Joint optimization of link scheduling, power control, and routing in Ad hoc wireless networks

Cross-layer design is an extensive research area in ad hoc wireless networks and is particularly important under energy constraints. The physical layer, link layer, and network layer are known to have great impact on network performance as well as on energy consumption; hence, the interactions between these layers should be studied. In this paper, we formulate an optimal link scheduling and power control policy that supports a particular data rate on each link in the network while satisfying the Signal to Interference plus Noise Ratio (SINR) and the maximum transmission power constraints at each node. We present an optimization problem considering both the energy consumed of each node in the routing path and the delay associated on each link as the link cost metrics. The problem is to find an optimal link scheduling, power control and routing policy that minimizes the end-to-end delay as well as the energy link cost subject to certain constraints. We provide numerical examples for our schemes and relationships between the parameters i.e. the higher the required data rate and the higher the SINR requirement; the system will become less energy-efficient since a high transmission power is needed. This paper is a preliminary step towards our distributed joint scheduling, power control and routing algorithm for ad hoc networks using cross layer approach.