Wireless Network Organization

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Wireless Network Organization

• Spring 07
• CS 527 Lecture 3

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Overview

• Classification of wireless networks
• Based on infrastructure
• Based on mobility
• Based on size of network
• Motivating real life examples of ad-hoc networks
• Networks in action
• Vehicular network
• Community wireless network
• Sensor Network

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Wireless Network classification - 1

• Based on infrastructure
• Infrastructure networks
• Base station/ Access point infrastructure
• Generally one-hop networks
• E.g. Cellular, Wireless LANs,
• Ad-hoc networks
• Remote nodes capable of coordinating to form a
  network
• Multi-hop wireless links common

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Wireless Network classification - 2

• Based on Mobility
• Static wireless networks
• Why do we need wireless access in such scenarios?
• Harsh Terrain
• Cost-effectiveness
• E.g. Enabling internet access to a remote
  village
• Mobile wireless networks
• A part of wireless nodes are mobile
• E.g. Cellular networks, Mobile Ad-hoc networks
  (MANETs)
• Challenges
• Sustaining opened connections
• E.g. Mobile IP
• Naming
• Moving to different network

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Wireless Network classification - 3

• Based on size of the network
• Body Area Networks
• E.g. Sensors inserted inside the body coordinate
• Personal Area Networks
• E.g. Home Networking, Bluetooth and Zigbee
  networks
• Local Area Networks
• E.g. Wireless LANs, WiFi
• Metropolitan Area Networks
• E.g. Community wireless networks
• Wide Area Networks
• E.g. Cellular and Satellite networks

Figure borrowed from http//www.cs.mun.ca/yzchen
/teaching/whu_2006/Introduction.pdf
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Overview

• Classification of wireless networks
• Based on infrastructure
• Based on mobility
• Based on size of network
• Motivating real life examples of ad-hoc networks
• Networks in action
• Vehicular network
• Community wireless network
• Sensor Network

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Some motivating real-life examples for ad-hoc
networks

• Mesh networks - Community Wireless networks
• Cost-effective way of enabling network access to
  remote areas
• Sensor networks
• Applications in a variety of fields
• Habitat monitoring is valuable to biologists
• Disaster monitoring
• Vehicular networks
• Intelligent Transport Systems
• Body area networks
• Healthcare

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Overview

• Classification of wireless networks
• Based on infrastructure
• Based on mobility
• Based on size of network
• Motivating real life examples of ad-hoc networks
• Networks in action
• Vehicular network
• Community wireless network
• Sensor Network

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Vehicular networks

• Concrete application of Mobile Ad-hoc network
  (MANET)
• Applications
• Automated driving, parking, etc.
• How is it different from control systems for
  individual vehicles?
• Information and warning functions
• Incidents, congestion, surface condition, etc.
• Communication-based longitudinal control
• Avoiding accidents and platooning vehicles
• Co-operative assistance systems
• Blind crossings
• Highway entries
• Miscellaneous
• Location-based services and multiplayer games

Figure borrowed from CarTALK2000
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Vehicular networks - Components

• Inter-vehicle communication (IVC)
• Topics discussed in previous slide
• Road-to-vehicle communication (RVC)
• Access to fixed networks
• Issues
• High speeds mean lesser time connected to a
  single access point
• Access point association, validation, connection
  initiation in this short period of time
• Will Mobile IP and variants work? (Hierarchical
  Mobile IP)
• Results are not very disappointing
• More than ten seconds of connectivity even at
  speeds of 180 km/h.

Figure borrowed from Drive-thru Internet IEEE
802.11 for "Automobile" users - Infocom '04
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Vehicular networks Discussion

• Use WLAN or Cellular networks
• Cellular is centralized (infrastructured)
• 802.11 is susceptible to resource reservation
  drawbacks and multipath
• Mobility is intrinsic
• Use of group communication
• How to group vehicles
• Set of vehicles
• Based on a particular location
• E.g. Platooning and co-operative driving (4 way
  stop signs)
• Advantages
• Battery power
• Dimension of the wireless node
• Examples
• California PATH project, Chauffeur of EU, CarTALK
  2000

Fun part! Watch videos of vehicular networks in
action at http//www.path.berkeley.edu/PATH/Public
ations/Videos/
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Overview

• Classification of wireless networks
• Based on infrastructure
• Based on mobility
• Based on size of network
• Motivating real life examples of ad-hoc networks
• Networks in action
• Vehicular network
• Community wireless network
• Sensor Network

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Community wireless networks

• Creation of a broadband wireless Metropolitan
  Area Network (MAN)
• E.g MIT Roofnet, SeattleWireless, CUWireless
• Characteristics
• Designed for low mobility
• Semi-infrastructured backbone network (Mesh)
• Long distance links common
• Uses
• Large Socio-economic impact
• Reduces physical infrastructure cost,
• Encourages unplanned growth of the network
• Extend Internet access into areas which do not
  have wired networking infrastructure.
• Lots of use in developing nations

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Community Wireless networks
Figure borrowed from paper Experiences in using
WiFi for Rural Internet in India
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Community Wireless Networks

• Links as long as 37 km (23 miles)
• Antenna design?

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Community Wireless Network

• Is 802.11 MAC protocol suitable?
• Timing parameters (E.g. Waiting for
  Acknowledgement across long distance links)
• How about TDMA based links?
• Such reservation based approach eliminates
  certain pattern of drops (hidden terminals) in
  802.11 which might have a huge effect on long
  distance links
• More while discussing MAC layer

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Overview

• Classification of wireless networks
• Based on infrastructure
• Based on mobility
• Based on size of network
• Motivating real life examples of ad-hoc networks
• Networks in action
• Vehicular network
• Community wireless network
• Sensor Network

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Sensor Network - Zebranet

• An example for the use of sensor networks in
  habitat monitoring of zebras at Kenya
• Brief description
• Sensor Nodes are mounted on zebras as "collars"
• Observer with wireless node collects information
  when in proximity with a zebra

Figure borrowed from http//www.princeton.edu/mr
m/ZNetASPLOS.pdf
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Zebranet - Challenges

• Large monitoring area
• All nodes (zebras and observer) are mobile
• Harsh environment acting on sensors - Water
  proof, shock proof, bite-proof
• No infrastructure
• Low power sensor nodes
• Intelligent Data collection mechanisms and
  storage requirements
• Infeasible for an observer to contact each zebra
  for collecting data
• Data aggregation

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Zebranet
Figure borrowed from http//www.princeton.edu/mr
m/ZNetASPLOS.pdf
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Zebranet

• Interesting data collected
• Valuable and accurate information to biologists
  without physical monitoring hassles
• Example Zebra movement

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Conclusion

• Various varieties of wireless networks with
  different network characteristics
• Lot of open and challenging problems for research
• Varies widely from wired networking
• Vast business market in near future!?
• High-Impact applications