Performance enhancement of OFDM systems with lower-complexity using DST based on successive interference cancellation

Abstract

Equalization is the most important algorithm to improve the Bit-Error-Rate (BER) performance in wireless communication systems. The Zero Forcing (ZF) equalizer, and the Minimum Mean Square Error (MMSE) equalizer suffer from noise enhancement, and high complexity, respectively. The ZF, and MMSE equalizers based on Successive Interference Cancellation (SIC) also suffer from error propagation, and high complexity, respectively. On the other hand, the MMSE, and the MMSE-SIC need the estimation of the Signal-to-Noise Ratio (SNR) to work properly. The Orthogonal Frequency Division Multiplexing (OFDM) systems are very sensitive to Carrier Frequency Offset (CFO) at the receiver side. In this paper, we propose a Joint Low-complexity Regularized ZF (JLRZF) equalizer based on SIC for the OFDM system that depends on the Discrete Sine Transform (DST). The proposed JLRZF-SIC scheme jointly performs the equalization and CFO compensation processes with low complexity using banded-matrix approximation. Simulation results show that the proposed JLRZF-SIC scheme improves the BER performance compared to other equalization algorithms.