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:
Apr. 19, 2005
Filed:
Mar. 08, 2001
Alain Chiodini, Mountain View, CA (US);
Alain Chiodini, Mountain View, CA (US);
Proxim Corporation, Sunnyvale, CA (US);
Abstract
Orthogonal frequency division multiplexing (OFDM) receiver embodiments of the invention demodulate quadrature amplitude modulated (QAM) signals transmitted in the five GHz frequency band and digitally correct for frequency offset errors in their digital signal processing (DSP) units. A method comprises a step in which an OFDM transmission is I/Q sampled and a portion of the received packet is selected. It is assumed that the coarse frequency offset has been estimated and that the remaining frequency offset after coarse frequency offset compensation does not exceed ±10 kHz (valid for 802.11a PHY implementation only). It is also assumed that a timing reference has been determined. A cost function is used to determine a fine-frequency offset. Once the fine frequency offset is determined, the estimate is used in the downstream digital signal processing.