Offset transmission scheme with full interference cancellation for an asynchronous cooperative four relay network

We use a simple offset transmission scheme with full interference cancellation (FIC) and orthogonal frequency-division multiplexing (OFDM) within a two-hop asynchronous cooperative four relay network to achieve full diversity and asymptotically full rate. The four relay nodes are arranged as two groups of two relay nodes with offset transmission scheduling. Therefore, the source can serially transmit data to the destination and the overall rate can approach one when the number of samples is large. However, the four-path relay scheme suffers from inter-relay interference which is caused by the simultaneous transmission of the source and another group of relays. The FIC approach is therefore used to remove inter-relay interference. A cyclic prefix (CP) is added in transmission at the source node to combat timing errors and through the use of time reversion in the destination node, CP removal is avoided at the relays. Bit error rate simulations are used to confirm the advantage of the scheme.