Research On Fountain Codes And Network Coding In Cooperative Relay System

With the rapid development of wireless communication technology, efficient and reliable data transmission draws more and more attentions. Faced with the current complicated and rapidly changing transmission environment, in many cases, the transmitter cannot be accurately informed the channel state, resulting in the increase of unreliability of information dissemination. In order to overcome the defect, fountain code is a reliable choice. With this method, the transmitter selects an accurate code rate adaptively without the appropriate channel state.The main object of the paper is to elaborate fountain codes technology and to describe the performance improvements introduced by the relay selection scheme and cooperation transmission strategy in a multi-relay cooperative communication scenario.The paper first introduces the development process of channel coding and the research background, and leads to the generation of fountain codes. The application of fountain codes and some knowledge about cooperative communication is followed. A detailed description of the fountain code’s generation, evolution of the technology and the application in different scenarios is explained. The encoding and decoding process has been analyzed in detail.Secondly the paper introduced application strategy of fountain codes in multi-relay cooperative communication scenario. The strategies of non-relay system, single relay system and multi-relay system are all described in the paper and the performance of each scheme is expressed by theoretical analysis and derivation of mathematical models. On this basis, an optimized relay selection strategy is proposed which is compared with the other strategies in simulation. Finally, in order to improve the performance throughput, we make a research of collaborative transmission approach between the base station and relays. A strategy based on network coding with variable factors is proposed in chapter four. The influence of different collaborative approaches and different parameters to the system performance are analyzed. According to the requirement of different scenarios, a reasonable selection of parameters makes the system throughput performance optimal.The paper verifies the potential applications of fountain codes in multi-relay system. With the deployment of the proposed relay selection strategy and the collaborative transmission scheme, the system can obtain a significant improvement in performance.