Quality driven modulation rate optimization for energy efficient wireless video relays

Modern mobile computing devices such as smart phones have become the major user-centric video data sources in future 5G wireless networks. However, battery energy efficiency becomes the critical bottleneck for such uplink multimedia contributors. In this paper we propose a new approach to reduce energy consumption while improving Quality of Experience (QoE), by innovatively investigating video encoding frame prioritization, mode, dependency, and rate control overheads, based on communication model of a transmitter device to an access-point via a relay device. In the proposed approach, we investigate various frame level encoding dependencies and different communication data rates to study their impacts on energy efficiency and QoE. We also incorporate some simple game theory concepts to determine the best compromise of energy-quality tradeoff between the transmitter and the relay. Simulation results demonstrate that cross layer exploration of encoding dependency and game theoretical rate control have significant energy saving and quality gain potentials.