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 a data to a reception end device in a Multi-Input Multi-Output (MIMO) system using a plurality of sub-carriers by a transmission end device, 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 per resource,
wherein the phase-shift-based precoding matrix is determined by multiplying the precoding matrix, the first diagonal matrix, and the unitary matrix,
wherein the precoding matrix is selected from a first codebook using a modulo operation of a resource index (k) based on a predetermined integer number, and
wherein the precoding matrix is cyclically selected from the first codebook not using feedback information received from the reception end device.
2. The method according to claim 1 , wherein the predetermined integer number is determined in consideration of a spatial multiplexing rate.
3. The method according to claim 1 , wherein the precoding matrix is selected from the first 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 first codebook.
4. The method according to claim 1 , wherein the phase-shift-based precoding matrix is represented by a following equation:
(
ℙ
N
t
×
R
)
(
ⅇ
jθ
1
k
0
…
0
0
ⅇ
jθ
2
k
…
0
⋮
⋮
⋱
⋮
0
0
…
ⅇ
jθ
R
k
)
(
𝕌
R
×
R
)
[
Equation
]
where ( N t ×R ) is the precoding matrix, N t is a number of TX antenna, ( R×R ) is the unitary matrix, “k” is a resource index, θi is a phase angle value, and R is a spatial multiplexing rate.
5. The method according to claim 1 , wherein the resource index (k) is one of a subcarrier index and a virtual subcarrier index.
6. A transceiver for transmitting a data in a Multi-Input Multi-Output (MIMO) system using a plurality of sub-carriers, the transceiver comprising:
a precoding-matrix decision module which determines a precoding matrix as a first part of a phase-shift-based precoding matrix, determines a first diagonal matrix for a phase shift as a second part of the phase-shift-based precoding matrix, determines a unitary matrix as a third part of the phase-shift-based precoding matrix, and determines the phase-shift-based precoding matrix by multiplying the precoding matrix, the first diagonal matrix, and the unitary matrix;
a precoding module for precoding by multiplying the phase-shift-based precoding matrix by a transmission symbol per resource,
wherein the precoding-matrix decision module selects the precoding matrix from a first codebook using a modulo operation of a resource index (k) based on a predetermined integer number, and
wherein the precoding-matrix decision module cyclically selects the precoding matrix from the first codebook not using feedback information received from a reception end device of the transmission symbol.
7. The transceiver according to claim 6 , wherein the predetermined integer number is determined in consideration of a spatial multiplexing rate.
8. The transceiver according to claim 6 , wherein the precoding-matrix decision module selects the precoding matrix from the first 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 first codebook.
9. The transceiver according to claim 6 , wherein the phase-shift-based precoding matrix is represented by a following equation:
(
ℙ
N
t
×
R
)
(
ⅇ
jθ
1
k
0
…
0
0
ⅇ
jθ
2
k
…
0
⋮
⋮
⋱
⋮
0
0
…
ⅇ
jθ
R
k
)
(
𝕌
R
×
R
)
[
Equation
]
where ( N t ×R ) is the precoding matrix, N t is a number of TX antenna, ( R×R ) is the unitary matrix, “k” is a resource index, θi is a phase angle value, and R is a spatial multiplexing rate.
10. The transceiver according to claim 6 , wherein the resource index (k) is one of a subcarrier index and a virtual subcarrier index.