Wireless and Mobile Computing and Networking at the University of Florida
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Wireless and Mobile Computing and Networking at the University of Florida Technology, Infrastructure & Research. University of Florida http://net-services.ufl.edu/wireless http://www.harris.cise.ufl.edu. Talk Overview. Technology Mobile Devices Wireless Networks The 802.11b Wireless LAN

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Wireless and Mobile Computing and Networking at the University of FloridaTechnology, Infrastructure & Research

University of Florida



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Talk Overview University of Florida

  • Technology

    • Mobile Devices

    • Wireless Networks

    • The 802.11b Wireless LAN

  • Infrastructure

    • The Wireless campus project

  • Synergistic Research Activities

    • Helal (CISE): Wireless & Mobile Tech for the Elders

    • Others ..

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(Mobile Information Appliances) University of Florida

Subscriber Identification

Module (SIM)

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Platform Limitations University of Florida

  • Limited battery power

  • Limited memory capacity

  • Limited processing power (in some devices)

  • Limited I/O modalities (no keyboard)

  • Limited display size, resolution & refresh rate

  • Wide variety of devices lacking platform standardization (started to change with advent of Java 2 Micro-Edition)

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Global University of Florida












Wireless Networks

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UMTS University of Florida

Wireless Networks

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Wireless Data Networks University of Florida

  • Unlicensed Frequency

    • The 802.11 Wireless LAN

    • Bluetooth

    • Infrared

  • Licensed Frequency

    • 2G-2.5G: D-AMPS, CDMA, GSM, iDEN, CDPD

    • 3G: CDMA2000, W-CDMA

  • Mobile Networking

    • CDPD: Wireless packet data

    • iDEN: Wireless packet data & Mobile IP

    • GPRS & EDGE: Wireless packet data & other mobile networking protocols (competition to Mobile IP)

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802.11 University of Florida

  • Unlicensed Frequency

    • indoor/outdoor coverage with cell sizes ranging from 300 feet (indoor) to 1000 feet (outdoor)

    • Bandwidth:

      • 802.11b: 11Mb/s

      • 802.11a: 100Mb/s

      • 802.11g: 54Mb/s;

      • Effective bandwidth in presence of multiple users is less (for instance: 6Mb/s in 803.11b)

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Network Limitations University of Florida

  • Low bandwidth

    • Limited spectrum, interference

  • High latency (in 2G and 3G)

  • High Bit Error Rate (BER)

    • bad carrier signal, handoffs

  • Frequent disconnection

  • Heterogeneity of network coverage

  • In many cases, lack of network infrastructure  Ad-hoc Networks

  • Preserving Return on Investment in presence of a rapidly evolving technology

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Challenges University of Florida

Mobile environment differs greatly from the traditional fixed-network environment. The difference is limitations that can be divided into two categories.

  • Platform diversity and limitations – which platform to use for a certain application?

  • Network limitations -- which network to support? What if the devices use different network interfaces?

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Which Platform? University of Florida

Mobile User

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Target Platforms University of Florida

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Operating Systems University of Florida

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Implementation Language University of Florida

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Wireless Infrastructure at UF University of Florida

Recognizing the importance and impact of using wireless and mobile technology in education and research, the University Network Services and Several University Colleges and Schools have committed to provide for the indoor and outdoor deployment of the 802.11b wireless LAN technology.

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Short History of Wireless at UF University of Florida

  • Lombardi’s initiative -- First Wireless Classroom Trial: in CSE Building, Spring 1999

    • 20 IBM thinkpads, 20 PC cards, two Bay Network access points (2Mbps), Static IP configurations – no authentication

  • The University IE Proposal to the National Science Foundation (even though was not funded, it brought together awareness and commitment of various University entities)

  • Outdoor campus deployment begun (Jan 2001)

  • CISE deployment (May 2001)

  • Law School deployment (July 2001)

  • College of Engineering all-classroom deployment (May 2001 – Nov 2001)

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Blueprints of the Big Picture University of Florida

We envision that many educational activities can be taken to a higher level of effectiveness if this opportune technology is exploited properly. In particular, we identify several undergraduate curricula that, for a long time, have been deprived from having the appropriate computing environments that they needed. Botany, geology, animal science, agriculture, anthropology, remote sensing, architecture, veterinary medicine, civil engineering, exercise physiology, and forestry are among the many curricula that would benefit significantly from the wireless outdoor laboratory, a concept that can be achieved with today’s technology. By bringing the (wireless) network and the (portable) computers much closer to the actual subjects of study (plants, humans, trees, crops, animals, roads, building, etc.), it will be possible to design and develop substantially effective curricula for undergraduate and graduate education.

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Goals of the Wireless Campus Project University of Florida

  • Create a Pervasive Computing environment within the University of Florida campus, by exploiting wireless, mobile networking technology and portable computing appliances.

  • Modify and extend existing curricula in several major areas to take advantage of the wireless connectivity that will blanket UF campus.

  • Explore research issues in Pervasive Computing (e.g. projects undertaken in the Harris Lab by Dr. Helal)

  • Potentially, integrate some University services into the wireless network.

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Objectives of the Wireless Campus Project University of Florida

  • Indoor and outdoor wireless connectivity

  • Ideally: Single IP, secure roaming solution – pending industry adoption of IPv6

  • Support for a variety of devices (notebooks, iPAQs, Palms, wearable computers, …)

  • Different views of network resources for different student groups

  • Anticipated use of thin client technology

  • Innovative solutions for software license management (not all mobile users active at once – licenses will need to be spread over multiple network domains (unusual)

  • Challenging requirements: security & scalability

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Sample Research Activities on Mobile and Wireless University of Florida

International Center on Pervasive Technology for Successful Aging

Dr. Bill Mann, Director

Dr. Sumi Helal, Director of Technology Development

Rehabilitation Engineering Research Center on

Technology for Successful Aging

University of Florida

Funded by

National Institute on Disability and

Rehabilitation Research

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Pervasive Technology for Elders University of Florida

  • Health care system ($$ & Nurses) will not sustain the increasing number of elders

  • Goal: how to help elders stay at home and live independently

  • Broad center activities:

    • Create smart spaces

    • Create magic Wands for interaction with smart spaces

    • Create and perform extensive testing of applications that use the smart home/phone infrastructure

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Sample Applications University of Florida

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Sample Applications University of Florida

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Main Entrance to ICTA University of Florida

Video Tele-conferencing

ICTAPlannedRenovationRoom 447, CSE Bldg.






Elder Home


Harris Mobile Computing




Workshop Area



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Pharmacy University of Florida








HTTP Interface




Medicine Bottle

Unlock request

Data written to port

Generated Pulse

TINI Board



Early Prototyping


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802.11 Wireless University of FloridaNetworking

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History University of Florida

  • In 1985, as an attempt to stimulate the production and use of wireless network products, the FCC modified Part 15 of the radio spectrum regulation, which governs unlicensed devices. The modification authorized wireless network products to operate in the Industrial, Scientific, and Medical (ISM) bands using spread spectrum modulation.

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FCC University of Florida ISM Restrictions

  • Frequency restrictions

    • 902-928 MHz

    • 2.4-2.4835 GHz

    • 5.725-5.850 GHz

  • 1 Watt power restriction

    • 100mW for WLANs

  • Spread Spectrum transmission

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History University of Florida

  • The first wireless LAN technologies operated in the 900MHz band and were low speed (1-2Mbps), proprietary offerings.

  • 1992, wireless LAN makers began developing products operating in the unlicensed 2.4 GHz frequency band.

  • IEEE approved 802.11 standard in 1997

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802.11 transmission methods University of Florida

  • FHSS

  • DSSS

  • IR

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Frequency Hopping Spread Spectrum (FHSS) University of Florida

  • minimum 75 non-overlapping channels with a maximum 1 MHz bandwidth

  • Three possible hop patterns (22 hops in a given pattern)

  • Minimum rate of 2.5 hops/s

  • Maximum dwell time of 400ms

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Direct Sequence Spread Spectrum (DSSS) University of Florida

  • Combines a data signal with a higher data rate bit sequence (chipping code). Minimum of 10.

  • 14 twenty-two MHz channels

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Characteristics of FHSS University of Florida

  • Lower cost

  • Lowest power consumption

  • More tolerant to signal interference

  • Lower potential data rates

  • Less range than direct sequence

  • Less interoperability

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Characteristics of DHSS University of Florida

  • Highest cost

  • Highest power consumption

  • Less tolerant to interference

  • Highest potential data rates

  • Better range than frequency hopping

  • Better interoperability

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802.11 Layers University of Florida

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802.11 Data Link Layer University of FloridaMechanisms



  • CRC checksum

  • Acknowledgments

  • Fragmentation

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802.11 Features University of Florida

  • Beacon frames

  • Authentication

  • Roaming

  • Security

  • Power saving

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Security Features University of Florida

  • Service Set Identifier (SSID) (also called Network Identifier or Network Name)

  • MAC address filtering

  • Wired Equivalent Privacy (WEP) encryption

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WEP Encryption University of Florida

  • Algorithm based on RSA RC4 algorithm

  • 40bit and 128bit keys

  • Security partially relies on maintaining the secrecy of the WEP key.

  • Shown to be weak

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Wireless Access Modes University of Florida

  • Ad hoc

  • Infrastructure

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802.11 Future University of Florida

  • 802.11g

    • 2.4Ghz frequency band, >20Mbps data rate

  • 802.11a

    • 5.7Ghz supporting data rates up to 54Mbs.

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UF Wireless Deployment University of Florida

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UF Wireless Deployment University of Florida

  • Cisco Aironet 350 series access points

  • Authenticated via Gatorlink userid

  • Not using WEP encryption

  • No registered MAC address

  • Area VLANs and a common configuration to allow roaming

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Compatibility University of Florida

  • Wireless Ethernet Compatibility Alliance (WECA)

    Wireless Fidelity - WiFi

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Channel Coordination University of Florida

  • 802.11b DSSS hardware only offers 11 channels.

  • At most, only three non-overlapping channels can be used (1,6, and 11).

  • Where common channels overlap there will be co-channel interference which will negatively impact performance.

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DSSS Channels University of Florida

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Channel Coordination University of Florida

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Vertical Channel Coordination University of Florida

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UF Core University of Florida

Basic Topology

Authentication Gateway

Core POP

Access Point

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UF Core University of Florida

VPN Authentication

Authentication Gateway


VPN Concentrator

Access Point

VPN connection

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VLAN Trunking University of Florida

  • VLAN trunking (802.1q) allows the transport of multiple 'logical' (Virtual) ethernets over one single physical ethernet.

  • This allows the delivery of authentication VLANs in parallel with building VLAN(s).

  • This use of VLANs allows roaming through wireless areas that share the same VLAN.

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VLAN Trunking Design University of Florida


Authentication VLAN passes through CORE POP at layer 2 only and is not routed. Routing for the VLAN is performed by the Authentication Gateway.

Routed connection for Authentication Network

Authentication VLAN

Authentication Gateway

802.11q Trunk

Authentication VLAN

Access Point

Building VLAN(s)

Building Network(s)

Authentication VLAN

Access Point

BPOP Switch

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UF Core University of Florida

Area VLAN Implementation


Authentication Gateway

Authentication VLAN

802.11q Trunk

Authentication VLAN

Authentication VLAN

Building Network(s)

Building Network(s)

Access Point

Access Point

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Problems/Issues University of Florida

  • Departmental wireless networks

  • Rogue wireless networks

  • Interference from other devices

  • Security

  • Malicious interference

  • Interoperability

  • Competing technology

  • Emerging technology

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Isolated Deployment University of Florida

If you are deploying wireless service and it can not be incorporated into the campus plan the following steps are critical:

  • Contact Network Services to coordinate frequency usage.

  • Change the SSID to a non-default setting (and do NOT use ‘ufw’).

  • Disable the SSID broadcasting capability.

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Current Wireless Campus Coverage University of Florida(Spring 2002)