Abstract
This paper considers the layered transmission between the source and the destination over two relays using super-position coding (SC). In this two-hop decode-and-forward (DF) relaying system, because of the network topology, the receiver continuously decodes only the base layer of the direct transmission from the source; the enhancement layer is decoded with a delay based on the transmission from one of the two relays sending and receiving in alternate time slots. Alternate relaying improves the spectral efficiency of the scheme, however it causes inter-relay interference (IRI), which may limit the system performance if not mitigated. To allow the proper data recovery at the relays and at the destination, we have designed successive interference cancellation decoding schemes that consider different power allocations to the base and enhancement layers. Specifically, based on the channel gains between different transmitter-receiver pairs, the transmissions from the source and the relays are aligned in time and power as to optimize the system throughput. Finally, based on the analytical derivations and simulations, we present numerical results for capacity improvements in the proposed scheme over the existing schemes.