Correlated Source Coding And Application To Cooperative Relaying

With the rapid development of multimedia mobile communication technologies, the demand for reliable and efficient transmission of information is growing. However, due to the impact of limited wireless bandwidth resources, multipath fading and other factors, it is difficult to achieve high-speed and reliable data transmission. To solve this problem we must adopt some new communication theories and technologies. Cooperative relaying technology can obtain spatial diversity through relay transmission, and alleviates the effect of multipath fading. Further, it may also reduce the transmission power of the user, extend network coverage, and is an efficient radio resource allocation solution. In all relaying transmission schemes, Compress-and-Forward(CF) is a better choice. The relay node compresses and forwards the received signal exploiting the correlation of received signals between the destination node and the relay node. Theoretical studies show this strategy can obtain some rate points that others can’t. However, practical CF schemes are far lagging behind the theory. In this thesis, correlated source coding and its application to CF scheme design are mainly studied.First, the related theories of correlated source coding are introduced, including source coding, correlated source coding and its distributed coding scheme, and joint source-channel coding(JSCC) of correlated sources. For JSCC, source coding and channel coding are discussed jointly, which can achieve the best balance point, so it becomes a hot topic in the field of modern coding.Then, we study a JSCC method of two correlated sources in the Gaussian channel based on Turbo code, including the generation of correlated sources, encoding at the two sources, and joint source-channel decoding algorithm at the destination node. Simulations for the effect on system performance of two sources at different correlation coefficients show that it is very close to the Shannon and Slepian-Wolf binding limits.Finally, for the three-node relay channel model, a Decode-Compress-and-Forward(DCF) relay transmission scheme is studied. The relay node performs soft output decoding, quantizing and encoding on the received signal, and forwards to the destination node. Based on the correlation between direct signals and relay signals, the destination node decodes with the joint decoding algorithm of correlated sources. Simulations are carried to evaluate the effect of different trade-off factors and the position of the relay node on the system performance. And comparison is made with the Decode-Amplify-Forward(DAF) protocol.