Energy and QoS Evaluation for a V2R Network

In this paper we study the quality of service (QoS) and energy performance of the carrier sense multiple access with collision avoidance (CSMA/CA) based 802.11p scheme, and our previously proposed modified version of packet reservation multiple access (M- PRMA) scheme for a vehicle-to-roadside (V2R) network in a motorway environment. The simulation results illustrate the deficiency of the 802.11p protocol in providing adequate QoS to support real-time communication for varying vehicular traffic loads expected on the motorway. The significant amount of energy required for carrier sensing in the 802.11p is realised when compared to the low listening energy expenditure levels of the M-PRMA protocol. We compare both protocols under realistic (experimental) vehicular flow in a motorway and show that power saving up to 12 x can be achieved if a time division multiple access (TDMA) approach such as M-PRMA is used or if the CSMA/CA listening power is reduced.