KR102202363B1 - Transmitter and transmitting method thereof - Google Patents

Abstract

The transmitting device is started. When the first input signal and the second input signal are input, the transmitting apparatus pre-phase shift or pre-phase shift/hopping the second input signal, and the first input signal and pre-phase shift or pre-phase shift/hopping A MIMO precoder for generating a first transmission signal and a second transmission signal by performing MIMO precoding by superimposing encoding the second input signal and an OFDM modulator for OFDM modulation on the first transmission signal and the second transmission signal.

Description

Transmission device and its signal transmission method {TRANSMITTER AND TRANSMITTING METHOD THEREOF}

The present invention relates to a transmission apparatus and a signal transmission method thereof, and more particularly, to a transmission apparatus for transmitting a signal using a multiple input multiple output (MIMO) method and a signal transmission method thereof.

In the information society of the 21st century, broadcasting and communication services are entering the era of full-scale digitalization, multi-channelization, broadband and high-quality. In particular, as the spread of high-definition digital TVs, PMPs, and portable broadcasting devices has recently increased, there is an increasing demand for supporting various reception methods for digital broadcasting services.

In response to this demand, broadcasting and communication-related technical organizations and industries have developed advanced technologies to provide various services that can satisfy users' needs. In particular, since multi-antenna transmission/reception techniques that increase transmission efficiency using limited frequency resources have been actively studied, in this regard, a search for a method for providing a better service to users through better performance is requested.

The present invention is in accordance with the above-described necessity, and an object of the present invention is to input the remaining input signals after pre-phase shifting or pre-phase shifting/hopping. The present invention provides a transmission apparatus for generating and transmitting a transmission signal through MIMO precoding overlapping a signal and a signal transmission method thereof.

Another object of the present invention is a transmission signal through MIMO precoding in which one of the input signals is pre-phase shifted or pre-phase shifted/hopped and then overlapped with the remaining input signals and post-phase hopping is performed. It is to provide a transmission apparatus for generating and transmitting a signal and a method for transmitting a signal thereof.

In order to achieve the above object, the transmission apparatus according to an embodiment of the present invention, when the first input signal and the second input signal are input, pre-phase shift or pre-phase shift/hopping the second input signal A MIMO precoder for generating a first transmission signal and a second transmission signal by performing MIMO precoding by overlapping encoding the first input signal and the pre-phase shift or the pre-phase shift/hopped second input signal, and And an OFDM modulator for OFDM modulation on the first transmission signal and the second transmission signal. Here, the MIMO precoder may perform the MIMO precoding using Equation 1 below.

In addition, the MIMO precoder may perform the MIMO precoding using Equation 2 below.

In addition, the MIMO precoder may perform the MIMO precoding using Equation 3 below.

In addition, the MIMO precoder may perform the MIMO precoding using Equation 4 below.

Meanwhile, the MIMO precoder performs MIMO precoding by additionally performing post-phase hopping after superimposing the first input signal and the pre-phase shift or the pre-phase shift/hopped second input signal. I can.

Here, the MIMO precoder may perform the MIMO precoding using Equation 5 below.

In addition, the MIMO precoder may perform the MIMO precoding using Equation 6 below.

In addition, the MIMO precoder may perform the MIMO precoding using Equation 7 below.

Meanwhile, the MIMO precoder may perform MIMO precoding by differentially allocating power to the first input signal and the second input signal before pre-phase hopping the second input signal.

Here, the MIMO precoder may perform the MIMO precoding using Equation 8 below.

Meanwhile, in the precoding method of the transmitting apparatus according to an embodiment of the present invention, when a first input signal and a second input signal are input, the second input signal is pre-phase shifted or pre-phase shifted/hopped, and the second input signal is 1 generating a first transmission signal and a second transmission signal by performing MIMO precoding by superimposing encoding the input signal and the pre-phase shifted or the pre-phase shifted/hopped second input signal, and the first transmission And OFDM modulating the signal and the second transmission signal.

Here, the generating step may perform the MIMO precoding using Equation 1 below.

In addition, the generating step may perform the MIMO precoding using Equation 2 below.

In addition, the generating step may perform the MIMO precoding using Equation 3 below.

In addition, the generating step may perform the MIMO precoding using Equation 4 below.

Meanwhile, in the generating step, post-phase hopping is additionally performed after superimposing the first input signal and the pre-phase shift or the pre-phase shift/hopped second input signal to perform MIMO precoding. I can.

Here, the generating step may perform the MIMO precoding using Equation 5 below.

In addition, the generating step may perform the MIMO precoding using Equation 6 below.

In addition, the generating step may perform the MIMO precoding using Equation 7 below.

Meanwhile, the generating may perform MIMO precoding by differentially allocating power to the first input signal and the second input signal before pre-phase hopping the second input signal.

Here, the generating step may perform the MIMO precoding using Equation 8 below.

According to various embodiments of the present disclosure as described above, in a MIMO Spatial Multiplexing scheme, transmit diversity may be increased and bit-error-rate (BER) performance may be improved.

1 is a block diagram for explaining the configuration of a transmission device according to an embodiment of the present invention;
2 to 8 are diagrams for explaining a MIMO precoding method according to various embodiments of the present invention;
9 is a block diagram illustrating a detailed configuration of a transmission device according to an embodiment of the present invention.
10 is a block diagram illustrating a detailed configuration of a MIMO precoder according to an embodiment of the present invention, and
11 is a flowchart illustrating a precoding method according to an embodiment of the present invention.
12 is a block diagram illustrating a configuration of a receiving device according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block diagram illustrating a configuration of a transmission device according to an embodiment of the present invention. Referring to FIG. 1, the transmission apparatus 100 includes a MIMO precoder 110 and an OFDM modulator 120.

The MIMO precoder 110 MIMO precodes a first input signal and a second input signal to generate a first transmission signal and a second transmission signal.

In this case, the first input signal and the second input signal input to the MIMO precoder 110 may be modulation symbols. That is, bits transmitted to a receiving device (not shown) are 4-QAM (Quadrature Amplitude Modulation), 16-QAM (or 16-NUC), 64-QAM (or 64-NUC), 256-QAM (or 256-NUC). ), 1024-QAM (or 1024-NUC), 4096-QAM (or 4096-NUC), and the like, the QAM symbol is demultiplexed into two input signals, and a MIMO precoder ( 110) can be sequentially input. In this case, the QAM constellation may be a uniform constellation (UC) or a non-uniform constellation (NUC). Here, a QAM having a non-uniform constellation may be referred to as NUC. Accordingly, the MIMO precoder 110 may generate a first transmission signal and a second transmission signal for MIMO transmission by performing MIMO precoding in symbol units.

Meanwhile, a detailed method of MIMO precoding the first input signal and the second input signal by the MIMO precoder 110 will be described later.

The OFDM modulator 120 modulates orthogonal frequency division multiplexing (OFDM) on the first transmission signal and the second transmission signal.

Specifically, the OFDM modulator 120 may OFDM-modulate each of the first transmission signal and the second transmission signal to map the OFDM frame. That is, the OFDM modulator 120 may perform OFDM modulation by mapping the precoded symbols of the first transmission signal and the precoded symbols of the second transmission signal to subcarriers of different OFDM frames, respectively.

Here, the OFDM frame may be transmitted to a receiving device (not shown) through the MIMO scheme. For example, an OFDM frame generated by OFDM modulation of the first transmission signal is transmitted to a receiving device (not shown) through a first transmission antenna (not shown), and the OFDM frame generated by OFDM modulation of the second transmission signal is It may be transmitted to a receiving device (not shown) through a second transmission antenna (not shown).

Hereinafter, a detailed method of performing MIMO precoding on input signals by the MIMO precoder 110 will be described.

Specifically, when the first input signal and the second input signal are input, the MIMO precoder 110 pre-phase shifts or pre-phase shifts/hops the second input signal, and performs a pre-phase shift with the first input signal. Alternatively, MIMO precoding may be performed by superposition encoding the pre-phase shifted/hopped second input signal.

Here, the pre-phase shift means shifting the phase of a QAM symbol, which is an input signal having a complex value, by a predetermined value. For example, when the pre-phase shift parameter θ is π/7, the phase of the QAM symbol may be shifted by π/7 by the pre-phase shift.

In addition, pre-phase shifting/hopping means shifting the phase of the QAM symbol by a predetermined value and sequentially hopping (or rotating) the phase of the QAM symbol by a predetermined value according to the symbol index. For example, when the pre-phase shift/hopping parameter θ(k) is π/7+k×π/2, the phase of the QAM symbol is shifted by π/7 by pre-phase shift/hopping, and the symbol index k Depending on, it can be hopped sequentially by π/2. Accordingly, as a result, the phase of the QAM symbol may be shifted by π/7+k×π/2 according to the symbol index k.

Hereinafter, various embodiments in which the MIMO precoder 110 performs MIMO precoding will be described. Meanwhile, pre-phase shift or pre-phase shift/hopping may be applied to one of the first input signal and the second input signal, but hereinafter, for convenience of description, the second input signal and the second input signal are It is assumed that pre-phase shift or pre-phase shift/hopping is performed on the input signal.

For example, the MIMO precoder 110 may perform MIMO precoding using Equation 1 as follows.

는 프리-페이즈 쉬프트 매트릭스,

는 중첩 인코딩 매트릭스, θ는 프리-페이즈 쉬프트 파라미터, ψ는 중첩 인코딩 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift matrix,

Is the superposition encoding matrix, θ is the pre-phase shift parameter, and ψ is the superposition encoding parameter.

Meanwhile, k is an index of symbols constituting each input signal. Meanwhile, since the symbols precoded by the MIMO precoder 110 are mapped to the OFDM frame by the OFDM modulator 120, k may be regarded as a subcarrier index of the OFDM frame. Here, in that each subcarrier constitutes an OFDM cell, when the number of OFDM cells is N _cells , k may be k=0,1,...,N _cell /2-1. Meanwhile, k may have the same meaning in the following embodiments.

을 곱하여, θ만큼의 위상이 프리-페이즈 쉬프트된 제2 입력 신호

×c2(k)를 생성할 수 있다.Referring to Equation 1, the MIMO precoder 110 pre-phase shifts the input signals by multiplying the input signals by a pre-phase shift matrix. That is, the MIMO precoder 110 is applied to the first input signal c ₁ (k) and the second input signal c ₂ (k).

The second input signal in which the phase is pre-phase shifted by θ by multiplying by

×c2(k) can be created.

×c₂(k)에

을 곱하여 제1 전송 신호 x₁(k)=cosψ×c₁(k)+

×sinψ×c₂(k)와 제2 전송 신호 x₂(k)=sinψ×c₁(k)-

×cosψ×c₂(k)를 생성할 수 있다.Further, the MIMO precoder 110 may generate a first transmission signal and a second transmission signal by performing superposition encoding on the first input signal and the pre-phase-shifted second input signal. Here, the superposition encoding is performed by multiplying the first input signal and the pre-phase shifted second input signal by the superposition encoding matrix. That is, the MIMO precoder 110 is the first input signal c ₁ (k) and the pre-phase shifted second input signal

×c to ₂ (k)

By multiplying the first transmission signal x ₁ (k)=cosψ×c ₁ (k)+

×sinψ×c ₂ (k) and the second transmission signal x ₂ (k)=sinψ×c ₁ (k)-

×cosψ×c ₂ (k) can be generated.

Hereinafter, referring to FIG. 2, a method of performing MIMO precoding will be described in the case of θ=π/7 and ψ=π/3 as an example. Meanwhile, in FIG. 2, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as the constellation diagram 210 and the constellation diagram 220, respectively.

The MIMO precoder 110 sequentially multiplies the first input signal c ₁ (k) and the second input signal c ₂ (k) by the pre-phase shift matrix 250 and the superposition encoding matrix 260 to obtain a first transmission signal. It is possible to generate x ₁ (k) and a second transmission signal x ₂ (k).

Specifically, when the first input signal c ₁ (k) and the second input signal c ₂ (k) are multiplied by the pre-phase shift matrix 250, the phase of the first input signal c ₁ (k) does not change, but 2 The phase of the input signal c ₂ (k) is pre-phase shifted by π/7. Accordingly, after the pre-phase shift matrix 250 is multiplied, the constellation of the second input signal c ₂ (k) becomes the same as the constellation 240, but the constellation of the first input signal c ₁ (k) (230) is the same as before.

×c₂(k)에 중첩 인코딩 매트릭스(260)를 곱하면, 제1 전송 신호 x₁(k)=cosπ/3×c₁(k)+

×sinπ/3×c₂(k)가 생성되고 제2 전송 신호 x₂(k)=sinπ/3×c₁(k)-

×cosπ/3×c₂(k)가 생성된다.And, the first input signal c ₁ (k) and the second input signal pre-phase shifted by π/7

When xc ₂ (k) is multiplied by the superimposed encoding matrix 260, the first transmission signal x ₁ (k)=cosπ/3×c ₁ (k)+

×sinπ/3×c ₂ (k) is generated and the second transmission signal x ₂ (k)=sinπ/3×c ₁ (k)-

×cosπ/3×c ₂ (k) is produced.

×c₂(k)을 기준으로 cosπ/3의 작은 파워를 갖는 c₁(k)가 중첩되는 성상점으로 표현될 수 있으므로, 제1 전송 신호 x₁(k)의 성상도는 성상도(270)와 같다. 그리고, 제2 전송 신호 x₂(k)의 성상도는 sinπ/3의 큰 파워를 갖는 c₁(k)를 기준으로 cosπ/3의 작은 파워를 갖는

×c₂(k)가 중첩되는 성상점으로 표현될 수 있으므로, 제2 전송 신호 x₂(k)의 성상도는 성상도(280)와 같다.Accordingly, the constellation of the first transmission signal x ₁ (k) has a large power of sinπ/3

Since c ₁ (k) having a small power of cosπ/3 based on ×c ₂ (k) can be expressed as an overlapping constellation point, the constellation of the first transmission signal x ₁ (k) is constellation 270 ) Is the same. And, the constellation of the second transmission signal x ₂ (k) has a small power of cosπ/3 based on c ₁ (k) having a large power of sinπ/3

Since xc ₂ (k) can be expressed as an overlapping constellation point, the constellation diagram of the second transmission signal x ₂ (k) is the same as the constellation diagram 280.

Meanwhile, ○ shown as a solid line in the constellation diagram 270 of FIG. 2 corresponds to a constellation point for the precoded transmission symbol of the first transmission signal x ₁ (k), and the solid line in the constellation diagram 280 of FIG. 2 □ shown as corresponds to a constellation point for the precoded transmission symbol of the second transmission signal x ₂ (k). In this way, the constellation point for each transmission signal is determined by the combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k) (that is, because it is mapped), the first The transmission signal x ₁ (k) and the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

In this way, each of the first transmission signal x ₁ (k) and the second transmission signal x ₂ (k) consists of a combination of the first input signal c ₁ (k) and the second input signal c ₂ (k), and is a MIMO method. Accordingly, transmission capacity may be increased in that transmission is transmitted to a receiving device (not shown) through different antennas.

In addition, in that the second input signal c ₂ (k) is pre-phase shifted and then overlapped and encoded with the first input signal c ₁ (k), the constellations of the transmission signals x ₁ (k) and x ₂ (k) Figs. 270 and 280 become spherical constellations. That is, in that the constellations 270 and 280 of the transmission signals x ₁ (k) and x ₂ (k) are transformed into a Gaussian form, the peak-symbol energy ( peak-symbol energy) may be reduced, and transmission diversity may be increased in a shaping gain and a fading channel, thereby improving BER performance.

On the other hand, in FIG. 2, the case of θ=π/7 and ψ=π/3 is described, but this is only an example, and it goes without saying that θ and ψ may have various values.

As another example, the MIMO precoder 110 may perform MIMO precoding using Equation 2 below.

는 프리-페이즈 쉬프트/호핑 매트릭스,

는 중첩 코딩 매트릭스, θ(k)는 k 번째 심볼에 대한 프리-페이즈 쉬프트/호핑 파라미터, ψ는 중첩 인코딩 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is an overlapping coding matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, and ψ is an overlapping encoding parameter.

As described above, pre-phase shifting/hopping is performed with pre-phase shifting and pre-phase hopping, and pre-phase hopping can be seen as sequentially rotating the phase of each symbol by a predetermined value according to the symbol index. have. Therefore, in Equation 2, the pre-phase shift/hopping parameter θ(k) is a function of the symbol index k, which is different from Equation 1.

Hereinafter, a method of generating transmission signals by MIMO precoding when θ(k)=π/7+k×π/2 and ψ=π/3 will be described with reference to FIG. 3. Meanwhile, in FIG. 3, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as the constellation diagram 310 and the constellation diagram 320, respectively.

The MIMO precoder 110 sequentially multiplies the first input signal c ₁ (k) and the second input signal c ₂ (k) by the pre-phase shift/hopping matrix 330 and the superposition encoding matrix 340 to obtain the first It is possible to generate a transmission signal x ₁ (k) and a second transmission signal x ₂ (k).

Specifically, when the first input signal c ₁ (k) and the second input signal c ₂ (k) are multiplied by the pre-phase shift/hopping matrix 330, the phase of the first input signal c ₁ (k) is changed. However, the phase of the second input signal c ₂ (k) is pre-phase shifted by π/7 and pre-phased/hopped sequentially by π/2 according to the symbol index k.

That is, when k=4n (n=0,1,...), the 4n-th symbol c ₂ (4n) of the second input signal is pre-phase shifted/hopped by π/7, and k=4n+1 ( If n=0,1,...), the 4n+1 th symbol c ₂ (4n+1) of the second input signal is pre-phase shifted/hopped by π/7+π/2, and k=4n+ In the case of 2(n=0,1,...), the 4n+2 th symbol c ₂ (4n+2) of the second input signal is pre-phase shifted/hopped by π/7+2×π/2, When k=4n+3 (n=0,1,...), the 4n+3 th symbol c ₂ (4n+3) of the second input signal is pre-phase shifted by π/7+3×π/2 /It is hoping.

×c₂(k)에 중첩 인코딩 매트릭스(340)를 곱하면, 제1 전송 신호 x₁(k)=cosπ/3×c₁(k)+

×sinπ/3×c₂(k)가 생성되고 제2 전송 신호 x₂(k)=sinπ/3×c₁(k)-

×cosπ/3×c₂(k)가 생성된다.And, the first input signal c ₁ (k) and the second input signal pre-phase shifted/hopped by π/7+k×π/2

When xc ₂ (k) is multiplied by the superimposed encoding matrix 340, the first transmission signal x ₁ (k)=cosπ/3×c ₁ (k)+

×sinπ/3×c ₂ (k) is generated and the second transmission signal x ₂ (k)=sinπ/3×c ₁ (k)-

×cosπ/3×c ₂ (k) is produced.

As described above, in that the phase of the second input signal c ₂ (k) is sequentially pre-phase hopped by a predetermined value according to the symbol index k, the transmission signals x ₁ (k) and x ₂ (k) The constellation may be expressed differently according to the symbol index k.

Specifically, when k=4n (n=0,1,...), the 4n-th symbol c ₂ (4n) of the second input signal is pre-phase shifted/hopped by π/7, so that the first transmission signal x The constellation of ₁ (k) is the same as the constellation 350-1, and the constellation of the second transmission signal x ₂ (k) is expressed as the constellation 350-2. In addition, when k=4n+1 (n=0,1,...), the 4n+1 th symbol c ₂ (4n+1) of the second input signal is pre-phase shifted by π/7+π/2. /Because it is hopping, the constellation of the first transmission signal x ₁ (k) is the same as the constellation 360-1, and the constellation of the second transmission signal x ₂ (k) is expressed as the constellation 360-2. . And, in the case of k=4n+2 (n=0,1,...), the 4n+2 th symbol c ₂ (4n+2) of the second input signal is free by π/7+2×π/2- Since phase shift/hopping, the constellation of the first transmission signal x ₁ (k) is the same as the constellation 370-1, and the constellation of the second transmission signal x ₂ (k) is the same as the constellation 370-2. Is shown. In addition, in the case of k=4n+3 (n=0,1,...), the 4n+3th symbol c ₂ (4n+3) of the second input signal is free by π/7+3×π/2- Since the phase shift/hopping, the constellation of the first transmission signal x ₁ (k) is the same as the constellation diagram 380-1, and the constellation of the second transmission signal x2 (k) is expressed as the constellation diagram 380-2. Lose.

On the other hand, in the constellation diagrams 350-1 to 380-1 of FIG. 3, ○ shown by a solid line corresponds to a constellation point for the precoded symbol of the first transmission signal x ₁ (k), and the constellation diagram 350-2 □ shown by a solid line in 380-2) corresponds to a constellation point for a precoded symbol of the second transmission signal x ₂ (k). In this way, the constellation point for each transmission signal is determined by a combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k), so the first transmission signal x ₁ (k ) And the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

Referring to FIG. 3, in that pre-phase hopping is performed sequentially by π/2 according to the symbol index, the constellations of transmission signals are rotated as 1 and 2 according to the symbol index. That is, since bit-to-symbol mapping is changed according to the symbol index, transmission diversity may be increased compared to the case of FIG. 2.

However, since the magnitude of the phases that are sequentially pre-phase hopped according to the symbol index is π/2, in the case of FIG. 3, symbol mapping for the constellations 350-1 to 380-2 of the transmitted signals is time-varying, but It maintains a certain constellation of the shape. Accordingly, in the case of FIG. 3 as well as before applying the pre-phase shift/hopping, peak-symbol energy may be reduced, and transmit diversity may be increased, thereby improving BER performance in a fading channel.

Meanwhile, in FIG. 3, the case of θ(k)=π/7+k×π/2 and ψ=π/3 is described, but this is only an example, and θ(k) and ψ may have various values. Of course.

As another example, the MIMO precoder 110 may perform MIMO precoding using Equation 3 below.

는 프리-페이즈 쉬프트 매트릭스,

는 중첩 인코딩 매트릭스, θ는 프리-페이즈 쉬프트 파라미터, ψ(k)는 k 번째 심볼에 대한 중첩 인코딩 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift matrix,

Is an overlapping encoding matrix, θ is a pre-phase shift parameter, and ψ(k) is an overlapping encoding parameter for the k-th symbol.

Referring to Equation 3, since the superposition encoding parameter ψ(k) is a function of the symbol index k, the superposition encoding parameter ψ(k) has different values according to the symbol index k. That is, Equation 3 is in that the magnitude and sign (ie, positive/negative) of the first and second input signals constituting the first and second transmission signals are different according to the symbol index k, There is a difference from Equation 1.

Hereinafter, a method of generating transmission signals by MIMO precoding will be described when θ=π/7 and ψ(k)=π/3+k×π/2 with reference to FIG. 4. Meanwhile, in FIG. 4, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as the constellation diagram 410 and the constellation diagram 420, respectively.

The MIMO precoder 110 sequentially multiplies the first input signal c ₁ (k) and the second input signal c ₂ (k) by the pre-phase shift matrix 430 and the superposition encoding matrix 440 to obtain a first transmission signal. It is possible to generate x ₁ (k) and a second transmission signal x ₂ (k).

Specifically, when the first input signal c ₁ (k) and the second input signal c ₂ (k) are multiplied by the pre-phase shift matrix 430, the phase of the first input signal c ₁ (k) does not change, but 2 The phase of the input signal c ₂ (k) is pre-phase shifted by π/7.

×c₂(k)에 중첩 인코딩 매트릭스(440)을 곱하면, 제1 전송 신호 x₁(k)=cos(π/3+k×π/2)×c₁(k)+

×sin(π/3+k×π/2)×c₂(k)가 생성되고 제2 전송 신호 x₂(k)=sin(π/3+k×π/2)×c₁(k)-

×cos(π/3+k×π/2)×c₂(k)가 생성된다. And, the first input signal c ₁ (k) and the second input signal pre-phase shifted by π/7

When xc ₂ (k) is multiplied by the superimposed encoding matrix 440, the first transmission signal x ₁ (k) = cos(π/3+k×π/2)×c ₁ (k)+

×sin(π/3+k×π/2)×c ₂ (k) is generated and the second transmission signal x ₂ (k)=sin(π/3+k×π/2)×c ₁ (k) -

×cos(π/3+k×π/2)×c ₂ (k) is generated.

In this case, since the overlap encoding parameter ψ(k) varies according to the symbol index k, the constellations of the transmission signals x ₁ (k) and x ₂ (k) may be expressed differently according to the symbol index k. .

×c₂(k)를 기준으로 cos(π/3+k×π/2)의 작은 파워를 갖는 c₁(k)가 중첩되는 성상점으로 표현될 수 있으므로, 제1 전송 신호 x₁(k)의 성상도는 성상도(450-1, 470-1)와 같고, 제2 전송 신호 x₂(k)의 성상도는 sin(π/3+k×π/2)의 큰 파워를 갖는 c₁(k)를 기준으로 cos(π/3+k×π/2)의 작은 파워를 갖는

×c2(k)가 중첩되는 성상점으로 표현될 수 있으므로, 제2 전송 신호 x₂(k)의 성상도는 성상도(450-2, 470-2)와 같다.Specifically, when k=4n (n=0,1,...) and k=4n+2 (n=0,1,...) (when k is an even number), the first transmission signal x ₁ The constellation of (k) has a large power of sin(π/3+k×π/2)

Since c ₁ (k) having a small power of cos(π/3+k×π/2) based on ×c ₂ (k) can be expressed as an overlapping constellation point, the first transmission signal x ₁ (k ) Is the same as the constellations (450-1, 470-1), and the constellation of the second transmission signal x ₂ (k) is c with a large power of sin(π/3+k×π/2) _With a small power of cos(π/3+k×π/2) based on ₁ (k)

Since xc2(k) can be expressed as an overlapping constellation point, the constellation diagram of the second transmission signal x ₂ (k) is the same as the constellation diagrams 450-2 and 470-2.

×c₂(k)가 중첩되는 성상점으로 표현될 수 있으므로 제1 전송 신호 x₁(k)의 성상도는 성상도(460-1, 480-1)와 같고, 제2 전송 신호 x₂(k)의 성상도는 cos(π/3+k×π/2)의 큰 파워를 갖는

×c₂(k)를 기준으로 sin(π/3+k×π/2)의 작은 파워를 갖는 c₁(k)가 중첩되는 성상점으로 표현될 수 있으므로, 제2 전송 신호 x₂(k)의 성상도는 성상도(460-2, 480-2)와 같다.On the other hand, when k=4n+1 (n=0,1,...) and k=4n+3 (n=0,1,...) (when k is odd), the first transmission signal x constellation of ₁ (k) is cos (π / 3 + k × π / 2) relative to the c ₁ (k) having a large power with a small power of sin (π / 3 + k × π / 2)

Since xc ₂ (k) can be expressed as an overlapping constellation point, the constellation of the first transmission signal x ₁ (k) is the same as the constellation diagrams 460-1 and 480-1, and the second transmission signal x ₂ ( The constellation of k) has a large power of cos(π/3+k×π/2)

Since c ₁ (k) having a small power of sin(π/3+k×π/2) based on ×c ₂ (k) can be expressed as an overlapping constellation point, the second transmission signal x ₂ (k ) Is the same as the constellation diagram (460-2, 480-2).

Meanwhile, ○ and □ shown by solid lines in the constellation diagrams 450-1 to 480-1 of FIG. 4 correspond to the constellation points for the precoded symbols of the first transmission signal x ₁ (k), and the constellation diagram 450 □ and ○ shown by solid lines in -2 to 480-2) correspond to constellation points for the precoded symbols of the second transmission signal x ₂ (k). In this way, the constellation point for each transmission signal is determined by a combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k), so the first transmission signal x ₁ (k ) And the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

Referring to FIG. 4, first, since the constellations of the transmission signals x ₁ (k) and x ₂ (k) become spherical, the peak-symbol energy compared to before applying the pre-phase shift Can be reduced and transmit diversity is increased to improve BER performance in a fading channel.

In addition, in that the superimposed encoding parameter ψ(k) varies according to the symbol index k, the precoded symbols constituting the transmission signals x ₁ (k) and x ₂ (k) are the first input having a large power. signal c ₁ (k) and the second input signal c ₂ a second input signal c ₂ (k) of the first input signal having the smaller power has a (k) is superposed to the generated symbol with a large power having a small power c ₁ (k) includes symbols generated by overlapping. Accordingly, transmission diversity may be increased even when a problem occurs in one transmission antenna during MIMO transmission. In addition, bit-to-symbol mapping is time-varying as the codes of the first and second input signals constituting the superimposed-encoded first transmission signal and the second transmission signal change according to the symbol index k. Transmission diversity may be increased compared to the case of 2.

Meanwhile, in FIG. 4, θ=π/7 and ψ(k)=π/3+k×π/2 have been described, but this is only an example, and θ and ψ(k) may have various values. Of course.

As another example, the MIMO precoder 110 may perform MIMO precoding using Equation 4 below.

는 프리-페이즈 쉬프트/호핑 매트릭스,

는 중첩 인코딩 매트릭스, θ(k)는 k 번째 심볼에 대한 프리-페이즈 쉬프트/호핑 파라미터, ψ(k)는 k 번째 심볼에 대한 중첩 인코딩 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is a superposition encoding matrix, θ(k) is a pre-phase shift/hopping parameter for the k th symbol, and ψ(k) is a superposition encoding parameter for the k th symbol.

In Equation 4, the pre-phase shift/hopping parameter θ(k) and the superimposed encoding parameter ψ(k) are functions of the symbol index k, and thus the pre-phase shift/hopping parameter θ(k) and the overlapping encoding parameter ψ (k) has a different value depending on the symbol index k. That is, in Equation 4, the phase of the second input signal c ₂ (k) is sequentially pre-phase-hopped by a constant value according to the symbol index k, and the first transmission signal x ₁ (k) and the second It is different from Equation 1 in that the magnitude and sign of the first input signal c ₁ (k) and the second input signal c ₂ (k) constituting the 2 transmission signal x ₂ (k) are different.

Hereinafter, referring to FIG. 5, a method of generating transmission signals by MIMO precoding when θ(k)=π/7+k×π/2 and ψ(k)=π/3+k×π/2 Let me explain. Meanwhile, in FIG. 5, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as the constellation diagram 510 and the constellation diagram 520, respectively.

The MIMO precoder 110 sequentially multiplies the first input signal c ₁ (k) and the second input signal c ₂ (k) by the pre-phase shift/hopping matrix 530 and the superposition encoding matrix 540 to obtain the first It is possible to generate a transmission signal x ₁ (k) and a second transmission signal x ₂ (k).

Here, since θ(k)=π/7+k×π/2, the phase of the second input signal c ₂ (k) is sequentially pre-phase hopped by π/2 according to the symbol index k, and ψ(k )=π/3+k×π/2, so the first input signal c ₁ (k) constituting the first transmission signal x ₁ (k) and the second transmission signal x ₂ (k) according to the symbol index k 2 The size and sign of the input signal c ₂ (k) are different.

Accordingly, the constellation of the first transmission signal x ₁ (k) is the same as the constellations 550-1, 560-1, 570-1, and 580-1, and the constellation of the second transmission signal x ₂ (k) May be represented as constellation diagrams 550-2, 560-2, 570-2, 580-2.

Meanwhile, ○ and □ shown by solid lines in the constellation diagrams 550-1 to 580-1 of FIG. 5 correspond to the constellation points for the precoded symbols of the first transmission signal x ₁ (k), and the constellation diagram 550 □ and ○ shown in solid lines in -2 to 580-2) correspond to constellation points for the precoded symbols of the second transmission signal x ₂ (k). In this way, the constellation point for each transmission signal is determined by a combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k), so the first transmission signal x ₁ (k ) And the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

5, the precoded symbols constituting the transmission signals x ₁ (k) and x ₂ (k) have a first input signal c ₁ (k) having a large power and a small power according to the symbol index. the symbols, to which the second input signal c ₂ (k) the first input signal c ₁ (k) having a superimposed is generated symbols and the second input signal c ₂ (k) with a small power with a large power is superimposed generated Includes them. In addition, the constellation of the precoded symbol has a spherical shape, and is shifted as ① and ② according to the symbol index.

Accordingly, even in the case of FIG. 5, the peak-symbol energy may be reduced compared to before applying the pre-phase shift/hopping, and transmission diversity may be increased, thereby improving BER performance in a fading channel.

Meanwhile, in FIG. 5, the case of θ(k)=π/7+k×π/2 and ψ=π/3+k×π/2 is described, but this is only an example, and θ(k) and ψ( Of course, k) can be of various values.

Meanwhile, the MIMO precoder 110 superimposes the first input signal and the pre-phase shifted or pre-phase shifted/hopped second input signal, and then performs post-phase shifting or post-phase hopping additionally to perform MIMO-free. You can do the coding.

Here, the post-phase shift means shifting the phase of a QAM symbol on which pre-phase shift or pre-phase shift/hopping and superposition encoding is performed by a predetermined value. For example, when the post-phase shift parameter Φ is π/7, the phase of the QAM symbol may be shifted by π/7 by the post-phase shift.

In addition, post-phase hopping refers to sequentially hopping a phase of a QAM symbol on which pre-phase shift or pre-phase shift/hopping and superposition encoding is performed by a predetermined value according to a symbol index. That is, for example, when the post-phase hopping parameter Φ(k) is k×π/7, the phase of the QAM symbol may be sequentially hopped by π/7 according to the symbol index k by post-phase hopping. .

On the other hand, the reason why the terms free and post are added to the phase shift and phase hopping in the present invention is because the post-phase shift and post-phase hopping are performed after the pre-phase shift and the pre-phase shift/hopping in order. to be.

In this case, the post-phase shift and post-phase hopping may be performed by multiplying the post-phase shift matrix and the post-phase hopping matrix, respectively. That is, the MIMO precoder 110 sequentially multiplies the input signals by the pre-phase shift matrix or the pre-phase shift/hopping matrix and the superposition encoding matrix as shown in Equations 1 to 4, and then post the result value. -MIMO precoding can be performed by additionally multiplying a phase shift matrix or a post-phase hopping matrix.

For example, the MIMO precoder 110 may perform MIMO precoding using Equation 5 below.

는 프리-페이즈 쉬프트/호핑 매트릭스,

는 중첩 인코딩 매트릭스,

는 포스트-페이즈 쉬프트 매트릭스, θ(k)는 k 번째 심볼에 대한 프리-페이즈 쉬프트/호핑 파라미터, ψ는 중첩 인코딩 파라미터, Φ는 포스트-페이즈 쉬프트 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is a post-phase shift matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, ψ is an overlap encoding parameter, and φ is a post-phase shift parameter.

Referring to Equation 5, Equation 5 is the same as the signal generated by Equation 2 and additionally multiplied by a post-phase shift matrix.

×sinψ×c₂(k), s₂(k)=sinψ×c₁(k)-

×cosψ×c₂(k)라고 할 때, 수학식 5에 따른 MIMO 프리코딩에 의해 전송 신호들 x₁(k)=s₁(k), x₂(k)=

×s₂(k)이 생성될 수 있다. 즉, 수학식 5에 의해 생성된 전송 신호들은 수학식 2에 의해 생성된 신호들 중 s₂(k)의 위상을 Φ 만큼 포스트-페이즈 쉬프트시킨 것과 동일하다.Specifically, the signals generated by Equation 2 are s ₁ (k) = cosψ × c ₁ (k) +

×sinψ×c ₂ (k), s ₂ (k)=sinψ×c ₁ (k)-

When x cosψ×c ₂ (k), transmission signals x ₁ (k) = s ₁ (k), x ₂ (k) = by MIMO precoding according to Equation 5

×s ₂ (k) can be created. That is, the transmission signals generated by Equation 5 are the same as those obtained by post-phase shifting the phase of s ₂ (k) by Φ among the signals generated by Equation 2.

Hereinafter, referring to FIG. 6, when θ(k)=π/7+k×π/2, ψ=π/3, and Φ=π/7, a method of generating transmission signals by MIMO precoding will be described. do. Meanwhile, in FIG. 6, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as a constellation 610 and a constellation 620, respectively.

The MIMO precoder 110 includes a pre-phase shift/hopping matrix 630, a superposition encoding matrix 640 and a post-phase shift matrix in the first input signal c ₁ (k) and the second input signal c ₂ (k). A first transmission signal x ₁ (k) and a second transmission signal x ₂ (k) may be generated by sequentially multiplying (650).

×sinπ/3×c₂(k), s₂(k)=sinπ/3×c₁(k)-

×cosπ/3×c₂(k)라 한다. Here, the input signals c ₁ (k) and c ₂ (k) are sequentially multiplied by the pre-phase shift/hopping matrix 630 and the superimposed encoding matrix 640 in that the result is the same as in FIG. Should be omitted. Meanwhile, signals generated by multiplying the input signals c ₁ (k) and c ₂ (k) by the pre-phase shift/hopping matrix 630 and the superposition encoding matrix 640 are s ₁ (k) = cosπ/3× c ₁ (k)+

×sinπ/3×c ₂ (k), s ₂ (k)=sinπ/3×c ₁ (k)-

Let ×cosπ/3×c ₂ (k).

×s₂(k)이 생성된다. 이와 같이, 제1 전송 신호 x₁(k)는 s₁(k)와 동일하고 제2 전송 신호 x₂(k)는 s₂(k)가 π/7만큼 포스트-페이즈 쉬프트된 것과 동일할 수 있다.In this case, when s ₁ (k) and s ₂ (k) are multiplied by the post-phase shift matrix 650 to generate transmission signals x ₁ (k) and x ₂ (k), transmission signals x ₁ (k)=s ₁ (k), x ₂ (k)=

×s ₂ (k) is generated. In this way, the first transmission signal x ₁ (k) is equal to s ₁ (k) and the second transmission signal x ₂ (k) may be equal to s ₂ (k) post-phase shifted by π/7. have.

Accordingly, the constellation of the first transmission signal x ₁ (k) is the same as the constellations (660-1, 670-1, 680-1, 690-1), and the constellation of the second transmission signal x ₂ (k) is It can be expressed as a constellation diagram (660-2, 670-2, 680-2, 690-2).

On the other hand, in the constellation diagrams 660-1 to 690-1 of FIG. 6, ○ shown by a solid line corresponds to a constellation point for the precoded symbol of the first transmission signal x ₁ (k), and the constellation diagram 660-2 □ indicated by a solid line in 690-2) corresponds to a constellation point for a precoded symbol of the second transmission signal x ₂ (k). In this way, the constellation point for each transmission signal is determined by a combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k), so the first transmission signal x ₁ (k ) And the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

6, the first aqueous phase of the transmitted signal x ₁ (k) degrees (660-1, 670-1, 680-1, 690-1) includes a first transmission signal x ₁ (k) shown in Figure 3 The constellation of (350-1, 360-1, 370-1, 380-1) is the same, and the constellation (660-2) of the second transmission signal x ₂ (k) is the second transmission shown in FIG. It is the same as the constellation 350-2 of the signal x ₂ (k). However, the second is also the aqueous phase of the transmission signal _{x 2 (k) (670-2,} 680-2, 690-2) is a (360-2 constellation of the second transmission signal x ₂ (k) shown in Figure 3, It can be seen that 370-2 and 380-2) are shifted by π/7 as in ③.

In this way, since the constellation of the transmission signal is shifted entirely by the post-phase shift, it is possible to obtain an additional transmission diversity gain.

As another example, the MIMO precoder 110 may perform MIMO precoding using Equation 6 below.

는 프리-페이즈 쉬프트/호핑 매트릭스,

는 중첩 인코딩 매트릭스,

는 포스트-페이즈 호핑 매트릭스, θ(k)는 k 번째 심볼에 대한 프리-페이즈 쉬프트/호핑 파라미터, ψ는 중첩 인코딩 파라미터, Φ(k)는 k 번째 심볼에 대한 포스트-페이즈 호핑 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is a post-phase hopping matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, ψ is an overlap encoding parameter, and φ(k) is a post-phase hopping parameter for the k-th symbol.

Referring to Equation 6, Equation 6 is the same as the signal generated by Equation 2 and additionally multiplied by a post-phase hopping matrix.

×sinψ×c₂(k), s₂(k)=sinψ×c₁(k)-

×cosψ×c₂(k)라고 할 때, 수학식 6에 따른 MIMO 프리코딩에 의해 전송 신호들 x₁(k)=s₁(k), x₂(k)=

×s₂(k)이 생성될 수 있다. 즉, 수학식 6에 의해 생성된 전송 신호들은 수학식 2에 의해 생성된 신호들 중 s₂(k)의 위상을 Φ(k)만큼 포스트-페이즈 호핑시킨 것과 동일하다.Specifically, the signals generated by Equation 2 are s ₁ (k) = cosψ × c ₁ (k) +

×sinψ×c ₂ (k), s ₂ (k)=sinψ×c ₁ (k)-

When × cosψ × c ₂ (k), transmission signals x ₁ (k) = s ₁ (k), x ₂ (k) = by MIMO precoding according to Equation 6

×s ₂ (k) can be created. That is, the transmission signals generated by Equation 6 are the same as those obtained by post-phase hopping the phase of s ₂ (k) by Φ (k) among the signals generated by Equation 2.

As described above, in that post-phase hopping sequentially rotates the phase of each symbol by a constant value according to the symbol index, the post-phase hopping parameter Φ(k) in Equation 6 is a function of the symbol index k. It is different from Equation 5 in that.

Hereinafter, referring to FIG. 7, when θ(k)=π/7+k×π/2, ψ=π/3, and Φ(k)=k×π/7, transmission signals are generated by MIMO precoding. Explain how. Meanwhile, in FIG. 7, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as the constellation diagram 710 and the constellation diagram 720, respectively.

The MIMO precoder 110 includes a pre-phase shift/hopping matrix 730, a superposition encoding matrix 740 and a post-phase hopping matrix in the first input signal c ₁ (k) and the second input signal c ₂ (k). By sequentially multiplying (750), a first transmission signal x ₁ (k) and a second transmission signal x ₂ (k) may be generated.

×sinπ/3×c₂(k), s₂(k)=sinπ/3×c₁(k)-

×cosπ/3×c₂(k)라 할 수 있다.Here, the input signals c ₁ (k) and c ₂ (k) are sequentially multiplied by the pre-phase shift/hopping matrix 730 and the superimposed encoding matrix 740, and the result is the same as in FIG. Should be omitted. Meanwhile, signals generated by multiplying the input signals c ₁ (k) and c ₂ (k) by the pre-phase shift matrix 730 and the superposition encoding matrix 740 are s ₁ (k) = cosπ/3×c ₁ (k)+

×sinπ/3×c ₂ (k), s ₂ (k)=sinπ/3×c ₁ (k)-

×cosπ/3×c ₂ (k).

×s₂(k)이 생성된다.In this case, when s ₁ (k) and s ₂ (k) are multiplied by the post-phase hopping matrix 750 to generate transmission signals x ₁ (k) and x ₂ (k), transmission signals x ₁ (k)=s ₁ (k), x ₂ (k)=

×s ₂ (k) is generated.

In this way, the second transmission signal x ₂ (k) may be generated by post-phase hopping s ₂ (k) by k×π/7 according to the symbol index k. For example, the 0th symbol x ₂ (0) of the second transmission signal is equal to s ₂ (0), and the 1st symbol x ₂ (1) of the second transmission signal is s ₂ (1) by π/7. It is the same as post-phase hopping, and the second symbol x ₂ (2) of the second transmission signal is the same as that s ₂ (2) is post-phase hopped by 2×π/7, and the third symbol of the second transmission signal x ₂ (3) is equal to s ₂ (3) post-phase hopped by 3×π/7.

Accordingly, the constellation of the first transmission signal x1(k) is the same as the constellations 760-1, 770-1, 780-1, and 790-1, and the constellation of the second transmission signal x2(k) is It can be represented as (760-2, 770-2, 780-2, 790-2).

On the other hand, in the constellation diagrams 760-1 to 790-1 of FIG. 7, ○ shown by a solid line corresponds to a constellation point for the precoded symbol of the first transmission signal x1(k), and the constellation diagrams 760-2 to 790-2) indicated by a solid line corresponds to a constellation point for a precoded symbol of the second transmission signal x2(k). In this way, the constellation point for each transmission signal is determined by a combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k), so the first transmission signal x ₁ (k ) And the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

7, the first aqueous phase of the transmitted signal x ₁ (k) degrees (760-1, 770-1, 780-1, 790-1) includes a first transmission signal x ₁ (k) shown in Figure 3 Is the same as the constellations 350-1, 360-1, 370-1, 380-1, and the constellation 760-2 of the second transmission signal x ₂ (k) is the second transmission shown in FIG. It is the same as the constellation 350-2 of the signal x ₂ (k). However, the second transmission signal constellation of Figure _2, x (k) constellation (770-2, 780-2, 790-2) of the second transmission signal x ₂ (k) shown in Figure 3 (360-2, It can be seen that 370-2 and 380-2) are shifted by k×π/7 as a whole according to the symbol index k.

In this way, the constellation of a transmission signal is hopped as a whole by post-phase hopping, and in particular, additional transmission diversity gains can be obtained in that the constellations of the transmission signal are hopped sequentially by a phase of a predetermined size according to the symbol index k.

Meanwhile, the pre-phase shift/hopping parameter, the superposition encoding parameter, the post-phase shifting parameter, and the post-phase hopping parameter used in FIGS. 6 and 7 are only examples, and they may be various values.

In addition, in FIGS. 6 and 7, it has been described that the pre-phase shift/hopping matrix and the superposition encoding matrix used in MIMO precoding have the same form as in Equation 2, but this is only an example. That is, the MIMO precoder 110 is a post-phase shift matrix in the pre-phase shift matrix or the pre-phase shift/hopping matrix and the superposition encoding matrix defined in Equations 1, 3 and 4 in addition to Equation 2 Alternatively, MIMO precoding may be performed by additionally multiplying the post-phase hopping matrix.

Hereinafter, a method of performing MIMO precoding by additionally multiplying the pre-phase shift/hopping matrix and the superposition encoding matrix defined in Equation 4 by the post-phase hopping matrix will be described as an example.

In this case, the MIMO precoder 110 may perform MIMO precoding using Equation 7 below.

는 프리-페이즈 쉬프트/호핑 매트릭스,

는 중첩 인코딩 매트릭스,

는 포스트-페이즈 호핑 매트릭스, θ(k)는 k 번째 심볼에 대한 프리-페이즈 쉬프트/호핑 파라미터, ψ(k)는 k 번째 심볼에 대한 중첩 인코딩 파라미터, Φ(k)는 k 번째 심볼에 대한 포스트-페이즈 호핑 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, θ(k) is the pre-phase shift/hopping parameter for the k-th symbol, ψ(k) is the superimposed encoding parameter for the k-th symbol, Φ(k) is the post for the k-th symbol -This is a phase hopping parameter.

Referring to Equation 7, Equation 7 is the same as the signal generated by Equation 4 and additionally multiplied by a post-phase shift matrix.

×c₂(k), s₂(k)=sinψ(k)×c₁(k)-cosψ(k)×

×c₂(k)라고 할 때, 수학식 7에 따른 MIMO 프리코딩에 의해 전송 신호들 x₁(k)=s₁(k), x₂(k)=

×s₂(k)이 생성될 수 있다. 즉, 수학식 7에서 생성된 전송 신호들은 수학식 4에 의해 생성된 신호들 중 s₂(k)의 위상을 Φ(k)만큼 포스트-쉬프트 호핑시킨 것과 동일하다.Specifically, the signals generated by Equation 4 are s ₁ (k)=cosψ(k)×c ₁ (k)+sinψ(k)×

×c ₂ (k), s ₂ (k)=sinψ(k)×c ₁ (k)-cosψ(k)×

When xc ₂ (k), transmission signals x ₁ (k) = s ₁ (k), x ₂ (k) = by MIMO precoding according to Equation 7

×s ₂ (k) can be created. That is, the transmission signals generated in Equation 7 are the same as those obtained by post-shifting the phase of s ₂ (k) among the signals generated by Equation 4 by Φ(k).

In the following, referring to FIG. 8, when θ(k)=π/7+k×π/2, ψ(k)=π/3+k×π/2, Φ(k)=k×π/7, MIMO A method of generating transmission signals by precoding will be described. Meanwhile, in FIG. 8, it is assumed that 4-QAM symbols are sequentially input to the MIMO precoder 110 in pairs to form a first input signal c ₁ (k) and a second input signal c ₂ (k). Accordingly, constellations of the first input signal c ₁ (k) and the second input signal c ₂ (k) may be expressed as the constellation diagram 810 and the constellation diagram 820, respectively.

The MIMO precoder 110 includes a pre-phase shift/hopping matrix 830, a superposition encoding matrix 840 and a post-phase hopping matrix in the first input signal c ₁ (k) and the second input signal c ₂ (k). A first transmission signal x ₁ (k) and a second transmission signal x ₂ (k) may be generated by sequentially multiplying (850).

×sin(π/3+k×π/2)×c₂(k), s₂(k)=sin(π/3+k×π/2)×c₁(k)-

×cos(π/3+k×π/2)×c₂(k)라 할 수 있다.Here, the result of sequentially multiplying the input signals c ₁ (k) and c ₂ (k) by the pre-phase shift/hopping matrix 830 and the overlapping encoding matrix 840 is the same as in FIG. Description will be omitted. Meanwhile, signals generated by multiplying the input signals c ₁ (k) and c ₂ (k) by the pre-phase shift/hopping matrix 830 and the superposition encoding matrix 840 are s ₁ (k) = cos(π/ 3+k×π/2)×c ₁ (k)+

×sin(π/3+k×π/2)×c ₂ (k), s ₂ (k)=sin(π/3+k×π/2)×c ₁ (k)-

×cos(π/3+k×π/2)×c ₂ (k).

×s₂(k)이 생성된다.In this case, when s ₁ (k) and s ₂ (k) are multiplied by the post-phase hopping matrix 850 to generate transmission signals x ₁ (k) and x ₂ (k), transmission signals x ₁ (k)=s ₁ (k), x ₂ (k)=

×s ₂ (k) is generated.

In this way, the second transmission signal x ₂ (k) may be generated by post-phase hopping s ₂ (k) by k×π/7 according to the symbol index k. For example, the 0th symbol x ₂ (0) of the second transmission signal is equal to s ₂ (0), and the 1st symbol x ₂ (1) of the second transmission signal is s ₂ (1) by π/7. It is the same as post-phase hopping, and the second symbol x ₂ (2) of the second transmission signal is the same as that s ₂ (2) is post-phase hopped by 2×π/7, and the third symbol of the second transmission signal x ₂ (3) is equal to s ₂ (3) post-phase hopped by 3×π/7.

Accordingly, the constellation of the first transmission signal x ₁ (k) is the same as the constellations 860-1, 870-1, 880-1, and 890-1, and the constellation of the second transmission signal x ₂ (k) is It can be expressed as a constellation diagram (860-2, 870-2, 880-2, 890-2).

Meanwhile, ○ and □ shown by solid lines in the constellation diagrams 860-1, 870-1, 880-1, and 890-1 of FIG. 8 are the constellations of the precoded symbols of the first transmission signal x ₁ (k). Constellation points for the precoded symbols of the second transmission signal x ₂ (k) corresponding to the store and shown in solid lines in the constellation diagrams (860-2, 870-2, 880-2, 890-2) Corresponds to. In this way, the constellation point for each transmission signal is determined by a combination of the 4-QAM first input signal c ₁ (k) and the 4-QAM second input signal c ₂ (k), so the first transmission signal x ₁ (k ) And the second transmission signal x ₂ (k) each have 16 (=4×4) constellation points.

8, a first aqueous phase of the transmitted signal x ₁ (k) degrees (860-1, 870-1, 880-1, 890-1) includes a first transmission signal x ₁ (k) shown in Figure 5 The constellation of (550-1, 560-1, 570-1, 580-1) is the same, and the constellation 860-2 of the second transmission signal x ₂ (k) is the second transmission shown in FIG. It is the same as the constellation 550-2 of the signal x ₂ (k). However, the second transmission signal constellation of Figure _2, x (k) constellation (870-2, 880-2, 890-2) of the second transmission signal x ₂ (k) shown in Figure 5 (560-2, It can be seen that 570-2 and 580-2) are shifted by k×π/7 as a whole according to the symbol index k.

In this way, the constellation of the transmission signal is shifted entirely by post-phase hopping, and in particular, it is possible to obtain an additional transmission diversity gain in that the constellation of the transmission signal is shifted by different phases according to the symbol index k.

Meanwhile, the MIMO precoder 110 may perform MIMO precoding by differentially allocating power to the first input signal and the second input signal before pre-phase shifting the second input signal.

That is, when a pair of modulation symbols input to the MIMO precoder 110 is asymmetric, the MIMO precoder 110 may additionally perform a process of allocating different powers to each input signal during MIMO precoding. have. For example, the MIMO precoder 110 may perform MIMO precoding using Equation 8 below.

는 파워 할당 매트릭스,

는 프리-페이즈 쉬프트/호핑 매트릭스,

는 중첩 인코딩 매트릭스,

는 포스트-페이즈 호핑 매트릭스, γ는 파워 할당 파라미터, θ(k)는 k 번째 심볼에 대한 프리-페이즈 쉬프트/호핑 파라미터, ψ는 중첩 인코딩 파라미터, Φ(k)는 k 번째 심볼에 대한 포스트-페이즈 호핑 파라미터이다.Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, x ₁ (k) is the k-th symbol of the first transmission signal, x ₂ (k) is the k-th symbol of the second transmission signal,

Is the power allocation matrix,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, γ is the power allocation parameter, θ(k) is the pre-phase shift/hopping parameter for the k-th symbol, ψ is the superposition encoding parameter, and Φ(k) is the post-phase for the k-th symbol This is a hopping parameter.

Referring to Equation 8, the MIMO precoder 110 multiplies the input signals c ₁ (k) and c ₂ (k) by a power allocation matrix, and then pre-phase shift/hopping matrix, superposition encoding matrix and post. -MIMO precoding is performed by sequentially multiplying the phase hopping matrix to generate transmission signals x ₁ (k) and x ₂ (k).

Here, when the power allocation parameter γ (0<γ<1) has a value other than 0.5, the MIMO precoder 110 can allocate different powers to input signals through the power allocation matrix during MIMO precoding. do. Accordingly, the transmission channel capacity can be improved.

Meanwhile, in the above-described example, it has been described that the MIMO precoder 110 allocates different powers to input signals through a power allocation matrix during MIMO precoding, but this is only an example, and the MIMO precoder 110 is input It is also possible to allocate the same power to the signals. That is, when the power allocation parameter γ is 0.5, the MIMO precoder 110 may allocate the same power to the input signals through the power allocation matrix. Meanwhile, the power allocation parameter γ according to the modulation method of the input signals may be as shown in Table 1 below.

Meanwhile, referring to Equation 8, it has been described that the pre-phase shift/hopping matrix, the superposition encoding matrix, and the post-phase hopping matrix used in MIMO precoding have the same form as Equation 6, but this is only an example.

That is, when MIMO precoding by additionally multiplying the power allocation matrix, it is of course possible to use the matrix defined in Equations 5 and 7 in addition to Equation 6.

In addition, the MIMO precoder 110 multiplies input signals by a power allocation matrix, and the signals generated accordingly are pre-phase shift matrix or pre-phase shift/hopping matrix defined in Equations 1 to 4 MIMO precoding may also be performed by sequentially multiplying the and the overlapping encoding matrix.

On the other hand, as described above in Equations 1 to 8, the first input signal c ₁ (k) and the second input signal c ₂ (k) are multiplied by matrices of a certain form, and the first transmission signal x is obtained by MIMO precoding. ₁ (k) and a second transmission signal x ₂ (k) are generated. Accordingly, each of the 2×2 matrices generated by multiplying the matrices used for MIMO precoding in each equation may be referred to as a precoding matrix.

9 is a block diagram illustrating a detailed configuration of a transmission device according to an embodiment of the present invention.

Referring to FIG. 9, the transmission apparatus 100 includes a QAM modulator 130, a demultiplexer 140, a MIMO precoder 110, an OFDM modulator 120, a first transmit antenna 151, and a second transmit antenna. Includes 152. Meanwhile, since the MIMO precoder 110 and OFDM modulator 120 of FIG. 9 are the same components as the MIMO precoder 110 and OFDM modulator 120 of FIG. 1, a detailed description of the overlapping part Should be omitted.

The QAM modulator 130 performs QAM modulation on input data. That is, the QAM modulator 130 uses various modulation schemes such as 4-QAM, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, 4096-QAM, etc. to the bits transmitted to the receiving device (not shown). After modulation, QAM symbols (or modulation symbols) generated by QAM modulation may be output to the demultiplexer 140. In this case, the QAM symbols may constitute a uniform constellation or a non-uniform constellation. Meanwhile, the QAM modulator 130 may modulate the input data by the same modulation method, or in some cases, the QAM modulator 130 may modulate the input data by different methods.

For example, the QAM modulator 130 modulates some bits with 4-QAM and modulates the remaining bits with 16-QAM, and outputs QAM symbols generated according to each modulation method to the demultiplexer 140. As another example, the QAM modulator 130 modulates some bits with 16-Uniform QAM and modulates the remaining bits with 64-Non uniform QAM (64-NUC), or modulates some bits with 64 Uniform QAM and modulates the remaining bits with 64 -Non uniform QAM (64-NUC) may be used to modulate, and QAM symbols generated according to each modulation method may be output to the demultiplexer 140.

In this way, the QAM symbol input to the demultiplexer 140 may be composed of various types of symmetric/asymmetric QAM symbol pairs.

The demultiplexer (or serial-to-parallel converter) 140 demultiplexes input symbols and outputs them to the MIMO precoder 110.

Specifically, the demultiplexer 140 demultiplexes the input QAM symbols, outputs some QAM symbols as the first input signal of the MIMO precoder 110, and outputs the remaining QAM symbols as the second input signal of the MIMO precoder 110 Can be printed as

For example, the demultiplexer 140 outputs odd-numbered QAM symbols (or even-numbered symbols) among input QAM symbols as a first input signal of the MIMO precoder 110, and outputs even-numbered QAM symbols ( Alternatively, odd-numbered symbols) may be output as a second input signal of the MIMO precoder 110.

As another example, the demultiplexer 140 may demultiplex the input symbols so that symbols modulated by the same modulation method are input as the same input signal of the MIMO precoder 110. As a specific example, the demultiplexer 140 outputs 4-QAM modulation symbols as a first input signal of the MIMO precoder 110 and outputs 16-QAM modulation symbols as a second input signal of the MIMO precoder 110. I can. Alternatively, the demultiplexer 140 outputs the modulation symbols modulated by the uniform constellation method as a first input signal of the MIMO precoder 110, and modulates the modulation symbols modulated by the non-uniform constellation method by the MIMO precoder 110. It can be output as a second input signal.

The MIMO precoder 110 generates transmission signals by performing MIMO precoding on the first input signal and the second input signal, and outputs the transmission signals to the OFDM modulator 120. To this end, the MIMO precoder 110 may include a power allocation unit 111, a pre-phase shifter 112, an overlap encoding and a post-phase shifter 113, as shown in FIG. 10.

The power allocator 111 may allocate power to the first input signal and the second input signal. Specifically, when the QAM symbols input as the first input signal and the QAM symbols input as the second input signal correspond to an asymmetric QAM symbol pair, the power allocating unit 111 includes a first input signal and a second input signal. In order to allocate different powers to the signals, the input signals are multiplied by the power allocation matrix, and the resultant values may be output to the pre-phase shifter 112.

와 같으며, 파워 할당 파라미터 γ는 상술한 표 1과 같을 수 있다. Here, an example of a power allocation matrix is

And the power allocation parameter γ may be the same as in Table 1 above.

×c₁(k),

×c₂(k)를 프리-페이즈 쉬프터(112)로 출력할 수 있다.Accordingly, when the first input signal input to the MIMO precoder 110 is c ₁ (k) and the second input signal is c ₂ (k), the power allocating unit 111

×c ₁ (k),

×c ₂ (k) can be output to the pre-phase shifter 112.

The pre-phase shifter 112 may pre-phase shift or pre-phase shift/hop the signals output from the power allocator 111.

Specifically, the pre-phase shifter 112 multiplies the signals output from the power allocating unit 111 by a pre-phase shift matrix or a pre-phase shift/hopping matrix, and the resultant value is multiplied by a superimposed encoder/post-phase. It can be output to the shifter 113.

와 같고, 프리-페이즈 쉬프트/호핑 매트릭스의 일 예는

와 같다. 이 경우, 프리-페이즈 쉬프트 매트릭스를 구성하는 프리-페이즈 쉬프트 파라미터는 θ와 같이 심볼 인덱스 k와 무관하게 일정한 값을 가지며, 프리-페이즈 쉬프트/호핑 매트릭스를 구성하는 프리-페이즈 쉬프트/호핑 파라미터는 θ(k)와 같이 심볼 인덱스 k의 함수일 수 있다.Here, an example of a pre-phase shift matrix is

And, an example of a pre-phase shift/hopping matrix is

Same as In this case, the pre-phase shift parameter constituting the pre-phase shift matrix has a constant value, such as θ, regardless of the symbol index k, and the pre-phase shift/hopping parameter constituting the pre-phase shift/hopping matrix is θ. As shown in (k), it may be a function of the symbol index k.

와 같은 프리-페이즈 쉬프트/호핑 매트릭스를 이용하는 경우, 프리-페이즈 쉬프터(112)는

×c₁(k),

×

×c₂(k)를 중첩 인코더/포스트-페이즈 쉬프터(113)로 출력할 수 있다. As a specific example, the pre-phase shifter 112

In the case of using a pre-phase shift/hopping matrix such as, the pre-phase shifter 112

×c ₁ (k),

×

Xc ₂ (k) can be output to the superimposed encoder/post-phase shifter 113.

The superposition encoder/post-phase shifter 113 may perform superposition encoding and post-phase hopping of signals output from the pre-phase shifter 112.

Specifically, the superimposed encoder/post-phase shifter 113 sequentially multiplies the signals output from the pre-phase shifter 112 by the superimposed encoding matrix and the post-phase shift matrix or the post-phase hopping matrix, and the resulting value May be output to the OFDM modulator 120.

또는

과 같을 수 있으며, 중첩 인코딩 매트릭스를 구성하는 중첩 인코딩 파라미터는 ψ와 같이 심볼 인덱스 k와 무관하게 일정한 값을 갖거나 ψ(k)와 같이 심볼 인덱스 k의 함수가 될 수 있다.Here, an example of a nested encoding matrix is

or

The superposition encoding parameter constituting the superposition encoding matrix may have a constant value, such as ψ, regardless of the symbol index k, or may be a function of the symbol index k, such as ψ(k).

와 같고, 포스트-페이즈 호핑 매트릭스의 일 예는

와 같다. 이 경우, 포스트-페이즈 쉬프트 매트릭스를 구성하는 포스트-페이즈 쉬프트 파라미터는 Φ와 같이 심볼 인덱스 k와 무관하게 일정한 값을 가지며, 포스트-페이즈 호핑 매트릭스를 구성하는 포스트-페이즈 호핑 파라미터는 Φ(k)와 같이 심볼 인덱스 k의 함수일 수 있다.Also, an example of a post-phase shift matrix is

And, an example of a post-phase hopping matrix is

Same as In this case, the post-phase shift parameter constituting the post-phase shift matrix has a constant value, such as Φ, regardless of the symbol index k, and the post-phase hopping parameter constituting the post-phase hopping matrix is Φ(k) and Likewise, it may be a function of symbol index k.

와 같은 중첩 인코딩 매트릭스를 이용하고

와 같은 포스트-페이즈 호핑 매트릭스를 이용하는 경우, 중첩 인코더/포스트-페이즈 쉬프터(113)는 제1 전송 신호 x₁(k)=(cosψ×

×c₁(k)+

×sinψ×

×c₂(k))와 제2 전송 신호 x₂(k)=

×(sinψ×

×c₁(k)-

×cosψ×

×c₂(k))를 OFDM 변조부(120)로 출력할 수 있다. As a specific example, the superimposed encoder/post-phase shifter 113

Using a nested encoding matrix such as

In the case of using a post-phase hopping matrix such as, the superimposed encoder/post-phase shifter 113 is the first transmission signal x ₁ (k) = (cos ψ x

×c ₁ (k)+

×sinψ×

×c ₂ (k)) and the second transmission signal x ₂ (k) =

×(sinψ×

×c ₁ (k)-

×cosψ×

×c ₂ (k)) can be output to the OFDM modulator 120.

Meanwhile, in FIG. 10, it has been described that the MIMO precoder 110 is composed of a power allocating unit 111, a pre-phase shifter 112, an overlap encoding and a post-phase shifter 113, but this is only an example.

That is, as described above, in that the MIMO precoder 110 performs MIMO precoding based on Equations 1 to 8, the MIMO precoder 110 may include at least some of the components of FIG. In addition, instead of the superposition encoding/post-phase shifter 113, a superposition encoder (not shown) that performs only superposition encoding may be provided to generate transmission signals.

For example, when the MIMO precoder 110 performs MIMO precoding based on Equations 1 to 4, the MIMO precoder 110 includes a pre-phase shifter 112 and an overlapping encoder (not shown). It may include, and when the MIMO precoder 110 performs MIMO precoding based on Equations 5 to 7, the MIMO precoder 110 superimposes the pre-phase shifter 112 and the encoding/post -May include a phase shifter 113. And, when the MIMO precoder 110 performs MIMO precoding based on Equation 8, the MIMO precoder 110 includes a power allocator 111, a pre-phase shifter 112, and superimposed encoding/post- A phase shifter 113 may be included.

The OFDM modulator 120 performs OFDM modulation on the first transmission signal and the second transmission signal output from the MIMO precoder 110.

Specifically, the OFDM modulator 120 performs OFDM modulation on each of the first transmission signal and the second transmission signal to map each of the first transmission signal and the second transmission signal to a different OFDM frame, and the first transmission signal is mapped. The OFDM frame may be output to the first transmit antenna 151 and the OFDM frame to which the second transmit signal is mapped may be output to the second transmit antenna 152.

The first antenna 151 and the second antenna 152 transmit a signal output from the OFDM modulator 120 to a receiving device (not shown) in a MIMO method. That is, the first transmission antenna 151 transmits the OFDM frame to which the first transmission signal is mapped to the receiving device (not shown) through the channel, and the second transmission antenna 153 is the OFDM frame to which the second transmission signal is mapped. May be transmitted to a receiving device (not shown) through a channel.

11 is a flowchart illustrating a precoding method according to an embodiment of the present invention.

First, when a first input signal and a second input signal are input, the second input signal is pre-phase shifted or pre-phase shifted/hopped, and the first input signal is pre-phase shifted or pre-phase shifted/hopped. 2 The input signals are superimposed and encoded to perform MIMO precoding to generate a first transmission signal and a second transmission signal (S1110).

Thereafter, the first transmission signal and the second transmission signal are subjected to OFDM modulation (S1120).

In step S1110, Equations 1 to 4 may be used during MIMO precoding, and specific methods related to each of these cases have been described above.

In addition, in step S1110, after superimposing the first input signal and the pre-phase shifted or pre-phase shifted/hopped second input signal, post-phase shifting or post-phase hopping is additionally performed to perform MIMO precoding. May be. In this case, Equations 5 to 7 may be used for MIMO precoding, and specific methods related to each of these cases have been described above.

Also, in step S1110, MIMO precoding may be performed by differentially allocating power to the first input signal and the second input signal before pre-phase shifting or pre-phase shifting/hopping the second input signal. In this case, Equation 8 may be used for MIMO precoding, and a specific method related to this case has been described above.

12 is a block diagram illustrating a configuration of a receiving device according to an embodiment of the present invention. Referring to FIG. 12, the reception device 1200 includes a first reception antenna 1211, a second reception antenna 1212, an OFDM demodulation unit 1220, a MIMO decoder 1230, a multiplexer 1240, and a QAM demodulation unit 1250. Includes.

The first receiving antenna 1211 and the second receiving antenna 1212 receive signals transmitted by the transmitting device 100 through a channel. In this case, since the transmitting device 100 and the receiving device 1200 transmit and receive signals in the MIMO method, each of the first receiving antenna 1211 and the second receiving antenna 1212 is a first Signals transmitted by the transmit antenna 151 and the second transmit antenna 152 may be respectively received.

The OFDM demodulation unit 1220 performs OFDM demodulation on signals received from the first and second reception antennas 1211 and 1212.

Specifically, the OFDM demodulator 1220 is a component corresponding to the OFDM modulator 120 of the transmission device 100 and performs an operation corresponding to the OFDM modulator 120.

That is, the transmitting device 100 transmits the OFDM frame mapped with the first transmission signal through the first transmission antenna 151 and transmits the OFDM frame mapped with the second transmission signal through the second transmission antenna 152. In this regard, the OFDM demodulation unit 1220 performs OFDM demodulation on signals received by the first and second reception antennas 1211 and 1212, respectively, and a first reception signal y ₁ generated according to OFDM demodulation. (k) and the second received signal y ₂ (k) may be output to the MIMO decoder 1230.

The MIMO decoder 1230 performs MIMO decoding using a signal received from the OFDM demodulator 1220.

Specifically, the MIMO decoder 1230 is a component corresponding to the MIMO precoder 110 of the transmission device 100 and performs an operation corresponding to the MIMO precoder 110.

That is, the MIMO decoder 1230 decodes the first received signal y ₁ (k) and the second received signal y ₂ (k) received from the OFDM demodulator 1220 based on the channel H and the precoding matrix P. Can be done.

Here, the precoding matrix P is a matrix used for MIMO precoding in the transmission apparatus 100, and may be, for example, a 2×2 complex matrix used for MIMO procoding in Equations 1 to 8. The precoding matrix P can be expressed as Equation 9 below.

×cosψ, p₁₂=

×

×sinψ, p₂₁=

×

×sinψ, p₂₂=-

×

×

×cosψ와 같다.For example, when the transmission device 100 performs MIMO precoding through the method described in Equation 8, p ₁₁ = in the precoding matrix P

×cosψ, p ₁₂ =

×

×sinψ, p ₂₁ =

×

×sinψ, p ₂₂ =-

×

×

Same as ×cosψ.

Meanwhile, information on a precoding matrix used in MIMO precoding by the transmitting device 100 is pre-stored in the receiving device 1200, or the receiving device 1200 may receive corresponding information from the transmitting device 100. .

Further, the channel H is a 2x2 complex matrix formed by two transmit antennas 151 and 152 and two receive antennas 1211 and 1212, and can be expressed as Equation 10 below.

Here, h ₁₁ is a channel value between the first receiving antenna 1211 and the first transmitting antenna 151, h ₁₂ is a channel value between the first receiving antenna 1211 and the second transmitting antenna 152, h ₂₁ denotes a channel value between the second receiving antenna 1212 and the first transmitting antenna 151, and h ₂₂ denotes a channel value between the second receiving antenna 1212 and the second transmitting antenna 152. Meanwhile, these can be obtained by channel estimation using a pilot signal or the like.

On the other hand, the first reception signal y ₁ (k) and the second reception signal y ₂ (k) are AWGN noise n ₁ of the first reception antenna 1211 and the second reception antenna 1212 as shown in Equation 11 below. It can be represented as a linear system including AWGN noise n ₂ .

Here, c ₁ (k) may be a first input signal of the MIMO precoder 110, and c ₂ (k) may be a second input signal of the MIMO precoder 110.

와 제 2 입력 신호 c₂(k)에 대한 추정치

를 생성하고, 생성된

와

를 멀티플렉서(1240)로 출력할 수 있다.Therefore, the MIMO decoder 1230 performs MIMO decoding based on Equation 12 below, and the estimated value for the first input signal c ₁ (k)

And the estimate for the second input signal c ₂ (k)

And the generated

Wow

May be output to the multiplexer 1240.

와

는 QAM 심볼일 수 있다.From here,

Wow

May be a QAM symbol.

The multiplexer (or parallel-to-serial conversion unit) 1240 multiplexes input symbols and outputs the multiplexed symbols to the QAM demodulator 1250.

Specifically, the multiplexer 1240 is a component corresponding to the demultiplexer 140 of the transmission device 100 and performs an operation corresponding to the demultiplexer 140.

That is, the multiplexer 1240 may inversely apply the demultiplexing rule used in the demultiplexer 140, multiplex the input QAM symbols, and output in a single stream form. To this end, the receiving device 1200 may pre-store information on the demultiplexing rule used by the demultiplexer 140 or may be provided from the transmitting device 200.

The QAM demodulation unit 1250 performs QAM demodulation on symbols output from the multiplexer 1240.

Specifically, the QAM demodulator 1250 is a component corresponding to the QAM modulator 130 of the transmission device 100 and performs an operation corresponding to the QAM modulator 130.

That is, the QAM demodulator 1250 may perform QAM demodulation on a QAM symbol input according to the modulation method used by the QAM modulator 130 to generate bits transmitted from the transmission device 100. To this end, the receiving device 1200 uses the modulation scheme used in the QAM modulator 130 (ie, 4-QAM, 16-QAM (or 16-NUC), 64-QAM (or 64-NUC), 256-QAM). (Or 256-NUC), 1024-QAM (or 1024-NUC), 4096-QAM (or 4096-NUC), etc., how the bits are modulated into QAM symbols, or which of the uniform/non-uniform constellation Information about whether or not it has been modulated in a manner) may be previously stored, or may be provided from the transmission device 100.

On the other hand, a non-transitory computer readable medium in which a program for sequentially performing a transmission method and a reception method according to the present invention is stored may be provided.

The non-transitory readable medium refers to a medium that stores data semi-permanently and can be read by a device, not a medium that stores data for a short moment, such as a register, cache, or memory. Also, such a program may be provided by being stored in a non-transitory readable medium such as a CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, or the like.

In addition, although a bus is not shown in the above-described block diagram showing the transmitting device and the receiving device, communication between components in the transmitting device and the receiving device may be performed through a bus. In addition, each device may further include a processor such as a CPU or a microprocessor that performs the various steps described above.

In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. In addition, various modifications are possible by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

110: MIMO precoder 120: OFDM modulator

Claims (22)

In the transmission device,
When the first input signal and the second input signal are input, pre-phase shift or pre-phase shift/hopping of the second input signal and the first input signal And performing multiple input multiple output (MIMO) precoding by overlapping encoding the pre-phase shift or the pre-phase shift/hopped second input signal to generate a first transmission signal and a second transmission signal. MIMO precoder; And,
Includes; an OFDM modulator for orthogonal frequency division multiplexing (OFDM) modulation on the first transmission signal and the second transmission signal, and
The MIMO precoder,
A transmission apparatus characterized in that the MIMO precoding is performed using any one of the following equations:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift matrix,

Is the superposition encoding matrix, θ is the pre-phase shift parameter, ψ is the superposition encoding parameter,

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is an overlapping encoding matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, ψ is an overlapping encoding parameter,

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift matrix,

Is the superposition encoding matrix, θ is the pre-phase shift parameter, ψ(k) is the superposition encoding parameter for the k-th symbol,

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is a superposition encoding matrix, θ(k) is a pre-phase shift/hopping parameter for the k th symbol, and ψ(k) is a superposition encoding parameter for the k th symbol. delete delete delete delete The method of claim 1,
The MIMO precoder,
After overlapping the first input signal and the pre-phase shift or the pre-phase shift/hopped second input signal, post-phase shift or post-phase hopping is performed. A transmitting apparatus, characterized in that performing additionally to perform MIMO precoding. The method of claim 6,
The MIMO precoder,
A transmitting apparatus characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix, is the superimposed encoding matrix,

Is a post-phase shift matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, ψ is an overlap encoding parameter, and φ is a post-phase shift parameter. The method of claim 6,
The MIMO precoder,
A transmitting apparatus characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, θ(k) is the pre-phase shift/hopping parameter for the kth symbol, ψ(k) is the superposition encoding parameter, and Φ(k) is the post-phase hopping parameter for the kth symbol . The method of claim 6,
The MIMO precoder,
A transmitting apparatus characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, θ(k) is the pre-phase shift/hopping parameter for the k-th symbol, ψ(k) is the superimposed encoding parameter for the k-th symbol, Φ(k) is the post for the k-th symbol -This is a phase hopping parameter. The method of claim 6,
The MIMO precoder,
And performing MIMO precoding by differentially allocating power to the first input signal and the second input signal before pre-phase shifting or pre-phase shifting/hopping the second input signal. The method of claim 10,
The MIMO precoder,
A transmitting apparatus characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the power allocation matrix,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, γ is the power adjustment parameter, θ(k) is the pre-phase shift/hopping parameter for the kth symbol, ψ is the superposition parameter, and Φ(k) is the post-phase hopping for the kth symbol It is a parameter. In the transmission method of the transmission device,
When the first input signal and the second input signal are input, pre-phase shift or pre-phase shift/hopping of the second input signal and the first input signal And performing multiple input multiple output (MIMO) precoding by overlapping encoding the pre-phase shift or the pre-phase shift/hopped second input signal to generate a first transmission signal and a second transmission signal. step; And,
Including; Orthogonal Frequency Division Multiplexing (OFDM) modulating the first transmission signal and the second transmission signal; and
The generating step,
A transmission method, characterized in that the MIMO precoding is performed using any one of the following equations:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift matrix,

Is the superposition encoding matrix, θ is the pre-phase shift parameter, ψ is the superposition encoding parameter,

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is an overlapping encoding matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, ψ is an overlapping encoding parameter,

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift matrix,

Is the superposition encoding matrix, θ is the pre-phase shift parameter, ψ(k) is the superposition encoding parameter for the k-th symbol,

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is a superposition encoding matrix, θ(k) is a pre-phase shift/hopping parameter for the k th symbol, and ψ(k) is a superposition encoding parameter for the k th symbol. delete delete delete delete The method of claim 12,
The generating step,
After overlapping the first input signal and the pre-phase shift or the pre-phase shift/hopped second input signal, post-phase shift or post-phase hopping is performed. A transmission method, characterized in that the MIMO precoding is performed by additionally. The method of claim 17,
The generating step,
A transmission method, characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix, is the superimposed encoding matrix,

Is a post-phase shift matrix, θ(k) is a pre-phase shift/hopping parameter for the k-th symbol, ψ is an overlap encoding parameter, and φ is a post-phase shift parameter. The method of claim 17,
The generating step,
A transmission method, characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, θ(k) is the pre-phase shift/hopping parameter for the kth symbol, ψ(k) is the superposition encoding parameter, and Φ(k) is the post-phase hopping parameter for the kth symbol . The method of claim 17,
The generating step,
A transmission method, characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, θ(k) is the pre-phase shift/hopping parameter for the k-th symbol, ψ(k) is the superimposed encoding parameter for the k-th symbol, Φ(k) is the post for the k-th symbol -This is a phase hopping parameter. The method of claim 17,
The generating step,
And performing MIMO precoding by differentially allocating power to the first input signal and the second input signal before pre-phase shifting or pre-phase shifting/hopping the second input signal. The method of claim 21,
The generating step,
A transmission method, characterized in that the MIMO precoding is performed using the following equation:

Here, c ₁ (k) is the k-th symbol of the first input signal, c ₂ (k) is the k-th symbol of the second input signal, and x ₁ (k) is the k-th symbol of the first transmission signal , x ₂ (k) is the k-th symbol of the second transmission signal,

Is the power allocation matrix,

Is the pre-phase shift/hopping matrix,

Is the nested encoding matrix,

Is the post-phase hopping matrix, γ is the power adjustment parameter, θ(k) is the pre-phase shift/hopping parameter for the kth symbol, ψ is the superposition parameter, and Φ(k) is the post-phase hopping for the kth symbol It is a parameter.

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