Maximizing the Probability of Delivery of Multipoint Relay Broadcast Protocol in Wireless Ad Hoc Networks with a Realistic Physical Layer

摘要

It is now commonly accepted that the unit disk graph used to model thephysical layer in wireless networks does not reflect real radio transmissions,and that the lognormal shadowing model better suits to experimentalsimulations. Previous work on realistic scenarios focused on unicast, whilebroadcast requirements are fundamentally different and cannot be derived fromunicast case. Therefore, broadcast protocols must be adapted in order to stillbe efficient under realistic assumptions. In this paper, we study thewell-known multipoint relay protocol (MPR). In the latter, each node has tochoose a set of neighbors to act as relays in order to cover the whole 2-hopneighborhood. We give experimental results showing that the original methodprovided to select the set of relays does not give good results with therealistic model. We also provide three new heuristics in replacement and theirperformances which demonstrate that they better suit to the considered model.The first one maximizes the probability of correct reception between the nodeand the considered relays multiplied by their coverage in the 2-hopneighborhood. The second one replaces the coverage by the average of theprobabilities of correct reception between the considered neighbor and the2-hop neighbors it covers. Finally, the third heuristic keeps the same conceptas the second one, but tries to maximize the coverage level of the 2-hopneighborhood: 2-hop neighbors are still being considered as uncovered whiletheir coverage level is not higher than a given coverage threshold, manyneighbors may thus be selected to cover the same 2-hop neighbors.