This brief examines current research on improving Vehicular Networks (VANETs), examining spectrum scarcity due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication bands and the use of opportunistic spectrum bands to mitigate congestion. It reviews existing literature on the use of opportunistic spectrum bands for VANETs, including licensed and unlicensed spectrum bands and a variety of related technologies, such as cognitive radio, WiFi and device-to-device communications. Focused on analyzing spectrum characteristics, designing efficient spectrum exploitation schemes, and evaluating the date delivery performance when utilizing different opportunistic spectrum bands, the results presented in this brief provide valuable insights on improving the design and deployment of future VANETs.

Autorentext

Rui Chen received the B.S., M.S. and Ph.D. degrees in Communications and Information Systems from Xidian University, Xi'an, China, in 2005, 2007 and 2011, respectively. From 2014 to 2015, he was a visiting scholar at Columbia University in the City of New York. He is currently an associate professor and Ph.D. supervisor in the school of Telecommunications Engineering at Xidian University. He has published about 80 papers in international journals and conferences and held 40 patents. He is a member of the IMT-2030 6G Promotion Group, conduct OAM communication technology development. He is an Associate Editor for International Journal of Electronics, Communications, and Measurement Engineering (IGI Global). His research interests include broadband wireless communication systems, array signal processing and intelligent transportation systems. Wen-Xuan Long received the B.S. degree (with Highest Hons.) in rail transit signal and control from Dalian Jiaotong University, Dalian, China, in 2017. She is currently pursuing the double Ph.D. degree in information and communication engineering at Xidian University, China, and the University of Pisa, Italy. Her expertise and general interests span the areas of wireless communications and signal processing, estimation and detection theory. Her research interests include the novel transmission dimension of wireless communication networks, including OAM wireless communications, and RIS-aided wireless communications. Nan Cheng received the Ph.D. degree from the Department of Electrical and Computer Engineering, University of Waterloo in 2016, and B.E. degree and the M.S. degree from the Department of Electronics and Information Engineering, Tongji University, Shanghai, China, in 2009 and 2012, respectively. He worked as a Post-doctoral fellow with the Department of Electrical and Computer Engineering, University of Toronto, from 2017 to 2019. He is currently a professor with State Key Lab. ofISN and with School of Telecommunications Engineering, Xidian University, Shaanxi, China. He has published over 70 journal papers in IEEE Transactions and other top journals. He serves as associate editors for IEEE Transactions on Vehicular Technology, IEEE Open Journal of the Communications Society, and Peer-to-Peer Networking and Applications, and serves/served as guest editors for several journals. His current research focuses on B5G/6G, space-air-ground integrated network, big data in vehicular networks, and self-driving system. His research interests also include AI-driven future networks.

Inhalt
Introduction.- Opportunistic Communication Spectra Utilization.- Opportunistic Spectrum Access Through Cognitive Radio.- Performance Analysis of WiFi Offloading in Vehicular Environments.- Conclusions and Future Directions.