Energy-Aware Relay Optimization and Power Allocation in Multiple Unmanned Aerial Vehicles Aided Satellite-Aerial-Terrestrial Networks

With the explosive growth of various connected devices and the supported services, the satellite-aerial-terrestrial network (SATN) can fulfill the requirements of the increasing data traffic with enlarged coverage and enhanced capacity. In particular, utilizing multiple unmanned aerial vehicles (UAVs) as relays in the SATN holds great promise for bringing lots of benefits in terms of high flexibility and high reliability. However, due to the limited power of UAVs and the long distance of the aerial-satellite links, how to improve system energy efficiency (EE) is still a challenging issue since existing works mainly paid their attentions to resource while neglecting relay strategy optimization among multiple UAVs. Toward this end, in this article we explore the problem of system EE maximization through jointly optimizing relay selection and power allocation as well as UAV deployment. An iterative algorithm is presented as our solution via alternately leveraging coordinate ascent and Lagrangian dual decomposition methods. Extensive simulation results demonstrate that our devised optimization strategy can significantly improve system EE and obtain the optimal relay selection and power allocation decisions.