| By virtue of the cooperation among nodes in a virtual antenna array consisted ofsingle antenna terminals, cooperative communications network system can achievediversity, and thus improve the reliability of data transmission. In this system,conventional channel coding technology cannot achieve effective diversity gains sincethe channel is a Rayleigh block fading (BF) channel. To solve this problem,researchers have proposed full diversity low-density parity-check (LDPC) codeswhich are applicable for this BF channel. Considering that the irregular codes havebetter performance than regular codes, this thesis devotes to implementing theresearch on the irregular full diversity LDPC.On the one hand, this thesis completes the construction of the irregular fulldiversity LDPC codes and irregular full diversity QC-LDPC codes. Firstly, based onthe PEG algorithm, the irregular full diversity LDPC codes are constructed. Then, inorder to reduce the storage needs and decoding complexity, full diversity QC-LDPCcodes are constructed. Simulation results show that, compared with conventionalLDPC codes, the irregular full diversity LDPC codes and QC-LDPC codesconstructed by the proposed method can achieve full diversity and obtain highercoding gains over BF channel.On the other hand, in order to evaluate the performance of full diversity LDPCcodes in practical cooperative communication systems, a four-node cooperativetransmission network, which is composed of two source nodes, a relay node and adestination node, is built based on universal software radio peripheral platform.Firstly, two source nodes broadcast parts of encoded data respectively. Secondly,relay node processes and then broadcasts the received data. Finally, the destinationnode decodes all the received data. Testing results in a real scenario show that thecooperative communication systems with full diversity LDPC codes outperform thenon-cooperative systems and the cooperative systems with non-full diversity codes. |
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