Introduction to MANET and Clustering in MANET
©2015
Academic Paper
37 Pages
Summary
The emergence of powerful hand held devices like cell phones, personal digital assistants (PDA), pagers coupled with the advancement of wireless communication system have paved the way for a variety of mobile computing and wireless networking technology recently. The history of wireless networking goes to early days Defense Advanced Research Projects Agency packet radio network.
The advantage of wireless networking is its ability to support user mobility and has created a new breadth to problem solving in this domain, resulting in unpredictable resource requirement and uncertainty in network connectivity. Solutions to these problems have boosted the market for wireless services.
Wireless ad hoc network is a collection of mobile devices forming a network without any supporting infrastructure or prior organization. Nodes in the network should be able to sense and discover with nearby nodes. Due to the limited transmission range of wireless network, multiple network “hops” may be needed for one node to another (source to destination or intermediate node) across the network. There are number of characteristics in wireless ad hoc networks, such as the dynamic network topology, limited bandwidth and energy constraint in the network. Mobile ad hoc network plays an important role in different applications such as military operations to provide communication between squads, in emergency cases in out-of-the-way places, in medical control etc.
Routing protocols play a significant role in the implementation of mobile ad hoc networks (MANET). Due to the characteristics of mobility of ad hoc networks it is crucial to find a path or route from the source to the destination node and perform the communication between nodes for a long period of time.
In MANET, a number of routing protocols using a variety of routing algorithms has been proposed – for example Dynamic Source Routing (DSR), Ad hoc On demand Distance Vector Routing (AODV), Temporally Ordered Routing Algorithm (TORA), Location Aided Routing (LAR) and periodic (proactive) protocols such as Destination Sequence Distance Vector (DSDV), Distributed Bellman Ford, where member nodes exchange routing information and know a current route to each destination periodically. Also, several protocols uses both reactive and proactive mechanisms, such as Zone Resolution Protocol (ZRP) Cluster Based Routing Protocol (CBRP) etc.
The advantage of wireless networking is its ability to support user mobility and has created a new breadth to problem solving in this domain, resulting in unpredictable resource requirement and uncertainty in network connectivity. Solutions to these problems have boosted the market for wireless services.
Wireless ad hoc network is a collection of mobile devices forming a network without any supporting infrastructure or prior organization. Nodes in the network should be able to sense and discover with nearby nodes. Due to the limited transmission range of wireless network, multiple network “hops” may be needed for one node to another (source to destination or intermediate node) across the network. There are number of characteristics in wireless ad hoc networks, such as the dynamic network topology, limited bandwidth and energy constraint in the network. Mobile ad hoc network plays an important role in different applications such as military operations to provide communication between squads, in emergency cases in out-of-the-way places, in medical control etc.
Routing protocols play a significant role in the implementation of mobile ad hoc networks (MANET). Due to the characteristics of mobility of ad hoc networks it is crucial to find a path or route from the source to the destination node and perform the communication between nodes for a long period of time.
In MANET, a number of routing protocols using a variety of routing algorithms has been proposed – for example Dynamic Source Routing (DSR), Ad hoc On demand Distance Vector Routing (AODV), Temporally Ordered Routing Algorithm (TORA), Location Aided Routing (LAR) and periodic (proactive) protocols such as Destination Sequence Distance Vector (DSDV), Distributed Bellman Ford, where member nodes exchange routing information and know a current route to each destination periodically. Also, several protocols uses both reactive and proactive mechanisms, such as Zone Resolution Protocol (ZRP) Cluster Based Routing Protocol (CBRP) etc.
Excerpt
Table Of Contents
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Location Aided Routing (LAR) and periodic (proactive) protocols such as Destination
Sequence Distance Vector (DSDV), Distributed Bellman Ford, where member nodes
exchange routing information and knows a current route to each destination periodi-
cally. Also, several protocols uses both reactive and proactive mechanism such as,
Zone Resolution Protocol (ZRP) Cluster Based Routing Protocol (CBRP) etc.
The basic idea of on-demand routing protocols, is that a source node sends a route
request and makes routing decision based on received route reply. This route reply
may be sent by destination or intermediate node. On-demand routing protocol has
several advantages. It offers flexibility, correctness and simplicity. Although, an on-
demand routing algorithm has the disadvantage of increasing per-packet overhead in
the network. This overhead decreases the availability of bandwidth resulting increase
of the transmission latency of each packet. As result, consumption of battery power is
more in transmitter and receiver end. Due to flooding i.e. propagation route requests it
is difficult to limit spreading of unnecessary packets.
Nodes
Wireless link
Figure 1: Infrastructure less (Ad Hoc) Network
The basic idea of proactive routing is periodically updating routing table via exchang-
ing routing information. According to routing table, source node knows path or next
hop to destination anytime when route needs. Route information is available as per
need in proactive routing. This method creates delay prior to data transmission.
However, proactive routing protocols are not suitable for mobile ad hoc networks, as
they continuously use large section of the network capacity and bandwidth to keep
the routing information. Proactive routing protocols tend to share out topological
changes and alternation widely in the network. The creation of a new link or termina-
tion of a new link at one end of the network may not be important piece of information
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at the other end. Hybrid routing protocols have best characteristics of both reactive
and proactive routing protocols. The main idea of the hybrid routing protocols is the
limiting the set of forwarding nodes and using the proactive routing algorithm for
nearly placed nodes which usually forward data to far placed nodes.
Motivation
In the last several decades research interest has increased in the area of mobile ad
hoc networks. These are in contrast with wireless networks that depend upon a pre
existing fixed infrastructure of base stations.
The main design goal of mobile ad hoc network was to meet the challenges as
follows:
a) Military Application:
The situation in the battlefield requires soldiers to move from place to place without
any constraint by wired communication and communication with each other is per-
formed without depending on any fixed infrastructure. It is impossible to have a fixed
backbone network in certain territories such as desert.
b) Propagation of electromagnetic signal:
The frequencies higher than 100 MHz are restricted by their propagation distance.
Therefore, for communication between two nodes in a multi hop routing protocol is
essential. This also justifies message must be transmitted from one node (source) to
other node(destination) via intermediate nodes i.e. in hops.
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Chapter 2:
Concept Review
2.1 Mobile Ad Hoc Network Features
A MANET has the following features:
2.1.1 Autonomous terminal.
In MANET, each mobile terminal nodes are autonomous and self-configuring nodes.
These nodes perform as a host and a router. Besides the basic processing ability as a
host, the mobile nodes can also perform functions of a router. So usually endpoints
and switches are interchangeable and inseparable in MANET.
2.1.2 Distributed operation.
The control and administration of the network operations, are controlled and managed
in a distributed type, among the terminal nodes. These nodes involved in a MANET
should team up amongst themselves and each node acts as a relay as per require-
ment, to implement functions e.g. security and routing.
2.1.3 Multi-hop routing.
Ad hoc routing algorithms can be single-hop or multi-hop in nature. This categoriza-
tion is mainly by considering different link layer attributes and routing protocols used
in MANET. Single-hop MANET is simpler than multi-hop in terms of protocol architec-
ture and for design and implementation. But there will be a compromise of lesser
functionality and applicability. When delivering data packets from a source node to its
destination node, the packets are forwarded via one or more intermediate nodes (in
multiple hops).
2.1.4 Dynamic network topology.
As the nodes in MANET are mobile, the network topology varies rapidly and unpre-
dictably with respect to time and space. As a result the link among the modes chang-
es with respect to time. The MANET should become accustomed to the traffic and
propagation conditions as well as the mobility patterns of the mobile network nodes.
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The mobile nodes in the network dynamically establish routing among themselves as
they move.
2.1.5 Varying link capacity.
High bit-error rates of wireless connection might be more in a MANET. One path may
be shared by several sessions. The channel are prone to noise, fading, and interfer-
ence. It has less bandwidth than a wired network. In some cases, the path between
any pair of users can traverse multiple wireless links and the link themselves can be
heterogeneous in nature.
2.1.6 Light-weight terminals.
In most cases, the MANET nodes are mobile devices with less processor capability,
constraint in memory size, and low power back up. Such devices need optimized
algorithms and mechanisms that implement the computing and also for communication.
2.1.7 Bandwidth-constrained and variable link capacity.
Wireless links have lower capacity than infrastructure wired counterparts.
2.1.8 Energy Constrained Operation.
Nodes in Mobile Ad Hoc Network rely on batteries as source for their energy.
2.1.9 Security Issue.
Mobile Wireless Networks are more prone to physical security threats than wired
counterparts.
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Chapter 3:
Applications of MANET
With the increase of use portable devices as well as progress in wireless communication,
ad hoc networking is gaining importance. Ad hoc networking can be applied anywhere,
where there is no communication infrastructure or the existing infrastructure is expensive
or difficult to implement. Ad hoc networking allows the devices to maintain links to the
network as well as easily adding as well as removing devices to and from the network.
The set of applications for MANETs is diverse, ranging from large-scale, mobile, highly
dynamic networks, to small, static networks that are constrained by power sources.
Besides the inheritance applications that move from traditional infrastructure environment
into the ad hoc context, a great deal of new services can and will be generated for the
new environment. Typical applications include:
3.1 Defense (Military battlefield applications)
In modern battlefield requires robust and reliable (secure) communication military
battlefield in many forms. Most communicating nodes are installed in mobile vehicles
used for defense. Defense personnel could carry telecomm devices that could talk to a
wireless base station or directly to other telecom devices if they are within the radio
range. However these forms of communication are considered to be primitive. At times
when wireless base station is destroyed by enemy, a soldier will be prohibited from
communicating with other soldiers if the called party is not within the radio range. This is
the scenario where mobile ad hoc networks come into play. Ad hoc networks are well
known as self organizing networks since they are robust when nodes disappear due to
destruction or mobility. Through multi hop communication soldiers can communicate to
remote soldiers via data hoping and data forwarding from one radio device to another.
3.2 Sensor Networks
Another application of MANETs is sensor networks. This technology is a network
composed of a very large number of small sensors. These can be used to detect any
number of properties of an area. Examples include temperature, pressure, toxins,
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pollutions, etc. Applications are the measurement of ground humidity for agriculture,
forecast of earthquakes. The capabilities of each sensor are very limited, and each
must rely on others in order to forward data to a central computer. Individual sensors
are limited in their computing capability and are prone to failure and loss. Mobile ad
hoc sensor networks could be the key to future homeland security.
3.3 Automotive Applications
Automotive networks are widely discussed currently. Cars should be enabled to talk
to the road, to traffic lights, and to each other, forming ad-hoc networks of various
sizes. The network will provide the drivers with information about road conditions,
congestions, and accident-ahead warnings, helping to optimize traffic flow.
3.4 Commercial Sector
Ad hoc network can be used in emergency/rescue operations for disaster relief efforts,
e.g. in flood, fire, earthquake. Emergency rescue operations must take place in case of
nonexistent and damaged communications infrastructure and rapid deployment of a
communication network is required. Information is relayed from one rescue team mem-
ber to another over a small handheld device with portability. Other commercial scenarios
include e.g. ship to ship ad hoc communication, enforcement of law etc.
3.5 Personal Area Network
Personal Area Networks (PANs) are formed between various mobile and fixed nodes
in an ad-hoc manner, e.g. for creating a small network. Nodes can form an autono-
mous network, interconnecting various devices. PANs becomes more meaningful
when connected to a larger private or public network.
3.6 Conferencing
Mobile Conferencing one of the most recognized application. Set up of an Ad Hoc
network is essential for mobile users where they need to gather in a project outside
the office environment in an ad hoc manner.
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3.7 Embedded Comp uting Application
Computing internetworking machines offer flexible and efficient ways of establishing
communication methods with the help of ad hoc networking.
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Chapter 4:
Issues and Challenges of MANET
4.1 Quality of service (QoS)
The parameters of performance level of services are known as QoS. Different appli-
cations have different QoS requirement. These QoS parameters may be computes on
per link, per flow, per node basis. Delay, jitter, packer loss rate, bit error rate, band-
width are some of the QoS parameters in MANET.
4.2 Routing
Routing is a crucial issue in MANET. The conventional routing protocols used on
wired networks do not perform satisfactory in MANET, which has basic characteristics
of mobility and rapid membership change. In Ad Hoc networks, we need new routing
protocols for following reasons:
i) The mobility resulting change of topology of the network which may be dynamic
in nature.
ii) Existing protocols show least desirable behavior when presented with a highly
dynamic and frequent changing interconnection topology.
Existing routing protocols face heavy a computational load on each mobile computing
device for the issues of processing power consumption and memory size.
Existing routing protocols are not designed for dynamic and self-starting behavior as
required to utilize Ad-Hoc networks.
Existing routing protocols for example, Distance Vector Protocol take a lot of time for
convergence upon the failure of a link, which is very frequent in Ad Hoc networks.
Existing routing protocols suffer from looping problems either short lived or long lived.
Methods adopted to solve the problem of looping in traditional routing protocols may
not be applicable to Ad Hoc networks.
Details
- Pages
- Type of Edition
- Erstausgabe
- Year
- 2015
- ISBN (PDF)
- 9783954898732
- ISBN (Softcover)
- 9783954898787
- File size
- 998 KB
- Language
- English
- Publication date
- 2015 (February)
- Keywords
- manet clustering Wireless ad hoc network Wireless service Dynamic Source Routing Ad hoc On demand Distance Vector Routing Temporally Ordered Routing Algorithm Destination Sequence Distance Vector Zone Resolution Protocol Cluster Based Routing Protocol
