Method and Apparatus for Modulation and Coding Scheme Adaption in a MIMO System

• US 20130142290A1
• Filed: 12/02/2011
• Published: 06/06/2013
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: Honor Device Company Limited
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Farmanbar, Hamidreza, Callard, Aaron, Baligh, Mohammadhadi
• Granted Patent: US 8,731,028 B2
• Time in Patent Office: Days
• US Class Current: 375/343
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03891 Spatial equalizers MIMO diversity systems H04B7/0413
• CPC Class Codes: H04L 25/03968 mean-square error [MSE]
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

Method and apparatus for decoding a transmitted signal by a receiver in a MIMO system into a first estimate component for estimating a first signal, a first interference component indicating interference resulting from a correlation relationship among a set of signals to be transmitted, and a first noise component. A base station generates the transmitted signal from the set of signals through a coding process, the coding process defining a correlation relationship amongst the set of signals. The correlation information about the correlation relationship is transmitted to the receiver directly or by a dedicated reference symbol. The decoding is performed by determining a linear receiver filter for the first signal in accordance with the correlation information, and de-correlating the first signal and interferences.

Claims

1. A method for signal processing in a communication system, comprising:

receiving, by a receiver, a transmitted signal sent by a transmitter through a channel, the transmitted signal being generated from a set of signals according to a coding process, the set of signals comprising a first signal and a plurality of other signals, the coding process defining a correlation relationship amongst the first signal and the plurality of other signals in the set, and including correlation information relating to the correlation relationship in the transmitted signal; and

decoding, in accordance with the correlation information, the transmitted signal into a first estimate component for estimating the first signal, a first interference component indicating interference resulting from the correlation relationship, and a first noise component indicating impact of the noise on transmission of the first signal.

2. The method of claim 1, further comprising:

decoding the received signal into a second estimate component for estimating a second signal of the set of signals, a second interference component caused by the correlation relationship among the set of signals, and a second noise component.

3. The method of claim 1, wherein the transmitter is a base station of a multi-user multiple input, multiple output (MIMO) system, and the receiver is a user equipment within the multi-user MIMO system.

4. The method of claim 1, wherein the correlation information is received by the receiver from the transmitter using one of a pilot signal, a control signal, or a dedicated reference symbol (DRS).

5. The method of claim 1, wherein the coding process used in generating the transmitted signal from the set of signals comprises a linear zero-forcing precoding performed by a precoder within the transmitter.

6. The method of claim 1, wherein the coding process used in generating the transmitted signal from the set of signals comprises a linear regularized zero-forcing precoding performed by a precoder within the transmitter.

7. The method of claim 1, wherein the coding process used in generating the transmitted signal from the set of signals comprises a dirty-paper non-liner precoding performed by a precoder within the transmitter.

8. The method of claim 1, wherein the decoding the received signal comprises:

determining a linear receiver filter for the first signal; and

performing a de-correlation of the first signal and interferences to generate the first estimate component for estimating the first signal, the first interference component, and the first noise component.

9. The method of claim 7, wherein the correlation information is a correlation matrix R_x=E[xx^H] or D=diag(R_x)⁻

1, wherein x=[x₁ x₂ . . . x_K]^T is the set of signals.

10. The method of claim 8, wherein the linear receiver filter for the first signal x_j is r_1×

N=[R_x]_{jth row} H^H (HR_xH^H+R_n)<sup>−

1</sup>, wherein x=[x₁ x₂ . . . x_K]^T is the set of signals, R_x=E[xx^H] is a correlation matrix of x=[x₁ x₂ . . . x_K]^T, H represents a combined impact of the channel and the coding process, and the channel H has a noise vector n with a correlation matrix R_n=E[nn^H].

11. The method of claim 9, wherein the linear receiver filter for the first signal x_j is s*r_1×

N=s*[R_x]_{jth row} H^H (HR_xH^H+R_n)<sup>−

1</sup>, wherein a scalar number is denoted as s.

12. The method of claim 9, wherein the first estimate component for the first signal x_j is

13. The method of claim 9, wherein the first interference component is

14. The method of claim 9, wherein a signal to interference and noise ratio (SINR) for the first signal is

15. The method of claim 7, wherein the de-correlation of the first signal and the interferences is derived through usage of a Cholesky factorization process.

16. An apparatus for signal processing in a communication system, the apparatus comprising:

a receiver configured to receive a transmitted signal sent by a transmitter through a channel, the transmitted signal being generated from a set of signals according to a coding process, the set of signals comprising a first signal and a plurality of other signals, the coding process defining a correlation relationship amongst the first signal and the plurality of other signals in the set, and including correlation information relating to the correlation relationship in the transmitted signal; and

a processor configured to decode, in accordance with the correlation information, the transmitted signal into a first estimate component for estimating the first signal, a first interference component indicating interference resulting from the correlation relationship, and a first noise component indicating impact of the noise on transmission of the first signal.

17. The apparatus of claim 16, wherein:

the processor is configured to generate a linear receiver filter for the first signal; and

the processor is configured to de-correlate the first signal and interferences to generate the first estimate component for estimating the first signal, the first interference component, and the first noise component.

18. The apparatus of claim 16, wherein the linear receiver filter for the first signal x_j is s*r_1×

N=s*[R_x]_{jth row} H^H (HR_xH^H+R_n)<sup>−

1</sup>, wherein x=[x₁ x₂ . . . x_K]^T is the set of signals, R_x=E[xx^H] is a correlation matrix of x=[x₁ x₂ . . . x_K]^T, H represents a combined impact of the channel and the coding process, and the channel has a noise vector n with a correlation matrix R_n=E[nn^H], a scalar number is denoted as s, the first estimate component for the first

19. The apparatus of claim 16, wherein the apparatus is an user equipment (UE).

20. An apparatus for signal processing in a communication system, the apparatus comprising:

a processor configured to generate a transmitted signal from a set of signals through a coding process, wherein the set of signals comprises a first signal and a plurality of other signals with a correlation relationship after the coding process; and

a transmitter configured to send the transmitted signal through a channel, the transmitted signal including correlation information about the correlation relationship among the set of signals through the channel, wherein the correlation information is related to a first interference component of the transmitted signal caused by the correlation relationship among the set of signals.

21. The apparatus of claim 20, wherein the transmitter is configured to send the correlation information using one of a pilot signal, a control signal, or a dedicated reference symbol (DRS).