A novel cooperative relay scheme employing fountain codes and rotated constellations

Signal Space Diversity (SSD) is a bandwidth-efficient diversity technique, which uses constellation rotation and interleaving technique to achieve diversity gain. The fountain code is a channel code with good performance. In this paper, a cooperative relay scheme employing fountain codes and rotated constellations is presented. By this scheme, the SSD is achieved in the transmission process from the relay nodes to the destination node through the cooperation among the relay nodes, thus, improving the error rate. No interleaver is needed. The use of fountain codes leads to the improvement of the communication efficiency in the point-to-multipoint transmission from the source node to the relay nodes and the reduction of the transmission time from the relay nodes to the destination node. The performance of the scheme is analysed and simulated. The analytical and simulation results show that the scheme has a good performance.