Apparatus for controlling power of relay in amplify-forward relay system and method using the same

• US 20080076349A1
• Filed: 03/12/2007
• Published: 03/27/2008
• Est. Priority Date: 09/27/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Eung Sun, Kim, Young-Doo, Ahn, Chang Wook, Hwang, Duck Dong
• Granted Patent: US 7,860,451 B2
• Time in Patent Office: Days
• US Class Current: 455/7
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks

Abstract

A method and apparatus for controlling a power of a relay are provided. The apparatus includes: a signal receiver which receives signals which are transmitted to a plurality of receiving antennas directly from a source or via at least one relay; a channel information acquirement unit which acquires channel information between the source and the at least one relay, and acquires channel information between the at least one relay and the plurality of receiving antennas; a power control signal generation unit which generates a power control signal, based on the acquired channel information and a maximum SNR; and a relay power control unit which transmits the generated power control signal to the relay and thereby controls a transmit signal power with respect to the at least one relay.

Claims

1. An apparatus for controlling a power of a controlled relay, the apparatus comprising:

a signal receiver which receives signals which are transmitted to a plurality of receiving antennas directly from a source or via at least one relay;

a channel information acquirement unit which acquires channel information between the source and the at least one relay, and between the at least one relay and the plurality of receiving antennas;

a power control signal generation unit which generates a power control signal, based on the acquired channel information and a signal-to-noise ratio (SNR) of at least one of the signals received; and

a relay power control unit which transmits the generated power control signal to the controlled relay to control a transmit signal power of the controlled relay.

2. The apparatus of claim 1, wherein the SNR corresponds to a maximum SNR of the signals received.

3. The apparatus of claim 2, wherein the maximum SNR corresponds to an SNR which is calculated before the signals received from the at least one relay are combined.

4. The apparatus of claim 3, wherein the power control signal generation unit generates a power control signal based on an eigenvector corresponding to a maximum generalized eigenvalue with respect to each of the at least one relay, based on the acquired channel information and the maximum SNR.

5. The apparatus of claim 4, wherein the power control signal generation unit generates the power control signal of the eigenvector corresponding to the maximum generalized eigenvalue with respect to each of the at least one relay based on the following equation,

6. The apparatus of claim 2, further comprising:

a receive mode determination unit which determines a receive mode based on the channel information and the power control signal with respect to the at least one relay.

7. The apparatus of claim 6, wherein the receive mode determination unit determines, as the receive mode, at least one of a receive mode of directly receiving only signals which are transmitted from the source via the plurality of receiving antennas, a receive mode of receiving signals which are transmitted from the source and the at least one relay via the plurality of receiving antennas, and a plurality of receive modes of receiving signals which are transmitted from the source and the at least one relay via only a single antenna among the plurality of receiving antennas, and corresponding to the plurality of receiving antennas respectively.

8. The apparatus of claim 7, wherein the receive mode determination unit calculates an SNR with respect to each of the plurality of receive modes, and determines, as the receive mode, a receive mode corresponding to the largest calculated SNR.

9. The apparatus of claim 7, wherein the receive mode determination unit determines the receive mode using the following equation:

10. A method of controlling a power of a controlled relay, the method comprising:

receiving signals which are transmitted to a plurality of receiving antennas directly from a source or via at least one relay;

acquiring channel information between the source and the at least one relay, and between the at least one relay and the plurality of receiving antennas;

generating a power control signal, based on the acquired channel information and an SNR of at least one of the signals received; and

transmitting the generated power control signal to the controlled relay to control a transmit signal power with respect to the controlled relay.

11. The method of claim 10, wherein the SNR corresponds to a maximum SNR of the signals received.

12. The method of claim 11, wherein the maximum SNR corresponds to an SNR which is calculated before the signals received from the at least one relay are combined.

13. The method of claim 11, wherein the generating generates a power control signal based on an eigenvector corresponding to a maximum generalized eigenvalue with respect to each of the at least one relay, based on the acquired channel information and the maximum SNR.

14. The method of claim 13, wherein the generating generates the power control signal of the eigenvector corresponding to the maximum generalized eigenvalue with respect to each of the at least one relay based on the following equation

15. The method of claim 11, further comprising:

determining a receive mode based on the channel information and the power control signal with respect to the at least one relay.

16. The method of claim 15, wherein the determining determines, as the receive mode, at least one of a receive mode of directly receiving only signals which are transmitted from the source via the plurality of receiving antennas, a receive mode of receiving signals which are transmitted from the source and the at least one relay, via the plurality of receiving antennas, and a plurality of receive modes of receiving signals which are transmitted from the source and the at least one relay, via only a single antenna among the plurality of receiving antennas, and corresponding to the plurality of receiving antennas respectively.

17. The method of claim 16, wherein the determining further calculates an SNR with respect to each of the plurality of receive modes, and determines as the receive mode a receive mode corresponding to the largest calculated SNR.

18. The method of claim 16, wherein the determining determines, the receive mode using the following equation:

19. A computer-readable recording medium storing a program for implementing a method of controlling a power of a relay, the method comprising:

receiving signals which are transmitted to a plurality of receiving antennas directly from a source or via at least one relay;

acquiring channel information between the source and the at least one relay, and acquiring channel information between the at least one relay and the plurality of receiving antennas;

generating a power control signal, based on the acquired channel information and a signal-to-noise ratio (SNR) of at least one of the signals received; and

transmitting the generated power control signal to the relay and thereby controlling a transmit signal power with respect to the at least one relay.

20. The method of claim 19, wherein the SNR corresponds to a maximum SNR of the signals received.