Trajectory Planning for UAVs equipped with RISs to Provide Aerial LoS Service for Mobile Nodes in 5G/Optical Wireless Communication Networks

Modern wireless communication systems are limited to line-of-sight (LoS) links due to high path loss and blockage issues in millimeter wave (5G) and beyond in optical/visible light communication networks. This letter proposes utilizing (optical) reconfigurable intelligent surface (RIS)-equipped UAV (RISeUAV) to support indirect aerial LoS (ALoS) links for mobile vehicles that deliver critical metropolitan emergency/security services. The RISeUAV performs as an aerial transponder and reflects optical and wireless communication signals in dense urban areas. The navigation problem of the RISeUAV is nontrivial where RISeUAV should be autonomously navigated through an energy-efficient obstacle-free path. Notably, the flight altitude should be relatively low to ensure the quality of ALoS service while the maximum possible ALoS links for vehicles are provided in an obstructed environment. However, designing the flight path for rendering valid ALoS service is an NP-hard problem that is not feasible in real-time for autonomous navigation. We model the RISeUAV navigation as an optimization problem and propose an efficient technique to make the problem computationally tractable in real-time using Benders’ decomposition method and sequential convex programming. Simulation results validate the effectiveness of the proposed method

Precision missile guidance for systems intercepting at small attack angles : a H‡ tracking approach

This paper uses the H1 tracking ideas in the missile guidance problem. The controller performs as a Precision guidance controller for small desired attack angles although theoretically the formulas are valid (when intercepting a maneuvering target in a precision guidance point of view) only for the case of head on collision. The controller essentially navigates the missile in a unique relative arc that is de ned by the missile and target location and the desired attack angle.<br /

Scheduling of a parcel delivery system consisting of an aerial drone interacting with public transportation vehicles

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This paper proposes a novel parcel delivery system which consists of a drone and public transportation vehicles such as trains, trams, etc. This system involves two delivery schemes: drone-direct scheme referring to delivering to a customer by a drone directly and drone–vehicle collaborating scheme referring to delivering a customer based on the collaboration of a drone and public transportation vehicles. The fundamental characteristics including the delivery time, energy consumption and battery recharging are modelled, based on which a time-dependent scheduling problem for a single drone is formulated. It is shown to be NP-complete and a dynamic programming-based exact algorithm is presented. Since its computational complexity is exponential with respect to the number of customers, a sub-optimal algorithm is further developed. This algorithm accounts the time for delivery and recharging, and it first schedules the customer which leads to the earliest return. Its computational complexity is also discussed. Moreover, extensive computer simulations are conducted to demonstrate the scheduling performance of the proposed algorithms and the impacts of several key system parameters are investigated