ESTIMATOR, COMMUNICATION DEVICE AND METHOD FOR ESTIMATING CARRIER FREQUENCY OFFSETS IN OFDM SYSTEMS

摘要

The present invention relates to an estimator for determining fractional frequency offsets, FFOs, in a communication signal. The estimator comprises a processor configured to obtain a communication signal s comprising at least k FFOs, where K is an integer larger than 1; determine a Log Likelihood Function, LLF, λ for the K FFOs; approximate the determined LLFƛ l as a series expansion comprising M basis functions φ_{mand associated expansion coefficients αm, where m = 1, 2,..., M; determine the K FFOs by maximizing the series expansion. Furthermore, the present invention also relates to a communication device, a corresponding method, a computer program, and a computer program product.}