Group Connectivity-Based UAV Positioning and Data Slot Allocation for Tactical MANET

Abstract

On a future tactical-battle field network, combat radio nodes will be deployed for various operations, forming a mobile ad-hoc network (MANET). However, because of the nodes' mobility, a single group might be divided into several small groups with fewer nodes. Conversely, several small groups might be merged into one group. In such an environment, an unmanned aerial vehicle (UAV) will provide an effective way to improve network coverage and connectivity among the small groups. However, some issues should be considered for the optimal deployment of the UAV. One issue is to find the proper position of the UAV, which enhances the connectivity among the groups, because a tactical network places a high priority on network survivability rather than throughput maximization. We also need to exploit real topographic information to obtain more accurate connectivity information among nodes. Second, an efficient resource allocation scheme for reliable communications through the UAV should be taken into account. Since most of the links between the UAV and the ground nodes are line-of-sight (LoS), due to the good quality of these links, the traffic via the UAV will be heavy in spite of the limited data slot resources. Moreover, the traffic flows of the network require diverse quality-of-service (QoS), and different priorities should be imposed upon the nodes depending on the involved tactical operations. In this paper, we formulate a UAV positioning problem maximizing group connectivity (GC) and a data slot-allocation problem maximizing GC utility. Subsequently, we propose an optimal positioning and slot allocation algorithm, which satisfies QoS requirement and supports the predetermined priorities of the nodes and the groups. Numerical analysis verifies that the proposed scheme is effective in UAV positioning and slot allocation, outperforming conventional methods.