Symbol-timing estimation using a second-derivative measure of a correlation function

摘要

A symbol timing estimation method is provided for use in a communication system, for example an orthogonal frequency division multiplexing system having a cyclic prefix extension CPE. Each symbol in a transmitted signal comprises N symbol samples, and the CPE has L symbol samples. The method comprises receiving the signal and processing the symbol samples in the received signal using N and L to obtain a correlation function q (d) for a first series of L samples and a second series of L samples following N samples after the first series. The obtained correlation function is normalised to produce a basic measure MCP(d) for symbol timing estimation. A second-derivative measure MCP_diff2 (d) for symbol timing estimation is also produced based on a second derivative of the basic measure, and the symbol timing is estimated based on the basic and second measures. Such a symbol timing estimation method can work over a wide range of channel conditions and can detect the first significant path reliably in a multi-path environment, even if there are delayed paths of higher energy.