Method of signal generation and signal generating device

• US 9,667,333 B2
• Filed: 09/30/2014
• Issued: 05/30/2017
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: Sun Patent Trust
• Original Assignee: Sun Patent Trust
• Inventors: Kimura, Tomohiro, Ouchi, Mikihiro, Murakami, Yutaka
• Primary Examiner(s): Huynh, Dung B
• Application Number:
  US14/501,780
• Publication Number:
  US 20150016570A1
• Time in Patent Office: 973 Days
• CPC Class Codes: H04B 7/0667 of delayed versions of same signal using space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0682 using phase diversity (e.g. phase sweeping)
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/0842 Weighted combining
• CPC Class Codes: H04L 1/0048 in conjunction with detection of multiuser or interfering signals, e.g. iteration between CDMA or MIMO detector and FEC decoder for spatial equalizer H04L25/03286
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 27/20 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/2634 Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• CPC Class Codes: H04L 27/26524 Fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators in combination with other circuits for demodulation
• CPC Class Codes: H04L 27/368 adaptive predistortion
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0082 at predetermined intervals
• CPC Class Codes: H04L 5/12 the signals being represented by different phase modulations of a single carrier

Abstract

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

Claims

1. A signal generation method comprising:

power-changing each of a first baseband signal generated from first information and a second baseband signal generated from second information, the first information being different than the second information;

phase-changing the power changed first baseband signal; and

precoding the phase changed first baseband signal and the power changed second baseband signal according to a predetermined matrix F to generate a first transmission signal and a second transmission signal for transmission on a same frequency band and at a same time, wherein

the phase of the first baseband signal is regularly changed according to a predetermined phase changing pattern using a phase change value sequentially selected from among N phase change value candidates, a difference between two adjacent phase change value candidates of the N phase change value candidates is 2π

/N, N being an integer greater than the number of baseband signals and each of the N phase change value candidates being selected at least once within a predetermined period.

2. The signal generation method according to claim 1, wherein

the power change is executed by multiplying the first baseband signal by u, and multiplying the second baseband signal by v, u and v denoting real numbers different from each other.

3. The signal generation method according to claim 1, wherein the precoding satisfies the relation:

(z1,z2)^T=F(s1,s2)^T

wherein z1 and z2 are signals after the precoding, and s1 and s2 are signals before the precoding.

4. A signal generation apparatus comprising:

a power changer power-changing each of a first baseband signal generated from first information and a second baseband signal generated from second information, the first information being different than the second information;

a phase changer phase-changing the power changed first baseband signal; and

a precoder precoding the phase changed first baseband signal and the power changed second baseband signal according to a predetermined matrix F to generate a first transmission signal and a second transmission signal for transmission on a same frequency band and at a same time, wherein

the phase of the first baseband signal is regularly changed according to a predetermined phase changing pattern using a phase change value sequentially selected from among N phase change value candidates, a difference between two adjacent phase change value candidates of the N phase change value candidates is 2π

/N, N being an integer greater than the number of baseband signals and each of the N phase change value candidates being selected at least once within a predetermined period.

5. A signal demodulation method for demodulating a reception signal obtained by receiving a plurality of transmission signals, the signal demodulation method comprising:

obtaining the reception signal, wherein

the transmission signals are generated by power-changing each of a first baseband signal generated from first information and a second baseband signal generated from second information, the first information being different than the second information, phase-changing the power changed first baseband signal, and precoding the phase changed first baseband signal and the power changed second baseband signal according to a predetermined matrix F to generate a first transmission signal and a second transmission signal for transmission on a same frequency band and at a same time, and

the phase of the first baseband signal is regularly changed according to a predetermined phase changing pattern using a phase change value sequentially selected from among N phase change value candidates, a difference between two adjacent phase change value candidates of the N phase change value candidates is 2π

/N, N being an integer greater than the number of baseband signals and each of the N phase change value candidates being selected at least once within a predetermined period; and

demodulating the reception signal in accordance with the sequentially selected phase change value.

6. A signal demodulation apparatus for demodulating a reception signal obtained by receiving a plurality of transmission signals, the signal demodulation apparatus comprising:

an obtainer obtaining the reception signal, wherein

the transmission signals are generated by power-changing each of a first baseband signal generated from first information and a second baseband signal generated from second information, the first information being different than the second information, phase-changing the power changed first baseband signal, and precoding the phase changed first baseband signal and the power changed second baseband signal according to a predetermined matrix F to generate a first transmission signal and a second transmission signal for transmission on a same frequency band and at a same time, and

the phase of the first baseband signal is regularly changed according to a predetermined phase changing pattern using a phase change value sequentially selected from among N phase change value candidates, a difference between two adjacent phase change value candidates of the N phase change value candidates is 2π

/N, N being an integer greater than the number of baseband signals and each of the N phase change value candidates being selected at least once within a predetermined period; and

a demodulator demodulating the reception signal in accordance with the sequentially selected phase change value.