Introduction to ad hoc networks

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• Introduction to ad hoc networks

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Cellular Wireless Networks
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Growth in Wireless System

• Rapid growth in cellular/PCS voice services over
  the last decade
• Cell phones everywhere!
• Wireless data fast growing
• WLAN 802.11b, 802.11a, Bluetooth, Home-RF
• Wide area wireless data services also growing.
• Technology trends
• Internet-based applications and services
  particularly useful to mobile users
• New terminal devices
• Compact size, low power, easy to use, build in
  wireless interfaces
• Tetherless connections
• Freedom in mobile

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Ad Hoc Wireless Networks

• Mobile Ad Hoc Networks (MANETs)
• Network characteristics
• No fixed infrastructure, instantly deployable
• Node portability, mobility
• Extend network access to unreachable areas, to
  meet instant and emergent requirements

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Ad Hoc Network Applications

• Disaster Recovery (flood, fire, earthquakes etc)
• Law enforcement (crowd control, border patrol,
  etc)
• Homeland defense
• Search and rescue in remote areas
• Sport events, festivals
• Ad hoc collaborative computing (Bluetooth)
• Indoor network appliances (Bluetooth, WiFi)
• Mobile access to Internet (Mesh Networks)
• Sensor networks (e.g., to replace mine fields)
• Automated battlefield

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Battlefield the Warfighters Information Network
(WIN)
How does the network perform as it is scaled to
100,000 heterogeneous devices?
OSPF, FishEye, or DAWN, routing?
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Network of Autonomous Agents
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News Battlefield Internet Helps Forces in Iraq

• Thu Apr 17, 216 AM ET. By DAVID RISING,
  Associated Press Writer
• NORTH OF BAGHDAD, Iraq - A computer system that
  tracks friendly and enemy forces and pinpoints
  hazards like minefields on video game-like touch
  screens got its first use in battle. Commanders
  are hoping it can cut down on friendly fire
  deaths.
• The Army's 4th Infantry Division is guided
  by a sophisticated computer network that tracked
  the division's 1st Brigade during a skirmish
  Wednesday or the Taji air base north of
  Baghdad.The computer network is known as Force
  21 Battle Command Brigade and Below, and works
  as a battlefield Internet that keeps track of
  fast-moving combat vehicles.
• On the system's networked screens, blue
  icons denote friendly forces and are constantly
  updated. Red icons show the enemy, which are
  added as they're spotted. The 4th Infantry also
  has unmanned aircraft that can handle
  surveillance tasks.
• Hazards like minefields, areas where poison
  gas has been reported or other pitfalls can be
  added so units can steer clear.
• Younger soldiers, many of them raised on
  video games, quickly learn how to use the system,
  Iacobacci said.

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Ad Hoc, Personal Networking with Bluetooth
headset
PDA
cell phone
storage
palmtop
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Bluetooth Network Piconet

• Piconets created ad-hoc
• Master-Slave concept
• Piconets defined by itsfrequency hopping sequence

slave 3
slave 1
master
slave 2
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Mobile Ad Hoc Networks (MANETs)

• Network Challenges
• No fixed infrastructure, instantly deployable
• Node portability, mobility
• Error-prone channel
• Limited resources bandwidth, energy supply,
  memory and CPU.
• Heterogeneous nodes (big/small fast/slow etc)
• Heterogeneous traffic (voice, image, video, data)
• Wireless multihop connection (to save power,
  overcome obstacles, enhance spatial spectrum
  reuse, etc)

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Attributes of mobile and wireless systems

• Wireless
• Limited bandwidth
• Variable link quality
• Link asymmetry
• High latency
• lt3ms indoor, gt100ms outdoor (cellular, Satellite)
• Heterogeneous air interfaces
• Easier snooping
• More signal processing!

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Attributes of mobile and wireless systems

• Mobility
• User and terminal location change
• Speed of terminal mobility impacts wireless
  bandwidth
• More variables
• Location, connectivity, bandwidth, I/O devices
  and security domain
• Easier spoofing
• More protocol processing!

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Attributes of mobile and wireless systems

• Portability
• Limited battery capacity
• Limited computing power
• Limited storage
• Small dimensions
• Less reliable
• More energy efficient design!

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Topic outline

• Wireless channel properties MAC protocols
• Routing and multicast in MANETs, scalability and
  reliability issues
• Mobility modeling and management
• Network capacity and transport performance
• Network security
• Application and QoS
• New Architectures

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Reading list for this lecture

• S. Corson and J. Macker, Mobile Ad hoc
  Networking (MANET) Routing Protocol Performance
  Issues and Evaluation Considerations, RFC
  2501, Jan., 1999http//www.ietf.org/rfc/rfc2501.t
  xt
• MANET link
• http//www.ietf.org/html.charters/manet-charter
  .html