View of A HYBRID HANDS-OFF TECHNIQUE IN VANET

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE A HYBRID HANDS-OFF TECHNIQUE IN VANET

SANGEETA¹, M.Tech Scholar, Dr. POOJA SAPRA², Mr. SUBHASH CHANDRA³

1,2,3World College of Technology and Management, MDU, Rohtak

Abstract - Vehicular Ad Hoc network is one of the most complex networks as it is hybrid network with short distance communication. The major issue with such kind of network is mobility of the nodes. As the moving speed of different vehicle is different as well as the high speed mobility of nodes it is difficult to maintain a lossless handoff over the network. When the network is hybrid network with Wi-Fi and WiMAX base stations, another issue is to perform the effective selection of the base station so that lossless and the instant communication will be performed. In this proposed work, we are covering these all issues relative to handoff. In this work, we have defined a two level parametric decision to perform an effective handoff in hybrid VANET network. The simulation result has shown efficient growth in the terms of performance.

Keywords - ad hoc network, mobility, WiMAX, hybrid n/w.

1. INTRODUCTION

Vanet- Vehicular Ad-Hoc Network is the network in which communication has been done in between road side units to cars, car to car in a short range of 100 to 300 m.

Existing authentication protocols to secure vehicular ad hoc networks (VANETs) raise challenges such as certificate distribution and revocation, avoidance of computation and communication bottlenecks, and reduction of the strong reliance on tamper- proof devices. In a VANET, vehicles will rely on the integrity of received data for deciding when to present alerts to drivers. Further in the future, this data may be used as the basis of control decisions for autonomous vehicles. If this information is corrupted, vehicles may present unnecessary or erroneous warnings to their drivers, and the results of control decisions based on this information could be even more disastrous. Information can be corrupted by two different mechanisms: malice and malfunction. Similarly, vehicles have two defense mechanisms: an internal filter and external reputation information.

In this work, we have defined a two level parametric decision to perform an effective handoff in hybrid VANET network. The first level parametric decision is performed on vehicles on the basis of the vehicle type, speed etc. But the prioritization vectors will work only in case of under loading or the normal case. But as the load over the base station will be increased, the switching

between the base station selections will be based on the strengths and characteristics of the base stations. The Analysis between two base stations will be done respective to the signal strength of the base station, capacity and load of the base station.

Another co-relative analysis between the base station selections will be performed respective to the dynamic distance analysis between two frames. According to this, the direction of the vehicle movement will be taken as the decision vector. A vehicle that is moving in the direction of the base station will be handover to that base station. A Simulation environment of highway on the bases of network simulation tool is created. First we discuss the general architecture and security architecture of VANET. Next our paper addresses the hand off concept, proposed work and simulation result with conclusion.

1.1: THE GENERAL ARCHITECTURE In this the basic architecture of VANETs has been shown in Fig.1. The architecture includes V2V, V2I communication, OBUs Application Units (AU), RSU and Access network. • Ad-hoc environment: It dwells intelligent vehicles (nodes) that contain fundamentally two components: • OBU (On Board Unit): GPS module, wireless communication module, Central control module (CCM), and human-machine

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE interface module are the four modules of

OBU unit. CCM encloses processing of serial port information, memory, judgment as well as decision making and data transceiver [5]. The OBU unit has communicational capabilities. The

connection of vehicle with RSU via DSRC radios is done by this unit where DSRC is at present acknowledged as mainly assuring standard of wireless to join I2V and V2V.

Fig.1: VANET Architecture AU (Application Unit): This unit facilitates

OBU to communicate by implementing program. The connection of AU to the OBU can be wired or wireless and AU could endure with the OBU in a particular physical component. Infrastructure environment: It includes RSU as well as access network. RSU (Road Side Units): It is a wave device usually permanent beside the road side or in devoted positions such as at the intersections or close to parking places.

The work of RSU is to act as a router among the vehicles on the road as well as provide connections to further network devices. Main functions of RSU are: o widening the range of communication of the ad-hoc network used to redistribute the data to further OBUs o convey the data to other RSUs to further forward it to other OBUs. The VANETs communication divided into two parts as explained below: Vehicle- to-Vehicle Communication: This is a wireless communication among vehicles.

This communication pattern is useful where message is been sent to a group of vehicles or a specific vehicle i.e. in a multicast or uni-cast situation. For paradigm to extend traffic safety, warning message ought to be sent to incoming vehicles after recognition of mishaps. Figure 3 represents diagram of V2V warning propagation.V2I (Vehicle-to-Infrastructure)

Communication: In this communication, when a potential danger is detected, sending of messages is done either via infrastructure i.e. through RSUs or a vehicle. For the communication among vehicles as well as RSUs, high bandwidth connection is used.

1.2: HANDS OFF: A CONCEPT

The term handover or Handover refers to the process in which transferring an ongoing call or data session from one channel connected to the core network to another. Satellite communication is the process of transferring satellite control responsibility from one earth station to another without loss or interruption of service. Handoff Classification Handoffs can be classified in several ways as discussed:

(i) Horizontal and Vertical Handoff:

Depending on the type of network technologies involved, handoff can be classified as either horizontal or vertical.

Traditional handoff, also called horizontal or intra-system handoff occurs when the MS switches between different BSs or APs of the same access network. On the other hand, vertical handoff or inter-system handoff involves two different network- interfaces representing different wireless access networks or technologies. (ii) Hard and Soft Handoff: This classification of

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE handoff depends upon the number of BSs

and/or APs to which an MS is associated with at any given moment. Hard handoff, also called “break before make”, involves only one BS or AP at a time. The MS must break its connection from the current access network before it can connect to a new one. In a soft handoff, also called

“make before break”, an MS can communicate and connect with more than one access network during the handoff process.(iii) Mobile-controlled, Mobile- assisted, and Network-controlled Handoff:

As the names suggest, these types of handoff classifications are based on the entity, MS or access network, which make the handoff decisions . Mobile-assisted handoff is the hybrid of mobile-controlled and network-controlled handoff where the MS makes the handoff decisions in cooperation with the access network.

1.3: HANDOFF PROCESS IN VANET The handoff procedure refers to the mechanism or sequence of messages exchanged by access points and a mobile unit resulting in a transfer physical layer connectivity and state information from one access point (AP) to another with respect to the mobile unit in consideration. The complete handoff process can be divided into three distinct logical steps: execution 1. Network Discovery: An MS with multiple active interfaces can discover several wireless networks based on broadcasted service advertisements from these wireless networks. The mobile unit scans for these messages on assigned channels and creates a list of APs prioritized by the received signal strength. There are two kinds of scanning methods defined in the standard:

active and passive [10]. In the passive mode, the mobile unit only listens to the hello messages. In the active mode, apart from listening to hello messages, the station sends additional station actively probes for the APs. 2. Handoff Triggering and Decision: This is the phase where the decision regarding “when” to perform handoff is made. In this phase, the target wireless access network is selected based on multiple criteria. 3. Handoff Execution:

This is the last phase of the handoff process where the actual transfer of the current

session to the new access network takes place. This requires the current network to transfer routing and other contextual information related to the MS to the newly selected access network as quickly as possible.

Many protocols (Márquez, Calafate, Cano &

Manzoni, 2011) have been introduced as discussed above but VANET handoff have issues due to highly dynamic environment a vehicle creates frequent handoff, which causes packet delay and packet losses. The term handoff refers to process of transferring network traffic from ongoing channel to another channel that is connected to the network due the shorter range of the channel. In this process the continuity of the services provided by the network is disturbed. To achieve the maximum services of the network the handoff procedure should be done in such a way that the user should not disturbed and handoff should also have done.

Handoff is classified in many ways (Lee, Yu, Yoo & Choi, 2008). Horizontal and Vertical Handoff: In vertical handoff (Kumari, 2013) node have two interfaces of network and according to its facility the node will choose one of the networks for communication. For example, a laptop has two interfaces a Wi- Fi and a wired interface it will choose the wired interface when Wi-Fi interface is unavailable. While in horizontal handoff procedure the node switches between different BS and APs lies within same network access such as 4G and WiMAX.

The process of handoff is different as compared to MANET (Hossain et al., 2010;

Hui, 2005).

2. RELATED WORK

In this paper [2], another handoff administration conspires that uses concurrent different bindings in IP based 3Gwireless networks. The proposed handoff plan minimizes packet losses and brings about insignificant postponements amid handoff. It demonstrates that another handoff technique utilizing synchronous various bindings lessens packet loss and causes insignificant deferral amid handoff in IP based 3G wireless networks. The essential thought of the strategy is to foresee a handoff utilizing wireless network

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE data as a part of the type of got signal

qualities and to all the while send packets bound for the mobile host to neighboring BSs ahead of time. In this paper [4], handoff is dependably a basic issue here.

This paper proposes a novel seamless handoff instrument for IEEE 802.11 wireless networks which bolster IEEE 802.11i security standard. This approach comprises of a Dynamic Tunnel Establishing system and a seamless handoff component. Both intra-and inter- subnet handoff cases are considered in our seamless handoff approach. This work concentrates on handoffs in DHCP-based IP networks as opposed to Mobile IP-upheld networks; however the proposed scheme can be effectively custom-made to Mobile IP-bolstered networks.In paper [6], an issue is represented where the IEEE 802.1X is used in mobile Worldwide Interoperability for Microwave Access (WiMAX) authentication. This method brings about a long postpone in WiMAX handoff. To determine this issue, this paper proposes a key caching system to dispose of the non- vital IEEE 802.1X authentication cost in WiMAX handoff. This mechanism is researched through analytic and simulation modeling. This paper has proposed a key caching instrument to speed up the inter- ASN-GW handoff for mobile WiMAX. With this instrument, when a MS leaves the old ASNGW, the MS key record (e.g. the MSK) is reserved in the old ASN-GW. In this paper [7] it is discussed that the accomplishment of the Internet has pulled in more individuals to join in network route is discussed. A cellular architecture is expected to enhance the correspondences quality and to lessen power utilization, both at the base and mobile stations. In a cellular situation, handoffs happen every now and again. In this paper, a handoff technique called neighbor-assisted agent architecture, which exploits the specially appointed network to enhance handoff execution, is proposed. Timing analytical and simulation results demonstrate that the proposed system can give a superior arrangement than mobile IP for handoff breaks amid high-speed movement. In this paper [8] the study in based on the soft- handoff instrument and contrasts its

execution and hard handoff. The study shows that in spite of the fact that a handset may conceivably expend additional radio links in soft handoff the instrument gives better chance to exchange the link effectively in the handoff system. This paper proposed an analytic model and a simulation model to concentrate on the execution of soft handoff. This study showed that the handoff network reaction time, the mobility of the client and the overlay time fundamentally influence the execution of soft handoff. Besides, it is watched that the call incompletion likelihood can be fundamentally influenced by the changes of the network reaction time and the non-overlay time. In this paper [14]

another soft handoff investigation for hierarchical code-division multiple-access (CDMA) cellular systems is introduced.

Here the technique first builds up an analytical strategy for examining the interference in hierarchical CDMA cellular systems. At that point it applies the acquired results to a soft handoff investigation model to consider the execution of soft handoff in hierarchical architectures. The model is built by first describing the interference imbalance in hierarchical CDMA deployments. It has been demonstrated that this system is superior to handoff investigation techniques that depend on got pilot signal power as it were.

3. THE PROPOSED WORK

The major issue with such kind of network is mobility of the nodes. As the moving speed of different vehicle is different as well as the high speed mobility of nodes it is difficult to maintain a lossless handoff over the network. The analysis of the work will be performed in terms of communication throughput and the network delay. The presented work is implemented in NS2 environment in a highway based network scenario. The proposed work is generating in three main levels:

1) Level 1: The level 1 analysis will be performed over the mobile nodes. Each of the mobile nodes in this network is defined with two main parameters called Mobility Speed and the type of vehicles.

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE 2) Level 2: In the second level, when two base

station either of same kind of the different kind will analyzed comparatively under different parameters to select the base station to which handover will be performed.

3) Level 3: the vehicle and the base station will be identified cooperatively. In this case the direction parameter will be taken as the selection parameter. It means the node will be analysis for the distance vector from two base stations under two time frames.

The Proposed algorithm is shown here:

1. Define a hybrid network with n number of nodes, with capability of WiMAX and Wi-Fi based data transmission.

2. Define m1 number of Wi-Fi base station and m2 number of WiMAX base station with respective range, channel strength etc.

3. For i=1 to n

4. If(TypeofData(node(i))=HIGH_PRIORITY TypeofVehicle (node(i))=HIGH_PRIORITY) 5. For j=1 to m2

6. Estimate SignalStength(BaseStation(j)), Throughput(BaseStation(j)) and TransmissionRate(BaseSation(j))

7. B=Find(MAX_SIGNAL_STRENGTH,HIGH_T HROUGHPUT,HIGH_TRANSMISSIONRATE) 8. Perform Communication(B,Node(i))

}

9. If(TypeofData(node(i))=LOW_PRIORITY ||

TypeofVehicle(node(i))=LOW_PRIORITY) {

10. For (j=1 to m1) {

11. Estimate SignalStength(BaseStation(j)), Throughput(BaseStation(j)) and

TransmissionRate(BaseSation(j))

12. B=Find(MAX_SIGNAL_STRENGTH,HIGH_T} HROUGHPUT,HIGH_TRANSMISSIONRATE) 13. Perform Communication(B,Node(i))

}

14. For i=1 to N {

15. If(Distance(Node(i),B)>CoverageRange) {

16. Print “Handover Required”

17. For (i=1 to n) {

18. If(TypeofData(node(i))=HIGH_PRIORITY ||

TypeofVehicle(node(i))=HIGH_PRIORITY) {

19. For (j=1 to m2) {

} }

23. Print “handover to wimax base station”

}

24. For (i=1 to n) {

25. If(TypeofData(node(i))=LOW_PRIORITY ||

TypeofVehicle(node(i))=LOW_PRIORITY) {

26. For (j=1 to m1) {

} }

30. Print “handover to wifi base station”

}

} Basic idea and challenge in existing work is that when a mobile node moves to a new subnet, the mobile router (MR) will receive broadcast packet from the target BS and most importantly perform the handoff procedure. The handoff procedure contains signal measurement, network layer movement detection, the duplicate address detection (DAD) procedure and registration.

The DAD procedure is time consuming and thus will cause the link to be disconnected.

In VANETs, since the vehicle is moving so fast that the handoff procedure must be simplified. The protocol, based on IP passing [10] or IP exchange, can acquire IP address faster than the traditional handoff procedure. The basic idea of this protocol is to perform the fast handoff by the assistance of other vehicles on the VANET.

Our idea comes from a real bus mentioned.

The bus is assumed to be equipped with the Wi-Fi and WiMAX interfaces, where the Wi-

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE Fi interface is for V2V communication and

the WiMAX interface is used to connect to the Internet. If there is any vehicle on the lanes of the opposite direction, the mobile router may acquire its IP address from the vehicle on the lanes of the opposite direction. In this work there is problem of packet delay and packet loss.

4. SIMULATION & RESULT

A Vehicular network is one of the most complex networks as it is hybrid network with short distance communication. To perform the complete work we have taken a Highway scenario in NS2 with 5 clusters and with one base station in each cluster and then perform the transmission between these clusters. The various assumptions made to perform the communication are as follows: (i) Mobile units have GPS (Global Positioning System) which allows access points and other mobile units to track their positions and directions.(ii) It is assumed that High priority vehicles are emergency vehicles, heavy vehicles with speed greater than 60 km/h , light vehicles with speed less than 80 km/hand low priority vehicles are heavy vehicles with speed less than 60 km/h and heavy vehicles with speed 80 km/h. (iii) It is also assumed that each of vehicles is having two interfaces for both

Wi-Fi and WiMAX. It is assumed that the speed of vehicle between 5 km/h to 100 km/h. The simulation area is of highway where the vehicles can move on one way road. It is also assumed that the base stations are Wi-Fi and WiMAX. There are five clusters which have fifty nodes. Each cluster has given different colors. There are one base station in each cluster and the transmission between these clusters. Each base station coverage area is 1000 meter. In the above snapshot handover is performed.

High priority and low priority signal works only in normal and under load condition but when load increases then ii checks the base station capacity accurately, throughput over the network and the distance from the base station.

In this work we have taken highway scenario and there are five clusters which have fifty nodes. Each cluster has given different colors. There are one base station in each cluster and the transmission between these clusters. Each base station coverage area is 1000 meter. After the simulation experiment, there are certain factors which need to be considered i.e.

number of packets, packet loss or bit rate etc. The experiment has shown efficient growth in the terms of performance in VANET simulation.

Table 1: Simulation Parameter

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE

Fig.2 : Hand-over technique

The performance metrics of interest are: Number of packets, Packet loss, Packet delay, Bit rate.

(a) (b)

Fig.3: (a) No. of packet transmitted ;( b)No. of packet loss

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Vol.03, Issue 04, April 2018, Available Online: www.ajeee.co.in/index.php/AJEEE

(a) (b)

Fig.4: (b) Packet delay in highway scenario; (b) bit rate 5. CONCLUSION

In this study, network is creating in highway scenario with five clusters and each cluster is represented by the different color. In each cluster there is one base station and transmission between these clusters. We proposed a handoff procedure that reduces the handoff latency. When a mobile node moves outside from its current cluster then there is need of another cluster mechanism to elect head of mobile node.

The selection of the handover is defined based on some parametric values.

Handover will be performed on the bases of distance, signal strength and load on the base station. Comparing with result of existing work, proposed work is better than existing.In future, we want to implement this work on greedy parameter routing protocol and we also want to implement in actual signal processing. In addition, we want to combine different routing protocols with the proposed handoff procedure and to analyze and compare their performances.

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