Distance ADaptive (DAD) Broadcasting for Ad Hoc Networks

In mobile ad hoc networks, it is often necessary to broadcast control information to all the constituent nodes in the network. Possible applications include searching for a destination node (as a part of routing) or a particular service such as DNS look-up. Flooding, which is often deployed to achieve the above objective, is expensive in terms of overhead and wastes valuable resources such as bandwidth and power. An improvement to flooding is to choose probabilistically a subset of nodes to rebroadcast. In this paper, we propose to use the signal-strength to improve the efficiency of broadcasting. We propose a protocol to select a set of nodes for rebroadcasting on the basis of their relative distance from the previous broadcast. We show how we can use the signal strength as an estimate of the relative node distance. Our simulations indicate that our approach can increase the efficiency of broadcasting significantly. Our simulations show that we can achieve the same coverage with approximately 20% less rebroadcasts. In addition, the time taken by the global broadcast is also reduced by more than 20%.