I. Introduction
In some important emerging applications, sources and destinations shall be designed to communicate through multiple, simultaneous, parallel routes, each of which is likely to be composed of multiple hops experiencing unusually adverse channel conditions. Such applications include, for instance, links-on-the-fly emergency networks operating over areas devastated by natural disasters and fifth-generation vehicular networks operating under severe, highly dynamic propagation environments [1]. In those cases, standard relaying protocols like conventional decode-and-forward (DF) may prove inappropriate, as retransmissions can be invoked too often in view of the adverse channel conditions. This could render unfeasible the communication process as a whole.
In conventional DF relaying, whenever a relay detects an erroneous message, the message is discarded and a retransmission is invoked.