Performance Modeling and Analysis of Decentralized Environmental Notification Message in Vehicular Networks

摘要

Decentralized Environmental Notification Message (DENM) is an event-driven protocol that is already standardized to significantly improve traffic safety and efficiency through direct V2V/I2V communication. Whether or not a DEN application could work well heavily depends on the sending profile-e.g. transmit power and sending frequency, the destination area shape-e.g. circle, rectangle, and ellipse, the channel contention-e.g. hidden and exposed terminal, saturated and unsaturated loads, and the performance indicators-e.g. packet delivery ratio, time delay, throughput, and channel utilization. We propose to theoretically modeling the working behaviours of DENM in the concerned destination shapes of circle, rectangle, and ellipse. We perform the extensive numerical calculations to investigate the effects of vehicle density and transmit power on the packet delivery ratio, delay, and throughput of DENM in the saturated and unsaturated conditions. We also estimate the channel utilization of DENM in each focused destination area with the presence of hidden and exposed terminals. The results show that the density of vehicles exponentially affects the packet delivery ratio and delay, and the transmit power and packet arrival rate linearly affect the packet delivery ratio, throughput, and delay. No matter the presence of exposed terminals, the channel utilization within the rectangle destination area prevails over within the ellipse and circle shapes. The results are expected to guide the practical large-scale deployment of DENM in near future.