Improved Performance of Alamouti Scheme Using Cyclic Delay Diversity and Doppler Diversity for MIMO Systems-Based

Abstract

This paper addresses a novel Alamouti space frequency block decoding scheme for multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) based systems using diversity techniques over highly frequency selective channels. Unlike the standard Alamouti space-frequency block code (SFBC), that suffer from performance degradation in highly frequency-selective channels, the proposed method combats this problem. Also, this scheme has capability to combine with different methods such as OFDM and some special diversity such as: cyclic delay diversity (CDD) and discontinuous Doppler diversity (DDoD). In addition, a novelty transceiver using CDD is proposed, which performs valuable results. In this paper, this scheme is called “Efficient Δh-Alamouti with CDD”. This efficient Alamouti encoder and decoder allow a high reliability and capacity enhancement. In order to evaluate its capability, we have implemented this scheme for the second generation terrestrial video broadcasting (DVB-T2) system. The properties of the proposed scheme is investigated over different channels. Also, mathematical analyses and simulation results of the bit error performance for the modified encoding method with these diversity techniques, perform mostly better than the other forms of encoding Alamouti over highly frequency-selective channels such as single frequency networks (SFN). The other advantages of the proposed method are simplicity, flexibility and standard compatibility.