Wireless Cooperative Communication Networks With Distributed Turbo Codes

Cooperative communication enables mobile user with one transmitting antenna to collaborate with other mobile users in the networks. Without adding additional transmitting power and spreading bandwidth, all the mobile users can benefit from transmit diversity and effectively combat the effects of selective fading in wireless communication. This spatial diversity is also called cooperation diversity. This dissertation thoroughly analyzes the common amplify-and-forward, decode-and-forward and coded cooperation protocols in terms of outage events and associated outage probabilities. We put forward the approximated expressions in high signal-to noise ration (SNR) regime and calculate cooperation diversity order. The theoretical prediction agrees with simulation results very well. They both demonstrate that these three cooperative communication schemes achieve full diversity gains. Based on the asymptotic expressions of outage probabilities in high SNR regime, partner selection strategies and power allocation strategies are discussed.Turbo codes are milestone in channel codes. Iterative decoding thoughts and soft decoding methods based on probability changed the study perspective of channel codes. The promising space-time block codes can provide spatial diversity gains and have simple encoding\decoding structure. The basic schemes and theory analysis of turbo codes and space-time block codes are introduced. The soft decoding methods based on probability of Turbo-STBC system are firstly proposed. Simulation results prove that Turbo-STBC system has low decoding complexity and excellent performance. The proposed decoding arithmetic is superior to the arithmetic based on the minimum Euclidean distance by 0.5 dB.Concatenated distributed turbo codes without space-time codes, concatenated distributed turbo codes with space-time codes, punctured distributed turbo codes without space-time codes and punctured distributed turbo codes with space-time codes are advanced by combining cooperative communication thoughts and encoding\decoding methods of turbo codes and space-time block codes. The theoretical analysis of distributed turbo code system is extremely difficult. The bit error rate (BER) asymptotic expressions of these four systems are brought forward over rayleigh quasi-static fading channel. And according to the simulation results, these four systems are compared and analyzed.