Differential Carrier Frequency Offset and Sampling Frequency Offset Estimation for 3GPP LTE

The Long Term Evolution (LTE) system, like other OFDM based systems, is very sensitive to synchronization errors which must be estimated and compensated. In this paper, maximum-likelihood (ML) estimates of the Carrier Frequency Offset (CFO) and Sampling Frequency Offset (SFO) are investigated in the framework of LTE downlink, aiming at precisely tracking time-varying fluctuations of the impairments. In order to make the tracking independent of the time index of the OFDM symbol, the differential CFO and SFO tracking algorithm are proposed. Combined with the phase ambiguity cancellation scheme, the differential tracking algorithm can work with high accuracy. The performances are analyzed and evaluated through simulations.