Antenna orientation optimization for minimum-energy multicast tree construction in wireless ad hoc networks with directional antennas

Energy conservation is a critical issue in wireless ad hoc networks since batteries are the only energy source to power the nodes. One major metric for energy conservation is to route a communication session along the routes which require the lowest total energy consumption when all nodes are equipped with a finite and non-renewable amount of energy. To explore advantages offered by the use of directional antennas, we consider the case of source initiated multicast traffic in wireless ad hoc networks that use switched antennas and have limited energy resources. In this paper, we present a constraint formulation in terms of mixed integer linear programming, which can be used for an optimal solution of the minimum-energy multicast problem in wireless ad hoc networks with directional antennas. The optimal solutions can be used to assess the performance of heuristic algorithms for mobile networks by running them at discrete time instances