Method of signal generation and signal generating device

• US 10,476,720 B2
• Filed: 01/03/2019
• Issued: 11/12/2019
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: Sun Patent Trust
• Original Assignee: Sun Patent Trust
• Inventors: Murakami, Yutaka, Kimura, Tomohiro, Ouchi, Mikihiro
• Primary Examiner(s): Tse, Young T
• Application Number:
  US16/239,145
• Publication Number:
  US 20190158330A1
• Time in Patent Office: 313 Days
• Field of Search: 375260, 375262, 375265, 375267, 375295, 375300, 375324, 375340, 370208, 370210, 370330, 370335, 370342
• 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:

phase-changing all of a plurality of baseband signals using each of a plurality of phase changing patterns, each of the plurality of phase changing patterns being different from each other;

inverse-fast-Fourier-transforming each of the plurality of baseband signals to which the phase change is applied, to each of a plurality of orthogonal frequency-division multiplexing (OFDM) transmission signals; and

applying Gard Interval insertion processing to each of the plurality of OFDM transmission signals for transmission on a same frequency band and at a same time, wherein

the phase of each of the plurality of baseband signals is regularly changed according to each of the plurality of phase changing patterns for each subcarrier of the plurality of OFDM transmission signals,

each of the plurality of phase changing patterns having N phase change value candidates,

N being an integer greater than two, and

each candidate of the N phase change value candidates being selected at least once within a determined period.

2. A signal generation apparatus comprising:

phase change circuitry phase-changing all of a plurality of baseband signals using each of a plurality of phase changing patterns, each of the plurality of phase changing patterns being different from each other;

inverse fast Fourier transform circuitry inverse-fast-Fourier-transforming each of the plurality of baseband signals to which the phase change is applied, to each of a plurality of orthogonal frequency-division multiplexing (OFDM) transmission signals; and

Gard Interval insertion circuitry applying Gard Interval insertion processing to each of the plurality of OFDM transmission signals for transmission on a same frequency band and at a same time, wherein

the phase of each of the plurality of baseband signals is regularly changed according to each of the plurality of phase changing patterns for each subcarrier of the plurality of OFDM transmission signals,

each of the plurality of phase changing patterns having N phase change value candidates,

N being an integer greater than two, and

each candidate of the N phase change value candidates being selected at least once within a determined period.

3. A signal demodulation method for demodulating a reception signal obtained by receiving a plurality of orthogonal frequency-division multiplexing (OFDM) transmission signals, the signal demodulation method comprising:

obtaining the plurality of OFDM transmission signals, wherein

the plurality of OFDM transmission signals are generated by phase-changing all of a plurality of baseband signals using each of a plurality of phase changing patterns, inverse-fast-Fourier-transforming each of the plurality of baseband signals to which the phase change is applied, to each of the plurality of OFDM transmission signals;

applying Gard Interval insertion processing to each of the plurality of OFDM transmission signals for transmission on a same frequency band and at a same time, each of the plurality of phase changing patterns being different from each other, wherein

the phase of each of the plurality of baseband signals is regularly changed according to each of the plurality of phase changing patterns for each subcarrier of the plurality of OFDM transmission signals, each of the plurality of phase changing patterns having N phase change value candidates, N being an integer greater than two, and each candidate of the N phase change value candidates being selected at least once within a determined period; and

demodulating the reception signal from the plurality of OFDM transmission signals.

4. A signal demodulation apparatus for demodulating a reception signal obtained by receiving a plurality of orthogonal frequency-division multiplexing (OFDM) transmission signals, the signal demodulation apparatus comprising:

reception circuitry obtaining the plurality of OFDM transmission signals, wherein

the plurality of OFDM transmission signals are generated by phase-changing all of a plurality of baseband signals using each of a plurality of phase changing patterns, inverse-fast-Fourier-transforming each of the plurality of baseband signals to which the phase change is applied, to each of the plurality of OFDM transmission signals, and applying Gard Interval insertion processing to each of the plurality of OFDM transmission signals for transmission on a same frequency band and at a same time, each of the plurality of phase changing patterns being different from each other, and

the phase of each of the plurality of baseband signals is regularly changed according to each of the plurality of phase changing patterns for each subcarrier of the plurality of OFDM transmission signals, each of the plurality of phase changing patterns having N phase change value candidates, N being an integer greater than two, and

each candidate of the N phase change value candidates being selected at least once within a determined period; and

demodulate circuitry demodulating the reception signal from the plurality of OFDM transmission signals.