Method and apparatus for sampling timing adjustment and frequency offset compensation
US6567480B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 1999 |
| Grant date | May 20, 2003 |
| Priority date | — |
| Expiry date | Aug 10, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0065
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A simplified method for sampling timing adjustment and frequency offset estimation in a TDMA cellular PCS environment using &pgr;/4 - shifted DQPSK comprises the steps of oversampling a received signal resulting from transmission of sequences of complex-valued symbols at a rate N times the symbol rate thereof so as to produce N sets of samples, comparing for each set of samples the differential phase angle between successively received complex-valued symbols, and determining which set of the N sets of samples has differential phase angles closest to ideal values to thereby obtain an optimal sampling timing. The differential phase angles are measured by multiplying a complex conjugate of a received complex-valued symbol and a succeeding symbol to produce a comparison vector having an angle equal to the differential phase angle between the received complex-valued symbol and the succeeding symbol. The differential phase angles are optionally rotated so that the angle thereof is between 0° and 90°. Frequency offset is estimated by determining a constant deviation of the differential phase angles from an ideal differential phase angle value for a plurality of successive comparis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.