Efficient modeling of network flooding performance with proactive retransmissions in mobile ad hoc networks

Network flooding is the key mechanism designed to reach mobile nodes and disseminate the information in MANETs. Increasing the number of floods is a good way to improve coverage, namely, the fraction of nodes that receive the flooding message. However, this also will increase the overhead and hence the interference. In this paper, we used two different methods of refloods/retransmissions; originator-based retransmissions, where the originator of a message will retransmit the same message, and relay-based retransmissions, where each relay that has received the message will retransmit the same message. To compare two retransmission methods, we modeled the relationships of the coverage, overhead, and interference over the various flooding methods such as classic flooding method and several relay-set reduced flooding methods. Our analytic methods and numerical simulations made it possible to evaluate a wide range of scenarios (3,500,000 scenarios) with much less computational effort. In addition to analytic methods and numerical simulations, packet level simulations were performed to justify the results obtained from our efficient performance models. Furthermore, we investigated the impact of proactive retransmissions on the overhead and coverage as a function of message generation rate. When sequentially considering one transmission, originator-based optimal retransmission, and relay-based optimal retransmission, CF coverage becomes lower and lower than efficient flooding methods at the higher node density and faster message generation rate.