A low-complexity sphere detection technique for orthogonal frequency division multiplexing systems in selective fading channels

This paper presents a low-complexity detection scheme, which consists of a lattice sphere decoder (LSD), for Orthogonal Frequency Division Multiplexing (OFDM) systems. The inter-carrier interference (ICI) resulting from selective fading channel destroys the orthogonality of the OFDM signal and poses a significant limitation on wireless OFDM systems. The aim of this paper is to propose an efficient detection technique in order to provide reliable communications using OFDM in selective fading channels. The proposed detection technique combines the new LSD with two regularization methods. Theoretical analysis and simulation results show that the proposed detection scheme substantially improves the symbol error rate (SER) performance of OFDM systems. Moreover, its complexity is 22 times lower than that reported in a previous work, and 51 times lower than the complexity of the original sphere decoding (SD) technique.