Transmission device, receiving device, information transmission method, information receiving method in wireless communication system, and recording medium

1. A transmission device in a wireless communication system, the transmission device comprising:

a layer mapper to map a codeword to one or more layers; and

a precoder to precode symbols mapped by the layer mapper, by using an n*n precoding matrix matched with an input precoding matrix indicator among n*n precoding matrixes included in a codebook for an n*n Multi Input Multi Output (MIMO), which includes the n*n precoding matrixes obtained by combining 4*4 precoding matrixes included in a codebook for a 4*4 MIMO,

wherein the codebook for the n*n MIMO includes preceding matrixes obtained by combining the 4*4 preceding matrixes in such a manner as to multiply each of the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO by an (n/4) 2 number of constants.

2. The transmission device as claimed in claim 1 , wherein the codebook for a 4*4 MIMO is a codebook for a 4*4 MIMO which is defined in LTE (Long Term Evolution) standards, and comprises a rank 4 codebook including 4*4 precoding matrixes, a rank 3 codebook including 4*3 precoding matrixes, a rank 2 codebook including 4*2 precoding matrixes, and a rank 1 codebook including 4*1 precoding matrixes.

3. The transmission device as claimed in claim 1 , wherein the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO correspond to unitary matrixes.

4. The transmission device as claimed in claim 1 , wherein the n*n precoding matrixes included in the codebook for the n*n MIMO correspond to unitary matrixes.

5. The transmission device as claimed in claim 1 , wherein n corresponds to a multiple of 4, which is equal to or greater than 8.

6. The transmission device as claimed in claim 1 , wherein, when n is equal to 8, each of the precoding matrixes included in the codebook for the n*n MIMO has a form of

⁢

[

α

1

⁢

R

1

α

3

⁢

R

3

α

2

⁢

R

2

α

4

⁢

R

4

]

by multiplying four 4*4 precoding matrixes including R 1 , R 2 , R 3 and R 4 by four constants including α 1 , α 2 , α 3 and α 4 , respectively, and the four constants meet a condition defined by

α

3

*

⁢

α

4

α

1

⁢

α

2

=

±

1

where α 3 * is a conjugate of α 3 .

7. The transmission device as claimed in claim 1 , wherein, with respect to each of the n*n precoding matrixes included in the codebook for the n*n MIMO, matrix multiplication of each of the n*n precoding matrixes by a Hermitian matrix of each of the n*n precoding matrixes becomes a unit matrix, and an inverse matrix of each of the n*n precoding matrixes exists.

8. The transmission device as claimed in claim 1 , wherein the codebook for the n*n MIMO includes precoding matrixes obtained by removing a repeated combination among the n*n precoding matrixes capable of being generated by combining the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO.

9. The transmission device as claimed in claim 8 , wherein the codebook for the n*n MIMO includes precoding matrixes obtained by removing a combination related to antenna mapping among n*n precoding matrixes, which are capable of being generated by combining the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO, and which are obtained by removing a repeated combination among the generated n*n precoding matrixes.

10. A method of an apparatus including a layer mapper and a precoder for transmitting information in a wireless communication system, the method comprising:

mapping, by the layer mapper, a codeword to be transmitted to one or more layers; and

precoding, by the precoder, symbols mapped by a layer mapper, by using an n*n precoding matrix matched with an input precoding matrix indicator among n*n precoding matrixes included in a codebook for an n*n Multi Input Multi Output (MIMO), which includes the n*n precoding matrixes obtained by combining 4*4 precoding matrixes included in a codebook for a 4*4 MIMO,

wherein the codebook for the n*n MIMO includes precoding matrixes obtained by combining the 4*4 precoding matrixes in such a manner as to multiply each of the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO by an (n/4) 2 number of constants.

11. A receiving device in a wireless communication system, the receiving device comprising:

a channel estimator to transmit a precoding matrix indicator selected according to a channel state by using a codebook for an n*n Multi Input Multi Output (MIMO) which includes n*n precoding matrixes obtained by combining 4*4 precoding matrixes included in a codebook for a 4*4 MIMO; and

a signal receiver to receive a precoded signal based on the transmitted precoding matrix indicator,

wherein the codebook for the n*n MIMO includes precoding matrixes obtained by combining the 4*4 precoding matrixes in such a manner as to multiply each of the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO by an (n/4) 2 number of constants.

12. A method of an apparatus including a channel estimator and a signal receiver for receiving information in a wireless communication system, the method comprising:

transmitting, by the channel estimator, a precoding matrix indicator selected based on channel state information by using a codebook for an n*n Multi Input Multi Output (MIMO) which includes n*n precoding matrixes obtained by combining 4*4 precoding matrixes included in a codebook for a 4*4 MIMO; and

receiving, by the signal receiver, a precoded signal based on the transmitted precoding matrix indicator,

wherein the codebook for the n*n MIMO includes precoding matrixes obtained by combining the 4*4 precoding matrixes in such a manner as to multiply each of the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO by an (n/4) 2 number of constants.

13. A transmission device in a wireless communication system, the transmission device comprising:

a layer mapper to map a codeword to one or more layers; and

a precoder to precode symbols mapped by the layer mapper, by using an n*n precoding matrix matched with an input precoding matrix indicator among n*n precoding matrixes included in a codebook for an n*n MIMO, which includes the n*n precoding matrixes obtained by combining 4*4 precoding matrixes included in a codebook for a 4*4 MIMO,

wherein the codebook for the n*n MIMO includes precoding matrixes obtained by removing a repeated combination among the n*n precoding matrixes capable of being generated by combining the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO.

14. The transmission device as claimed in claim 13 , wherein the codebook for the n*n MIMO includes precoding matrixes obtained by removing a combination related to antenna mapping among n*n precoding matrixes, which are capable of being generated by combining the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO, and which are obtained by removing a repeated combination among the generated n*n precoding matrixes.

15. A method of an apparatus including a layer mapper and a precoder for transmitting information in a wireless communication system, the method comprising:

mapping, by the layer mapper, a codeword to be transmitted to one or more layers; and

precoding, by the precoder, symbols mapped by a layer mapper, by using an n*n precoding matrix matched with an input precoding matrix indicator among n*n precoding matrixes included in a codebook for an n*n MIMO, which includes the n*n precoding matrixes obtained by combining 4*4 precoding matrixes included in a codebook for a 4*4 MIMO,

wherein the codebook for the n*n MIMO includes precoding matrixes obtained by removing a repeated combination among the n*n precoding matrixes capable of being generated by combining the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO.

16. The method as claimed in claim 15 , wherein the codebook for the n*n MIMO includes precoding matrixes obtained by removing a combination related to antenna mapping among n*n precoding matrixes, which are capable of being generated by combining the 4*4 precoding matrixes included in the codebook for the 4*4 MIMO, and which are obtained by removing a repeated combination among the generated n*n precoding matrixes.