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.

This work proposes two low-complexity and high-performance cell ID detection schemes for cellular communication systems. The first one, called real-correlation multiple differential detection (RMDD), derived from our previous work on cell ID detection called CERCD method, has much less complex multiplication operations while maintains the same performance. Although CERCD algorithm is more robust than existing cell detection methods in AWGN and multipath channel conditions, its performance still can be further improved. As such, the second scheme, called multiple differential detection (MDD), is proposed to improve CERCD method. Simulation results show that MDD has much better performance in frequency-selective channels. Performances and computational complexities of proposed schemes are also evaluated and analyzed under different channel environments to demonstrate their effectiveness.

This work presents a new technique which can blindly perform the fine synchronization for single-carrier block-transmission (SCBT) systems without using unique words (UW). The proposed technique, called simplified weighted LS method for single-carrier systems (SWLS-SC), combines the concept of the decision feedback structure and SWLS estimator for OFDM systems. Together with specifically derived weighting factors, the proposed scheme has much better estimation accuracy than the well-known linear least-square (LLS) method for SC systems, while its BER performance can approach that of the ideal synchronization condition. With the proposed estimator, the system throughput can be further increased, because there is no need to insert UW for fine synchronization. The theoretical estimation bounds are also derived to prove the effectiveness of the proposed scheme.

In this paper, an efficient sphere decoding algorithm (SDA) applied to solve the inter-symbol-interference (ISI) data detection problem is proposed. This proposed algorithm takes advantages of the SDA to obtain the solution close to ML solution with the simplified K-best tree search method for the ISI data detection under ISI effect. Compared with the frequency-domain MMSE or Zero-Forcing equalization techniques for SCBT (Single-Carrier Block Transmission) systems, this algorithm can perform at least 1.5dB better than frequency- domain equalizers under the environment of randomly generated channel impulse responses.