Opportunistic routing (OR) protocols for ad hoc networks basically consist of selecting a few forwarders between the source and destination and prioritizing their transmission. The performance of OR protocols depends on how these two steps are performed. The aim was to reduce the number of transmissions to deliver packets to the destination. In this paper, we first present a mathematical model to compute the total number of packets including duplicate packets generated by OR protocols. We use the model to analyse well-known OR protocols and understand the reason behind their increase in number of transmissions. Next, we propose an OR scheme transmission-aware opportunistic ad hoc routing (TOAR) protocol, which attempts to minimize retransmissions. Our proposed OR protocol uses tree structures to select forwarders and prioritize them. The use of tree structures helps in identifying primary forwarders which carry packets farthest to the destination during each transmission round. TOAR also helps in choosing secondary forwarders which will transmit packets missed out by the forwarder. The optimized selection of forwarders results in significant reduction in retransmissions, a smaller forwarder list set, and improvement in goodput.
Similarly, a mathematical model was proposed to compute the total number of transmissions of the whole network in REF .
TOAR : transmission-aware opportunistic ad hoc routing protocol
Computer Science