Lightweight packet scheduling algorithms for content uploading from mobile devices to media cloud

In this paper, we consider how to optimally schedule packet transmissions from mobile devices over two network interfaces when uploading content files to the media cloud. Our design objective is to minimize total energy consumption while respecting a deterministic delay constraint. We present a convex optimization formulation of the problem, and show that it can be decoupled into two sequential sub-problems: (i) how to allocate all packets onto the two interfaces, and (ii) how to schedule packet transmission durations over each interface. Analytical solutions for both sub-problems reveal two insightful design principles. First, the optimal packet allocation policy should follow a "water-filling" algorithm based on the noise level of each interface. Second, packets allocated to each wireless interface should be transmitted with equal duration while filling up the prescribed delay limit. Similar insights shall carry forward to future mobile devices with more than two interfaces.