The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 20, 2003
Filed:
Aug. 10, 1999
Nima Brardjanian, Eatontown, NJ (US);
Yong J. Lee, Holmdel, NJ (US);
Alex Matusevich, Morris Plains, NJ (US);
Mohsen Sarraf, Rumson, NJ (US);
Sheng-Jen Tsai, Bridgewater, NJ (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
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 comparison vectors by correlating the rotated comparison vectors against a bank of unit vectors to determine a maximum correlation.