1. Wireless Network Organization
Spring 07
CS 527 – Lecture 3

2. 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

3. 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

4. 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

5. 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 [

6. 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

7. 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

8. 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

9. 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]

10. 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 for "Automobile" users - Infocom '04]

11. Vehicular networks – Discussion
Use WLAN or Cellular networks
Cellular is centralized (infrastructured)
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

12. 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

13. 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

14. Community Wireless networks
Figure borrowed from paper [Experiences in using WiFi for Rural Internet in India]

15. Community Wireless Networks
Links as long as 37 km (23 miles)
Antenna design?

16. Community Wireless Network
Is 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 which might have a huge effect on long distance links
More while discussing MAC layer

17. 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

18. 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 [

19. 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

20. Zebranet
Figure borrowed from [

21. Zebranet Interesting data collected
Valuable and accurate information to biologists without physical monitoring hassles
Example: Zebra movement

22. 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