A Novel Sampling Frequency Offset Estimation Algorithm for OFDM Systems Based on Cyclostationary Properties

Abstract

Sampling frequency synchronization in orthogonal frequency division multiplexing (OFDM) communications is critical for achieving the full advantages offered by this modulation scheme. In this paper, we propose a novel and efficient, blind, cyclostationarity-based sampling frequency synchronization (CB-SFS) algorithm for estimating the sampling frequency offset (SFO) in OFDM communications by exploiting the relationship between the sampling frequency and the cyclostationary properties of the sampled received signal. The proposed scheme is ignorant of the channel coefficients and does not require pilots. These two properties are rather unique in this context and are not possessed by previous schemes which achieve comparable estimation performance. These properties also make the proposed CB-SFS scheme suitable for a wide range of communications scenarios. The main novelty of the new scheme is the understanding that SFO alters the cycle frequencies at the receiver, yet these frequencies are a priori known for the discrete-time (DT) transmitted signal, as they result from the periodic operation of the DT signal generation scheme at the transmitter. We show that the mismatch between the measured and the expected cycle frequencies is directly related to the SFO. Complexity analysis and numerical simulations are carried out and demonstrate the superiority of the proposed CB-SFS algorithm compared to the existing approaches. It is illustrated that the proposed algorithm can achieve a smaller estimation error at the same complexity order of current algorithms while providing a higher spectral efficiency and robustness to additive stationary noise and to multipath.

Keywords

• Orthogonal frequency division multiplexing
• sampling frequency offset
• synchronization
• cyclostationary processes
• almost cyclostationary processes