Precoding method, transmitting device, and receiving device

Abstract

A transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

Claims

1. A transmission device comprising: modulation circuitry configured to generate two modulated signals to be demodulated by a reception device, the modulation circuitry generating the two modulated signals by modulating two data sequences by using a modulation scheme selected from among a plurality of modulation schemes; precoding circuitry configured to generate two precoded signals by performing phase change on the two modulated signals while switching between precoding matrices in accordance with Equation 1; power adjustment circuitry configured to generate two amplitude-changed signals by changing the amplitudes of the two precoded signals; and transmission circuitry configured to transmit the two amplitude-changed signals from different antennas at a same frequency and at a same time, wherein Equation 1 is expressible as: $F\left[i\right]=\frac{1}{\sqrt{2}}\left(\begin{array}{cc}{e}^{j{}_{11}\left(i\right)}& e^{j\left({}_{11}\left(i\right)+\right)}\\ e^{j{}_{21}\left(i\right)}& e^{j\left({}_{21}\left(i\right)++\right)}\end{array}\right),$ and Equation 1 satisfies Equation 2, Equation 2 expressible as: $\frac{e^{j\left({}_{11}\left(x+1\right)-{}_{21}\left(x+1\right)\right)}}{e^{j\left({}_{11}\left(x\right)-{}_{21}\left(x\right)\right)}}=e^{j\left(\frac{}{N}\right)}$ $\mathrm{for}x\left(x=0,1,2,\mathrm{.Math.},N-2\right),$ where N=2, =0, .sub.11(i) and .sub.21(i) are each a real number equal to or more than 0 and less than 2, i is an integer equal to or more than 0 and equal to or less than N1, and is a circular constant.

2. A transmission method comprising: generating two modulated signals to be demodulated by a reception device, the two modulated signals being generated by modulating two data sequences by using a modulation scheme selected from among a plurality of modulation schemes; generating two precoded signals by performing phase change on the two modulated signals while switching between precoding matrices in accordance with Equation 3; generating two amplitude-changed signals by changing the amplitudes of the two precoded signals; and transmitting the two amplitude-changed signals from different antennas at a same frequency and at a same time, wherein Equation 3 is expressible as: $F\left[i\right]=\frac{1}{\sqrt{2}}\left(\begin{array}{cc}{e}^{j{}_{11}\left(i\right)}& e^{j\left({}_{11}\left(i\right)+\right)}\\ e^{j{}_{21}\left(i\right)}& e^{j\left({}_{21}\left(i\right)++\right)}\end{array}\right),$ and Equation 3 satisfies Equation 4, Equation 4 expressible as: $\frac{e^{j\left({}_{11}\left(x+1\right)-{}_{21}\left(x+1\right)\right)}}{e^{j\left({}_{11}\left(x\right)-{}_{21}\left(x\right)\right)}}=e^{j\left(\frac{}{N}\right)}$ $\mathrm{for}x\left(x=0,1,2,\mathrm{.Math.},N-2\right),$ where N=2, =0, .sub.11(i) and .sub.21(i) are each a real number equal to or more than 0 and less than 2, i is an integer equal to or more than 0 and equal to or less than N1, and is a circular constant.

3. A reception device comprising: reception circuitry configured to receive a reception signal transmitted from two different antennas of a transmission device, the reception signal including two precoded signals; and demodulation circuitry configured to demodulate the reception signal to output two data sequences by using a modulation scheme selected from among a plurality of modulation schemes, wherein the transmission device transmits the two precoded signals by: generating two modulated signals by modulating two data sequences by using the selected modulation scheme; generating the two precoded signals by performing phase change on the two modulated signals while switching between precoding matrices in accordance with Equation 5; generating two amplitude-changed signals by changing the amplitudes of the two precoded signals; and transmitting the two amplitude-changed signals from different antennas at a same frequency and at a same time, wherein Equation 5 is expressible as: $F\left[i\right]=\frac{1}{\sqrt{2}}\left(\begin{array}{cc}{e}^{j{}_{11}\left(i\right)}& e^{j\left({}_{11}\left(i\right)+\right)}\\ e^{j{}_{21}\left(i\right)}& e^{j\left({}_{21}\left(i\right)++\right)}\end{array}\right),$ and Equation 5 satisfies Equation 6, Equation 6 expressible as: $\frac{e^{j\left({}_{11}\left(x+1\right)-{}_{21}\left(x+1\right)\right)}}{e^{j\left({}_{11}\left(x\right)-{}_{21}\left(x\right)\right)}}=e^{j\left(\frac{}{N}\right)}$ $\mathrm{for}x\left(x=0,1,2,\mathrm{.Math.},N-2\right),$ where N=2, =0, .sub.11(i) and .sub.21(i) are each a real number equal to or more than 0 and less than 2, i is an integer equal to or more than 0 and equal to or less than N1, and is a circular constant.

4. A reception method comprising: receiving a reception signal transmitted from two different antennas of a transmission device, the reception signal including two precoded signals; and demodulating the reception signal to output two data sequences by using a modulation scheme selected from among a plurality of modulation schemes, wherein the transmission device transmits the two precoded signals by: generating two modulated signals by modulating two data sequences by using the selected modulation scheme; generating the two precoded signals by performing phase change on the two modulated signals while switching between precoding matrices in accordance with Equation 7; generating two amplitude-changed signals by changing the amplitudes of the two precoded signals; and transmitting the two amplitude-changed signals from different antennas at a same frequency and at a same time, wherein Equation 7 is expressible as: $F\left[i\right]=\frac{1}{\sqrt{2}}\left(\begin{array}{cc}{e}^{j{}_{11}\left(i\right)}& e^{j\left({}_{11}\left(i\right)+\right)}\\ e^{j{}_{21}\left(i\right)}& e^{j\left({}_{21}\left(i\right)++\right)}\end{array}\right),$ and Equation 7 satisfies Equation 8, Equation 8 expressible as: $\frac{e^{j\left({}_{11}\left(x+1\right)-{}_{21}\left(x+1\right)\right)}}{e^{j\left({}_{11}\left(x\right)-{}_{21}\left(x\right)\right)}}=e^{j\left(\frac{}{N}\right)}$ $\mathrm{for}x\left(x=0,1,2,\mathrm{.Math.},N-2\right),$ where N=2, =0, .sub.11(i) and .sub.21(i) are each a real number equal to or more than 0 and less than 2, i is an integer equal to or more than 0 and equal to or less than N1, and is a circular constant.

Description

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