Joint delay and power control in single-server queueing systems

Many power-aware resource allocation problems in packet networks can be modeled as single-server queueing systems, in which the power consumption depends on the actual service rate. We consider the scenario in which the queue service rate is controlled to minimize server power consumption. We show that power control methods that tune the service rate by using the queue length or the arrival rate exhibit a non-monotonic curve of delay vs. load. This may lead to malfunctioning in end-to-end flow/congestion control protocols, which are based on the assumption that delays increase with increasing load. We propose a new policy, in which the service rate is changed while keeping almost flat the delay curve, which permits to achieve a close-to-optimal trade-off between power and delay.