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International Journal of Wireless and Mobile Networking (IJWAMN)Vol. 2, No. 1(May 2014) 11
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Route Stability in Mobile Ad-Hoc Networks
Pooja M R
1
, Arpitha T S
2
, Apoorva S A
3
, Gurudath K S
4

1.
Associate Professor, Dept of CS&E, Vidyavardhaka College of Engineering, Mysore, Karnataka, India
2.
Span Infotech, India
3.
Accord Software Systems, India
4.
Synowledge PV Services India Ltd

Abstract:
A Mobile Ad Hoc Network (MANET) is a wireless network consisting of mobile nodes,
which can communicate with each other without any infrastructure support. In these
networks, nodes typically cooperate with each other, by forwarding packets for nodes
which are not in the communication range of the source node. A fundamental issue
arising in mobile ad-hoc networks (MANETs) is the selection of the optimal path between
any two nodes. A method that has been advocated to improve routing efficiency is to
select the most stable path so as to reduce the latency and the overhead due to route
reconstruction. In this work we study the stability of a routing path, which is subject to
link failures caused by node mobility, and we consider as metrics of interest the duration
and the availability of a path. Moreover, using the results on path duration and
availability, we show how to determine the optimal path in terms of route stability, under
the Random Direction mobility models.

Keywords- MANETs, node mobility, mobility model, path availability, optimal path.
1. INTRODUCTION
Mobile Ad hoc Network (MANET) is different from traditional wireless networks in many
ways. One of the basic differences is that a MANET is a multi-hop wireless network, i.e., a
routing path is composed of a number of intermediate mobile nodes and wireless links connecting
them which can communicate with each other without any infrastructure support. In these
networks, nodes typically cooperate with each other, by forwarding packets for nodes which are
not in the communication range of the source node. Since nodes can move at any time, wireless
links are prone to be broken. Any link breakage along an established routing path will lead to a
path failure. A shortest path may fail sooner than another path connecting a given source and
destination pair. Frequent routing discovery is costly and inefficient.
Mobile ad hoc network (MANET) consists of mobile platform which communicate with each
other through wireless links, without infrastructure base stations. Each node not only is a host but
also a router that maintains routes to and forwards data packets for other nodes in the network
that may not be within direct wireless transmission range. Topology of a mobile ad hoc network
will often change rapidly; this behavior needs some management and solving problem of this type
of networks. If source and destination nodes are not within the transmission range of each other,
intermediate nodes are needed to serve as intermediate routers for the communication between
the two nodes [1]. Moreover, mobile platforms moves autonomously and communicate via
dynamically changing network. Thus, frequent change of network topology is a main challenge
for many important topics, such as routing protocol robustness, and performance degradation [2,
3].

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Originally, the MANET was proposed for military applications in the battlefield. However,
future MANETs could be deployed in various environments. City-wide MANETs (Bai et al.,
2003) have attracted research attentions recently because of its potential applications. Different
from movements in the battlefield, movements in a city are highly restricted by roadways, i.e., the
following movement rules must be obeyed: a vehicle or person can only move along roads, turn
or stay at intersections. In addition, the driving speed of a vehicle on a specific road segment
cannot exceed its prescribed speed limit. A similar mobility pattern is described in the Manhattan
mobility model (Bai et al., 2003). Therefore, it is possible for us to make a relatively accurate
prediction for mobility of mobile nodes, which will provide a good insight for finding reliable
routing paths.

Traffic relaying in MANETs, however, is a difficult task. Node mobility, signal interference
and power outages make the network topology frequently change. As a consequence, the links
along a route may fail, and an alternate path must be found. To avoid the degradation of the
system performance, several solutions for route creation and maintenance have been proposed in
the literature, taking into account various metrics of interest. A method that has been advocated to
improve routing efficiency is to select the most stable path [4], [5], [6], [7] so as to avoid packet
losses and limit the latency and overhead due to route reconstruction. Specifically, an algorithm
should be able to select a route based on some knowledge of the nodes motion and on a
probability model of the future availability of the route. Furthermore, if an estimate of the route
duration is available, route disruption can be avoided by creating an alternative path before the
current one breaks [7].
2. ASSUMPTIONS AND DEFINITIONS
While studying path duration and availability in MANETs, we make the following assumptions.
(i) The network comprises of nodes having a common transmission range, R, and has the same
mobility pattern.
(ii) Nodes move independently of each other.
(iii)The received signal only depends on its distance from the transmitter.
(iv)Communication links are bidirectional.
Let us consider two generic nodes, A and B, and let X (A) and X (B) be their positions,
respectively, at time t. We define the distance between the two nodes at time t as d A, B (t) = ||X
(A)-X (B) ||. According to assumption (3), a communication link between A and B exists if the
two nodes are within the radio range of each other. Then, considering assumption (1), we say that
a link between A and B exists at time t if d A, B (t) <R, and this link is bidirectional.
A. SSA Routing Protocol
Signal Stability based Adaptive (SSA) is a routing protocol, which finds route based on signal
strength, and location stability. In SSA, a mobile node measures the signal strength received
from other nodes, and this information is used to estimate the link stability between them. The
location stability mechanism is considered only as a supplement to signal-strength
measurements.

B. Link Stability
Link stability refers to the ability of a link to survive for certain duration. The higher the link
stability, the longer is the link duration. The stability of a link depends on how long two nodes,
which form that link, remain as neighbors. Two nodes are neighbors when they remain within
each other’s communication range, or the signal strength is above certain threshold. Mobility
causes link breakage and leads causes link breakage and leads to route recovery.
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C. Path Duration and Path Availability
We define the path duration as the time interval from when the route is established until one of
the links along the route becomes unavailable, while we say that a path is available at a given
time instant t when all links along the path are active at time t.

D. Mobility Patterns
Node mobility is one of the most important characteristics of MANET. There have been
various mobility models or patterns proposed for MANETs. These patterns try to capture most
of the common mobility patterns, but few patterns capture realistic movements of nodes in
MANETs. Here we focus on bidimensional random mobility [8], and we consider nodes
moving according to the Random Direction (RD) mobility model, which was first introduced in
[9], [10]. According to such model, each node alternates periods of movement (move phase) to
periods during which it pauses (pause phase); at the beginning of each move phase, a node
independently selects its new direction and speed of movement [9]. Speed and direction are
kept constant for the whole duration of the node move phase.
3. SYSTEM DESIGN
3.1 Product Description
A fundamental issue arising in mobile ad hoc networks (MANETs) is the selection of the optimal
path between any two nodes. A method that has been advocated to improve routing efficiency is
to select the most stable path so as to reduce the latency and the overhead due to route
reconstruction. In this work, we study both the availability and the duration probability of a
routing path that is subject to link failures caused by node mobility. In particular, we focus on the
case where the network nodes move according to the Random Direction model, and we derive
both exact and approximate (but simple) expressions of these probabilities. Through our results,
we study the problem of selecting an optimal route in terms of path availability. Finally, we
propose an approach to improve the efficiency of reactive Routing protocols.

3.2 Module Description
There are mainly three modules, they are:
1. Module for Routing
By this Module the server determines the nodes in Range and determines the nodes within
range among which communication has to be started applying proper Routing Algorithms.
2. Module for finding the path
The implicit neighbor detection techniques used by routing protocols is based on periodic
broadcast of hello messages by a node, allowing neighbors to detect it. Two nodes that are at
two hop distance can be made to believe that they are neighbors, by simply replaying their
messages by the middle node. This is how the path is found out between nodes. The search
mechanism goes this way:
• UP-CLOCKWISE
• UP-ANTICLOCKWISE
• DOWN-CLOCKWISE
• DOWN-ANTICLOCKWISE

3. Module for Network Establishment
By this Module the Network among which transmission has to take place is determined. The
number of Nodes and the Network range is detected.
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3.3 Performance Requirements
Increased admin security: The PC should be highly secured and accessible only by the
administrator to avoid the misuse of the application.
Portability: The GUIs of this application is user-friendly so it is very easy for the user to
understand and respond to the same.
Reliability: This system has high probability to deliver us the required queries and the
functionalities available in the application.
Response time: The time taken by the system to complete a task given by the user is found to be
very less.
Scalability: The system can be extended to integrate the modifications done in the present
application to improve the quality of the product. This is meant for the future works that is to be
done on the application.

3.4 Requirement Analysis
Requirement analysis in system engineering and software engineering encompasses those tasks
that go into determining the needs or conditions to meet for a new or altered product, taking
account of the possibly conflicting requirements of the various stake holders, such as
beneficiaries or users.
3.4.1 Functional Requirements
These are statements of services the system should provide, how the system should react to
particular inputs and how the system should behave in particular situations.
• Simulation should run and it should simulate the network.
• Topology should have mobile nodes with pre defined frequency.
• Nodes should keep entering and leaving the network.
• Nodes should have all the information about itself.
• Get the network path and number of hops of the transmission.
• Get the Path availability and probability of the overall network.
3.4.2 Non Functional requirements
Non-Functional requirements presents a systematic and pragmatic approach to ‘building quality
into’ software systems. System must exhibit software quality attributes, such as accuracy,
performance, security, and modifiability. Since NFRs might not be absolutely achieved, they may
simply be satisfied sufficiently. To reflect this, NFRs are represented ‘soft goals’ whose
interdependencies, such as tradeoffs and synergy, are captured in graphs.
4. ARCHITECTURE OF PROPOSED METHOD
4.1 Existing System
A mobile ad hoc network, sometimes called a mobile mesh network, is a self-configuring network
of mobile devices connected by wireless links. Each device in a MANET is free to move
independently in any direction, and will therefore changes its links to other devices frequently.
Each must forward traffic unrelated to its own use, and therefore be a route. The primary
challenge in building a MANET is equipping each device to continuously maintain the
information required to properly route traffic. MANETs are a kind of wireless ad hoc networks
that usually has a routable networking environment on top of a link layer ad hoc network. They
are also a type of mesh network, but many mesh networks are not mobile or not wireless.
4.2 Proposed System
We focus on the stability of a routing path, which is subject to link failures caused by
node mobility.
International Journal of Wireless and Mobile Networking (IJWAMN)Vol. 2, No. 1(May 2014) 15
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We define the path duration as the time interval from when the route is established until
one of the links along the route becomes unavailable
While we say that a path is available at a given time instant t when all links along the
path are active at time t.
Then, our objective is to derive the probability of path duration till time t and the
probability of path availability at time t.
4.3 Design Consideration
The software is framed in such a way that it provides the flexibility for analyzing for various
sender and recipient maintaining account in same or different bank. A Joint bank account is
owned together (jointly) by two or more people. A joint account agreement is typically needed to
open such an account. This agreement will detail whether transactions require the signatures of all
parties or whether one party can take actions on his/her own. The way to restrict each holder’s
authority over the account is to request collective signing arrangements. To support this feature
we have come up with a scheme in which an e-cheque signed by all the Joint Account Holders,
when submitted for clearance, can be verified that it is signed by all the Joint Account Holders by
the clearing bank using a single verification equation. We propose to use the concept of Forward-
secure Multi-signatures for signing e-cheques used with Joint Accounts.
4.3.1 Development Methods
The development method used in this software design is the modular or functional development
method. In this, the system is broken down into different modules, with a certain amount of
dependency among them. The input-output data that flows from one-module to another will show
the dependency.
4.3.2 Process Flow Chart
A flowchart is a common type of chart that represents an algorithm or process, showing the steps
as boxes of various kinds, and their order by connecting these with arrows. Flowcharts are used in
analyzing, designing, documenting or managing a process or program in various fields.

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5. RESULTS AND OBSERVATIONS

Fig 5.1 is the primary page which allows user to Run, stop and reset the simulation.
International Journal of Wireless and Mobile Networking (IJWAMN)Vol. 2, No. 1(May 2014) 17
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Fig 5.1 Simulation Run

Fig 5.2 shows the options in the simulations. By selecting Topology button, user can view the
network, by selecting Throughput button, user can calculate the network throughput and number
of collisions, by clicking on Statistics button, user can calculate the overall statistics of the
network, by clicking on Traffic button, user can know the network traffic and by selecting Exit
button, user comes out of the simulation.



Fig 5.2 Simulation Run with Options

In fig 5.3 blue circles represent the nodes and brown line indicates the nodes moving according to
Random Direction Mobility Model.
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Fig 5.3 Network Topology



Fig 5.4 Throughput and Collision calculator

Fig 5.4 shows the calculator which is used to calculate the throughput based on number of
covered nodes in the network and number of collisions which is based on the formula number of
collisions in each node/ broadcastpeers (No of active nodes at that point of time) in the network.



Fig 5.5 General Status Update of the Network
Fig 5.5 provides the status of the mobile ad hoc network like number of Broadcastpeers (active
nodes in the network at that point of time), broadcast peers count will be equal to number of
nodes in the network, leaves (a node which can’t be destination to itself), channelnoise nodes
International Journal of Wireless and Mobile Networking (IJWAMN)Vol. 2, No. 1(May 2014) 19
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(nodes from which the optimal path can’t be established), Uptime (time during which the node is
active), average number of connections( number of immediate neighbors) capacity (source
capacity of each node) and used capacity (capacity/broadcastpeers) at that point of time.


Fig 5.6 Traffic Update

Fig 5.6 provides the traffic update like number of bytes up (avg bytes up / broadcastpeers where
bytes up is the number of bytes sent), bytes down (avg bytes down / broadcastpeers where bytes
down is the number of bytes received), bytes dropped (avg Bytes Dropped / broadcastpeers) ,
bytes collided (avg Bytes Collided / brodcastpeers), packet queue (avg Packet Queue
/brodcastpeers) of the mobile ad hoc network at that point of time.
6. CONCLUSION
We studied the duration and availability probabilities of routing paths in MANETs—a
fundamental issue to provide reliable routes and short route disruption times. We focused on the
Random Direction mobility model and derived both exact and approximate (but simple)
expressions for the probability of path duration and availability. We used these results to
determine the optimal path in terms of route stability; in particular, we showed some properties of
the optimal path.. Finally, based on our findings, we proposed an approach to find and select
routes, which accounts for the expected data transfer time over the path and allows to reduce the
overhead of reactive routing protocols.

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