Adaptive LDPC with DSTBC in Cooperative System


In the first part of the paper we proposed an adaptive LDPC iterative decoder depending on the prior knowledge of CSI after evaluating its performance under AWGN and Rayleigh flat fading channel. The proposed code leads to lower the delay caused by the iterative decoder beside acceptable performance, when reducing its iteration to a certain value that is satisfied the parity check operation instead of restricted it to uncertain value which may or may not grantees the converges. In the second part of the paper, LDPC was employed as an outer code with the DSTBC cooperative system. The collaborative system was simulated with two nodes, dual hope based on two relay protocol (DemAF and DAF). The concatenation of LDPC and DSTBC has been proved to be effective in achieving both diversity and coding gain. Adopting one of the introduced protocol is related to many factors, each one has its own advantage and disadvantage. To get the best strategy which equilibrates between the complexity and the performance, the proposed code in the first part was employed. The results demonstrate that the adaptive code successes in significant error floor reduction associated with the DemoAF protocol at the same time results in reducing the delay associated with the DAF protocol