Density-aware directional forwarding strategy for vehicular ad hoc networks

Abstract

The characteristics of Vehicular Ad-Hoc Networks (VANETs) such as highly dynamic topology impose various challenges and constraints on routing protocols. These challenges should be managed effectively by the routing protocol. Geographic forwarding-based routing protocols are found to be effective in VANET, where geographic location information is utilized to select the next-hop for packet forwarding. Forwarding strategy is known as the core of such protocols to select the suitable forwarder among neighbouring nodes that can enhance the performance of routing strongly. Several research works have been developed to improve the forwarding strategy in VANET. However, some key issues such as utilizing the vehicle density to improve forwarding decision and reduce network congestion were not addressed. In this paper, an innovative forwarding strategy, called Density-aware Directional (DAD), with a joint consideration of vehicle density factor and directional forwarding is proposed for next-hop selection. It is aimed to manage the number of candidate next-hops as function of density and reduce routing loop by involving a directional angle. The proposed forwarding strategy was analyzed numerically to verify that it achieves the target properties.

Measurement-Based Analysis on Vehicle-to-Vehicle Connectivity in Tunnel Environment

“…Ω is the scale parameter and Γ(•) represents the Gamma function. Furthermore, the PDF of the received SNR considering the Nakagami fading model can be written as [25]:…”

“…Besides, wireless propagation environments have shown to have signifcant impact on the connectivity. In [17,[19][20][21][22][23][24][25][26], theoretical fading models (e.g., Rayleigh, Rice, Weibull, and Nakagami) were considered, based on which the authors presented analytical models. Moreover, the impacts of diferent channel parameters (e.g., shadow fading, PL exponent, and small scale fading parameters) on the link connectivity probability of the VANET were studied in these papers.…”

“…A larger path loss exponent may result in a smaller connectivity probability [28]. In [24,25,29], the efect of lognormal shadowing on connectivity probability was analyzed. It is shown that lognormal shadowing can improve the VANET connectivity.…”