Computation offloading strategies based on energy minimization under computational rate constraints

The aim of this paper is to propose a computation offloading strategy to be used in mobile cloud computing in order to minimize the energy expenditure at the mobile handset, while guaranteeing a computational rate constraint imposed by the application. We start from a single mobile handset assisted by a single server and then we generalize the approach to the multiuser case. In the multiuser scenario, we derive the optimal transmit power, number of bits per symbol and CPU cycles assigned to each virtual machine in order to minimize the energy consumption at each mobile user, still satisfying a computational rate constraint dictated by the application requirements. We take explicitly into account the channel random fading and provide theoretical results proving the existence of an optimal solution of the problem. Then we corroborate our theoretical findings with simulation results, showing for which classes of application and under what channel conditions, computation offloading can provide a significant performance gain.