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In this paper, two types of diversity which are space and time diversity are analyzed. The analyses are conducted base on optimization and characteristics analysis. Some methods for optimize this scheme are studied and analyzed to produce the desired results. The objectives of this project are to improve the cooperative communication for better diversity reception and to investigate the range improvement as the cooperative communication is implemented. Performance enhancement for the system that have diversity is established when the communication error probability is decreased at a high channel signal-to-noise ratio (SNR) compared to any system that have less or no diversity.

A new technique for constructing the Quasi Cyclic Low density Parity Check (QC-LDPC) codes based on splitting rows into sub rows method is proposed. The proposed QC-LDPC code, at BER of 10−6 achieves 0.1dB coding gain over the PEG-LDPC codes. Moreover, in the high E b / N 0 region, the proposed code with girths 16 and 20 respectively, achieve 0.056 dB and 0.27 dB at a BER of 10−5 over the randomly constructed code. Simulation results portray that large girth QC-LDPC codes achieve a 0.1dB coding gain over randomly constructed codes and perform 1.3dB from the Shannon-limit at a BER of −6 with a code rate of 0.89 for block length of 1332.