Optimizing queueing cost and energy efficiency in a wireless network

We consider the joint minimization of queueing cost and power consumption in a wireless network, over all power control policies at the transmitters. Approximately optimal policies are derived through the use of a comparison to a single link system offering lower bounds for both performance metrics. The derived policies are of a simple form: the total power consumed at any instant is a monotonic function of a linear combination of the queue backlogs at that instant, while the portions of power allocated to each transmitter are such that the resulting link speeds are proportional to the queue backlogs. Simulations show that the lower bounds become tight -and so the policies become optimal- as the average power approaches the lowest value for which stability is maintained. Moreover, these policies are shown to perform better than gradient projection -based power adaptive algorithms such those arising in formulations using static optimization problems.