Application Of Turbo Product Codes In Coded Cooperation Systems

For wireless communications, the technique of MIMO is very important to obtain diversity gain in the users'uplink fading channels. But due to the limits in size and price, it's difficult to have many antennas to some mobile terminals. For solving this problem, the technique of cooperative diversity is imposed. Novel coded cooperative communication schemes based on Turbo Product Codes (TPC) are presented for better performances.First, the technique for cooperative diversity is introduced. A virtual multi-antenna system is created by two mobile terminals with only one single-antenna. By analyzing the performance of achievable rate region, it is shown that the cooperative diversity system has better performance than the non-cooperative scheme.Then, the encoding and decoding principles of Turbo Product Codes are studied. From the view of encoding, TPC is a product code; from the point of decoding, TPC is the extension of Turbo codes. Based on the ideas of encoding and decoding about TPC, this thesis analyses the details of Chase iterative decoding algorithms of TPC, and compares the simulation results of TPC under different situations on the AWGN channel. Some key factors about TPC are analyzed, based on the simulation results.Finally, by introducing the existing coded cooperation systems and Turbo Product Codes, the system model of coded cooperation based on TPC is given out. Different parts of the Turbo Product Code words are transmitted to the base station through different users'uplink fading channels to obtain diversity gain. In this system model, only parity bits are transmitted in the second frame. Then this model is improved. Not only parity bits but also information bits are transmitted to the base station in the second frame in order to combat the fading effect in wireless channels. By computer simulations, the system performance can be improved effectively in the same system bandwidth and transmitting power, compared with non-cooperative scheme. At the same time, the improved scheme has better performances.