TBM: An Efficient Trajectory-Based Multicast Routing Protocol for Sparse UAV networks

Abstract

Multicast is an essential operation for Unmanned Aerial Vehicle (UAV) networks, which supports important functions such as information dissemination and swarm coordination. However, most existing routing protocols for UAV networks aim at unicast routing, and there are few multicast protocols dedicated to UAV networks. Furthermore, most existing multicast protocols for mobile wireless networks usually maintain a forwarding structure, and they are inefficient in UAV networks due to the unique characteristics of UAVs, such as high-speed movement and sparse distribution. For many UAV applications, the trajectories of UAVs are pre-planned in advance through mission planning and trajectory planning, and the location and motion information of UAVs can be obtained through positioning technology and inertial sensors. In this paper, we propose an efficient Trajectory-Based Multicast (TBM) routing protocol for UAV networks. TBM utilizes the trajectory information to compute the encounters between UAVs, then a priority metric that characterizes the ability of a UAV to forward a message to multiple destination nodes is calculated. Based on the priority metric, TBM constructs a priority encounter graph, which considers the timeliness and stability of message forwarding, thus finding a multicast forwarding sequence with low delay and high delivery ratio. Through extensive simulations, we demonstrate the effectiveness and efficiency of TBM.