Research Of Key Technologies For BICM-ID System Transmitting Over Multi-path Fading Channel In Wireless Communications

Multi-path fading and frequency efficiency are two main problems in wirelesscommunications with high data rate transmission over limit bandwidth resource.Equalization techniques at the receiver can mitigate the intersymbol interference(ISI)caused by multi-path fading. And high order modulation schemes can achieve high datarate transmission. In this paper, we focus on the equalization techniques and high ordermodulation schemes. For the problem that nowadays’ equalizers have highcomputational complexity, we propose a low complexity equalization algorithm. Weuse BICM-ID technique this paper as the high order modulation scheme. And it’srecognized that symbol mapping is the curial design parameter that influences codinggain over iterations. We use simulated annealing algorithm to design optimal symbolmapping. At the end, we combine these two techniques efficiently to design a receiverwith low complexity and high performance simultaneously. The main contribution ofthis paper includes:1) After investigation and comparison, we point out that frequency domainequalization can offer better performance than time domain equalization with lowercomputational complexity, and decision feedback equalization outperforms linearequalization over wireless channels. We propose a frequency domain decision feedbackturbo equalization algorithm with extremely low complexity than existed, with almostthe same performance.2) The influence that symbol mapping has on BER performance can becharacterized by distance criteria, which can quantity the goodness of a symbolmapping as a cost function. We first analyze the efficiency of the criteria, then usesimulated annealing(SA) algorithm to design a symbol mapping that has minimum costof the cost function. In addition, we also show that multi dimension(multi-D) BICM-IDcan achieve higher coding gain than the conventional two dimension BICM-ID systemwith same modulation scheme.3) We combine the proposed equalization algorithm and multi-D BICM-IDtechnique efficiently applying the symbol mapping given by SA algorithm. And designa low complexity wireless communication receiver that can effectively deal with themulti-path fading problem at a high data rate transmission.