Method for generating precoder in multi user multiple input and multiple output communication system

1. An access point for communicating with a plurality of stations in a multi user multiple input and multiple output (MU MIMO) communication system, the access point comprising:

at least one processor configured to execute instructions to implement operations comprising:

receiving channel information and quality information of a channel from a plurality of stations;

determining whether a first condition is satisfied on the basis of the received channel information and quality information;

when the first condition is satisfied, selecting a type of matrix inversion from among a plurality of matrix inversion types for precoding, and generating a precoder based at least in part on the selection;

when the first condition is not satisfied, generating a precoder without selecting a type of matrix inversion from among the plurality of matrix inversion types;

determining whether a second condition different from the first condition is satisfied on the basis of the received information;

when the second condition is satisfied, selecting a type of decomposition from among a plurality of decomposition types for precoding, and generating a precoder based at least in part on the selection of the type of decomposition, and when the second condition is not satisfied, generating a precoder without selecting the type of decomposition from among the plurality of decomposition types.

2. The access point for communicating with a plurality of stations of claim 1 , wherein said determining whether the first condition is satisfied comprises:

receiving channel information and quality information of the channel from at least some of the plurality of stations to determine a number of streams to be provided to the plurality of stations, and determining whether a rank reduction is required or desirable on the basis of the determined number of streams.

3. The access point for communicating with a plurality of stations of claim 2 , wherein said selecting the type of matrix inversion comprises:

receiving interference canceling capability information from the plurality of stations; and

selecting the type of matrix inversion on the basis of interference canceling capabilities of the plurality of stations.

4. The access point for communicating with a plurality of stations of claim 3 , wherein the operations further comprise:

executing a selective matrix inversion if the interference canceling capability satisfies a predetermined standard; and

executing a full matrix inversion if the interference canceling capability does not satisfy a predetermined standard.

5. The access point for communicating with a plurality of stations of claim 4 , wherein said executing the selective matrix inversion comprises:

after executing a rank selection according to the rank reduction,

executing a matrix inversion on the rank-selected matrix.

6. The access point for communicating with a plurality of stations of claim 4 , wherein said executing the full matrix inversion comprises:

after executing an inversion on a full matrix in which a rank selection is not performed,

executing a rank selection according to the rank reduction on a full matrix in which the inversion is executed.

7. The access point for communicating with a plurality of stations of claim 1 , wherein said determining whether the second condition is satisfied comprises:

determining a number of streams to be provided to the plurality of stations on the basis of the received information, and determining whether a plurality of streams needs to be or should be applied to any one station of the plurality of stations.

8. The access point for communicating with a plurality of stations of claim 7 , wherein said selecting the decomposition type comprises:

determining a modulation and coding scheme (MCS) on the basis of the received information; and

determining a decomposition type to be used for generating the precoder, on the basis of the modulation and coding scheme.

9. The access point for communicating with a plurality of stations of claim 7 , wherein said selecting the decomposition type comprises:

determining a decomposition type to be used for generating the precoder, on the basis of the quality information of the channel.

10. The access point for communicating with a plurality of stations of claim 7 , wherein said selecting the decomposition type comprises:

selecting either a SVD (Singular Value Decomposition) or a GMD (Geometry Mean Decomposition).

11. An access point for communicating with a plurality of stations in a multi user multiple input and multiple output (MU MIMO) communication system, the access point comprising:

at least one processor configured to execute instructions to implement operations comprising:

receiving channel information and quality information of a channel from a plurality of stations to determine a number of streams to be provided to the plurality of stations;

determining whether a rank reduction is to be implemented on the basis of the determined number of streams;

when the rank reduction is to be implemented, selecting a generating method of an inversion matrix for generation of a precoder on the basis of interference canceling capability information (ICCI) of the plurality of stations; and

when the rank reduction is not to be implemented, generating the precoder without selecting an inversion matrix on the basis of ICCI.

12. The access point for communicating with a plurality of stations of claim 11 , wherein the selecting of the generating method of the inversion matrix for generation of the precoder on the basis of interference canceling capability information of the plurality of stations comprises:

comparing interference canceling abilities of the plurality of stations with a predetermined standard to select an execution order of a rank selection according to the rank reduction, and a matrix inversion.

13. The access point for communicating with a plurality of stations of claim 12 , wherein said comparing the interference canceling abilities of the plurality of stations with the predetermined standard to select the execution order of the rank selection according to the rank reduction, and the matrix inversion comprises:

first executing the rank selection according to the rank reduction, if the interference canceling capabilities of the plurality of stations satisfy a predetermined standard; and

executing the rank selection according to the rank reduction later, if the interference canceling capabilities of the plurality of stations do not satisfy the predetermined standard.

14. The access point for communicating with a plurality of stations of claim 13 , wherein the operations further comprise:

generating a ZF (Zero Forcing) precoder, using the generated inversion matrix.

15. The access point for communicating with a plurality of stations of claim 13 , wherein the operations further comprise:

generating an MMSE (Minimum Mean Squared Error) precoder, using the generated inversion matrix.

16. An access point that generates a precoder of a multi user multiple input and multiple output communication system, the access point comprising:

at least one processor configured to execute instructions to implement operations comprising:

receiving channel information and quality information of a channel from a plurality of stations;

determining a number of streams to be provided to the plurality of stations, and a modulation and coding scheme (MCS), on the basis of the received information;

when a plurality of streams are to be allocated to any one of the plurality of stations, selecting a decomposition type to be used for generation of a precoder, on the basis of at least one of the quality information of the channel and the MCS; and

when a plurality of streams are not to be allocated to any one of the plurality of stations, generating the precoder without selecting the decomposition type on the basis of at least one of the quality information of the channel and the MCS.

17. The access point that generates a precoder of claim 16 , wherein said determining the decomposition type comprises:

determining either a SVD (Singular Value Decomposition) or a GMD (Geometric Mean Decomposition).

18. The access point that generates a precoder of claim 17 , wherein said determining the decomposition type comprises determining either SVD or GMD on the basis of the modulation and coding scheme.

19. The access point that generates a precoder of claim 17 , wherein the quality information of the channel comprises a SNR (Signal to Noise Ratio) of the channel, and

said determining the decompression type comprises determining either SVD or GMD on the basis of the SNR of the channel.

20. The access point that generates a precoder of claim 16 , wherein the operations further comprise:

generating one of a BD (Block Diagonalization) precoder, a G-ZF (Generalized-Zero Forcing) precoder and a G-MMSE (Generalized MMSE) precoder, using the determined decomposition type.