Context severity based opportunistic service reprioritization for IEEE 802.11p VANETs

IEEE 802.11p Wireless Access for Vehicular Environments (WAVE) is the approved communication protocol for Vehicular Ad-hoc Networks (VANETs) and Intelligent Transportation System (ITS) applications. WAVE offers service differentiation by prioritizing packets based on an application´s requested QoS. These priorities are static and do not account for network load or vehicle´s context severity. In this paper, we propose a novel opportunistic service reprioritization (OSR) technique for IEEE 802.11p (WAVE). It dynamically promotes and/or demotes vehicle´s load to different access categories, by taking into account the vehicle´s context severity and network link layer bounds. We show the feasibility of our approach by formulating the opportunistic service reprioritization technique as a Linear Programming (LP) problem and solve it to guarantee optimal QoS with respect to severity for all access categories. We compare our opportunistic service reprioritization technique with WAVE and show significant improvement. The weighted average delay in OSR outperforms classical WAVE, on average by 90%.