A wireless network typically refers to a system that allows devices to connect to the internet or communicate with each other without using cables. It relies on radio waves to transmit data between devices and access points. Wireless networks can be categorized based on their range and purpose, such as personal area networks (PANs), local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). They enable convenient and flexible connectivity, but factors like signal interference, security concerns, and network congestion can affect performance.
2. contents
Taxonomy of networks
Categoies of wireless network
Ad-hoc network
– Characteristics of ad-hoc network
– Application of ad-hoc network
Sensor networks
– Characteristics of sensor network
– Application of sensor network
– Lmitation of ad-hoc and sensor networks
3. What is network?
Network:
Network is series of points or nodes
Interconnected by communication paths
Network can interconnect with other
netowrks contains subnetworks
4. Taxonomy of wireless
networks
wireless networks
fixed mobile access ad hoc
networks networks networks
cellular random wireless sensor
networks access internets networks
networks
5. Categories of wireless
networks
Cellular (one hop) networks
Wireless ad hoc (multi hop)networks.
Wireless Sensor Networks
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Seminar on Wireless Ad hoc &
Sensor Networks
7. What is Ad-hoc?
A local area network, or some small
networks, parts are time-limited, and only
usable for the duration of a communication
session
The routers are free to move randomly,
organize themselves arbitrarily
The wireless topology vary rapidly and
unpredictably
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Seminar on Wireless Ad hoc &
Sensor Networks
10. 802.11 – Architecture of an ad-hoc network
Direct communication within a
limited range
– Station (STA):
terminal with access
mechanisms
to the wireless medium
– [Independent] Basic Service
Set
group of stations using the same
radio frequency
• You may use SDM or FDM to
establish several BSS
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Seminar on Wireless Ad hoc & Sensor
Networks
11. Dynamic network topology
The mobile nodes are free to move randomly
and organize themselves arbitrarily; thus, the
network's wireless topology may change rapidl
and unpredictably.
move
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Seminar on Wireless
Ad hoc & Sensor
Networks
12. What are ad hoc/sensor networks?
Sometimes there is no coverages
– remote areas, ad hoc meetings, disaster areas
– cost can also be an argument against an infrastructure
Sometimes not every station can hear every other station
– Data needs to be forwarded in a “multihop” manner
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Seminar on Wireless Ad hoc &
Sensor Networks
13. Advent of Ad hoc Wireless
Networks(Cont)
0 1 2 3 4 5 6 7
14. 14
Comparisons between Cellular and
Ad Hoc Wireless Networks (I)
Cellular Networks Ad Hoc Wireless Networks
Fixed infrastructure-based Infrastructureless
Guaranteed bandwidth (designed for
voice traffic)
Shared radio channel (more suitable for
best-effort data traffic)
Centralized routing Distributed routing
Circuit-switched (evolving toward
packet switching)
Packet-switched (evolving toward
emulation of circuit switching)
Seamless connectivity (low call drops
during handoffs)
Frequent path breaks due to mobility
High cost and time of deployment Quick and cost-effective deployment
Reuse of frequency spectrum through
geographical channel reuse
Dynamic frequency reuse based on
carrier sense mechanism
Easier to employ bandwidth reservation Bandwidth reservation requires complex
medium access control protocols
15. 15
Comparisons between Cellular and
Ad Hoc Wireless Networks (II)
Cellular Networks Ad Hoc Wireless Networks
Application domains include mainly
civilian and commercial sectors
Application domains include battlefields,
emergency search and rescue operations,
and collaborative computing
High cost of network maintenance
(backup power source, staffing, etc.)
Self-organization and maintenance
properties are built into the network
Mobile hosts are of relatively low
complexity
Mobile hosts require more intelligence
(should have a transceiver as well as
routing/switching capability)
16. Mobile Ad hoc Networks
mobile hosts
multi-hop routes between nodes
may not use infrastructure
16
17. Motivation
Ad-hoc nodes are typically battery powered and
may not support energy scavenging
Node and network lifetime must be prolonged
Most energy consumption is at the node’s
transceiver
Minimum transmit power decreases contention
Higher number of simultaneous transmissions
can be allowed
Increase in Capacity
17
18. Motivation (Cont)
wireless networks
have special limitations and
properties such as limited bandwidth,
highly dynamic topology, link
interference, limited range of links,
and broadcast.
18
19. Characteristics and tradeoffs
Characteristics
– Self-organized
– Self-deployed
– Decentralized
– Dynamic network topology
Tradeoffs
– Limited Bandwidth
– Need Multi-hop router
– Energy consumption problem
– Security problem
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20. Characteristics of MANETs
Dynamic topology
– links formed and broken with mobility
Possibly uni-directional links
Constrained resources
– battery power
– wireless transmitter range
Network partitions
A
B A
B
20
21. Limitations of MANET
Power: network life limited by
battery life
Short radio range
Packet Collisions
Network topology changes
Address allocation
21
22. Mobile Ad Hoc Networks (MANET)
4/10/08 22
One day Workshop on Wireless
Ad Hoc Networks
23. Broadcasting
Unlike wired network, every hop is broadcasting
Every packet can reach every node in the radio range of the
sender
Flooding messages make the problem even worse
Wasted bandwidth
High collision rate
23
24. Applications
Personal area networking
Cell phone, laptop, PDA , tablet pc
Meeting room/conference
Emergency operations
Search and rescue(Disaster &Relief)
Policing and fire fighting
Civilian environments
Taxi cab network
Boats, aircrafts
Military use
On the battle field
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31. CHARACTERISTICS OF WIRELESS
SENSOR NODES AND NETWORKS
Batteries in an ad hod network can be
recharged, while they are not replaceable
in wireless sensor networks.
The goal of a wireless sensor network is to
prolong battery life at the expense of QoS
and bandwidth utilization [7], whereas the
objective of an ad hoc network is to
provide QoS.
Seminar on Wireless Ad hoc &
Sensor Networks
05/02/09
32. Applications
• Structural, seismic
Bridges, highways, buildings
• Smart roads
Traffic monitoring, accident detection,
recovery assistance highway
camera microphon
e
• Contaminants detection
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One day Workshop on Wireless Ad
Hoc Networks
34. Wireless Sensor Networks (WSN)
Sensing
Computation
Networking
Circulatory
Net
New technologies have
reduced the cost, size and
power of micro-sensors and
wireless interfaces
Environmental
Monitoring
Benefits from 3 technologies
• digital circuitry
• wireless communication
• silicon micro-machining
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One day Workshop on Wireless Ad
Hoc Networks
35. 35
7
Comparisons between Cellular and
Ad Hoc Wireless Networks (I)
Cellular Networks Ad Hoc Wireless Networks
Fixed infrastructure-based Infrastructureless
Guaranteed bandwidth
(designed for voice traffic)
Shared radio channel (more suitable
for best-effort data traffic)
Centralized routing Distributed routing
Circuit-switched (evolving
toward packet switching)
Packet-switched (evolving toward
emulation of circuit switching)
Seamless connectivity (low
call drops during handoffs)
Frequent path breaks due to
mobility
High cost and time of
deployment
Quick and cost-effective
deployment
Reuse of frequency spectrum
through geographical channel
reuse
Dynamic frequency reuse based on
carrier sense mechanism
Easier to employ bandwidth Bandwidth reservation requires
on Wireless Ad Hoc Networks
36. 36
Comparisons between Cellular and
Ad Hoc Wireless Networks (II)
Cellular Networks Ad Hoc Wireless Networks
Application domains include mainly
civilian and commercial sectors
Application domains include battlefields,
emergency search and rescue operations,
and collaborative computing
High cost of network maintenance
(backup power source, staffing, etc.)
Self-organization and maintenance
properties are built into the network
Mobile hosts are of relatively low
complexity
Mobile hosts require more intelligence
(should have a transceiver as well as
routing/switching capability)
Seminar on Wireless Ad Hoc
Networks
37. CONCLUSION
Ad-hoc and sensor network is everywhere .
The development of Ad-hoc wireless
networks & senior networks
provides tremendous opportunities in
many areas including & industrial environments.
38. FUTURE?
Ad hoc Wireless Network
Everywhere
Seminar on Wireless Ad hoc &
Sensor Networks
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