1. INTRODUCTION TO AD HOC WIRELESS NETWORKS
2/12/08
Seminar on Wireless Ad Hoc & Sensor Networks

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. Network: What is 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
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
Seminar on Wireless Ad hoc & Sensor Networks
5/02/09

6. Cellular Networks Cellular Networks Networking Wireless Hosts
Infrastructure dependent
High setup costs
Large setup time
Reliable

7. Seminar on Wireless Ad hoc & Sensor Networks
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
Seminar on Wireless Ad hoc & Sensor Networks
05/02/09

8. A wireless ad hoc network

9. IEEE in OSI Model
Wireless

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
Seminar on Wireless Ad hoc & Sensor Networks
05/02/09

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.
Seminar on Wireless Ad hoc & Sensor Networks
move
05/02/09

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
Seminar on Wireless Ad hoc & Sensor Networks
05/02/09

13. Advent of Ad hoc Wireless Networks(Cont)1 2 3 4 5 6 7

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. 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

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

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.

19. Characteristics and tradeoffs
Self-organized
Self-deployed
Decentralized
Dynamic network topology
Tradeoffs
Limited Bandwidth
Need Multi-hop router
Energy consumption problem
Security problem

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

21. Limitations of MANET Power: network life limited by battery life
Short radio range
Packet Collisions
Network topology changes
Address allocation

22. Mobile Ad Hoc Networks (MANET)
4/10/08
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

24. Applications Personal area networking Emergency operations
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
Military applications
Ad hoc wireless networks is useful in establishing communication in a battle field.
Collaborative and Distributed Computing
A group of people in a conference can share data in ad hoc networks.
Streaming of multimedia objects among the participating nodes.
Emergency Operations
Ad hoc wireless networks are useful in emergency operations such as search and rescue, and crowd control.
A Wireless Mesh Network is a mesh network that is built upon wireless communications and allows for continuous connections and reconfiguration around blocked paths by "hopping" from node to node until a connection can be established.

25. Wireless Ad Hoc Sensor Networks
                                                                                                                                                      
Wireless Ad Hoc Sensor Networks

26. Layers in Use Ad-hoc networks – link layer: medium access control
– network layer: routing
– transport layer: TCP/IP

27. NETWORK LAYETRS:

28. Ad-hoc routing protocols
AODV: Ad-hoc On-Demand Distance Vector Routing LMR: Lightweight Mobile RoutingTORA: Temporally-Ordered Routing Algorithm ABR: Associatively-Based Routing SSR: Signal Stability Routing DSR: Dynamic Source Routing
Table Driven:DSDV: Destination-sequenced Distance-vector Routing CGSR: Cluster-head Gateway Switch Routing
WRP: Wireless Routing Protocol 28
05/02/09 28

29. functional diagram of a wireless sensor communication node.

30. IEEE in OSI Model

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. One day Workshop on Wireless Ad Hoc Networks
Applications
Structural, seismic
Bridges, highways, buildings
Smart roads
Traffic monitoring, accident detection, recovery assistance
highway
camera
microphone
Contaminants detection
4/10/08
One day Workshop on Wireless Ad Hoc Networks 32 32

33. Wireless Ad Hoc Sensor Networks
                                                                                                                                                      
Wireless Ad Hoc Sensor Networks

34. Wireless Sensor Networks (WSN)
New technologies have reduced the cost, size and power of micro-sensors and wireless interfaces
Circulatory Net
Sensing
Computation
Networking
Environmental Monitoring
Benefits from 3 technologies
digital circuitry
wireless communication
silicon micro-machining
4/10/08
One day Workshop on Wireless Ad Hoc Networks 34

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 reservation
Bandwidth reservation requires complex medium access control protocols
on Wireless Ad Hoc Networks 35 35

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 36 36

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.
CONCLUSION

38. Ad hoc Wireless Network Everywhere
FUTURE?
Ad hoc Wireless Network
Everywhere
Seminar on Wireless Ad hoc & Sensor Networks
05/02/09

39. Seminar on Wireless Ad hoc & Sensor Networks
Thanks
Seminar on Wireless Ad hoc & Sensor Networks
05/02/09