Distributed Joint Source Channel Network Coding

A distributed joint source channel network coding scheme using low density parity check codes is proposed for a wireless sensor networks, in which two correlated source nodes communicating information to one destination node with the help of one relay node. In wireless sensor networks, the sensor node is power-limited and can not be updated in real time, thus, it has limited information processing capacity. This paper is intended to use joint coding techniques to compress the source information to have low energy consumption, and enhance the performance of the transmission system.Chapter 2 is the introduction part, firstly, this paper introduces the research significance and background of the distributed source coding and joint source-channel coding, carries on the detailed analysis of the application prospect and research status of joint coding scheme. Then the paper lists some existing typical examples of the joint coding method. Secondly, this paper states the network coding and joint channel network coding theory, and further analyze the superiority and necessity of the joint scheme.In chapter 3, this paper proposes the distributed joint source channel network coding scheme which is based on the low density parity check codes. In this scheme, for each source node, both distributed compression and channel error correction are simultaneously achieved by transmitting the parity bits together with a fraction of the information bits of a systematic channel code. The relay node effectively utilize the correlations in decoding and deletes part of the data bits, which effectively reduces the error propagation caused by the relay node. Then the destination node jointly decodes. The simulation results show the effctiveness of the proposed scheme. In chapter 4, the improved joint scheme is proposed based on unequal information compression so that the source node can obtain a variable coding rate, which is closer to the actual application scenarios and is conducive to a better decoding performance.