Data transmitting and receiving method using phase shift based precoding and transceiver supporting the same
A method for performing a precoding based on a generalized phase shift or a precoding based on an extended phase shift in a Multi-Input Multi-Output (MIMO) system employing several sub-carriers, and a transceiver for supporting the same are disclosed. A phase-shift-based precoding matrix is generalized by multiplying a diagonal matrix for a phase shift by a unitary matrix for maintaining orthogonality between sub-carriers. In this case, a diagonal matrix part may be extended by multiplying a precoding matrix for removing interference between sub-carriers by a diagonal matrix for a phase shift. By generalization and extension of the phase-shift-based precoding, a transceiver is more simplified, and communication efficiency increases.
1. A method for transmitting data from a transmission end device to a reception end device in a Multi-Input Multi-Output (MIMO) system using a plurality of sub-carriers, the method comprising:
determining a precoding matrix as a first part of a phase-shift-based precoding matrix;
determining a first diagonal matrix for a phase shift as a second part of the phase-shift-based precoding matrix;
determining a unitary matrix as a third part of the phase-shift-based precoding matrix; and
precoding by multiplying the phase-shift-based precoding matrix by a transmission symbol according to a resource,
wherein the phase-shift-based precoding matrix is determined by multiplying the precoding matrix, the first diagonal matrix, and the unitary matrix, and wherein the precoding matrix is selected from only a portion of the precoding matrixes included in a first codebook predetermined between the transmission end device and the reception end device.
2. The method according to claim 1 , wherein the precoding matrix is selected from a second codebook which constitutes the portion of the first codebook from which the precoding matrix is selected.
3. The method according to claim 2 , wherein the precoding matrix is cyclically selected from the second codebook with a predetermined repetition period with respect to a resource index (k).
4. The method according to claim 3 , wherein the precoding matrix is selected from the second codebook according to an index acquired by (k mod N),
wherein (k mod N) is a modulo operation of the resource index (k) based on a number (N) of precoding matrixes included in the second codebook.
5. The method according to claim 1 , wherein the phase-shift-based precoding matrix is represented by the following equation:
(
ℙ
N
t
×
R
)
(
ⅇ
j
θ
1
k
0
…
0
0
ⅇ
j
θ
2
k
…
0
⋮
⋮
⋱
⋮
0
0
…
ⅇ
j
θ
R
k
)
(
𝕌
R
×
R
)
,
wherein ( N t ×R ) is the precoding matrix, N t is a number of a transmission antenna, ( R×R ) is the unitary matrix, “k” is a resource index, θ i is a phase angle value, and R is a spatial multiplexing rate.
6. The method according to claim 1 , wherein the precoding matrix is selected from the portion of the first codebook without using feedback information received from the reception end device.
7. A transceiver for transmitting data in a Multi-Input Multi-Output (MIMO) system using a plurality of sub-carriers, the transceiver comprising:
a precoding-matrix decision module for determining a precoding matrix as a first part of a phase-shift-based precoding matrix, determining a first diagonal matrix for a phase shift as a second part of the phase-shift-based precoding matrix, determining a unitary matrix as a third part of the phase-shift-based precoding matrix, and determining the phase-shift-based precoding matrix by multiplying the precoding matrix, the first diagonal matrix, and the unitary matrix; and
a precoding module for precoding by multiplying the phase-shift-based precoding matrix by a transmission symbol according to a resource,
wherein the precoding-matrix decision module selects the precoding matrix from only a portion of the precoding matrixes included in a first codebook predetermined between a transmission end device and a reception end device.
8. The transceiver according to claim 7 , wherein the precoding-matrix decision module selects the precoding matrix from a second codebook which constitutes the portion of the first codebook from which the precoding matrix is selected.
9. The transceiver according to claim 8 , wherein the precoding-matrix decision module cyclically selects the precoding matrix from the second codebook with a predetermined repetition period with respect to a resource index (k).
10. The transceiver according to claim 9 , wherein the precoding-matrix decision module selects the precoding matrix from the second codebook according to an index acquired by (k mod N),
wherein (k mod N) is a modulo operation of the resource index (k) based on a number (N) of precoding matrixes included in the second codebook.
11. The transceiver according to claim 7 , wherein the phase-shift-based precoding matrix is represented by the following equation:
(
ℙ
N
t
×
R
)
(
ⅇ
j
θ
1
k
0
…
0
0
ⅇ
j
θ
2
k
…
0
⋮
⋮
⋱
⋮
0
0
…
ⅇ
j
θ
R
k
)
(
𝕌
R
×
R
)
,
wherein ( N t ×R ) is the precoding matrix, N t is a number of a transmission antenna, ( R×R ) is the unitary matrix, “k” is a resource index, θ i is a phase angle value, and R is a spatial multiplexing rate.
12. The transceiver according to claim 7 , wherein the precoding matrix decision module selects the precoding matrix from the portion of the first codebook without using feedback information received from the reception end device.
13. A method for a reception end device receiving a data from a transmission end device in a Multi-Input Multi-Output (MIMO) system using a plurality of sub-carriers, the method comprising:
determining a precoding matrix as a first part of a phase-shift-based precoding matrix;
determining a first diagonal matrix for a phase shift as a second part of the phase-shift-based precoding matrix;
determining a unitary matrix as a third part of the phase-shift-based precoding matrix; and
decoding a transmission symbol according to a resource based on the phase-shift-based precoding matrix,
wherein the phase-shift-based precoding matrix is determined by multiplying the precoding matrix, the first diagonal matrix, and the unitary matrix, and
wherein the precoding matrix is selected from only a portion of the precoding matrixes included in a first codebook predetermined between the transmission end device and the reception end device.
14. The method according to claim 13 , wherein the precoding matrix is selected from a second codebook which constitutes the portion of the first codebook from which the precoding matrix is selected.
15. The method according to claim 14 , wherein the precoding matrix is cyclically selected from the second codebook with a predetermined repetition period with respect to a resource index (k).