Autocorrelation threshold generation based on median filtering for symbol boundary detection in an OFDM receiver
US7274757B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 5, 2004 |
| Grant date | Sep 25, 2007 |
| Priority date | — |
| Expiry date | Dec 13, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/261
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An OFDM receiver has an autocorrelation circuit configured for generating autocorrelated power values from samples of received short preamble symbols in a received data packet, and a median filter configured for generating a median autocorrelation value from at least a prescribed minimum number of the autocorrelated signal values. A comparator is configured for detecting a symbol boundary, identifying an end of the short preamble symbols, based on the autocorrelated signal values falling below a threshold that is based on the median autocorrelation value. Hence, the threshold used to identify the symbol boundary is dynamically calculated on a per-packet basis, eliminating errors due to varying energy levels or propagation characteristics from different packet sources; moreover, the median autocorrelation value minimizes effects due to noise components, minimizing false detection errors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.