; and

clearing the transmission from its buffers.

15. A method for smart relay operations, the method comprising:

determining information related to a channel between a communications device and a controller;

determining a precoder based on the information;

receiving, at a smart relay, a transmission made by the communications device destined for the controller;

amplifying the received transmission;

applying the precoder to the received transmission; and

transmitting the precoded transmission to the controller.

16. The method of claim 15, wherein determining information for a channel comprises:

detecting a transmission schedule for the communications device;

measuring a transmission from the communications device destined for the controller; and

computing the information from the measured transmission.

17. The method of claim 15, wherein determining a precoder comprises:

receiving a response of a channel between the smart relay and the controller (U<sub>M×

K</sub>) from the controller;

receiving a multiple input, multiple output channel response (Δ

<sub>M×

N</sub>) from the controller;

computing the precoder (Π

<sub>K×

K</sub>) so that

U<sub>M×

K</sub>·

Π

<sub>K×

K</sub>·

V<sub>K×

N</sub>=Δ

<sub>M×

N</sub>

is satisfied, where V<sub>K×

N</sub> is a response of a channel between the communications device and the smart relay.

18. The method of claim 15, wherein determining a precoder comprises:

receiving a response of a channel between the smart relay and the controller (U<sub>M×

K</sub>) and a response of the channel between the communications device and the controller (H<sub>M×

N</sub>) from the controller;

computing the precoder (Π

<sub>K×

K</sub>) so that

U<sub>M×

K</sub>·

Π

<sub>K×

K</sub>·

V<sub>K×

N</sub>=α

·

H<sub>M×

N</sub>,

is satisfied, where α

is a value related to transmit power, and V<sub>K×

N</sub> is a response of a channel between the communications device and the smart relay.

19. The method of claim 15, wherein determining a precoder comprises computing the precoder (Π

<sub>K×

K</sub>) so that

P′

<sub>K×

D</sub>=Π

<sub>K×

K</sub>·

V<sub>K×

N</sub>·

P<sub>N×

D</sub>,

where

[(P′

<sub>K×

D</sub>)^T(P<sub>N×

D</sub>)^T]

is determined by

$\left[\begin{array}{cc}{U}_{M\times <br><br>K}& H_{M\times <br><br>N}\end{array}\right]·<br><br>\left[\begin{array}{c}{P}_{K\times <br><br>D}^{\mathrm{\prime <br><br>}}\\ P_{N\times <br><br>D}\end{array}\right],$

where U<sub>M×

K</sub> is a response of a channel between the smart relay and the controller, H<sub>M×

N</sub> is a response of the channel between the communications device and the controller, P<sub>N×

D</sub> is a precoder matrix, and P′

<sub>K×

D</sub> is a new precoder matrix.

20. The method of claim 15, wherein determining a precoder comprises:

transmitting a response of a channel between the communications device and the smart relay (V<sub>M×

K</sub>) to the controller; and

receiving the precoder from the controller, wherein the precoder is based on V<sub>M×

K</sub>.

21. The method of claim 20, wherein the precoder is computed as

(H_M×

N+U<sub>M×

K</sub>·

V<sub>K×

N</sub>)·

P′

<sub>N×

D</sub>=H<sub>M×

N</sub>·

P<sub>N×

D</sub>,

where U<sub>M×

K</sub> is a response of a channel between the smart relay and the controller, H<sub>M×

N</sub> is a response of the channel between the communications device and the controller, P<sub>N×

D</sub> is a precoder matrix, and P′

<sub>N×

D</sub> is a new precoder matrix.

22. The method of claim 20, wherein the precoder is computed as

H_M×

N+U<sub>M×

K</sub>·

V<sub>K×

N</sub>,

where U<sub>M×

K</sub> is a response of a channel between the smart relay and the controller, and H<sub>M×

N</sub> is a response of the channel between the communications device and the controller.