84 Int. J. Ad Hoc and Ubiquitous Computing, Vol. 22, No. 2, 2016 Copyright © 2016 Inderscience Enterprises Ltd. Adaptive RSU re-routing under delay constraint in multi-hop vehicular networks Kuo-Lung Wang Department of Computer Science, National Chiao Tung University, Hsinchu 300, Taiwan Email: klwang@cs.nctu.edu.tw Tsan-Pin Wang* Department of Computer Science, National Taichung University of Education, Taichung 407, Taiwan Email: tpwang@mail.ntcu.edu.tw *Corresponding author Chien-Chao Tseng Department of Computer Science, National Chiao Tung University, Hsinchu 300, Taiwan Email: cctseng@cs.nctu.edu.tw Abstract: Vehicular wireless networks (VWNs) offer wireless multi-hop communications between vehicles and roadside units (RSUs). A multi-hop wireless network with carry-and-forward routing may suffer from longer delay in packet delivery. However, the applications may demand stringent delay requirement in multi-hop VWNs. Therefore, this paper proposes an adaptive RSU re-routing strategy to alter the current associated RSU to the best RSU under delay or throughput constrains for applications in multi-hop VWNs. Performance results show that the proposed strategy is able to adaptively select a suitable packet size for the trade-off between delay and throughput to satisfy the diverse requirements of applications in multi-hop VWNs. Keywords: IEEE 802.11p; vehicular networks; multi-hop; carry-and-forward routing. Reference to this paper should be made as follows: Wang, K-L., Wang, T-P. and Tseng, C-C. (2016) ‘Adaptive RSU re-routing under delay constraint in multi-hop vehicular networks’, Int. J. Ad Hoc and Ubiquitous Computing, Vol. 22, No. 2, pp.84–95. Biographical notes: Kuo-Lung Wang is currently a PhD candidate in the Department of Computer Science at National Chiao Tung University, Taiwan. His research interests include computer security and vehicular networks. Tsan-Pin Wang is currently a Professor and Chair in the Department of Computer Science at National Taichung University of Education, Taichung, Taiwan. He received the BS in Applied Mathematics; MS and PhD in Computer Science and Information Engineering, from National Chiao Tung University, Taiwan, in 1990, 1992 and 1997, respectively. From 1992 to 1993, he was a System Engineer in the R&D Division of Taiwan NEC Ltd. From 1997 to 2001, he was an Assistant Professor at Providence University. From 2001 to 2005, he was an Associate Professor at Providence University. From 2006 to 2009, he was the Chairman of the Department of CIS, National Taichung University. He is in the Editor Board of International Journal of Wireless and Mobile Networks (IJWMN), AIRCC. His research interests include mobile computing, mobile communications, vehicular networks, wireless internet and voice over IP. Chien-Chao Tseng is currently a Professor in the Department of Computer Science at National Chiao-Tung University, Hsin-Chu, Taiwan. He received his BS in the Industrial Engineering from National Tsing-Hua University, Hsin-Chu, Taiwan, in 1981; MS and PhD in Computer Science from Southern Methodist University, Dallas, Texas, USA, in 1986 and 1989, respectively. His research interests include mobile computing and wireless internet.