Joint Carrier and Sampling Frequency Offset Estimation Based on Harmonic Retrieval

The performance of an OFDM system is highly sensitive to both carrier and sampling frequency offsets. This paper proposes a new joint carrier and sampling frequency offset estimation scheme for OFDM communications suitable for a frequency-selective fading channel. The joint carrier frequency offset (CFO) and sampling frequency offset (SFO) estimation in OFDM is reformulated and resolved as a harmonic retrieval problem. Accurate estimation can be reached even when only one OFDM symbol is used, hence making this method appropriate for offsets with a high level of variability in time. Extension to block processing is presented. Moreover the presented method proved to be robust against large CFO-SFO values, a claim that can not be made for other joint estimation techniques.