Delay-throughput performance of load-adaptive power-controlled multihop wireless networks with scheduled transmissions

The majority of current research on power control in ad-hoc wireless networks concentrates on enhancing throughput performance while disregarding delay requirements. Under such cases, the throughput enhancement is achieved at the expense of increased packet delay that would not be acceptable in many practical situations. In this paper, we study the performance of a load-adaptive power-controlled demand-assigned time division multiple access (DA/TDMA) wireless network, where a central controller may be employed to schedule transmissions under varying network load. We show that multi-hopping is not necessarily the optimal routing strategy to follow in every circumstance. In fact, even though multi-hopping, or alternatively the strategy to transmit at minimum required power levels, may contribute to increased spatial reuse, it causes substantial delay increase when compared to single hop transmissions, especially under light network loads. We thus propose a load adaptive power control protocol for integrated medium access control (MAC) and routing that requires the nodes to transmit at high power under light network load (resulting in a direct transmission between the source and the destination) and switch to multi-hop low power transmissions under heavy network load.