Outage probability for multimodal cooperative networks

We consider the performance of small-scale heterogeneous cooperative networks in which some nodes can transmit and/or receive using channels not available to other nodes, i.e., multimodal communication networks. As an example, we assume the presence of an additional wired channel in a conventional diamond relay network operating under the Laneman protocol, and we find analytical expressions for outage probability assuming communications over the wired and wireless channels are jointly optimized. We consider two cases: adding a channel between the source and a relay, and adding a channel between a relay and the destination. We show that a channel placed between the source and a relay separated by a poor wireless channel improves performance with few assumptions on the characteristics of the wire and over a wide range of wire channel transmit powers.