Traditionally, the cooperative communications usually uses Decode-and-Forward (DF) strategy. However, there is easily error propagation phenomenon by the strategy, when the quality of the communication link between source and relay is poor. To solve the problem, a novel Raptor coded cooperation scheme, which can be used in the Coded Cooperation (CC) strategy, is proposed to achieve rather high coding gains and full diversity gains in high Signal-to-Noise Ratio (SNR) regime. In this scheme, different Raptor codes are employed at the source and relay nodes, so the codeword at each node is independent and unequal. Meanwhile, the codeword at relay node is the parity check section of the codeword at the source node. Therefore, after receiving the data transmitted from different independent links, the destination node tries to decode them jointly by the intrinsic relationship among them, to obtain additionally spatial diversity gains in transmission. In addition, in order to reduce the complexity of Raptor encoding and decoding, the Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) codes are constructed by integer sequence and employed as the pre-coding. Simulations indicate that the proposed Raptor CC scheme achieves 2 dB and 1 dB performance gains compared with those of the traditional DF based one and a scheme with the combination of a Raptor code and a Distributed Space-Time Block Code (DSTBC), respectively, at Bit Error Rate (BER) of 10-4 . Moreover, the performance improves about 2 dB and 7 dB at the outage of 10-2 , when compared with those of the CC strategy and DF strategy, respectively.
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