Reputation-Based Collaborative Approach To Rectify Selfish Vehicles In Ieee802.11p For Vanet

Abstract

Network Resources Are Limited And Finite, Particularly For Several Users Sharing The Same Medium. In Other Words, When The Same Users Gain Throughput And Bandwidth Advantage, Others Can Lose Their Transmission Opportunity. Particularly Infrastructure-Less Ad Hoc Networks, Like VANET(Vehicular Ad Hoc Network), Rely On The Cooperation Of Nodes.Nodes(Vehicles) In VANET May Behave Selfishly And Deviate From The Regular And Cooperative Functionality, Wishing To Conserve Their Resource. The Implementation Of IEEE802.11p Is To Provide Safe Communication Among Vehicles, And It Employs CSMA/CA(Carrier Sense Multiple Acess With Collision Avoidance) As A Default Medium Access Control. Concurring To CSMA/CA, All The Vehicles With The Packet To Send Should Follow The Channel First. The Vehicle Takes After The Backoff Mechanism(Bom) When The Channel Is Busy. However, Certain Vehicles Intentionally Manipulate The Bom To Increase Their Access Probability And Gain More Bandwidth Share Than Well-Behaved Vehicles. This Problem Leads To Throughput Degradation And Channel Crowdedness. This Study Developed A Cooperative Watchdog And Credit-Based CSMA/CA(WC-CSMA/CA) Mechanism To Overcome These Issues By Motivating The Selfish Vehicles(Svs) To Cooperate Again In The Network. It Has Two Main Phases. Identification Phase: Assigned Verifier Vehicles(Vvs) As A Watchdog To Monitor The Vehicles' Abnormal Behavior And Identify The Svs That Manipulate The Bom. Motivation Phase: Motivates The Identified Svs To Be Well-Behaved Again By Giving Credits, Considering Their Waiting Time And Number Of Connection Trials, While Accessing The Channel.The Simulation Is Conducted On OMNET++, Using 25,50,100 Vehicles For Different Vehicle Densities In A 1km Road. From The Simulation Result For 50 Vehicles. The Average Throughput Is Increased From 12800.5mbit/Sec To 15752.3mbit/Sec, A 23.06% Enhancement. Average Waiting Time And Average Queuing Delay Are Reduced From 3.04ms To 2.5ms And 0.53ms To 0.45ms, Which Is A 17.94% And 15.5% Improvement. Attaining The Result, We Have Concluded That The Proposed WC-CSMA/CA In The Presence Of Svs Acquired A Better Performance In All Metrics And Different Vehicle Densities Compared With The Original CSMA/CA Because Of Its Cooperative Mechanism