Reactive Robust Routing with Opportunistic Large Arrays

An opportunistic large array (OLA)-based reactive routing protocol, which we call OLA routing on-demand (OLAROAD), is investigated for mobile ad hoc networks for varying node densities. An OLA is a simple form of cooperative transmission (CT) in which a group of simple relays or forwarding nodes operate without any mutual coordination, but naturally fire together in response to energy received from a single source or another OLA. OLAROAD incorporates CT into both route discovery and data transmission. It avoids the overhead involved in finding a conventional multi-hop route and individual addressing of relay nodes, which are problems of the other CT-based routing schemes. Through extensive simulations using the random way point mobility model, we show that the packet delivery ratio (PDR) and latency of OLAROAD doesn ´t change with density whereas a traditional multi-hop scheme like AODV incurs much more overhead and delay as the density increases. We also compare the end-to-end delays where we take into account the delay due to route breakages and also the delay in data transmission.