Cooperation Coding Modulating Technology Research Based On LDPC Coding

It is known that wireless resources are limited. However the demand of the reliability in data transmission is increasing. With the development of wireless mobile communication technology, the requirement for data transmission rate is rising. As a result, how to improve data transmission rate has become a critical problem in wireless mobile communication field.The relay technology contributes to the development of wireless mobile communication. Based on the relay technology, cooperative diversity technology is proposed by Andrew Sendonaris for the first time. After in-depth research by J.N.Laneman and T.E.Hunter et al. various kinds of cooperative communication protocols emerge in endlessly. Currently, cooperative communication technology has been developed more mature. The most common cooperative communication protocols are amplify-and-forward (AF) protocol, decoding-and-forward (DF) protocol and coded cooperation (CC) protocol. Coded cooperative protocol is mainly studied in this paper and the channel coding we used is LDPC (Low Density Parity Code).Firstly, some theoretical research of the conventional CC protocol has been done and then some programming simulations have been proposed. Secondly, signal space diversity technology is introduced to improve the system performance. Thirdly, the scheme is applied to the multiple access relay channel (MARC). In this paper, the optimal rotation angle and the optimal mapping scheme are found first by using the tool of Extrinsic information transfer (Exit) chart. And then the correctness of the optimal rotation angle and the optimal mapping scheme is verified by performance simulation. Based on the optimal rotation angle and the optimal mapping scheme, the performance simulation with binary channel coding and the performance simulation with non-binary channel coding are compared together. For the same scheme, obvious coding gain can be obtained when non-binary channel coding used compared to the scheme when binary channel coding used. Some diversity gain can be obtained for the proposed scheme compared to the conventional scheme with the same channel coding. Besides, in order to highlight the performance advantage of LDPC, we compared the system performance of the scheme with LDPC and convolutional code. The result displayed that the LDPC coded scheme has the better performance than the convolutional code coded scheme.