On maximizing the utility of uplink transmissions in sensor networks under explicit fairness constraints

We consider wireless sensor networks with multiple gateways, multiple classes of traffic, and no restrictions on routing and transmission scheduling other than those imposed by the wireless medium. The objective is to schedule uplink transmissions in order to maximize the overall system utility under explicit fairness constraints. We propose a decomposition algorithm drawing upon large-scale decomposition ideas in mathematical programming. We show that in the region of small powers, in which most sensor networks operate, this algorithm terminates with an optimal solution in a finite number of iterations. Moreover, we show that an associated subproblem can be transformed to a maximum weighted matching problem and is therefore solvable in polynomial time. We also consider how to optimize sensor power levels in order to save energy while achieving a certain utility goal. Our approach can efficiently determine the optimal transmission policy for dramatically larger problem instances than an alternative enumeration approach.