Fine-frequency offset estimation
US6882691B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 8, 2001 |
| Grant date | Apr 19, 2005 |
| Priority date | — |
| Expiry date | Oct 6, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/266
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.