1. Mobile & Ad Hoc Network
Chandra Prakash
Assistant Professor
LPU
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2. Course Overview
Textbook:
• C. Siva Ram Murthy and B.S. Manoj, Ad Hoc Wireless
Networks: Architectures and Protocols , Pearson Education,
Inc.
• C.K Toh, Ad Hoc Mobile Wireless Networks, Pearson
Education, 2007
+ ( Research Papers literature)
Goal: Fundamental, design issues, solution to these issues–
architecture & protocol , developments in ad-Hoc Field
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3. Related Sites
• Advanced Network Technologies Division, NIST,
– Wireless Ad Hoc Networks, http://w3.antd.nist.gov/wahn_home.shtml
• Autonomous Networks Research Group, USC
– WSN bibliography, http://ceng.usc.edu/~anrg/SensorNetBib.html
• IETF MANET WG
– http://www.ietf.org/html.charters/manet-charter.html
• IEEE 802 WG
– http://grouper.ieee.org/groups/802/dots.html
• Virtual lab
http://virtual-labs.ac.in/cse28/ant/ant/7/references/
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4. Objectives of the Chapter
 Introduction
 Fundamentals of Wireless Communication Technology
 The Electromagnetic Spectrum
 Radio Propagation Mechanisms
 Characteristics of the Wireless Channel
 Evolution of mobile Cellular Networks
 Generations of Cellular Mobile Communication
 GSM, GPRS,CDMA ,PCS, UMTS
 Wireless LANs, Wi-Fi
 IEEE 802 Networking Standard
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5. We know
• What is NETWORK ?
• Type of Networks
– Wired
– Wireless
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6. Introduction
• Wireless Networking:
– refers to any kind of networking that does not involve cables.
• Wireless telecommunications networks are generally implemented
and administered using a transmission system called radio waves.
• This implementation takes place at the physical level (layer) of
the network structure
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7. Some mobile devices
Clamshell handhelds
Tablets
Net–enabled mobile phones
Palm-sized
Laptop computers

8. Type of Networks
By Network Formation and Architecture
• Infrastructure-based network.
• Infrastructureless (ad hoc) network.
By Communication Coverage Area.
1. Wireless Wide Area Networks (Wireless WANs)
• Infrastructure-based networks
• Connections can be made over large geographical areas, across cities or even
countries
• Use of multiple antenna sites or satellite systems maintained by wireless service
providers.
• Examples :Cellular networks (like GSM networks or CDMA networks) and satellite
networks
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9. Type of Networks
2. Wireless Metropolitan Area Networks (Wireless MANs).
– Referred as fixed wireless , infrastructure-based networks
– Enable users to establish broadband wireless connections among multiple locations ,for
example, among multiple office buildings in a city or on a university campus
– Serve as backups for wired networks
– Radio waves and infrared light can be used to transmit data.
3. Wireless Local Area Network (Wireless LANs)
– Enable users to establish wireless connections within a local area with in a 100 m range
– Provide flexible data communication systems that can be used in temporary offices or
other spaces that can operate in infrastructure-based or in ad hoc mode
– Include 802.11 (Wi-Fi) and Hiperlan2
4. Wireless Personal Area Networks (Wireless PANs).
– Enable users to establish ad hoc, wireless communication among personal wireless
devices such as PDAs, cellular phones, or laptops that are used within a personal
operating space, typically up to a 10 meter range.
– Two key Wireless PAN technologies are
• Bluetooth : is a cable-replacement technology that uses radio waves to transmit data
to a distance of up to 9–10 m,
• Infrared: connect devices within a 1 m range.
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10. Wireless Network Technology
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11. Wireless Networks
• Wireless Networks
– Infrastructured Network
• Cellular Network (3GPP or 3GPP2)
• Wireless LAN (IEEE 802.11)
– Infrastructureless Network
• Ad Hoc Network
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Internet
WLAN
Cellular
[Mobile/Wireless] Ad Hoc NetworksChandra Prakash, LPU

12. Fundamental of Wireless Networks
 Fundamentals of Wireless Communication Technology
where v is the speed of the wave (c in a vacuum, or less in other
media), f is the frequency and λ is the wavelength.
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13. The Electromagnetic Spectrum
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14. The Electromagnetic Spectrum
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15. The Electromagnetic Spectrum
Spectrum allocation
15Frequency bands and their common usesChandra Prakash, LPU

16. Fundamental of Wireless Networks
 Radio Propagation Mechanisms
 Reflection
 Diffraction
 scattering
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17. Fundamental of Wireless Networks
 Characteristics of the Wireless Channel
 Path loss
 Fading
 Interference
 Doppler shift
 Multiple Access Techniques
 Frequency Division Multiple Access (FDMA)
 Time division multiple access (TDMA)
 Code division multiple access (CDMA)/Spread spectrum multiple
access (SSMA)
 Space division multiple access (SDMA)
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18. Frequency Division Multiple Access
• Available bandwidth is divided into multiple frequency channels/bands
• Frequency band are separated from each other by guard frequency band to
eliminated inter channel interference.
• But this result in under-utilization of frequency spectrum.
• FDMA can be used with both analog and digital signal.
• Eg: analog system for portable telephone and automobile telephone.
• Base station (BS) dynamically allocates a different carrier frequency to each node.
• To conserve energy at Mobile station (MS) the uplink frequency is always lower
than downlink frequency.
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19. Time Division Multiple Access
• Share available bandwidth in the time domain (time slot/channels).
• Each node is assigned one or more time slots in each frame, and the node
transmits only in those slots.
• Guard intervals are introduced between time slot to prevent
synchronization error and inter-symbol interference.
• FDMA requires devices to have the capability of simultaneously receiving
and transmitting signals, which leads to increased cost.
• But in TDMA device can use same slot for transmitting and receiving
signals
• Used in GSM Global System for Mobile Communication
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20. Time Division Multiple Access
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21. Code Division Multiple Access
• All users share the same frequency all the time
• Every channel uses the entire spectrum.
• Individual conservation are encoded with a pseudo-random digital
sequence.
• CDMA employs spread-spectrum technology and a special coding scheme
(where each transmitter is assigned a code) to allow multiple users to be
multiplexed over the same physical channel.
• CDMA was first used during World War II by English Allies.
• Two techniques
– Frequency Hopped Multiple Access (FHMA)
• The sender receiver change frequency (calling hopping) using the same pseudo-
random sequence, hence they are synchronized
– Direct Sequence Multiple Access (DSMA)
• In CDMA, the narrowband message signal is multiplied by a very large bandwidth
signal called spreading signal (code) before modulation and transmission over the
air.
• To pick out the signal of specific user, this signal is modulated with a unique code
sequence.
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22. Difference in TDMA,FDMA and
CDMA
An analogy to the problem of multiple access is a room (channel) in
which people wish to talk to each other simultaneously. To avoid
confusion, people could take turns speaking (time division), speak at
different pitches (frequency division), or speak in different languages
(code division).
CDMA is analogous to the last example where people speaking the same
language can understand each other, but other languages are
perceived as noise and rejected. Similarly, in radio CDMA, each
group of users is given a shared code. Many codes occupy the same
channel, but only users associated with a particular code can
communicate.
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23. Space division multiple access
• FDMA TDMA and CDMA transmits signal in all direction
(omnidirectional in nature )
• SDMA uses directional transmitters/antennas to over angular
regions.
• Different area/region can be served using the same frequency
channel.
• Best suited to satellite systems.
• Use spot beam antennas
• The different beam area can use TDMA, FDMA, CDMA
• Sectorized antenna can be thought of as a SDMA
• Adaptive antennas can be used in the future (simultaneously steer
energy in the direction of many users)
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24. Space division multiple access
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spot beam
antenna
SDMA controls the radiated energy for each user in space.
The different beam area can use TDMA, FDMA, CDMA
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25. Wireless Network Setup
• There are two types of wireless network types.
– Infrastructure
– Ad Hoc
Infrastructure
• Referred to as a “hosted” or “managed” wireless network.
• Consists of one or more access points (know as gateways or wireless
routers) being connected to an existed network.
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26. Infrastructure Wireless Network
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27. Ad-Hoc Wireless Network
• Also referred to as an “unmanaged” or “peer to peer” wireless
network
• it consists of each device connecting directly to each other.
• Allow someone sitting outside in the garden with a laptop to
communicate with his desktop computer in the house and access the
Internet.
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28. The MANET problem
• Mobile
Random and perhaps constantly changing
• Ad-hoc
Not engineered
• Networks
Elastic data applications which use networks to communicate
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29. Motivation
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30. Terminology and Paradigms
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31. Basics
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32. Wireless Ad-hoc Network
• A wireless ad-hoc network is a decentralized type of wireless
network.
• The network is ad hoc because it does not rely on a pre-existing
infrastructure, such as routers in wired networks or access points in
managed (infrastructure) wireless networks. Instead,
each node participates in routing by forwarding data for other nodes,
and so the determination of which nodes forward data is made
dynamically based on the network connectivity.
• In addition to the classic routing, ad hoc networks can
use flooding for forwarding the data.
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33. Mobile Ad-hoc Network
• Self-configuring network of mobile routers (and associated
hosts) connected by wireless links
• This union forms a random topology
• Routers move randomly free
• Topology changes rapidly and unpredictably
• Standalone fashion or connected to the larger Internet
• While MANETs are self contained, they can also be tied to an
IP-based global or local network – Hybrid MANETs
• Suitable for emergency situations like natural or human-
induced disasters, military conflicts, emergency medical
situations, etc.
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34. Fundamental Concepts
• Ad hoc networks are autonomous networks operating either in
isolation or as “stub networks” connecting to a fixed network
• Do not necessarily rely on existing infrastructure
– No “access point”
• Each node serves as a router and forwards packets for other nodes in
the network
• Topology of the network continuously changes
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35. Differences to other wireless
networks
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36. Mobile Ad Hoc Networks (MANET)
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Mobile nodes
Access points
Backbone
Wireless Mobile Network
MANET
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37. Ad Hoc Networks vs. …
• Ad hoc networks vs. Wireless mobile networks
– Infrastructureless vs. Infrastructured Network
– All devices of an ad hoc network are likely to have similar
constraints
• Ad hoc networks vs. Peer-to-peer networks
– P2P devices use existing networked structures such as Internet
– All P2P networks are not ad hoc network
• Because NOT all ad hoc network utilize an existing structure
for the communication among devices
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38. Ad hoc networks
• Temporary network composed of mobile nodes without
preexisting communication infrastructure, such as Access
Point (AP) and Base Station (BS).
– Each node plays the role of router for multi-hop routing.
• Self-organizing network without infrastructure networks
– Started from DARPA PRNet in 1970
• Cooperative nodes (wireless)
– Each node decode-and-forward packets for other nodes
• Multi-hop packet forwarding through wireless links
– Proactive/reactive/hybrid routing protocols
• Most works based on CSMA/CA to solve the interference
problem
– IEEE 802.11 MAC
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39. Ad Hoc Network
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Ad hoc networks
Mobile ad hoc networks
(MANETs)
Wirelss Mesh Networks
(WMN)
Wireless
sensor networks
 The application areas, the security requirements and the
constraints of the single devices differ …
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40. Cellular Net vs. Ad Hoc Net
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41. Cellular Net vs. Ad Hoc Net
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42. Cellular and ad hoc wireless
networks.
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43. Cellular and ad hoc networks.
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44. Comparison of wireless cellular and wireless ad-hoc network
concepts
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45. MANET Application
Applications Descriptions/Services
Tactical Networks •Military communication, operations
•Coordination of military object moving at high speeds such as fleets
of airplanes or ships
•Automated battlefields
Sensor networks •Collection of embedded sensor devices used to collect real time data
to automate everyday functions. Data highly correlated in time and
space, e.g., remote sensors for weather, earth activities; sensors for
manufacturing equipments.
•Can have between 1000 -100,000 nodes, each node collecting sample
data, then forwarding data to centralized host for processing using low
homogeneous rates.
Emergency
services
•Search, rescue, crowd control, and commando operations as well as
disaster recovery
•for e.g. Early retrieval and transmission of patient data ( record,
status, diagnosis ) from /to the hospital
•Replacement of a fixed infrastructure in case of earthquakes,
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46. MANET Application
Applications Descriptions/Services
Commercial
environments
•E-commerce, e.g., electronic payments from anywhere (i.e., in taxi).
•Business:
dynamic access to customer files stored in a central location on
the fly provide consistent databases for all agents
Mobile office
•Vehicular services:
transmission of news ,road conditions ,weather, music
local ad hoc network with nearby vehicles for road/accident
guidance
Home and
enterprise
networking
•Home/office wireless networking(WLAN), e.g., shared whiteboard
application, use PDA to print anywhere, trade shows
•Personal area network (PAN)
Educational
applications
•Set up virtual classrooms or conference rooms
•Set up ad hoc communication during conferences, meetings, or
lectures
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47. MANET Application
Applications Descriptions/Services
Entertainment Multiuser games
Robotic pets
outdoor internet access
Location- aware
Services
Follow- on services, e.g., automatic call forwarding, transmission of the
actual workspace to the current location
Information services
push, e.g., advertise location-specific services, like gas stations
pull, e.g., location-dependent travel guide; services( printer, fax,
phone, server, gas stations) availability information; caches,
intermediate results, state information, etc.
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48. Major Applications
• Military
• Emergency Service
• Collaborative and Distributed Computing
• Wireless Mesh Network
• Wireless Sensor Network
• Telematics
• Wireless Personal Area Network
• Home Network
• Ad Hoc Relay for Cellular Network
• Networks for ubiquitous computing
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Demands for
group
communications
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49. Military
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50. Emergency Service
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51. MANET – Overview
• MANET
– No infrastructure
– Self organizing networks
– Communications via mobile
nodes
– Dynamic topology
– Heterogeneity bandwidth-
constrained variable-capacity
links
– Limited physical security
– Nodes with limited battery life
and storage capabilities
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52. Issues in Ad Hoc Networks
• Medium access scheme
• Routing
• Multicasting
• Transport layer protocol
• QoS provisioning
• Security
• Energy management
• Addressing and service discovery
• Scalability
• Deployment considerations
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