LLR–Based Hybrid On–Off Relaying in Rayleigh Fading

In this work, a relay selection and activation scheme is proposed for wireless cooperative networks. This is done based on the calculation of the log-likelihood ratio (LLR) at the various nodes in the network. Once a relay node is active, it may forward a signal to the destination node using either amplify–and–forward (AF) or decode–and-forward (DF), in a hybrid manner. The toggling between the 2 forwarding protocols is also based on the calculation of the LLR. Closed– form expressions for the the BER, outage probability and the capacity of the proposed scheme are derived. The proposed scheme shows superior performance when compared to its counterparts from the literature.