Distributed Beam Tracking for Vehicular Communications via UAV-assisted Cellular Network

Abstract: In this paper, we propose a distributed beam tracking scheme for millimeter-wave unmanned aerial vehicle (UAV)-assisted communication systems. In the considered network, aerial node base (aNB) connects the ground vehicles (GV) through directive beams to mitigate the path loss. However, line-of-sight (LoS) blockage may result in the link disconnection, which leads to the corruption of observations. To address the issues, we extend the one-to-one beam tracking into the multi-node cooperative beam tracking scheme. For the multi-node cooperative problem, we propose the distributed extended Kalman filter (EKF) based on the angle of arrival estimation technique to overcome the high nonlinearity and field-of-view (FoV) limitation of the observation model. While the multi-node cooperation scheme alleviates the corruptions of the observations, it may also causes the error propagation between neighbor nodes. Thus, we incorporate the resilient network control into the proposed scheme. Consequently, a distributed EKF-based multi-node cooperative beam tracking protocol is proposed for the correction of corrupted observations and a link stability. We show that our proposed scheme provides the robust beam tracking results by simulations, which is more efficient than conventional beam tracking schemes in centralized networks.