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:
Jul. 07, 2009
Filed:
Dec. 30, 2005
Rajiv Laroia, Basking Ridge, NJ (US);
Junyi LI, Bedminster, NJ (US);
Sundeep Rangan, Hoboken, NJ (US);
Hemanth T. Sampath, Bethesda, MD (US);
Rajiv Laroia, Basking Ridge, NJ (US);
Junyi Li, Bedminster, NJ (US);
Sundeep Rangan, Hoboken, NJ (US);
Hemanth T. Sampath, Bethesda, MD (US);
QUALCOMM Incorporated, San Diego, CA (US);
Abstract
A method and apparatus for joint time and frequency synchronization for orthogonal frequency division multiplexing (OFDM) systems. A multitone pilot signal is sent in a designated OFDM symbol period. The receiver synchronizes to the pilot signal in a two-stage procedure. The first stage estimates the frequency offset coarsely with a frequency-domain correlation method and estimates the time offset with smoothed time-domain correlation. In a multipath channel, the smoothed time offset estimate is used to locate a cyclic prefix interval which captures the maximum total signal energy. The second stage improves the frequency estimate with a computationally efficient numerical optimization method.