Optimal Network-Centric Planning for Airborne Relay Communications

摘要

This paper presents a network-centric mission planning system for airborne relay communications. Examples of airborne relays include aircrafts, such as the battlefield airborne communication node; unmanned aerial vehicles, such as Facebook's Aquila; balloons, such as Google Project Loon; and nano/microsatellites. There are two integrated components of mission planning: 1) the subscriber planner (run on each subscriber's radio, phone, or attached computer) that finds the optimal transmission scheme for each subscriber communicating to/through an airborne relay by accounting for realistic channel, traffic, and energy effects and 2) the orbit (force-level) planner (run at a centralized controller prior to deployment of the airborne relay) that optimally designs the orbit of an airborne relay to maximize the overall network performance. For a given orbit of an airborne relay, the subscriber planner combines channel measurement and prediction (by accounting for terrain, aircraft, and antenna effects) to calculate signal-to-noise-ratio (SNR) and link rate. Then, the subscriber planner decides when and at what rate to transmit while optimizing the expected throughput for uplink/relay communications. The subscriber planner is shown to significantly outperform random and SNR threshold-based transmissions. On the other hand, the orbit planner first selects the optimal parameters of an elliptical orbit to maximize the network performance measured by the subscriber planner. This elliptical orbit is converted to an operational orbit by optimally selecting waypoints and locating smooth turning points while minimizing the airborne relay's fuel consumption. The orbit planner software with an interactive graphical user interface is implemented to return the optimal orbit for the airborne relay that optimizes the network performance measured by the subscriber planner.