Technology Studies And Performance Analysis On Turbo Codes In Wireless Communication

As the developments of the wireless communication and networking during these years, and the broad applications of the new generation of advanced error control coding such as Turbo code and LDPC code, more and more new technologies have been proposed and applied in this research field. These new technologies and applications, such as MIMO-OFDM technologies, cooperative communicaton, multi-cell resource management and optimizations, and high speed video transmission applications, along with the applications based on heterohenerous wireless networks, have higher reqirements for the key technologies of physical and data link layers, such as channel coding, modulation, and the cooperation between these technologies and transmission schemes of data link layers and higher layers.The research work of this paper based on Turbo code, in Rician fading channel and other communication scenarios, studies the theories and performances of the related technologies such as interleaving, coding, decoding, and hybrid ARQ schemes of physical and data link layers, for getting better system performance of the Turbo system and making it more suitble for these new services and technologies mentioned above.The main research works and contributions in this paper include the following points:First, this paper is based on key technologies of physical layer of wireless communication networks, such as high efficient error correcting code-Turbo code. And this paper researches the theory and application of three kinds of Turbo interleavers with good performances-DRP, ARP and QPP interleavers, the related four decoding methods-MAP, Max-Log-MAP, Log-MAP and SOVA, different code lengths, and their influences to the BER performance, especially the Error-Floor performance of Turbo system.Second, this paper also focuses on the critical technologies of link layer of the wireless communication network, such as the ARQ and Hybrid ARQ schemes. Our research applies the scheme of RCPT based on the Turbo code, discusses the influences of different channel conditions and Rician K factors to the throughput and package error rate performances of three different kinds of Hybrid ARQ schemes, analyses and compares the results. Third, in our research, we find that based on the same code length and decoding algorithm, QPP interleaver has the best Error-Floor performance, which is the smallest value. Though Type-Ⅲ Hybrid ARQ, which has the highest complexity, has the best performance, we also find that when the transmission channel is relative stable, the Type-Ⅱ HARQ could obtain better performance without bringing extra complexity. So in this case, type-Ⅱ Hybrid ARQ would be the best choice. The results and analysis in this paper can be the important referances for further research works in this field.