A Blind Fine Synchronization Scheme for SC-FDE Systems

Abstract

This work presents a blind fine synchronization scheme, which estimates and compensates residual carrier-frequency offset (RCFO) and symbol timing offset (STO), for single-carrier frequency-domain equalization (SC-FDE) systems. Existing fine synchronization schemes for SC-FDE systems rely on time-domain unique words (UW) sequences as reference signals to assure the estimation accuracy, at the cost of decreased system throughput. The proposed technique, named simplified weighted least-square method for single-carrier systems (SWLS-SC), combines the decision feedback structure and SWLS estimator for OFDM systems. Together with specifically derived weighting factors, it has much better estimation accuracy than the well-known linear least-square (LLS) method for SC-FDE systems, and its BER performance can approach that of the ideal synchronization condition. The proposed technique is more effective than existing techniques, in terms of both performance and throughput. Theoretical estimation bounds are also derived to verify the effectiveness of the proposed method.