Wireless and Mobile Computing and Networking at the University of FloridaTechnology, 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 • Infrastructure • The Wireless campus project • Synergistic Research Activities • Helal (CISE): Wireless & Mobile Tech for the Elders • Others ..
(Mobile Information Appliances) Subscriber Identification Module (SIM)
Platform Limitations • 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)
Global Satellite dik © Suburban Urban In-Building Pico-Cell Micro-Cell Macro-Cell In-Room (BlueTooth) Wireless Networks
UMTS Wireless Networks
Wireless Data Networks • 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)
802.11 • 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)
Network Limitations • 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
Challenges 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?
Which Platform? Mobile User
Wireless Infrastructure at UF 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.
Short History of Wireless at UF • 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)
Blueprints of the Big Picture 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.
Goals of the Wireless Campus Project • 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.
Objectives of the Wireless Campus Project • 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
Sample Research Activities on Mobile and Wireless 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
Pervasive Technology for Elders • 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
Main Entrance to ICTA Video Tele-conferencing ICTAPlannedRenovationRoom 447, CSE Bldg. Meeting Table Front door Workstations Elder Home Mockup Harris Mobile Computing Laboratory Servers Window Workshop Area Storage Pins
Pharmacy Client Request Query Query Reply Response Response HTTP Interface Proxy Server Scanner Medicine Bottle Unlock request Data written to port Generated Pulse TINI Board Circuit UnLatch Early Prototyping Video
History • 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.
FCC 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
History • 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
802.11 transmission methods • FHSS • DSSS • IR
Frequency Hopping Spread Spectrum (FHSS) • 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
Direct Sequence Spread Spectrum (DSSS) • Combines a data signal with a higher data rate bit sequence (chipping code). Minimum of 10. • 14 twenty-two MHz channels
Characteristics of FHSS • Lower cost • Lowest power consumption • More tolerant to signal interference • Lower potential data rates • Less range than direct sequence • Less interoperability
Characteristics of DHSS • Highest cost • Highest power consumption • Less tolerant to interference • Highest potential data rates • Better range than frequency hopping • Better interoperability
802.11 Data Link LayerMechanisms • CSMA/CA • RTS/CTS • CRC checksum • Acknowledgments • Fragmentation
802.11 Features • Beacon frames • Authentication • Roaming • Security • Power saving
Security Features • Service Set Identifier (SSID) (also called Network Identifier or Network Name) • MAC address filtering • Wired Equivalent Privacy (WEP) encryption
WEP Encryption • 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
Wireless Access Modes • Ad hoc • Infrastructure
802.11 Future • 802.11g • 2.4Ghz frequency band, >20Mbps data rate • 802.11a • 5.7Ghz supporting data rates up to 54Mbs.
UF Wireless Deployment • 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
Compatibility • Wireless Ethernet Compatibility Alliance (WECA) Wireless Fidelity - WiFi
Channel Coordination • 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.