Title: A density-based contention window control scheme for unicast communications in vehicular ad hoc networks

Authors: Ali Balador; Carlos Calafate; Juan-Carlos Cano; Pietro Manzoni

Addresses: Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain ' Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain ' Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain ' Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain

Abstract: Achieving a well-designed medium access control (MAC) protocol is a challenging issue to improve communications efficiency due to the dynamic nature of vehicular ad hoc networks (VANETs). IEEE 802.11p standard was selected as the best choice for vehicular environments considering its availability, maturity, and cost. The common problem in all IEEE 802.11 based protocols is scalability, exhibiting performance degradation in highly variable network scenarios. Experimental results for the IEEE 802.11-based MAC protocol show the importance of contention window adjustment on communications performance; however the vehicular communications community has not yet addressed this issue in unicast communication environments. This paper proposes a novel contention window control scheme for VANET environments based on estimating the network density, which is then used to dynamically adapt the CW size. Analysis and simulation results show that our proposal provides better overall performance compared with previous proposals, even in high network density scenarios.

Keywords: IEEE 802.11p; contention window control; network density estimation; unicast communication; VANETs; vehicular ad hoc networks; medium access control; MAC protocols; vehicular communications; simulation.

DOI: 10.1504/IJAHUC.2017.080913

International Journal of Ad Hoc and Ubiquitous Computing, 2017 Vol.24 No.1/2, pp.65 - 75

Received: 02 Apr 2015
Accepted: 24 Nov 2015

Published online: 12 Dec 2016 *

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