A TDMA Approach for OFDM-Based Multiuser RadCom Systems

This paper is focused on the multiuser implementation of fusion of radar and communication(RadCom)in internet-of-vehicles(IoV)scenarios.Traditional time-division multiple access(TDMA)technology degrades the velocity detection performance of orthogonal frequency-division multiplexing(OFDM)-based RadCom systems.We propose a new TDMA approach for OFDM-based RadCom systems,where multiuser communication and radar detection are completed synchronously.We consider a continuous-wave TDMA OFDM structure in which random user data or Zadoff-Chu(ZC)sequences are transmitted in one symbol duration to ensure detection performance.As an application of interference cancellation method,user data demodulation and environment sensing can be simultaneously accomplished by our proposed approach.We carry out numerical evaluation and show wireless communication and radar detection performance over the continuous-wave TDMA OFDM-based RadCom approach.

On the security of warning message dissemina-tion in vehicular Ad hoc networks

Information security is an important issue in vehicular networks as the accuracy and integrity of information is a prerequisite to the satisfactory performance of virtually all vehicular network applications.We study the information security of a vehicular Ad hoc network whose message could be tampered by malicious vehicles.An analytical framework is developed to analyze the process of message dissemination in a vehicular network with malicious vehicles randomly distributed in the network.The probability that a destination vehicle at a xed distance can receive the message correctly from the source vehicle is obtained.Simulations are conducted to validate the accuracy of the theoretical analysis.Our results demonstrate the impact of network topology and the distribution of malicious vehicles on the correct delivery of a message in vehicular Ad hoc networks,and provides insight on the design of security mechanisms to improve the security of message dissemination in vehicular networks.

Space-air-ground integrated vehicular network for connected and automated vehicles:Challenges and solutions

Unlimited and seamless coverage as well as ultra-reliable and low-latency communications are vital for connected vehicles,in particular for new use cases like autonomous driving and vehicle platooning.In this paper,we propose a novel Space-Air-Ground integrated vehicular network(SAGiven)architecture to gracefully integrate the multi-dimensional and multi-scale context-information and network resources from satellites,High-Altitude Platform stations(HAPs),low-altitude Unmanned Aerial Vehicles(UAVs),and terrestrial cellular communication systems.One of the key features of the SAGiven is the reconfigurability of heterogeneous network functions as well as network resources.We first give a comprehensive review of the key challenges of this new architecture and then provide some up-to-date solutions on those challenges.Specifically,the solutions will cover the following topics:(1)space-air-ground integrated network reconfiguration under dynamic space resources constraints;(2)multi-dimensional sensing and efficient integration of multi-dimensional context information;(3)real-time,reliable,and secure communications among vehicles and between vehicles and the SAGiven platform;and(4)a holistic integration and demonstration of the SAGiven.Finally,it is concluded that the SAGiven can play a key role in future autonomous driving and Internet-of-Vehicles applications.