Signal demodulation and diversity combining in a communications system using orthogonal modulation
US5930305A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1996 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Feb 23, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/712
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
For combining diversity path signals comprising symbols each modulated in accordance with one of a plurality of orthogonal (e.g. Walsh) functions, a diversity combiner includes, for each path, a demodulator to demodulate each modulated signal symbol in accordance with a selected one of the orthogonal functions, a phase estimator to estimate a phase rotation and amplitude of the diversity path signal from the demodulated signal, and a complex signal multiplier to derotate the phase and weight the amplitude of the diversity path modulated signal in dependence upon the estimated phase rotation and amplitude. The combiner sums real parts of the phase-derotated and weighted modulated signals of the diversity paths, demodulates the combined signal in accordance with all of the orthogonal functions, and selects the maximum demodulated signal for each symbol thereby to determine for the symbol the selected one of the orthogonal functions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.