Optimal Energy Scheduling for Rate-Guaranteed Download Over Faded Multichannel Networks

Abstract

In this contribution, we consider emerging wireless content delivery networks (CDNs), where multiple (possibly nomadic) clients download large-size files from <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">battery-powered</i> proxy servers via faded links that are composed of multiple slotted orthogonal bearers (e.g., logical subchannels). Since the considered transmit proxy servers are battery-powered mobile routers, a still open basic question deals with searching for optimal energy-allocation (e.g., energy scheduling) policies that efficiently split the available energy over the (faded) bearers. The target is to <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">minimize</i> the resulting (average) download time when constraints on the average available energy per information unit (IU), peak-energy per slot, and minimum energy per bearer (e.g., rate-induced constraints) are simultaneously active. The performance and the robustness of the resulting optimal energy scheduler are tested on the last hop of Rayleigh-faded mesh networks that adopt the so-called ldquodirty paper strategyrdquo for broadcasting multiple traffic flows that are generated by proxy servers equipped with <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">multiple</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">antennas</i> .