Improving QoS of VANET Using Adaptive CCA Range and Transmission Range both for Intelligent Transportation System

Abstract

Connectivity and spatial frequency reuse are very important performance influencing factors in Vehicular Ad-hoc NETwork (VANET). In proposed work connectivity in VANET is measured in terms of Vehicular Average Connected Coverage (VACC). Interference on road is measured in terms of Average Highly Interference Region ratio (AvgHIR). A new Adaptive Transmission and Clear Channel Assessment (CCA) Power scheme (ATCCAPsch) is proposed. ATCCAPsch varies Transmission Range (TR) along with CCA range to improve VACC, AvgHIR, spatial frequency reuse and hence overall QoS performance of VANET. ATCCAPsch performs its operations based on selected threshold “MINimum Transmission Range of Vehicle ( $$minTR_{v\_sel}$$ )” and “Required Number of Neighbours ( $$RNNgb_{sel}$$ )”. Comprisal of $$minTR_{v\_sel}$$ and $$RNNgb_{sel}$$ is done in the definition of VANET’s Multi-Objective optimization Problem (VANET-MOP). VANET Multi-Objective optimization Model (VANET-MOM) is defined and implemented to solve VANET-MOP to determine $$RNNgb_{sel}$$ and lower bound of $$minTR_{v\_sel}$$ ( $$lbhvh\_minTR_{v\_sel}$$ ). VANET-MOM incorporates ATCCAPsch in another newly proposed algorithm “VATCCAPschSim” to evaluate VACC and AvgHIR. Multi Objective Optimization (MO-Opt) tool “gamultiobj” is used to serve the purpose. Performance of proposed ATCCAPsch is verified in NS-3 simulator for single channel and infrastructureless VANET. ATCCAPsch decreased mean delay per hop by 1.86, 25.9 and 16.8% for given MAXimum Transmission Range of Vehicle ( $$maxTR_{v}$$ ) 250, 400 and 1000 m resp. as compared to Fixed Transmission and CCA Power SCHeme (FTCCAPsch). ATCCAPsch is also enhancing other Quality of Services (QoS) like packet delivery ratio, delay and jitter of VANET.