Maximizing the Delivery of MPR Broadcasting Under Realistic Physical Layer Assumptions

It is now commonly accepted that the unit disk graph used to model thephysical layer in wireless networks does not reflect real radiotransmissions, and that a more realistic model should be considered forexperimental simulations. Previous work on realistic scenarios has beenfocused on unicast, however broadcast requirements are fundamentally different andcannot be derived from the unicast case. Therefore, the broadcast protocolsmust be adapted in order to still be efficient under realisticassumptions. In this paper, we study the well-known multipoint relaybroadcast protocol (MPR), in which each node has to choose aset of 1-hop neighbors to act as relays in order to cover the whole2-hop neighborhood. We give experimental results showing that theoriginal strategy used to select these multipoint relays does notsuit a realistic model. On the basis of these results, we propose newselection strategies solely based on link quality. One of the keyaspects of our solutions is that our strategies do not require anyadditional hardware and may be implemented at the application layer,which is particularly relevant to the context of ad hoc and sensornetworks where energy savings are mandatory. We finally provide newexperimental results that demonstrate the superiority of our strategiesunder realistic physical assumptions.