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Master Thesis on Vehicular Ad-hoc Network (VANET)

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In present, many people during the public died each year in vehicle accidents, therefore in almost countries some safety data i.e. traffic lights & velocity limits are applied, simply however it is not a better solution. Also government and number of automation industries regarded that vehicular safety is real challenging task [1]. Then equally result, to enhance people traffic safety of a new progressed particular technology is formulated i.e. VANET [4]. It is progress type of MANET (Mobile Ad-hoc Network). VANET manages a network within which vehicles are act nodes and applied as mobile nodes to construct a robust infrastructure-less ad-hoc network. In Figure 1 illustrates the basic components of VANET architecture. It builds the network among Inter-Vehicle, Vehicle-to-Roadside and Inter-Roadside communicating networks [4]. Moreover, apart from accidental-safety and security types, there are also broad varieties of applications in VANET are available and potential that can extend passenger comfort like predictable mobility by GPS, web browsing and information modify and so on. Vehicular Ad-hoc Network (VANET) is a novel formulated form of Mobile Ad-hoc Network (MANET), where moving nodes are vehicles same automobiles, cars, buses etc [2].

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Master Thesis on Vehicular Ad-hoc Network (VANET)

  1. 1. For More : https://www.ThesisScientist.com 1 Chapter 1 INTRODUCTION 1.1 Introduction In present, many people during the public died each year in vehicle accidents, therefore in almost countries some safety data i.e. traffic lights & velocity limits are applied, simply however it is not a better solution. Also government and number of automation industries regarded that vehicular safety is real challenging task [1]. Then equally result, to enhance people traffic safety of a new progressed particular technology is formulated i.e. VANET [4]. It is progress type of MANET (Mobile Ad-hoc Network). VANET manages a network within which vehicles are act nodes and applied as mobile nodes to construct a robust infrastructure-less ad-hoc network. In Figure 1 illustrates the basic components of VANET architecture. It builds the network among Inter- Vehicle, Vehicle-to-Roadside and Inter-Roadside communicating networks [4]. Moreover, apart from accidental-safety and security types, there are also broad varieties of applications in VANET are available and potential that can extend passenger comfort like predictable mobility by GPS, web browsing and information modify and so on. Vehicular Ad-hoc Network (VANET) is a novel formulated form of Mobile Ad-hoc Network (MANET), where moving nodes are vehicles same automobiles, cars, buses etc [2].
  2. 2. For More : https://www.ThesisScientist.com 2 Figure1.1 Generalized VANET Architecture 1.2 Description of Broad Area: Vehicular Ad hoc Network (VANET) belongs to wireless communication network area. Vehicular Ad hoc Network (VANET) is the issuing fields of Mobile Ad Hoc Networks (MANETs) in which vehicles act equally the mobile nodes inside the network. The main motto of VANET is to increase safety of road users and allow comforting based application to the passengers [3]. Figure 1.2: Illustration of Vehicular Ad hoc Network It is the wireless network in which communicating involves position by wireless connections mounted on each node (vehicle) [1] according to the IEEE 802.11p standard. Each node among Vehicular Ad hoc Network (VANET) act as some, the participant and router of the network as the nodes communicates by early intermediate nodes that lies between their own transmission range or transmission field [8]. These Networks are self organizing network so it does not rely on any fixed network infrastructure. Although some determined nodes act as the Roadside Units (RSUs) to facilitate the vehicular networks for accessing the safety and comfort based applications. It integrating Ad hoc networks, wireless networks and cellular technology
  3. 3. For More : https://www.ThesisScientist.com 3 to accomplish intelligent inter vehicle communication (IVC) and Roadside to vehicle communication (RVC).There are many challenges in Vehicular Ad hoc Network (VANET) that are needed to be solved in order to provide reliable services like stable and reliable routing Hence more research is needed to be conducted in order to make these network more applicable and reliable. As vehicles have dynamic behaviour, high speed and mobility that make routing and security even more challenging [2]. 1.2.1 VANET Overview: Vehicle Ad hoc Networks (VANETs) is a subclass of Mobile Ad Hoc Networks (MANETs) that gives emerged as from recent increase inside wireless technology and sensors networks [2, 4]. Vehicular Ad hoc Networks (VANETs) constitute one of ad- hoc network‘s real applications where communicating between vehicles and near fixed equipment is potential. It reduces some traffic congestion and vehicles crashes which are serious effects during the world [4]. 1.2.2 VANET Architecture: Vehicular Ad hoc Network (VANET) is computer architecture [5] comprises of three
  4. 4. For More : https://www.ThesisScientist.com 4 Figure 1.3: VANET System Architecture different types of fields such as in-vehicle, ad hoc, and infrastructure fields and many single elements such as application unit, on-board unit, and road-side unit. The figure 1.2 [24] indicates the all components and fields of VANET [24]. A. In-Vehicle Domain: This domain comprises of one or more applications units (AUs) and an individual On-Board Unit (OBU) that occupies in a vehicle [19]. Applications Units (AUs) is in vehicle entity, multiple AUs can constitute plugged in with an individual OBU and contribution the OBU working and wireless resources. An On-Board Unit (OBU) is applied for rendering the vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication. An OBU is equipped on a individual network device based on IEEE 802.11p radio technology; essentially network device is applied for sending, finding and forwarding the safety and non safety messages inside the ad hoc domain.
  5. 5. For More : https://www.ThesisScientist.com 5 B. Ad hoc Domain: This VANET domain composed of vehicles or nodes that equipped in On-Board Unit (OBUs) and road-side units (RSUs), that making the VANET. A road side unit is a physical device located at determined places like hospitals, shopping complexes, colleges, road highways etc. An RSU is equipped on at least a network device based in IEEE 802.11p standard [30]. The main role of RSU is to allow for the internet connectivity to the OBUs. On-Board Units (OBUs) phase a mobile ad hoc network that appropriates communications between vehicles without the required for a centralised coordination illustrate. Two vehicles directly communicating via On-Board Units (OBUs) if wireless connectivity is among them; else multi-hop communications are used to forward data [30]. C. Infrastructure Domain: The infrastructure domain comprises of Road-Side Units (RSUs) and wireless Hot-Spots (HS) that the vehicles access as safety and comfort based applications [18, 29]. These two types of infrastructure access, road-side units (RSU) and Hot-Spots (HS).In case that incomplete road- side units (RSUs) nor Hot-Spots (HT) allow for internet access, OBUs can as well utilise communicating abilities of various radio networks or technologies such as GPRS, GSM, Wi-Max, whenever they are integrated inside the On- Board Unit (OBU), in detail for non-safety applications. D. Application Units (AUs): An Applications Units (AUs) is in-vehicle entity, multiple AUs can constitute plugged within a particular OBU and treating the OBU working and wireless resources [29]. Examples of Application Units (AUs) are i) safety applications devices same hazard-warning, or ii) a navigation system with communicating capabilities. Multiple Application Units can constitute plugged in with an individual On-Board Unit (OBU) at the same time and share the On-Board Units (OBUs) processing and wireless resources. An Application Unit (AU) communicates only via the On-Board Unit (OBU), which deals completely mobility and networking operates on the Application Unit (AU) place. The distinction among an Application Unit (AU) and an On- Board Unit (OBU) is merely logical and an Application Unit (AU) can be physically co-located on OBU [12].
  6. 6. For More : https://www.ThesisScientist.com 6 E. On-Board Units (OBUs): The On-Board Unit (OBU) used as vehicle to vehicle (V2V) communications and vehicle to infrastructure or road side unit (V2I) communications [29]. It also allows for communication services to the application units and as well forwards data on place of other On-Board Units (OBUs) in the ad hoc domain. An On-Board Unit (OBU) is equipped with at least a individual network device in IEEE 802.11p standard. This network device is responsible for sending, finding and forwarding safety and non safety messages in the ad-hoc field. The main purposes and processes of On-Board Unit (OBU) includes wireless radio access, geographical ad hoc routing, network congestion control, reliable message transfer, data security, IP mobility support, and others. F. Road-Side Units (RSUs): A Road-Side Unit (RSU) is a physical device located at determined positions on roads and highways, or at committed locations such as colleges, petrol pumps, hospitals, restaurants etc [19, 29]. A Road-Side Unit (RSU) is equipped on at least a network device based on IEEE 802.11p. The main purposes of RSU are to allow for the internet connectivity to the OBUs. An overview of the main purposes performed near RSU is given under. i. Covering the communication range of an ad hoc network by intends of distribution of data to other OBUs and co-operating with early RSUs in forwarding or in distributing safety data (Figure 1.4). ii. Operating safety applications, such as towards vehicle-to-infrastructure warning (e.g. low bridge warning, work-zone warning), and act as data source (Figure 1.5). iii. Allowing for internet connectivity to all OBUs for accessing safety and non safety applications (Figure 1.6).
  7. 7. For More : https://www.ThesisScientist.com 7 Figure 1.4: RSU extends communication range Figure 1.5: RSU acts as information source
  8. 8. For More : https://www.ThesisScientist.com 8 Figure 1.6: RSU providing internet access 1.2.3 VANET Network Architecture Types: The network architecture [10] of VANETs primarily seperated into three categories: Cellular/WLAN, Pure Ad hoc, and Hybrid. All of these are describe as follows: A. Cellular/WLAN Network Architecture: This type of network architecture [10] applied Wireless LAN/Wi-MAX access indicates fixed and cellular gateways at traffic intersections are applied in place to connect to the Internet, for routing functions or collect traffic data . VANET can combine both WLAN and cellular network to pattern this type of network therefore that a WLAN is used whereas an access point is available or differently a 3G connection is used [10]. B. Ad hoc Network Architecture: The cellular/WLAN network architecture is very costly as it applying a fixed gateways, access points and other hardware devices to pattern the network, therefore to mitigate this problem vehicles and entirely the roadside units (RSUs) or roadside wireless devices can pattern a pure ad hoc network between themselves. It assists in both safety and non safety applications such as vehicle to vehicle communicating, electronic toll collection etc [10]. C. Hybrid Network Architecture: Hybrid network architecture is a combination of both cellular/WLAN network architecture network and ad hoc network that shown in figure. This is also a
  9. 9. For More : https://www.ThesisScientist.com 9 possible solution for VANET [10]. The hybrid architecture can provide better coverage but arises a new problem such as the seamless transition of the communication among different wireless systems [10]. 1.2.4 Standards, Regulations and Layered Architecture of VANET: In Vehicular Ad hoc Networks (VANET) all participating organisations or authorities or institutions must be agree on common standard. IEEE has introduced the IEEE 802.11p standard and IEEE P1609 standard [29]. The fundamental technology in this standardization work is called Dedicated Short-Range Communication (DSRC) presented in IEEE 1609 standard [29], which is essentially IEEE 802.11a standard adjusted for low overhead operations. The main aim of DSRC is to enhance public safety and non safety applications, and to improve traffic flow by infrastructure-to- vehicle communications and vehicle-to-vehicle communication. A WAVE system is a radio communications system that provides seamless and interoperable transportation services [10, 29]. These services recognized by the U.S. National Intelligent Transportation Systems (ITS) Architecture and many others transportation infrastructure industries. These services include vehicle-to-vehicle communications and vehicle-to-roadside communications over 1000 m coverage area in which vehicles
  10. 10. For More : https://www.ThesisScientist.com 10 Figure 1.7: DSRC/WAVE Standards and Communication Stack. may be moving at speeds up to 140 km/h. Figure 1.8: Channels available for DSRC The communications supplied by Wireless Access in Vehicular Environment (WAVE) generally occur over distances up to 1000 m among roadside stations and mostly high speed, and include wide variety of applications like safety applications such as lane change warning [10, 29]. Vehicle collision avoidance and emergency services such as ambulances, police, fire bus and rescue vehicles. Networking services provide data delivery between WAVE devices and management services to all the layers. The scope of the WAVE standards is to define services, operating at the network and transport layers that support wireless connectivity among vehicle-based devices, and between
  11. 11. For More : https://www.ThesisScientist.com 11 fixed roadside devices and vehicle-based devices, using the 5.9 GHz DSRC /WAVE mode. The protocol architecture defined by these standards is shown in Figure 3.5. The overall WAVE architecture includes the following standards: (i) IEEE 1609.1, (ii) IEEE 1609.2, (iii) IEEE 1609.3, (iv) IEEE 1609.4, and (v) IEEE 802.11p. The IEEE 1609.1 defines an application, the Resource manager that uses the network stack for communications. The IEEE 1609.2 defines security, secure message formatting, processing, and message exchange. Channelization and the upper layers of the network stack are defined in IEEE 1609.4 and IEEE 1609.3, respectively. The Physical Layer (PHY) and the Medium Access Control (MAC) protocol are based on the IEEE 802.11 PHY and MAC standards, and are defined by the IEEE 802.11p [29]. 1.2.5 Some Others Wireless Technologies in VANET: A. Wi-Fi/WLAN: Wireless fidelity (Wi-Fi) can allow for wireless access for vehicle-to-vehicle communications or vehicle-to-infrastructure communication. IEEE 802.11 standards can be applied to allow for wireless connectivity; IEEE 802.11a provides a data rate of 54 Mbps with a communication range of at least 140 m range for outdoor and 38 m indoor and works at 5 GHz [29]. Another standard because IEEE 802.11 is IEEE 802.11g, which provides the same data rate and covers the same lay out as IEEE 802.11a but working at 2.4 GHz. IEEE 802.11b works at 2.4 GHz and provides a data rate of up to 11 Mbps.
  12. 12. For More : https://www.ThesisScientist.com 12 Figure 1.9: VANET Architecture with Mobile WiMAX B. WiMAX: WiMAX or IEEE 802.16e is an amendment to the worldwide interoperability for microwave access (WiMAX) adopted by IEEE in the year 2004. IEEE 802.16e provides a high data rate and deals a wide transmission range and provides high quality of service (QoS) and reliable communications that makes it suitable for those applications requiring these features such as voice over internet protocol (VoIP) applications and multimedia applications [29]. The WiMAX is capable to handle fast moving nodes or vehicles in a mesh network structure. WiMAX achieves a high data rate of up to 35 Mbps applying multiple-input and multiple-output (MIMO), with an orthogonal frequency division multiplexing (OFDM) and covers a transmission range of 15 Km/s. WiMAX technology used in highway monitoring network system that deals with accident and improving road management of highway, which is helpful to form high efficient emergency handling system. 1.3 Motivation Traffic safety is a major challenge distinguished by the major players in the automotive industry and by many governments. Traffic delays extend to increase, wasting many hours for peak time travellers. Apart from traffic safety and efficiency, characteristics
  13. 13. For More : https://www.ThesisScientist.com 13 like internet access, entertainment, payment services and information updates into can be incorporated into vehicles to improve passenger comfort. Normally a driver, has incomplete information about road conditions, speed and location of vehicles around them, and is forced to make decisions like breaking and lane changing without the benefit of whole data. Real time communication between vehicles or between vehicles and road-side infrastructure can improve traffic safety and efficiency [7]. For example, if a vehicle needs to slow down due to an accident ahead, it will broadcast warning messages to neighbouring vehicles. The vehicles behind it will thus be warned before they actually see the accident, helping the drivers react faster. In another scenario, if vehicles can transmit traffic congestion information to other vehicles in its transmission range, it can help other vehicles receiving the information to chose alternate routes and avoid traffic congestion. Vehicular Ad hoc Networks (VANETs), an extension of mobile ad hoc networks (MANET) [8], were developed with a view to enable real-time communication between mobile nodes (either vehicles or road side infrastructure) over wireless links, mainly with a consider to enable traffic safety and efficiency. The communication between two or more nodes in a Vehicular Ad hoc Networks (VANET) faces many unique challenges [8]. This is especially true for safety-critical applications like collision avoidance, pre-crash sensing, lane change etc. Factors like high vehicle speeds, low signal latencies, changing topology, total message size, traffic density etc. induce challenges that makes conventional wireless technologies and protocols unsuitable for Vehicular Ad hoc Networks (VANETs).Apart from the performance challenges, there are many security issues unique to VANET like authenticating message sender, verifying validity of message data (like vehicle position), providing node privacy with non-repudiation, certificate revocation, availability etc. All these performance and security requirements contribute to make VANET safety applications challenging unlike other wireless applications. 1.4 Problem Statement: There are many comparative studies and surveys that compare various ad hoc routing in VANET environment. The simulations performed in these comparative studies are
  14. 14. For More : https://www.ThesisScientist.com 14 very basic do not incorporate with the large number of nodes in real Vehicular Ad hoc Network environment. The main aim of our dissertation work is to firstly investigate the reactive and proactive routeing protocols than analyze the performance of selected reactive (AODV) varying number of mobile nodes or vehicle node densities (100, 150, 200, 250 and 300) i.e. low vehicle-node density (100 and 150 mobile nodes) medium vehicle-node density (200 and 250 mobile nodes) and high vehicle-node density (300 mobile nodes) with constant mobility 10m/s. Then the selected routing protocols (AODV, DSR) have been simulating via a simulation tool i.e. Riverbed and compared in terms of throughput and packet end to end delay. 1.5 Aims and objectives: The main aim of this dissertation is to improve the performance of AODV with varying number of mobile nodes or vehicle node densities i.e. low vehicle-node density (100 and 150 mobile nodes) medium vehicle-node density (200 and 250 mobile nodes) and high vehicle-node density (300 mobile nodes) with constant mobility 10m/s. The simulation study based on different performance metrics i.e. throughput and packet end to end delay. To achieve this aim we have set the following objectives:  To take a detailed literature survey to review the current state of art of routing protocols used in Vehicular Ad hoc Networks.  To explore different classification of routing protocols in Vehicular Ad hoc Networks. Furthermore also identify the major performance issues in such networks.  To evaluate the performance of selected routing protocols with varying number of mobile nodes.  Perform a detail comparative analysis of selected routing protocols by taking three performance metrics. 1.6 Methodology:
  15. 15. For More : https://www.ThesisScientist.com 15 In this dissertation, following steps are carried out to achieve the objectives of this thesis work. 1.6.1 Literature Review: In these steps a detailed literature review of any published work that relevant to the dissertation area is carried out. 1.6.2 Understanding Background Information: In this step a detail study of the area of dissertation is carried out for better understanding of the subject of dissertation. It is simple to start with Mobile Ad hoc Network (MANET) which are the base of Vehicular Ad hoc Network. 1.6.3 Functionality of Routing Protocols: In this step a detail study of various ad hoc routing protocols: reactive routing protocols (AODV) and proactive routing protocols (DSDV, OLSR) is carried out for understanding the functionality of routing protocols. 1.6.4 Simulation Tool: In this step a detail study of various network simulators, mobility generators and VANET simulators is carried out. And select a simulation tool for our dissertation work. 1.6.5 Simulation: In this dissertation work we employed Riverbed for performance improvement of AODV routing protocol , with varying number of mobile nodes or vehicle node densities i.e. low vehicle-node density (100 and 150 mobile nodes) medium vehicle-node density (200 and 250 mobile nodes) and high vehicle-node density (300 mobile nodes) with constant mobility 10m/s. 1.6.6 Improvement of Results: In this step we improving the AODV routing protocol by our proposed mechanism that is based on active route time out and hello interval 1.7 Security Challenges of VANETs: To have a improve understanding of possible attacks on VANET system; it is essential for us to determine the adversaries [26]. This helps in determining the evaluated of resources needed to secure a vehicular system. The following wide classes of adversaries are identified in a vehicular environment [26].
  16. 16. For More : https://www.ThesisScientist.com 16 A. Active vs. Passive: In this type of attack, an attacker cans merely eavesdropping on the wireless channel [26]. This attack changes from a noisy next door neighbour to a government way testing to profile drivers. An active attacker can give or change/drop or replay messages in order to give false data to the network vehicles so that attacker can maximize his reach in the network regardless of the costs (e.g. a greedy driver posing as an emergency vehicle and clearing way for the attacker to proceed). B. Insider vs. Outsider: An insider is an authenticated member of the network who can communicate with other members [26]. Being a part of the network, an insider is already in possession of some network credentials, like public keys. An insider can cause more damage to the system by tampering with an OBU, than an outsider who has limited access to the system. As far as an outsider is concerned, he normally does not possess any cryptographic credentials or direct physical access to the system. C. Malicious vs. Rational: A malicious attacker has no personal benefits from the attacks. In this of attacks the main aim of an attacker is to harm the participating nodes or the functionality of the network (e.g. terrorists who deliberately cause traffic accidents) [26]. On the other hand, a rational attacker has personal profit from the attacks and hence is more predictable in terms of the attack means and the attack target. D. Independent vs. Colluding: Attackers can act independently or in collusion where they exchange information and cooperate to make attacks more effective [26]. For example colluding vehicle can report an imaginary traffic jam or accident to convince other drivers (since the report comes from multiple vehicles others are likely to believe it) and clear way for the attackers [11]. E. Local vs. Extended: In this type of attacks, an attacker can be limited in scope, even if he controls several entities such as vehicles or RSU etc. which makes him local [26]. This is because the limited range of OBUs and RSUs make the attack scope limited. And an extended attacker is who that controls several entities that are scattered across the network, thus extending his scope. This
  17. 17. For More : https://www.ThesisScientist.com 17 distinction is particularly important in privacy-violating attacks and wormhole attacks [11]. 1.8 Attacks on VANETs: A Vehicular communication (VC) system can be compromised by an attacker by manipulating either vehicular system or the security protocols. Hence two kinds of attacks can be visualised against vehicular systems [29]: attacks against messages and attacks against vehicles. A general overview of the attacks is mentioned below. A. Forgery Attacks: In forgery attack [29], an attacker diffuse wrong or misleading information to the whole network to affect the behaviour of other vehicles or RSUs .For example suppose an attacker want to divert the traffic of given road than he diffuses the misleading or wrong information to the whole network so that other vehicles move in wrong direction and road is free it for themselves) that shown in figure 1.12. Figure 1.10: Forgery Attack
  18. 18. For More : https://www.ThesisScientist.com 18 B. Cheating with Sensor Information: In this type of attack [29], an attacker modify or falsify their current or past positions, speed, direction, etc. in order to escape liability, mostly in the cases of an accident drivers may be tempted to cheat with some information or tempered the evidences so that anyone cannot determine the location of their car at a given time. C. In-Transit Traffic Tampering: This type of attacks arises if any node acting as a relay can disrupt communications of other nodes, i.e. it can drop or the manipulated the messages, or meaningfully modify the messages [29]. By using this way, all receivers of traffic notifications may get wrong information because most critical traffic notifications or safety messages can be manipulated by the attacker. In fact, tampering with in-transit messages may be simpler and more powerful than forgery attacks. D. Masquerading: In this type of attacks, an attacker actively impersonates to be another vehicle by using fake identities [29]. An attacker can perform Message fabrication, alteration, replay attacks and forming black holes. for example, an attacker masquerading or tries to act as an emergency vehicle(Police ,Fire bus ,Ambulance ,Rescue vehicle) to mislead or defraud other vehicles to slow down and yield. E. Privacy Violation: In this type of attack vehicle‘s identity is used to track their location. Location privacy and anonymity are important issues for vehicles users [26, 29]. For example generally some car rental companies track their own cars. F. Denial of Service (DoS): In this type of attacks an attacker may want to bring down the Vehicular Ad hoc Networks (VANET) or even cause an accident [29]. There are many ways to perform this type attacks, either by sending messages that would lead to wrong results or by jamming the wireless channel so that vehicles cannot exchange safety messages. Some Other types of Attacks in VANET: There is several other type of attacks that includes sophisticated versions of basic attacks or a combination of basic attacks on messages as well as attacks on vehicles.
  19. 19. For More : https://www.ThesisScientist.com 19 i. Spamming: The presence of spam messages on Vehicular Ad hoc Networks increases the transmission latency. Spamming is more difficult to control and manage because of a centralised and basic infrastructure [12]. ii. Global Positioning System (GPS) Spoofing: The GPS satellite maintains the locations table with the geographic location and identities of all vehicles on the network i.e. Vehicular Ad hoc Network. In GPS spoofing attack, an attacker can fool vehicles into thinking that they are in a different location by producing fake readings in the GPS devices [12]. iii. Black Hole Attack: A black hole attack in ad hoc network or Vehicular Ad hoc Network is arises when participating nodes refuse to participate in the network or when an established node drops out [13]. iv. Sybil attack: The basic objective of Sybil attack is to create a large number of fake vehicles for misleading others vehicles. E.g. an attacker creates large number of fake vehicles; these vehicles are to tell other vehicles that there is a jam ahead and force them to take alternative route [12]. 1.9 Mobility Models: In order to achieve good result from VANET simulations tests, there is need to generate mobility model [13].Different types of mobility models that define the set of rules for defining the movement pattern. Mainly mobility models are separated into two levels [18]: Macroscopic level and Microscopic level. The mobility of cars, roads, buildings, etc. are comes under macroscopic model. The movement of vehicles and their behaviour are classified as Microscopic Model. There are different types of mobility models have been used in VANET simulations they are classified on the basis of level of data generate. These models are described below. A. Survey Model: To represent the realistic human behaviour in urban mesh environments, a survey models is used [13]. The survey model relies on data collected through various surveys performed on the several human activities. The survey was recorded for the human performance, tasks, and activities. E.g. UDel mobility model is a tool for simulating urban mesh networks.
  20. 20. For More : https://www.ThesisScientist.com 20 B. Event Driven Model: Event driven models, also called trace models, they are used to observe the movement of human beings and vehicles, this model generate traces based on the mobility of human beings and vehicles [13]. Event driven models could be gathered to develop a probabilistic mobility model that reflects the real movement on the map. The problem with this model is that only the characteristics of mobile nodes with access points were considered; no relationship among the nodes was considered. As a result, probabilistic models cannot support the ad hoc mode of VANET [18]. C. Software Oriented Model: Various simulators like VISSIM, CORSIM and TRANSIM can generate the traces of urban microscopic traffic. To extract the road topologies, maps, streets or other location based information for the network simulators VanetMobiSim uses database and Voronoi graphs [13] .The problems with such simulators are that cannot generate realistic levels of details and they can only operate at traffic level. D. Synthetic Model: This model has fascinated lot of researchers and lot of work has been carried out in synthetic model. Mathematical equations are used by all models in this category for the development of realistic mobility models [13]. Synthetic model is further classified in to five main categories:  Stochastic model: This model deals with the random motion.  Traffic Stream model: This model examines the all mechanical properties of mobility model.  Car Following model: This model monitors the complete behaviour of car-to- car interaction.  Queue model: Queue model can be understood by a very simple example considers cars as standing in queues and roads as queue buffers.  Behavioural models: This model examines how movement is influenced by social interaction.
  21. 21. For More : https://www.ThesisScientist.com 21 Chapter 2 LITERATURE REVIEW In this chapter a detail literature review on Vehicular Ad- Hoc Networks (VANETs) has been carried out. This chapter also describes a detail overview of VANET routing protocols, at the same time this chapter also describes several VANET simulators, network simulators and mobility generators that used in simulation for Vehicular Ad hoc Networks. 2.1 State of the Art In recent years, various researchers have examined and compare various ad-hoc Routing Protocols taking into consideration different performance metrics while basis for performance evaluation. In this section describes the literature review of various research papers and journals related to Vehicular Ad hoc Networks (VANET). Ameur et al. [27]: In this paper authors present a systematic comparative study of three routing protocols: DSDV, AOMDV and AODV in low, high and middle density regions. In their work, authors was developed a road traffic scenario with taking 50 vehicle as low density ,100 for middle density and 150 for high density region
  22. 22. For More : https://www.ThesisScientist.com 22 respectively. For the simulation purpose, authors used NS-2.34 network simulator in LINUX platform and VanetMobiSim simulator for generated road topology for simulations purposes. After the simulation result, authors conclude that in low density region AODV and AOMDV score almost same range of packet delivery ratio whereas DSDV packet delivery ratio was situated in between in range of 60-80.In the middle density region the graph shows that AODV and AOMDV have packet delivery ratio lies between 90 to 100 ranges, whereas DSDV packet delivery ratio is in range of 60- 80. And in high density region the graph shows the AODV and AOMDV score same packer delivery ratio in range of 90-100, whereas DSDV packet delivery ratio was degrades to 20-3 Amit N. Thakare et al. [10]: In this paper authors analyzed the performance of AODV and DSR routing protocols using ns-2 simulator with Random Waypoint mobility model. After arriving simulation results they resolve that packet loss of DSR is higher as equated to AODV and ratio of packet received was higher for AODV as compared to the DSR routing protocol. Artimy et al. [18]: in this paper authors try to make best use of DSRC channels by proposing a cluster based multi channel communication scheme. In this scheme authors assumed that each vehicles is equipped with two DSRC transceiver that can work on two different channel simultaneously. In their work they divide time in to periods that can be repeated every T millisecond. And each period is further divide into sub periods for exchange data. Davesh et al. [12]: In this paper authors analyzed the performance of AODV and DSR routing protocols using ns2 simulator with changing number of nodes. After getting simulation results they conclude that AODV shows very high packet delivery ratio in 40 mobile nodes, simply substantially decreases if the simulation node increases. DSR express less end to end delay as equated to the AODV. Finally they concluded that AODV performs best because it allow for almost identical result in all assumption and DSR suits for lower scalability networks in which mobile nodes move at moderate speed.
  23. 23. For More : https://www.ThesisScientist.com 23 Fan li. et al. [15]: Here authors provides a comprehensive and comparative survey that dealing with all issues related to Vehicular Ad hoc Networks like its wireless access technologies and standards, its characteristics , challenges ,security issues, its applications and various simulators. In their work, authors present comprehensive and comparative study that focuses on the issues surrounding VANET and its applications that help to tackle the all issues related to the VANET. In this paper authors also briefly described the several network simulators like NS-2, MOVE, Trans, VanetMobiSim, GloMoSim, NCTUns and QualNet. Goel A. et al. [22]: In this paper authors investigate methods on how to propagate safety related messages to accidental areas. They outline a scenario, in which an accident happened on a city highway then how a safety message is propagated within one mile of the accidental area, for telling to the other vehicles to slow down and take alternative route. Gupta P. et al. [16]: In this paper authors compared and analyzed the performance of AODV and DSR routing protocols using default random direction point mobility model. For performance evaluation of considered protocols they used ns-2 simulator with varying pause time. After arriving simulation results they conclude that DSR outperformed AODV in delay and throughput on little number of nodes with lower load and mobility while AODV performed better than DSR on big number of nodes with higher load and mobility. They also found that DSR has low throughput and delay since of aggressive use of caching and stale routes. Jerome Haerri et al. [3]: Here, authors evaluate and improve the performance of the AODV and OLSR routing protocols under two topical and realistic mobility models for VANET. In their work for the performance evaluation authors used the OMNET++ simulator .In this paper authors design a convoy scenario that contains several parameters like 400km*400km simulation area, 60 seconds simulating time, 500m communication range, 1440B packet size, 27m inter vehicle distance and UDP transport protocol .The main objective of this function is improves the communication performance of routing protocols by increasing the density around the receiver. In their work authors also analyse the properties of the two mobility models in high density
  24. 24. For More : https://www.ThesisScientist.com 24 urban fields. Finally after the simulation result authors conclude that the performance of AODV is better than OLSR and OLSR routing protocol appear more affected by the density than AODV, the reason behind is that proactive routing protocol maintains the full network topology while reactive routing protocol create routes when they need. Jorjeta G. et al. [32]: In this paper authors discussed several security related issues of mobile ad hoc networks. In their work, authors described the black hole attack in mobile ad hoc networks and proposed a feasible solution for it. Authors used the Global Mobile Simulator in this proposed solution and found to achieve the required reliability and security with minimal overhead and delay. In their work, authors used several performances metrics like routing overhead, packet delivery ratio, average end to end delay to evaluate the performance of AODV. To evaluate the packet delivery ratio authors take several parameters such as25 number of nodes, 5Minutes simulation time and 800m by 800m simulation area. Thus, in recent years, several researchers have analyzed and compare various ad-hoc Routing Protocols accepting into consideration different performance metrics as basis for performance evaluation. They have used different simulators and simulation models as the same. In the next section describes a conclusion of this chapter. Kamble et al. [26]: Here Authors, proposed an AODV-R routing protocol that is improved version of AODV routing protocol. In their work to achieve these objective authors developed a link reliability model based on the vehicular velocity distribution on highways. In this papers authors applying a hybrid approach combining both macroscopic and microscopic traffic flow models is highway mobility model and also applying the link reliability model to improve the performance of the current routing protocols in VANETs and incorporated vehicular reliability model into the AODV routing protocol to create a new protocol named as AODV-R routing. Authors compare both AODV and AODV-R. In their work for the performance comparison and evaluation authors was taking four performance metrics such as Average packet delivery ratio, link failures, and average end to end delay. After the simulation result authors found that AODV-R shows higher average end to end values than AODV and route establishment in AODV-R takes longer than that in AODV because of the processing of multiple routing request and replies.
  25. 25. For More : https://www.ThesisScientist.com 25 Manvi S. et al. [17]: In this paper authors analyse performance of two routing protocols AODV and OLSR by using OPNET Modeler 14.5.In their work ,authors create a network scenario of 40 nodes with the comparison of network load media access delay and throughput to examine the AODV and OLSR routing protocols with simulation parameters like 600*600 m campus area , 40 nodes and 20 minutes simulation time .According to the authors simulation result OLSR routing protocol shows low media access delay and low network load in comparison of AODV , with the overall performance OLSR is better than AODV but it is not necessary that OLSR is always better than AODV. Monika et al. [6]: In this paper authors analyzed the performance of AODV and DSR routing protocols for Vehicular Ad-hoc network with and without RSU (Road Side Unit). For performance evaluation of conceive protocols they used Estimate Simulator. After getting simulation results they conclude that throughput was highest for AODV as compared to DSR with varying number of nodes so AODV performed better than DSR. They also determined that in presence of RSU whole performance of network was better as compared to absence of RSUs. N.UMAPATHI et.al.[34]:Swarm Intelligence Based Dynamic Source Routing as Improved Quality of Service. The OPNET simulation tool is used to evaluate the performance. When a source node forwards a packet to a destination, it appears into its route cache to see if it already has destination route. When it locates an unexpired way to the destinations, it uses it to forward the packet. If the node lacks such a way, then way discovery is initiated by broadcasting a route request. After simulation results shows that the improved performance of routing in the network. Nzouonta J. et al. [23]: In this paper authors proposed a Road based vehicular traffic (RBVT) routing which is a class of VANET routing protocols for the city based environments. In this work ,authors described a road based vehicular traffic (RBVT) routing protocol that uses real time vehicular traffic information to create road based paths between endpoints. And also authors outline how to improve the end to end performance for the high contention areas by using the distributed mechanism.
  26. 26. For More : https://www.ThesisScientist.com 26 Prabha R et. Al.[36]: Here, authors evaluate an improved multipath MANET routing using link estimation and swarm intelligence. For the performance evaluation author can take OPNET as an simulation tool. It can be observed that link quality plays a very important role for obtaining better QOS in multipath routing protocols. Routing being nondeterministic polynomial (NP) hard, various meta-heuristic-based routing algorithms have also been proposed in literature using swarm intelligence meta heuristic. Popular meta-heuristic algorithms including genetic algorithm and particle swarm optimization (PSO) have shown to have drawbacks when the solution to be found is multimodal. Simulation results indicate its better performances compared to other methods. Reza Fotohi et. Al.[37]:Here in this paper author Improvement over AODV Routing Protocol by Limiting Visited Hop Count mechanism. For the performance evaluation author can take NS-2 as an simulation tool.In this paper, an improved AODV routing protocol for mobile ad-hoc networks. The work was accomplished by limited TTL (Time to Live) of RREP packet that the route reply (RREP) packet of AODV is modified to limited TTL information of nodes, and evaluated the four performance measures (i.e. PDR, throughput, good put and jitter with different number of nodes). Then the performance of our work with regular AODV in one scenario with 20 to 80 nodes. After Simulation results author shows that the improved AODV protocol provides better delivery ratio throughput and jitter over the normal AODV routing protocol the proposed technique improve 20% of overall performance. SangeetaKurundkaret. Al.[35]:Here, authors evaluate the Mobile Ad-hoc Network (MANETs) are self-configurtion network of mobile nodes connected by wireless links. Self-configurability and fast deployment feature of the MANET makes it most attractive choice for users. Routing in such networks is a key issue which decides network performance. Ad Hoc On-Demand Distance Vector (AODV) one of the widely used reactive routing algorithms. Energy consumption and delay are the main concern for a number of researchers. Some of the battery powered nodes drain out faster than others. Simulation results are observed for wireless network scenarios with variation of node mobility, pause time, network area and packet sent rate. So finally authors conclude that NS-2 simulator is used to compare performances of AODV and I-AODV.
  27. 27. For More : https://www.ThesisScientist.com 27 Shastri A. et al. [14]: Here authors, reveals the performance analysis of reactive routing protocols AODV, AOMDV and DSR. In their work, authors performed comparison with proactive routing protocol DSDV. In this paper authors used NS-2.34 simulation tool for simulation purpose with taking various parameters such as 200 second simulation time, 1000*1000 m simulation area and 100 bytes packet size, by using performance metrics such as packet delivery ratio, average packet loss ratio and average end to end delay of packets are investigated on the basis of vehicle velocity and vehicle density. According to the authors simulation result, DSDV routing protocol shows the worst packet delivery ratio and AOMDV and AODV have highest average end to end delays. Sun Xi. et al. [4]: Here, authors evaluate the performance of AODV, ADV and DSR routing protocols by taking some performance metrics such as packer drop ratio, throughput. In their work, authors to use an open source simulator tool namely NCTUns-6.0.In this paper, authors using three different mobility patterns for three Indian Metros cities: Kolkata, Chennai and Mumbai. After the simulation result authors conclude that almost same performance of ADV and AODV routing protocol for all different city scenarios, and DSR have less overhead than ADV and AODV so DSR is not suitable for highly dynamic network. Uma mani et al. [8]: Here authors examined the performance of AODV, DSR, and OLSR routing protocol with different nodes density and the number of data traffic sources in order to shows their advantages and limitations in the context of Vehicular Ad hoc Networks. In their work, authors considered two propagation models, the first one is the Two Ray Groungand second one is the adaption model. The first one assumes an unobstructed flat environment and second one takes into account the terrain characteristics and define three terrain categories. For the simulation purpose authors used Territories‘ Mobile mobility model and NS-2.23 network simulator. After the simulation result authors conclude that AODV routing protocol shows higher end to end values. Vidhale et al. [2]: Here, authors evaluate the MANET routing protocols in VANET environment by using different mobility models available in VanetMobiSim. In their work, authors using different simulation parameters such as number of nodes, packet
  28. 28. For More : https://www.ThesisScientist.com 28 size, simulation area and performance metrics, average end to end delay, normalized routing load. After the simulation result authors conclude that DSR has better packet delivery fraction (PDF) and lesser routing overload than others. But in the case of end to end delay AOMDV protocol performed better than others. Also it shows that reactive routing protocols performance degrading in space graph model. So finally authors conclude that AOMDV is more appropriate than DSR in VANET. Wang S. et al. [24]: Here, authors proposed a hybrid media access technique for cluster based vehicular networks ,this technique is based on the scheduled based approach such as TDMA for intra cluster based communications and management , and contention based approach for the inter cluster based communications and management. In this scheme authors used a control channel for delivering the safety and non safety application related messages to the nearby clusters. ZuhongFeng et.Al.[33]:Here in this paper author improved routing protocol Ad- AODV Based on AODV. For the performance evaluation author can take NS-2 as an simulation tool. AODV routing protocol only pays attention to the path that is the shortest without taking the energy and load of the nodes. After simulation results, the Ad-AODV routing protocol improves the efficiency of Ad Hoc network, and the packet delivery ratio, lowers the average end-to-end delay and reduces the routing load. The packet delivery ratio of Ad-AODV and AODV in the different residence time of the different number of nodes. The delivery rate of Ad-AODV is an average of 2.4% higher than AODV. In the case of the simulation of forty nodes, the delivery rate of Ad-AODV is an average of 1.5% higher than AODV. Chapter 3 BACKGROUND STUDY 3.1 Introduction There are several routing protocols designed for Vehicular Ad hoc Networks classified either as proactive or reactive that have been describes in next section. There are some ad hoc routing protocols which are combination of both proactive and reactive routing characteristics. These protocols are known as hybrid routing protocols. This chapter is
  29. 29. For More : https://www.ThesisScientist.com 29 organized as follows: Section 3.2 introduces the various routing protocols for Vehicular Ad hoc Networks. Section 3.3 describes the various VANET reactive routing protocols: AODV and DSR. Section 3.4 presents the VANET proactive routing protocols: DSDV and OLSR. The various mobility generators, network simulators and VANET simulators are describes in Section 3.5. Section3.6 presents the current state of the art. Section 3.7 describes a detail overview of several VANET applications. 3.2 VANET Routing Protocols Routing is a mechanism to establish and to select a particular route in order to send data from source to destination [14, 16]. There are various routing algorithm designed for ad-hoc networks. Figure 3.1 VANET Routing Protocols Classification of various VANET routing protocols can be divided in two broad categories: proactive or Table Driven Routing Protocols (DSDV, OLSR, FSR) and reactive or On-demand routing protocols (AODV, DSR, TORA) that shown in figure 3.1. In the next section describes a detail overview of various reactive routing protocols (AODV, DSR). 3.3 Reactive/On Demand Routing Protocols Reactive routing protocols were planned to reduce the overheads by maintaining information for active routes at each node [8]. This means that each node determined and maintained routes only when it requires sending data to a particular destination. It
  30. 30. For More : https://www.ThesisScientist.com 30 using two main mechanisms for route establishment: Route discovery and Route maintenance [17, 25]. Route discovery mechanism uses two messages: Route Request (RREQ) and Route Reply (RREP). Figure 3.2: Route Request Propagation in Reactive Routing Protocols The basic approach is when a node needs to send a message to a particular destination, it broadcasts the RREQ message in the network that shown in figure 2.2 When RREQ message found a destination node then destination node send a RREP message to source node that shown in figure 2.3.
  31. 31. For More : https://www.ThesisScientist.com 31 Figure 3.3: Route Reply Propagation in Reactive Routing Protocols 3.3.1 Ad hoc On Demand Distance Vector (AODV): Ad hoc On Demand Distance Vector (AODV) is a pure reactive routing protocol which is able of both unicasting and multicasting. In Ad hoc On Demand Distance Vector (AODV), like all reactive protocols, it works on demand basis when it is required by the nodes within the network [8, 14]. When source node has to send some data to destination node and then initially it spreads Route Request (RREQ) message which is forwarded by intermediate nodes until destination is achieved. A route reply message is unicasted back to the source node if the receiver is either the node using the called for address, or it has a valid route to the called for address that is shown is figure 3.4.
  32. 32. For More : https://www.ThesisScientist.com 32 (a) (b)
  33. 33. For More : https://www.ThesisScientist.com 33 Figure 3.4: AODV Route Discovery Process. (a) Propagation of the RREQ. (b) Path of the RREP to the source. A. Working of Ad Hoc On Demand Distance Vector Routing (AODV): In this type of routing [14, 16] allows the communication among two nodes via intermediated nodes, if those two nodes are not within the range of each other. To establish a route between source to the destination, AODV using route discovery phase, along which Route Request message (RREQ) messages are broadcasted to all its neighbouring nodes. This phase makes sure that these routes do not forms any loops and find only the shortest possible route to the destination node. It also uses destination sequence number for each route entry, which ensures the loop free route, this is the one of the main benefit of AODV routing protocol. For example if two different sources send two different requests to a same destination node, then a requesting node selects the one with greatest sequence number. In the route discovery phase several control messages are defined in AODV that are defined as follows. i. RREQ (Route Request): When any node wants to communicate with other node then it broadcast route request message (RREQ) to its neighbouring nodes [14, 16]. This message is forwarded by all intermediate nodes until destination is reached. The route request messages (RREQ) contains the some information such as RREQ id or broadcast id, source and destination IP address, source and destination sequence number and a counter. ii. RREP (Route Reply): When any intermediate nodes received Route Request (RREQ) message then it unicast the route reply message (RREP) to source node either it is valid destination or it has path to destination and reverse path is constructed between source and destination [14, 16]. Each route reply message (RREP) packet consist of some information such as hop count, destination sequence number, source and destination IP address. iii. RERR (Route Error): Whenever there is any link failure arises in the routing process then route error message (RERR) is used for link failure
  34. 34. For More : https://www.ThesisScientist.com 34 notifications. The route error message (RERR) consists of some information such as Unreachable Destination node IP Address, Unreachable Destination node Sequence Number. B. Routing in AODV: There are various mechanisms which are followed in AODV routing approach: i. AODV Route Discovery phase: To establish a route between source node to the destination node, AODV using route discovery phase, along which the Route Request message (RREQ) messages are broadcasted to all its neighbouring nodes [14]. This phase makes sure that these routes do not forms any loops and find only the shortest possible path to the destination node. It also uses destination sequence number for each route entry that ensures the loop free route, this is the one of the main benefit of AODV routing protocol. For example if two different sources sends two different request to a same destination node, then a destination node selects only that node having largest sequence number. In the route discovery phase several control messages are defined in AODV protocol. ii. AODV Route Table Management: In AODV, Routing table management is required to avoid those entities of nodes that do not exist or having invalid route from source to destination. The need for routing table management is important to make communication loop free. It consists of following characteristics to maintain the route table for each node. • Destination IP address • Total number of hops to the destination • Destination sequence numbers • Number of active neighbours • Route expiration time iii. AODV Route Maintenance: In AODV, when any node in the network detects that a route is not valid anymore for communication it delete all the associated entries from the routing table .And it sends the Route
  35. 35. For More : https://www.ThesisScientist.com 35 reply message (RREP) to all current active neighbouring nodes to inform that the route is not valid anymore for communication purpose. 3.3.2 Dynamic Source Routing Protocol (DSR) Dynamic Source Routing is a responsive routing protocol that is based on the concept of source routing [8, 16]. Source routing means source has the complete knowledge of entire route to the destination before transmitting data. In DSR each node holds a route cache where it enters all possible learned routes. It using two main mechanisms: Route discovery and Route maintenance. A. Route Discovery: When a source node requires sending a data packet to destination node in the network, it first appears in its Route Cache to find a valid hop sequence to the destination [1]. If such a route lives, the source node attaches to the packet header the finish route to the destination and forwards the packet to the next node. The next node checks the packet header and forwards the packet to the next node. The process terminates when the packet reaches the destination. If the source node cannot find a valid hop sequence to the destination in its Route Cache then it initiates a route discovery process [17]. Figure 3.5: Route Request Propagation in DSR
  36. 36. For More : https://www.ThesisScientist.com 36 Figure 3.6: Route Reply Propagation in DSR  In route discovery process a route request (RREQ) message is broadcasts to all its neighbouring nodes, adding a unique request ID to each request to prevent other nodes from transmitting the same request [17].Figure 3.8 shows the RREQ message propagation in the network. And figure 3.9 shows the propagation of RREP message that carries the entire hop sequence. B. Route Maintenance: Route Maintenance is done by the propagation of route error message (RERR). Whenever any active node sees or detects the link failure, it propagates the route error message to its upstream neighbours along the reverse path till it reaches the source node. To verify the correct operation of the router links, HELLO messages and acknowledgement messages can be used [18]. 3.4 Proactive/Table Driven Routing Protocols These types of protocols are table based as they maintain table of connected nodes to transmit data from one node to another and each node part of its table with another node. These protocols desire to maintain up-to-date and consistent routing information in the network. Thus, every node maintains one or more routing table to store routing data about every other node in the network. So due to this reason, these type of protocols are not preferred for large network. There are different types of proactive routing protocols: Destination Sequence Distance Vector Routing (DSDV), Optimized link state routing (OLSR), Fisheye State Routing (FSR) [11].
  37. 37. For More : https://www.ThesisScientist.com 37 3.4.1 Destination Sequence Distance Vector Routing (DSDV) Destination Sequence Distance Vector Routing (DSDV) is a table driven routing protocol based on the Bellman-Ford algorithm. In this type of routing protocol every node in the network share packet with its entire neighbour [19]. And packet contain information such as node‘s IP address, last known sequence number, hop count. Whenever there is topology change in network each node advertises its routing status after a fixed time or immediately. Working of Destination Sequence Distance Vector Routing (DSDV) The main objective of DSDV routing protocol is to avoiding loop formation and maintains its simplicity. In DSDV whenever any node want to transmitted a packet or information to the destination node, it using the routing table [18]. Routing tables are maintained by each node in the network, each node routing table maintains some information like destination address, number of hops required to reach the destination and sequence number. Thus the routing table consist of following entries <destination, distance, next hop> [18]. Whenever any node want to sending a message to other node than it adds a sequence number in the routing entries, the sequence number indicates the newness of the information to the routing table. In DSDV routing protocol routes with the latest sequence number are ever preferred for forwarding a message to one node to other. If one or more source has same sequence number and sending a message to the same destination then in this case route with lower distance is preferred [18]. 3.5 Simulation Tools The simulation software or tools have been classified into three different categories. They are (a) Vehicular mobility generator (b) Network simulator (c) VANET simulators [10]. VANET mobility generators are used to generate realistic motion traces of the vehicles motion to increasing level of realism in VANET simulation. These traces subsequently imported into a network simulator as an input prescribe to study the performance of the protocol application. Network simulators are used to perform detailed packet-level simulation of source, destinations, reception, route, background load, links, data traffic transmission and channels [10]. Finally, VANET
  38. 38. For More : https://www.ThesisScientist.com 38 simulators provide both network simulation and traffic flow simulation. In the next few parts, we will discuss vehicular mobility generators, network simulators and VANET simulators in greater depth with their features, functions [20]. 3.5.1 Mobility Generators VANET mobility generators are used to generate traces of the vehicles motion that can be usually saved and subsequently imported into a network simulator in order to study the performances of the protocol application [20]. As mentioned earlier, it is important to generate realistic movement traces in order to rigorously evaluate VANET protocols because the overall performances depend on the connectivity which, in turn, relies on the movement traces [19]. A. TSIS-CORSIM: TSIS-CORSIM (Traffic Software Integrated System Corridor Simulation) is a powerful commercial traffic simulation package, developed at the University of Florida and funded by the Federal Highway Administration (FHWA). It is a microscopic simulation model that is especially designed to simulate highways and surface streets and, thus, includes traffic signals and stop signs [20]. This simulator is made up of two main components, NETSIM for simulating surface streets, and FRESIM for simulating freeways. Unfortunately, TSIS- CORSIM simulator requires Microsoft Windows and Internet Explorer to run. It can simulate very complex traffic scenarios and thus it can take a large amount of information as input [21]. B. STRAW: Street Random Waypoint (STRAW) mobility generator gives the more accurate simulation results by using a vehicular mobility model based on the procedure of literal vehicular environment [20, 29]. Its current implementation is written for the JiST/SWANS discrete-event based simulator. STRAW is part of the Car-to-Car Cooperation project also known as C3 project. C. SUMO: Simulation of Urban Mobility (SUMO) is an open source, highly portable microscopic road traffic simulation package that deals with very large number of nodes in Vehicular Ad hoc Network [20]. It can be used on most of the operating system. Since high portability and its GNU General public license SUMO has become more popular and most widely utilized in Vehicular Ad hoc Networks.
  39. 39. For More : https://www.ThesisScientist.com 39 It has developed into a full featured case of traffic modelling utilities uses own formats as road networks and traffic involve generation and routing utilities [4].The main merits of SUMO is that it is OpenGL GUI based, highly portable, open source, easily simulation arrange, portable libraries, implications different formats, collision free movement and large number of map determined for improve understanding. Simply it has some limitations such as, less easy interface and its draws do not support NS-2, GloMoSim and QualNet. D. MOVE: Mobility model generator for Vehicular network (MOVE) is a mobility generator constructed in top of the SUMO (Simulation of Urban Mobility) and quickly generates realistic mobility models for VANET simulations. The MOVE‘s output is a quality trace file that consists of realistic vehicle movement‘s data which can be used by popular simulation tools such as NS-2 or GloMoSim or QualNet. MOVE consists of two main components: Mobility model and traffic model generator. Mobility Model Generator provides a user friendly interface for giving mobility model for simulations using SUMO. It also appropriates the user to create customized topology or import maps. Work Traffic Model generator takes the SUMO trace file as the input and generates the network traffic model as required by either NS-2 or QualNet. It allow for all the assemble option of NS-2 TCL files, like specifying MAC, routing protocol to use, etc [20]. E. FreeSim: FreeSim is an open source and portable microscopic and macroscopic free-flow traffic simulator. Traffic and graph algorithms can be easily produced and performed for the full network or for individual vehicles or nodes [20, 29]. FreeSim is ideal for Intelligent Transportation System (ITS) simulation because Vehicles in FreeSim can communicate with the system monitoring traffic on the freeways. The main features of FreeSim are: It is GUI based, extremely portable, easy to simulation set-up, easy to use, open source and large number of examples available for better understanding. But it has some limitations also like not import different formats, and its traces do not support NS-2, GloMoSim, QualNet, SWANS [21]. F. CityMob: CityMob is a highly portable, open source, GUI based mobility model generator generally used in Vehicular Ad hoc Networks (VANETs) [20].
  40. 40. For More : https://www.ThesisScientist.com 40 The main advantages of CityMob like easy to create simulation set-up and easy to use , for better seeing large number of example is available But its biggest limitations is that it generated traces does not support NS- 2,GloMoSim,QualNet,SWANS. And real and user defined maps is not available here [20, 29]. 3.5.2 VANET Simulators A. GrooveNet: GrooveNet is a hybrid simulator that integrated both network and mobility simulator. It allows to communication among real and simulated vehicles. GrooveNet is an open source hybrid simulator that integrated both network and mobility simulator [20, 29]. It allows communication between real and simulated vehicles. Its modular architecture integrates mobility, trip, and message broadcast models throughout physical layer and Link layer communication models [20]. B. TraNS: TraNS (Traffic and Network Simulation Environment) is the first VANET simulator. It is a simulation tool that incorporates both mobility generator and network simulator for leading realistic VANET simulation [20]. It allows to a tool to build realistic VANET simulations. TraNS also supplies a feedback between mobility model and vehicular behaviour. It can operate in two ways: application-centric mode and network centric mode. In the network- centric way, there is no feedback supplied from NS-2 to SUMO. So the link between NS-2 and SUMO is done through a parser. Parser analyses the mobility trace file gave by SUMO simulator and then converts it to a suitable format for NS-2 simulator. In the case of application-centric way, the feedback between NS-2 and SUMO is provided through an interface called TraCI. In this way SUMO and NS-2 must run simultaneously [20, 29]. C. NCTUns: National Chiao Tung University Network Simulator (NCTUns) is a VANET simulator that combines both traffic and network simulator in to a single module that constructed using C++ programming language and confirms high level of GUI. It is a highly extensible and robust network simulator in no requires being worry about the code complexity [20]. It supports parallel simulations as determined network on multi core machines. The main merits of
  41. 41. For More : https://www.ThesisScientist.com 41 NCTUns is that it can simulate IEEE 802.11a, IEEE 802.11b, IEEE 802.11e, IEEE 802.16d, IEEE802.11g and IEEE 802.11 technologies, and confirms large number of nodes. NCTUns includes bidirectional and unidirectional communication. Compared to TraNS, NCTUns combines traffic and network simulator together in a single module and returns feedback to supports VANET. However, the maximum number of nodes that can be simulated by single simulation by NCTUns is just 4096. But it has some limitations such as, complex set up procedure and it can works only on Fedora 9 Linux platform [20]. 3.5.3 Network Simulators Network simulators perform detailed packet-level simulation of source, destinations, reception, route, background load, links, data traffic transmission and channels. There are several types of network simulators some of them are describes as follows. A. NS-2: Network Simulator (Version 2), called as the NS-2, is simply an event driven, open source, portable simulation tool that used in studying the dynamic nature of communication network. Several different NS-2 versions have been published throughout the last few years; the latest version of NS-2 is the NS- 2.35 [20]. Users are feeding the name of a TCL simulation script as an input statement of NS-2 executable command ns. NS-2 uses two key languages one is the C++ and second is the Object-oriented Tool Command Language (OTCL). In NS-2 C++ defines the internal mechanism (backend) of the simulation objects, and OTCL defines external simulation environment (i.e., a frontend) for setting up and configuring the objects. After simulation, NS-2 gives simulation outputs either in form of NAM files or trace files [20]. In NS- 2 some limitation can be found in terms of the installation process on windows based operating systems. To run NS-2 on window based environment a software program is used for creating Unix-like environment known as Cygwin; downloading and installing of Cygwin on windows based system is quite complex because of large size of packages of Cygwin [20]. B. OPNET: Optimized Network Engineering Tool (OPNET) is a commercial network simulator environment used for simulations of both wired and wireless
  42. 42. For More : https://www.ThesisScientist.com 42 networks [20]. Several different OPNET versions have been released over the last few years; the latest version of OPNET is the OPNET 16.0. At present OPNET is licensed under Riverbed technologies. It allows the user to design and study the network communication devices, protocols, individual applications and also simulate the performance of routing protocol. It supports many wireless technologies and standards such as, IEEE 802.11, IEEE 802.15.1, IEEE 802.16, IEEE 802.20 and satellite networks. OPNET IT Guru Academic Edition is available for free to the academic research and teaching community. It provides a virtual network environment that models the behaviour of an entire network including its switches, routers, servers, protocols and individual application. The main merits of OPNET are that it is much easier to use, very user friendly graphical user interface and provide good quality of documentation [20]. C. GloMoSim: GloMoSim (Global Mobile Information System Simulator) is a scalable simulation environment especially designed of MANET and its applications [20]. It is open source, portable and includes a large set of routing protocols and several physical layer implementations. It was retired in 2000 but it is still possible to download for educational purposes only. On the other side, Scalable Network Technologies introduced the commercial version of GloMoSim (Global Mobile Information System Simulator) named as QualNet (Quality Networking) simulator. The main merits of QualNet simulator (Quality Networking), is that it is portable, highly scalable and extremely powerful simulator. One of the main merits of QualNet is that it is run on both Windows and Unix/Linux platforms [20]. D. QualNet: Quality Networking (QualNet) simulator is a highly scalable, fastest simulator for large heterogeneous network that supports the wired and wireless network protocol. QualNet execute any type of scenario 5 to 10 times faster than other simulators [20]. It is highly scalable and simulate up to 50,000 mobile nodes. And this simulator is designed as a powerful Graphical User Interface (GUI) for custom code development [20]. The main merits of QualNet simulator (Quality Networking), is that it is portable, highly scalable and extremely powerful simulator. One of the main merits of QualNet is that it is run on both Windows and Unix/Linux platforms [20].
  43. 43. For More : https://www.ThesisScientist.com 43 E. VanetMobiSim: VanetMobiSim is an extension of the CANU Mobility Simulation Environment (CanuMobiSim) which focuses on vehicular mobility and features realistic automotive motion models at both microscopic and macroscopic levels [20, 24]. At the microscopic level it supports mobility models such as Intelligent Driving Model with Lane Changing (IDM/LC) and Intelligent Driving Model with Intersection Management (IDM/IM). It also supports car to infrastructure and car to car communication, which supports traffic lights, multi-lane roads, separate directional flows stop signs and traffic signs at intersections. VanetMobiSim is based on JAVA and can generate movement traces in different formats, supporting different simulation for mobile networks including ns-2, GloMoSim, and QualNet [20]. F. SWANS: SWANS (Scalable Wireless Ad hoc Network Simulator) was proposed to be a best alternative to the NS-2 simulator for simulating the wireless and ad hoc networks. On the basis of comparative study of simulators like SWANS, GloMoSim, and NS-2, it is found that SWANS simulator is the most scalable and more memory efficient. SWANS take Java file as an input. It is a scalable wireless network simulator built top on the JIST platform and good capabilities like NS-2 and GloMoSim [20, 29]. 3.6 Classification of the VANET Applications: The future applications of Vehicular Ad hoc Networks (VANET) are categorized in to three major groups as comfort oriented applications, convenience-oriented applications and safety oriented applications [11]. Safety oriented related applications appear for the increasing safety of passengers by exchanging relevant information via vehicle to vehicle (V2V) and vehicle to infrastructure (V2I). And comfortable and convenience applications improve passenger‘s comfort and traffic efficiency. 3.6.1 Safety-Oriented Applications: These types of applications help the driver to avoid possible dangers via the exchange of information among vehicles. They are the most important applications as they serve to avoid accidents [11].
  44. 44. For More : https://www.ThesisScientist.com 44 Figure 3.7: Safety Applications provided by VANET They can accept control of the vehicle in case of dangerous situations, as in the case of the automatic braking, or simply send warning messages to drivers. Some safety oriented application presented in Table 3.1[11]. Table 3.1: Examples of Safety-Oriented Applications Name Description Intersection violation warning It warns drivers while they are going to pass over a red light. On-coming traffic warning It helps the driver throughout overtaking manoeuvres Electronic brake warning It describes to the driver that a preceding vehicle has performed a fast braking. Vehicle stability warning It alerts drivers that they should activate the vehicle stability control system. Post-crash notification A vehicle required in an accident sends warning messages in broadcast to approach vehicles. Traffic signal violation warning A roadside unit sends messages in broadcast to warn drivers of possible violations of traffic signals. Lane change warning It helps drivers to perform a safe lane change. 3.6.2 Convenience-Oriented Applications: These types of applications improve the efficiency of the roads and to save drivers time and money. Some Convenience oriented application presented in Table 2.2[11].
  45. 45. For More : https://www.ThesisScientist.com 45 Figure 3.8: Convenience Oriented Application Provided by VANET Some examples of Convenience Oriented Applications as shown in table 3.2. Table 3.2: Examples of Convenience-Oriented Applications Name Description Intersection management V2V and V2R communicating allow a better intersections management Limited access and detour warning A roadside unit sends data in broadcast about limited access areas or possible detours. Electronic toll collection A vehicle shows unicast communication with a toll gate roadside unit and pays the toll without stopping. Parking availability notification A vehicle calls to a roadside unit for a list of available parking spaces, and the roadside unit sends the list to the vehicle. Congested road notification A vehicle in a congested road sends information in broadcast to other vehicles.
  46. 46. For More : https://www.ThesisScientist.com 46 3.6.3 Commercial-Oriented Applications: These types of applications serve to establish the travelling more comfortable and productive, for example, by means of the internet connection. Some Commercial oriented application shown in Table 3.3[11]. Table 3.3: Examples of Commercial-Oriented Applications Name Description Remote diagnosis The driver can begin a wireless connection with the dealer in order to upload the vehicle diagnostics data to detect possible problems. Media or map download A vehicle can start a wireless connection with the home network or a hot-spot to transfer maps and multimedia contents. Service announcement Restaurants and early businesses can use a roadside unit to send promotional content to the drivers of the vehicles that are in their communication range. 3.7 Safety Related VANET Applications: As showed in [9], there are five potential safety applications in VANETs:  Intersection violation warning  Electronic brake warning  On-set traffic warning  Vehicle stability warning  Lane change warning 3.7.1 Intersection Violation Warning (IVW): The intersection violation warning (IVW) application warns drivers when they are going to pass over a red light. It is possible to achieve this application by placing a RSU with a traffic light controller, so that the RSU broadcast traffic light data. Vehicles that receive these data can warn the driver about the presence of a red light to avoid accidents in time [15]. 3.7.2 Electronic Brake Warning (EBW): The electronic brake warning (EBW) application describes to the driver that a preceding vehicle has performed a sudden
  47. 47. For More : https://www.ThesisScientist.com 47 braking [15]. This is useful when the considered of the braking vehicle is obstructed by other vehicles. 3.7.3 On-set Traffic Warning: The on-set traffic warning (OTW) application helps the driver during overtaking manoeuvres, by providing data about on-set traffic. 3.7.4 Vehicle stability warning (VSW): The Vehicle Stability Warning application alerts drivers that they should activate the vehicle stability control system due to the hazardous driving conditions (ice, oil). 3.7.5 Lane Change Warning: the Lane Changing warning application warns the driver who is intending to perform a lane change when it is unsafe to do so. Chapter 4 PROPOSED WORK This chapter will describe proposed simulation methodology and algorithm used in the performance improvement of AODV routing protocol. In this chapter a brief discussion of the software simulation environment used in the dissertation and their performance parameters used for the improvement of AODV routing protocol have been discussed. 4.1 Software Simulation Environment 4.1.1. Front End Tool Riverbed
  48. 48. For More : https://www.ThesisScientist.com 48 This dissertation work using a simulation tool ‗Riverbed‘ for simulating AODV routing protocol. Riverbed is a network simulator that provides multiple solutions for managing networks and applications e.g. planning, network operation, research and development (R&D), network engineering and performance management [7,46]. It allows the user to design and study the network communication devices, protocols, individual applications and also simulate the performance of routing protocol [7,46]. It supports many wireless technologies and standards such as, IEEE 802.11, IEEE 802.15.1, IEEE 802.16, IEEE 802.20 and satellite networks. Riverbed IT Guru Academic Edition is available for free to the academic research and teaching community. It provides a virtual network environment that models the behaviour of an entire network including its switches, routers, servers, protocols and individual application. It provides a virtual network environment that models the behaviour of an entire network including its switches, routers, servers, protocols and individual application. The main merits of Riverbed are that it is much easier to use, very user friendly graphical user interface and provide good quality of documentation. Riverbed Modeller constitutes a network simulation program based on C and C++, which offers a convenient GUI in order to facilitate users to conduct network experiments. Riverbed Modeller includes model libraries that represent various network hardware devices from many vendors and various communication protocols. Thus, the Riverbed Modeller users are able to simulate large network environments with network devices and routing protocols of will, without the need of pursuing real equipment, saving this way cost. The specific program also gives the capability to add or modify existing models, and bases its simulations on the Discrete Event Simulation system which uses defined processes to model network events. Additionally, traffic patterns can be simulated by the use of network layer traffic flows, by well-defined applications or by transport layer application demands. The sequence of the needed acts needed for a network simulation, includes the design and configuration of the network topology, the selection of the desired measured
  49. 49. For More : https://www.ThesisScientist.com 49 metrics, the simulation run and the analysis of the calculated statistics. Eventually, Riverbed Modeller is considered a reliable program when it comes to network evaluation, usually met on computer networking publications and also used by industry. These advantages of the program led the author to select it as the tool to facilitate the intended experiments. 4.1.2. Back End Tool (Visual Studio 2010) Visual Studio is a complete set of development tools for building ASP.NET Web applications, XML Web Services, desktop applications, and mobile applications. Visual Basic, Visual C#, and Visual C++ all use the same integrated development environment (IDE), which enables tool sharing and reliefs the introduction of mixed- language solutions. In increase, these languages use the functionality of the .NET Framework, which supplies access to key technologies that change the development of ASP Web applications and XML Web Services. Microsoft Visual Studio is an integrated development environment (IDE) from Microsoft. It is used to formulate computer programs for Microsoft Windows, as well as web sites, web applications and web services. Visual Studio applies Microsoft software development platforms such as Windows API, Windows Forms, Windows Presentation Foundation, Windows Store and Microsoft Silver light. It can develop both native code and managed code. Visual Studio includes a code editor confirming IntelliSense as well as code refactoring. The integrated debugger works both as a source-level debugger and a machine-level debugger. Other built-in tools include a forms designer for building GUI applications, web designer, class designer, and database schema designer. It takes plug-ins that enhance the functionality at almost every level—including adding confirm for source-control systems (like Subversion) and adding new tool sets like editors and visual designers for domain-specific languages or tool sets for other views of the software development lifecycle(like the Team Foundation Server client: Team Explorer). 4.2 Proposed Simulation Methodology
  50. 50. For More : https://www.ThesisScientist.com 50 The Proposed Simulation Methodology can be divided into four major steps that shown in figure 3.1. The first step is the modelling, it means to create network model. The second step is to select and apply simulation statistics on the scenarios. Third step is to simulate the scenarios and finally view and analyses results of selected protocols. Figure 4.1.Flow Chart of Proposed Simulation Methodology 4.3 Statistics for Simulation In Riverbed there are two kinds of statistics, one is Global statistics and the other is the Object statistics. Global statistics can be defined as the statistics that can be collected from the entire network. Table 4.1. Simulation Parameters Simulation Parameters Examined Protocols AODV
  51. 51. For More : https://www.ThesisScientist.com 51 Number of Nodes 100, 150, 200, 250 Types of Nodes Mobile Simulation Area 1500*1500 meters Simulation Time 1200 seconds Mobility 10 m/s Pause Time 100 seconds Performance Parameters Throughput, Delay Traffic type FTP Mobility model used Random waypoint Data Type Constant Bit Rate (CBR) Packet Size 512 bytes Wireless LAN MAC Address Auto Assigned Physical Characteristics IEEE 802.11g (OFDM) Data Rates(bps) 54 Mbps Transmit Power 0.005 RTS Threshold 256 Packet-Reception Threshold 95 Long Retry Limit 4 Max Receive Lifetime(seconds) 0.5 Buffer Size(bits) 256000 On the other hand Object statistics can be defined as the statistics that can be collected from the individual nodes. In Table 1 describe the simulation parameters that are used in this simulation in order to evaluate and improve the performance of AODV routing protocols over a MANET network. A campus network of size 1500 m x 1500 m is using for simulating varying number of mobile nodes. The all mobile nodes are spreading within this area. Each scenario takes 1200 seconds (simulation time) for running. In this simulation default random waypoint mobility model is used and all mobile nodes in all scenarios moving with constant speed of 10 m/s and pause time 100 seconds. Under each simulation we check the behaviour of AODV routing protocol with constant mobility (10 m/s) and constant pause time. For examining average statistics of the delay and throughput for the AODV routing protocol of VANET, we collected DES (global discrete event statistics) on each protocol and Wireless LAN. We take the FTP traffic in the application configuration object this sets the application to model the high load FTP traffic for analyse the effects on routing protocols.
  52. 52. For More : https://www.ThesisScientist.com 52 Table 4.2. Scenarios Used Scenarios Name No. of Mobile Nodes Scenario 1 100 Scenario 2 150 Scenario 3 200 Scenario 4 250 In profile configuration object we configured the profile with high load FTP application. The nodes were wireless LAN mobile nodes with data rate of 54 Mbps. After defining profile configuration we configure Mobility Configuration object for defining the mobility pattern and model that the nodes will follow during the simulation. 4.4. Proposed Methodology Here, we present different adaptable parameters to optimize AODV routing algorithm and describe their effects on energy constraints. The parameters we target to optimize
  53. 53. For More : https://www.ThesisScientist.com 53 AODV routing algorithm are Active Route Timeout, Hello Interval and Time-To-Live (TTL). The Active Route time out is the lifetime of the routing table. After this period of time the MANET will not consider this route. Hello interval is the time taken by the source node to send the hello message to the other node to make a contact with the intermediate node [7]. For each parameter, we present a discussion on how the parameter affects energy consumption through routing QoS and present an adaptation policy to reduce energy consumption by finding the appropriate value of these parameters considering the current channel conditions. 4.5. Proposed Algorithm You Found proposed Algorithm on For More : https://www.ThesisScientist.com
  54. 54. For More : https://www.ThesisScientist.com 54 Chapter 5 RESULT AND ANALYSIS In this chapter a detailed analysis of results of simulation study has been described. The analysis of AODV and EAODV (Enhance AODV) routing protocols have been performing on the basis of different performance metrics such as end to end delay and throughput with varying number of nodes. 5.1 Introduction: This chapter present a performance analysis and improvement of AODV routing protocols for Vehicular Ad hoc Network. Both protocols were simulated using Riverbed and were compared in terms of throughput and end to end delay with varying number of mobile nodes or vehicle node densities. 5.2 Simulation Setup: This dissertation work using a simulation tool ‗Riverbed‘ for performing simulation. A campus network of size 1500 m x 1500 m is using for simulating varying number of mobile nodes. The all mobile nodes are spreading within this area. Each scenario takes 1200 seconds (simulation time) for running. Under each simulation we check the behaviour of AODV routing protocol with 10 m/s speed and constant (200) pause time. For examining average statistics of the network load, delay and throughput for the AODV routing protocol of VANET we collected DES (global discrete event statistics) on each protocol and Wireless LAN. 5.3 Results and Analysis: There are various kinds of performance metrics for the performance evaluation of the routing protocols such as delay, throughput. These performance metrics are very necessary for evaluation of the routing protocols in a communication network. In this dissertation work for performance evaluation and improvement of AODV in terms of three performance metrics such as delay and throughput. These protocols need to be
  55. 55. For More : https://www.ThesisScientist.com 55 checked against certain parameters for their performance. If a routing protocol gives low end to end delay so this means routing protocol is efficient as compare to the protocol which gives higher end to end delay. Similarly if a routing protocol has low network load is called as the efficient routing protocol. The same is the case with the throughput as it represents the successful deliveries of packets in time. If a protocol shows the high throughput so this means it is the best and efficient protocol rather than the routing protocol which have low throughput. These parameters have great influence in the selection of an efficient routing protocol in any communication network. In the next subsections all considered performance metrics with simulation results has been described. 5.3.1. Throughput: Throughput can be defined as the ratio of the total amount of data reaches a destination from the source. The time it takes by the destination to receive the last message is called as throughput. It can express as bytes or bits per seconds (byte/sec or bit/sec). There are some factors that affect the throughput such as; changes in topology, availability of limited bandwidth, unreliable communication between nodes and limited energy. A high throughput is absolute choice in every network.
  56. 56. For More : https://www.ThesisScientist.com 56 Figure 5.1: Improved throughput for 100 Nodes In figure 5.5-5.8, the graph represents the throughput in bits per seconds. The x-axis denotes the simulation time in minutes and the y-axis denotes throughput in bits per seconds. In first scenario of 100 nodes of our experimentation, packets travels are shown as throughput with peak value of approx. 28 lac. bits per seconds. In second scenario which EAODV packets transfer rate increases too high due to our approach In third scenario of 150 nodes of our experimentation, packets travels are shown as throughput with peak value of approx. 2250890 bits per seconds at pause time100 and active route time 5 to30 sec, and hello interval (1,1.1).
  57. 57. For More : https://www.ThesisScientist.com 57 Figure 5.2: Normal throughput for 100 Nodes
  58. 58. For More : https://www.ThesisScientist.com 58 Figure 5.3: Improved and Normal throughput for 100 Nodes Figure 5.4: Improved throughput for 150 Nodes
  59. 59. For More : https://www.ThesisScientist.com 59 Figure 5.5: Normal throughput for 150 Nodes
  60. 60. For More : https://www.ThesisScientist.com 60 Figure 5.6: Improved and Normal throughput for 150 Nodes Figure 5.7: Improved throughput for 200 Nodes
  61. 61. For More : https://www.ThesisScientist.com 61 Figure 5.8: Normal throughput for 200 Nodes Figure 5.9: Improved and Normal throughput for 200 Nodes
  62. 62. For More : https://www.ThesisScientist.com 62 Figure 5.10: Improved throughput for 250 Nodes
  63. 63. For More : https://www.ThesisScientist.com 63 Figure 5.11: Normal throughput for 250 Nodes Figure 5.12: Improved and Normal throughput for 250 Nodes Table 5.2 Throughput for Different Nodes No. of Mobile Nodes Throughput (Normal) Throughput (Improved) 100 939248.9 1058982
  64. 64. For More : https://www.ThesisScientist.com 64 150 3227315 3566213 200 5788778 6202190 250 6497495 6769384 5.4 Inference from Result and Analysis The simulation result shows the performance behaviour of the considered protocol in terms of end to end delay and throughput. The values of parameters for the default and improved values of delay and throughput for 100, 150, 200 and 250 are shown in Table 5.3. The default and improved average values of delay and throughput are also shown. Table 5.3 Average values of Delay & Throughput for AODV Routing Protocol Mobile Nodes Scenario Active Route Timeout Hello Interval Time- To-Live Throughput
  65. 65. For More : https://www.ThesisScientist.com 65 100 Normal 5 (1,1.1) 1 939248.9 Improved 25 (1,1.1) 1 1058982 150 Normal 10 (1,1.1) 1 3227315 Improved 5 (1,1.1) 2 3566213 200 Normal 10 (1,1.1) 1 5788778 Improved 20 (1,1.1) 2 6202190 250 Normal 30 (1,1.1) 1 6497495 Improved 5 (1,1.1) 2 6769384 Chapter 6 CONCLUSION In this dissertation, AODV routing protocol with varying number of moving nodes or vehicles (100, 150, 200 and 250) and a constant speed of 10m/s with 200s pause time
  66. 66. For More : https://www.ThesisScientist.com 66 has been evaluated and improved. AODV protocol is evaluated and improves in terms of throughput. These performance metrics used in our evaluation represents performance aspects of performance in a network. Throughput addresses the reliability of the protocols. The simulation model of VANET network is simulated using Riverbed simulator and analyzed and improves for AODV routing protocol. We applied some methodology to improve the performance of AODV protocol by modifying the values of parameters like Active Route Timeout, Time to live (TTL) and Hello Interval and make E-AODV routing protocol. We applied this modified AODV (E-AODV) to different numbers of nodes like 100, 150, 200 and 250 and concluded that this is effective in all the cases. It is concluded that E-AODV has better Quality of services such as throughput as compared to AODV protocol. Future Work: Future work will improve the performance of existing ad hoc routing protocols with varying number of mobility, under other network scenario by varying the network size and mobility models using Qualnet and OPNET 17.5 using genetic based swarm optimization appraoch. REFERENCES
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