Leveraging Parallel Communications for Minimizing Energy Consumption on Smartphones

Recent energy measurements on smartphones have shown that parallel communications (e.g., data transfer and voice call) require less energy than their stand-alone execution. Guided by these results, we investigate the possibility of scheduling communications in pairs for minimizing the energy consumption. We define two energy optimization problems to postpone delaytolerant services and perform them in parallel with real-time services in order to save energy. The first problem, called Single Delay-Tolerant Assignment (SDA), allows at most one delay-tolerant service to be paired with each real-time service, whereas the second problem, called Multiple Delay-Tolerant Assignment (MDA), allows multiple delay-tolerant services to be paired (in different times) with the same real-time service. For the SDA problem, we propose an optimal algorithm. For the MDA problem, which is computationally intractable, we give an approximation algorithm. We evaluate the benefits of the energy-efficient pairing strategy via simulations on synthetic traces. The MDA algorithm can save up to the 60% of the energy consumption using 4G network assuming an intensive smartphone usage, while the SDA algorithm saves up to the 20%.