14251

12897

كارشناسي ارشد

مخابرات سيستم

اصفهان : دانشگاه صنعتي اصفهان

1397

سيزده، ۷۰ص.: مصور، جدول، نمودار

فرامرز هندسي

نغمه سادات مويديان

1397/10/26

كتابنامه

برق و كامپيوتر

مهندسي برق و كامپيوتر

ID12897

Hybrid TDMA CSMA CA based MAC Protocol for Vehicular Ad hoc Networks in a Cluster based Topology Farshid SalimiPour farshid salimi@ec iut ac ir Date of Submission 2018 06 27 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor hendessi@cc iut ac irAbstract Vehicular Ad hoc Networks VANETs have attracted a lot of attention in the research community inrecent years due to their promising applications VANETs help improve traffic safety and efficiency Eachvehicle can exchange information to inform other vehicles about the current status of the traffic flow or adangerous situation such as an accident The Application for V2V and V2I can be divided into the followingthree services safety services traffic management and user oriented services Safety services have specialrequirements in terms of quality of service In fact bounded transmission delays as well as low access delaysare mandatory in order to offer the highest possible level of safety At the same time user oriented servicesneed a broad bandwidth Medium Access Control will play an important role in satisfying these requirements In VANETs the nodes share a common wireless channel by using the same radio frequencies and thereforean inappropriate use of the channel may lead to collisions and a waste of bandwidth Hence channel sharingis the key issue when seeking to provide a high quality of service Road safety and traffic managementapplications require a reliable communication scheme with minimal transmission collisions which thusincrease the need for an efficient Medium Access Control MAC protocol This protocol must be designedto share the medium between the different nodes both efficiently and fairly However the design of the MACin a vehicular network is a challenging task due to the high speed of the nodes the frequent changes intopology the lack of an infrastructure and various QoS requirements In this thesis we introduced a newhybrid MAC protocol with TDMA CSMA CA multiple access in a cluster based topology In TDMA periodwe have to select a cluster head as a central coordinator In this protocol we use TDMA to guarantee thechannel access for all nodes to send receive their safety message and CSMA CA method to service channelreservation for nodes who have non safety message for transmission Simulation result show that ourproposed scheme has improved throughput and channel utilization in CSMA CA period and control channelaccess delay in TDMA period in compare of present standard Keywords Vehicular Ad hoc Networks MAC Protocols Collision Hybrid Multiple Access based on TDMA CSMA CA

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