OFDM Post-FFT Frequency Recovery Based on Silent Sub-Carriers

Abstract

The problem of post-FFT carrier frequency recovery is investigated in the paper proposing a novel approach for both pilot structure and receiver design. In particular, a novel pilot distribution is introduced in order to minimize overlaps between two pattern shifted replicas. This allows to replaces conventional pilots with nulls in the frequency domain, introducing the so called silent pilots. As a result, the optimal receiver turns out to be very robust against severe Rayleigh fading multipath and characterized by low complexity. Performance has been analytically and numerically evaluated, comparing the proposed approach with state of the art alternatives, in both AWGN and multipath fading channels, showing considerable performance improving.