Feedback-free method for the demodulation of higher-level MQAM signals without knowledge of the transmitted symbols
US5854570A · kind A · utility
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2References
6Claims
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Key dates
| Filing date | Aug 26, 1997 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Aug 26, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3872
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
For demodulation of higher-level MQAM signals without knowledge of the transmitted symbols, the clock phase error is calculated first after the sampling of the baseband signal with a clock frequency corresponding to the MQAM signal, and the corresponding time shift of the baseband signal is compensated therewith by interpolation (clock synchronization). Subsequently, the carrier frequency deviation and the carrier phase deviation are calculated feedback-free according to the principle of the maximum likelihood theory using Fourier transformation or by convolution in the time domain, and thus the data sequence is compensated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.