Magic: A Lightweight System For Localizing Multiple Devices Via A Single Lora Gateway

In this paper, we investigate localizing multiple wireless devices in the context of Internet of Things (IoTs). Considering the massive amount of IoT devices deployed in an IoT system, we establish an economical and lightweight Moving-Anchor multi-tarGet IoT loCalization system (MAGIC), which is capable of localizing multiple targets simultaneously in a low-power and low-cost manner. To be specific, MAGIC utilizes a single mobile anchor with GPS and LoRa gateway to localize multiple IoT devices embedded with LoRa tags. The single anchor moves to different positions and makes location estimations at each step based on the distance measurements between each target and itself. To find the optimal moving strategy of the anchor, we formulate an optimal path problem aiming to minimize the total length of the path with guaranteed localization accuracy. Since solving the optimal path problem requires the localization information at all the positions, which is unavailable during the moving process, we instead solve an optimal step problem in each step that minimizes the length of the next step without relying on future information. We address the non-convex issue of the problem by decomposing it into a set of convex subproblems by partitioning the feasible domain, which yields a suboptimal solution. Simulation results and practical experiments validate the effectiveness of the proposed MAGIC system and demonstrate its practical value in realistic IoT scenarios.