Non-data-aided carrier frequency offset estimation for OFDM and downlink DS-CDMA systems

We address the problem of non-data aided frequency offset estimation for non-circular transmissions over frequency-selective channels in a downlink DS-CDMA system or an OFDM communications context. We observe that twice the frequency offset is a cyclic frequency of the received signal. We thus introduce an estimator relying on the maximisation of the empirical cyclocorrelations. We analyse its asymptotic behaviour and obtain a closed-form expression for the asymptotic covariance. This enables us to design relevant system parameters. Simulations are provided and confirm our assertions