Multi-value modulation/demodulation method and multi-value modulation/demodulation device
US7961813B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 2006 |
| Grant date | Jun 14, 2011 |
| Priority date | — |
| Expiry date | Jan 20, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2017
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
N (integer equal to or above 3) quaternary phase shift keying (QPSK) outputs having different amplitude levels, i.e., r2=r1×2−(i−1), i=2 . . . N with respect to a maximum amplitude level r1 are superposed after power amplification to form M(=22N)-valued/quadrature amplitude modulation (QAM), and N-1 outputs si except the quaternary phase shift keying QPSK-1 having the maximum amplitude r1 are subjected to power amplification in this formation, then the outputs are combined by a directional coupler to obtain a combined signal, and an output of the quaternary phase shift keying QPSK-1 and the combined signal are transmitted from two systems of antennas to be vectorially superposed and combined in a space.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.