Apparatus and method for determining optimum integer perturbation vector of low complexity in multiple antenna system
An apparatus and a method for determining an optimum integer perturbation vector of a low complexity in a multiple antenna system include a transmitter that transmits data using an optimum integer perturbation vector of a low complexity in a multiple antenna system includes a module pre-processor, a shift pre-processor, and a precoder. The modulo pre-processor adds an integer perturbation vector to a transmission signal vector. The shift pre-processor phase-shifts a pseudo inverse matrix of a channel matrix using a phase angle. The precoder precodes a transmission signal vector perturbed by the integer perturbation vector using the phase-shifted pseudo inverse matrix of the channel matrix.
1. A transmitter capable of transmitting data using an optimum integer perturbation vector of a low complexity in a multiple antenna system, the transmitter comprising:
a modulo pre-processor configured to add an integer perturbation vector to a transmission signal vector;
a shift pre-processor configured to phase-shift a pseudo inverse matrix of a channel matrix using a phase angle; and
a precoder configured to precode a transmission signal vector perturbed by the integer perturbation vector using the phase-shifted pseudo inverse matrix of the channel matrix.
2. The transmitter of claim 1 , further comprising:
a decoupler configured to decouple a first channel vector and a second channel vector of the pseudo inverse matrix of a channel matrix, and decouple a real part and an imaginary part of a transmission signal vector.
3. The transmitter of claim 2 , further comprising:
a perturbation vector determination unit configured to determine a real value and an imaginary value of the integer perturbation vector independently based on a first Equation by coupling with the decoupled first channel vector and the decoupled real part of the transmission signal vector, and couple with the decoupled second channel vector and the decoupled imaginary part of the transmission signal vector, wherein the first equation is defined as:
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4. The transmitter of claim 3 , wherein the first channel vector and the second channel vector are defined by a second and third Equation, wherein the second equation is:
h i + =[R{{tilde over (h)} i + } T I{{tilde over (h)} i + } T ] T ,
and the third equation is:
{dot over (h)} i + =[−I{{tilde over (h)} i + } T R{{tilde over (h)} i + } T ] T
where h i + is the first channel vector, {dot over (h)} i + is the second channel vector, R{} denotes a real part, I{} denotes an imaginary part, [A] T denotes a transpose matrix of a matrix A, and {tilde over (h)} i + is an i-th column vector of {tilde over (H)} + .
5. The transmitter of claim 1 , wherein the phase angle is determined through a repetitive process defined using:
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6. The transmitter of claim 1 , wherein the phase angle is determined based on:
h 1,θ + ⊥span({dot over (h)} 1,θ + , . . . , {dot over (h)} K,θ + ) & {dot over (h)} 1,θ + ⊥span(h 1,θ + , . . . , h K,θ + )
where h 1,θ + is a phase-shifted first channel vector, and {dot over (h)} 1,θ + is a phase-shifted second channel vector.
7. A method for transmitting data using an optimum integer perturbation vector of a low complexity in a multiple antenna system, the method comprising:
adding an integer perturbation vector to a transmission signal vector;
phase-shifting a pseudo inverse matrix of a channel matrix using a phase angle; and
precoding a transmission signal vector perturbed by the integer perturbation vector using the phase-shifted pseudo inverse matrix of the channel matrix.
8. The method of claim 7 , further comprising:
decoupling a first channel vector and a second channel vector of the pseudo inverse matrix of a channel matrix, and decoupling a real part and an imaginary part of a transmission signal vector; and
determining a real value and an imaginary value of the integer perturbation vector independently based on a first equation by coupling with the decoupled first channel vector and the decoupled real part of the transmission signal vector, and coupling with the decoupled second channel vector and the decoupled imaginary part of the transmission signal vector, wherein the first equation is defined as:
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9. The method of claim 8 , wherein the first channel vector and the second channel vector are defined by a second equation defined as:
h i + =[R{{tilde over (h)} i + } T I{{tilde over (h)} i + } T ] T , and
a third equation defined as:
{dot over (h)} i + =[−I{{tilde over (h)} i + } T R{{tilde over (h)} i + } T ] T
where h i + is the first channel vector, {dot over (h)} i + is the second channel vector, R{} denotes a real part, I{} denotes an imaginary part, [A] T denotes a transpose matrix of a matrix A, and {tilde over (h)} i + is an i-th column vector of {tilde over (H)} + .
10. The method of claim 7 , wherein the phase angle is determined through a repetitive process based on:
for i=2:K,
θ
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-
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h
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+
T
h
.
i
+
h
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+
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h
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)
.
11. The method of claim 7 , wherein the phase angle is determined based on a third equation defined as:
h 1,θ + ⊥span({dot over (h)} 1,θ + , . . . , {dot over (h)} K,θ + ) & {dot over (h)} 1,θ + ⊥span(h 1,θ + , . . . , h K,θ + )
where h 1,θ + is a phase-shifted first channel vector and {dot over (h)} 1,θ + is a phase-shifted second channel vector.