VANET Applications Under Loss Scenarios & Evolving Wireless Technology

In this work we study the impact of wireless network impairment on the performance of VANET applications such as Cooperative Adaptive Cruise Control (CACC), and other VANET applications that periodically broadcast messages. We also study the future of VANET application in light of the evolution of radio access technologies (RAT) that are used to exchange messages. Previous work in the literature proposed fallback strategies that utilizes on-board sensors to recover in case of wireless network impairment, those methods assume a fixed time headway value, and do not achieve string stability. In this work, we study the string stability of a one-vehicle look-ahead CACC platoon under different network loss scenarios, and propose to adapt the time headway parameter of the model according to a network reliability metric that we defined based on packet burst loss length to maximize traffic flow efficiency while maintaining a string stable platoon. Our findings show that careful adjustment of headway value according to the wireless network reliability allows the platoon to maintain string stable operation while maximizing traffic flow. We also study the impact that evolving wireless technology can have on VANET applications such as CACC, where we study the performance when using DSRC and 5G NR V2X. In addition, we study the evolution of RATs used in VANET application, and we propose DSRC+, as a possible enhancement to traditional DSRC, that utilizes modern modulation/coding schemes and performs random blind retransmission to improve packet delivery ratio. We finally study the trade-offs in the choice of RAT in VANET applications such as CACC, concluding that RATs with time-division channel access can be reliable with lower packet loss, but performs poorly when needing to disseminate messages over longer CACC platoons