APPARATUS AND METHOD FOR INTERFERENCE CANCELLATION IN MULTI-ANTENNA SYSTEM

• US 20080227422A1
• Filed: 03/14/2008
• Published: 09/18/2008
• Est. Priority Date: 03/14/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Samsung Electronics Co. Ltd., Board of Regents of the University of Texas System (University of Texas System)
• Inventors: KWUN, Jong-Hyung, Heath, Robert, HWANG, In-Soo, KWAK, Jin-Sam, Andrews, JEFF, SHIM, SeiJoon
• Granted Patent: US 8,135,349 B2
• Time in Patent Office: Days
• US Class Current: 455/278.1
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0028 Formatting
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

An apparatus and method for interference cancellation in a multi-antenna system are provided. A transmission apparatus includes a channel identifier, a scheduler, an interference canceller, and a transmitter. The channel identifier identifies channel information of each of a plurality of receiving ends located in a service area and neighbor cell interference information on each receiving end. The scheduler selects at least one receiving end. The interference canceller precodes transmitted signals in order to cancel interference between receiving ends located in the same cell and neighbor cell interference. The transmitter transmits the precoded transmitted signals to the selected at least one receiving end.

Claims

1. An apparatus in a multi-antenna system, comprising:

a channel identifier for identifying channel information of at least one of a plurality of receiving ends located in a service area and for identifying neighbor cell interference information of each receiving end;

a scheduler for selecting at least one receiving end from the plurality of receiving ends using the channel information of the receiving ends;

an interference canceller for preceding transmission signals using channel information and neighbor cell interference information of the at least one receiving end in order to cancel interference between receiving ends located in the same cell and neighbor cell interference; and

a transmitter for transmitting the precoded transmission signals to the selected at least one receiving end.

2. The apparatus of claim 1, wherein the channel identifier identifies the channel information of the receiving ends and the neighbor cell interference information of each receiving end using feedback signals received from the receiving ends.

3. The apparatus of claim 1, wherein the interference canceller precodes a transmission signal through Block Diagonalization (BD) that uses the channel information and neighbor cell interference information of the at least one receiving end.

4. The apparatus of claim 1, wherein the interference canceller determines transmission power of each of a plurality of transmit antennas for respectively transmitting a signal to each receiving end depending on channel states of the at least one receiving end.

5. The apparatus of claim 1, further comprising:

an adaptive modulator for adaptively modulating a signal, which is to be transmitted to each receiving end, depending on channel states of the receiving ends selected in the scheduler and for transmitting the adaptively modulated signal to the interference canceller.

6. The apparatus of claim 1, further comprising:

an adaptive modulator for adaptively modulating a signal, which is to be transmitted to each receiving end, depending on channel states of the receiving ends selected in the scheduler; and

a pre-compensator for pre-compensating the adaptively modulated signal for channel distortion and outputting the pre-compensated signal to the interference canceller.

7. The apparatus of claim 6, wherein the pre-compensator comprises a water filling unit and a Singular Value Decomposition (SVD) operation unit.

8. The apparatus of claim 6, wherein the pre-compensator comprises a symbol remapping block and a pre-equalizer.

9. The apparatus of claim 8, wherein the symbol remapping block performs vector perturbation.

10. The apparatus of claim 1, wherein the transmitter comprises:

at least one transmit antenna; and

an antenna mapper for mapping the precoded transmission signals to the at least one transmit antenna.

11. An apparatus in a multi-antenna system, comprising:

a receiver for receiving a signal using at least one antenna;

a channel estimator for estimating effective channel information and neighbor cell interference information of a transmitting end using the received signal; and

a feedback controller for feeding back the effective channel information and neighbor cell interference information to the transmitting end.

12. The apparatus of claim 11, wherein the channel estimator estimates the effective channel information and the neighbor cell interference information of the transmitting end using a pilot signal comprised in the received signal.

13. The apparatus of claim 11, further comprising:

an interference canceller for canceling neighbor cell interference comprised in the received signal using the neighbor cell interference information received from the channel estimator; and

a demodulator for demodulating the signal from which the neighbor cell interference has been canceled.

14. The apparatus of claim 13, further comprising:

a symbol demapper for converting symbols, which are comprised in the signal received from the interference canceller, into symbols before preceding in a transmitting end for a pre-compensator to pre-compensate a transmitted signal for channel distortion, and transmitting the converted symbols to the demodulator.

15. A method for canceling interference in a multi-antenna system, the method comprising:

identifying channel information of at least one of a plurality of receiving ends located in a service area;

identifying neighbor cell interference information of each receiving end;

selecting at least one receiving end from the plurality of receiving ends using the channel information of the receiving ends;

preceding transmission signals using channel information and neighbor cell interference information of the at least one receiving end to cancel interference between receiving ends located in the same cell and neighbor cell interference; and

transmitting the precoded transmission signals to the selected at least one receiving end.

16. The method of claim 15, wherein the identifying of the channel information comprises:

identifying the channel information of the receiving ends and the neighbor cell interference information of each receiving end using feedback signals received from the receiving ends.

17. The method of claim 15, wherein the preceding comprises:

preceding the transmission signals through Block Diagonalization (BD) using the channel information and neighbor cell interference information of the at least one receiving end.

18. The method of claim 15, further comprising:

adaptively modulating a signal to be transmitted to each receiving end depending on channel states of the selected at least one receiving end, and

preceding the adaptively modulated signal.

19. The method of claim 15, further comprising:

adaptively modulating a signal to be transmitted to each receiving end depending on channel states of the selected at least one receiving end; and

pre-compensating the adaptively modulated signal for channel distortion depending on channel information of each receiving end, and

preceding the pre-compensated signal.

20. The method of claim 19, wherein the pre-compensating comprises:

performing water filling and Singular Value Decomposition (SVD).

21. The method of claim 19, wherein the pre-compensating comprises:

performing symbol remapping and pre-equalization.

22. The method of claim 15, wherein the transmitting to the selected at least one receiving end comprises:

identifying channel states of signals to be transmitted to the at least one receiving end;

selecting antennas for transmitting the signals if the channel state is less than a threshold value;

determining transmission power of the selected antennas depending on the channel states of the transmitted signals; and

transmitting signals to the receiving ends using the determined transmission power.

23. The method of claim 22, wherein the channel information is a Signal to Interference and Noise Ratio (SINR).

24. The method of claim 22, further comprising:

equally allocating the transmission power of the antennas if the channel state is greater than the threshold value.

25. A method for canceling interference in a receiving apparatus of a multi-antenna system, the method comprising:

estimating effective channel information and neighbor cell interference information of a transmitting end using a signal received through at least one antenna; and

feeding back the effective channel information and neighbor cell interference information to the transmitting end.

26. The method of claim 25, wherein the estimating of the effective channel information and neighbor cell interference information comprises:

estimating the effective channel information and neighbor cell interference information of the transmitting end using a pilot signal comprised in the received signal.

27. The method of claim 25, further comprising:

canceling neighbor cell interference comprised in the received signal using the estimated neighbor cell interference information; and

demodulating the signal from which the neighbor cell interference has been canceled.

28. The method of claim 27, further comprising:

converting symbols, which are comprised in the signal from which the neighbor cell interference has been canceled, into symbols before preceding in a transmitting end for a pre-compensator to pre-compensate a transmitted signal for channel distortion, and

demodulating the converted symbols.