Research On Network Coding Cooprative Communication System

The fading characteristic of wireless channel is a major challenge for wireless communications. Diversity is an effective technology to fight against the decline of the fading channel. However, the traditional diversity techniques, such as time diversity and frequency diversity, take up extra system resources. Although space diversity needs no additional resources, it is difficult to achieve in hardware. Cooperative communication can get diversity gain by letting nodes send the information of their partners. However, this may cost additional energy consumption, which will results in the loss of system throughput. Integrating network coding into cooperative diversity, the network coding cooperative communication system consumes no additional resources, meanwhile, the system BER performance was improved.At first, this dissertation introduced the basic principles of cooperative communication and its collaboration agreements. The basic principles of network coding were also introduced. On this basis, the dissertation studied several schemes of network coding applying to cooperative communication.Then the dissertation combined cooperative communication, network coding and channel coding, proposed two different kinds of network coding cooperative communication systems: one based on convolutional codes and the other based on double binary Turbo codes, created their system model and introduced their decoding algorithms.Finally, MATLAB simulation platform was built based on the additive white Gaussian noise channel to simulate the BER performance of both systems.The two systems are using Viterbi decoding algorithm and Max-Log-MAP decoding algorithm separately. Simulation results show that the BER performance of network coding cooperative communication system is obviously improved, especially the second one because the Soft-In-Soft-Out iterative decoding algorithm was used.