Abstract:

An improved low density parity check (LDPC)aided low density lattice code coded cooperation (LDLC-CC) scheme is proposed for the relay cooperative system. The relay node decodes the LDLC codeword transmitted from the source node and forwards the additional parity check information based on LDPC and LDLC encoding to the destination. By taking advantage of the characteristics of parity check matrix with lower triangular structure, the shaping and encoding operations in source and relay can be simply implemented base on corresponding parity check matrices. Furthermore, the LDLC parity check matrices constitute a higherdimensional matrix with lower triangular structure. A joint iterative soft decoding algorithm is also proposed in destination. It establishes the connection between LDLC decoding and LDPC soft decoding and achieves obvious coding gain than that with hard decoding. Simulation results show that the proposed LDPC aided LDLC-CC scheme can achieve up to 5 dB gain compared to the conventional direct transmission LDLC scheme without cooperation in Rayleigh slow fading channel.