Wireless and Mobile Computing and Networking at

the University of FloridaTechnology, Infrastructure & Research

University of Floridahttp://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)

Wireless Networks

Satellite

Macro-CellMicro-Cell

Urban

In-Building

Pico-Cell

Global

Suburban

dik ©In-Room(BlueTooth)

Wireless Networks

UMTS

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

ChallengesMobile 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

Target Platforms

Platform Mobile Information Device (MID)

Palm-sized Devices

Jupiter class (HPC)

Laptops Tablet PC Desktop

Examples Cell phone PDA Tablets Notebook Fujitsu, ViewSonic, ..

Workstation

Screen Size Extremely small Small Small to medium

Medium to large

Medium to large

Large

Location/ Use

Extremely small and mobile

Small and extremely mobile

Fairly small and mobile

Fairly powerful devices, mobile

Fairly powerful devices, mobile

Large devices, fixed location

Input devices / navigation

Specialized keys.

Limited, small keypad and/or pen-based.

Usually pen-based, small keyboard

Full-size keyboard, mouse, voice

Stylus, wireless KB and Voice

Keyboard, mouse, voice, etc.

Operating SystemsOS KVM Palm

OS Symbian EPOC

Windows CE / Pocket PC

Windows 98/NT/2000, Unix, Mac OS

Memory footprint

Very Small

small Small to Medium

Small to medium Large

Memory requirements

A few 100KB

1MB – 4MB

4 MB – 32 MB

16 MB – 32MB > 32 MB

Development/debugging tools

Some Some Some Some Numerous

Implementation Language

Language C/C++ Java C#

Code Native, platform specific Universal, platform independent

Platform specific

Development difficulty/speed

Fair/medium Moderate/fast fair/fast

Porting to other platforms

Difficult Very little or no porting Difficult

Development/Debugging tools

Excellent Excellent Excellent

Speed Excellent/platform optimized

Poor to good, usually not platform optimized

Excellent/platform optimized

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 PictureWe 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

International Center on Pervasive Technology for Successful Aging

Dr. Bill Mann, DirectorDr. Sumi Helal, Director of Technology Development

Rehabilitation Engineering Research Center onTechnology for Successful Aging

University of FloridaFunded by

National Institute on Disability and Rehabilitation Research

Sample Research Activities on Mobile and Wireless

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

Check locks on doors and

windows

Other Services

Automatically refillprescription

Check iflaundry is done

Call in a nurse

Call in for help and

Assistance

Monitorof kitchen:oven and

stove on/off;temp.

Turn on/offlights (and

visually inspect)

other rooms.

Sense and see visitors/strangers

at front door

Order grocerieswith dietary restrictions

X10Controller

Internet(services)

X10 PowerlineHome Network

High-speed HomeLAN Network

Wireless CellularPacket Network

WirelessLocal Connectivity

Home BroadbandService Provider

Wireless packetdata (cellular)

Wireless Localconnectivity(802.11x, or Bluetooth)

WirelessAccess Point

Static IP

Static IP

WirelessAccess Point

WirelessAccess Point

Networked Home Server

Dual InterfaceSmart Phone

X10Module

Wireless, ad-hoc appliances, devices, orinformation sources: (e.g.: TV remote control, door knob, Smart Tags, Garage door opener, Java rings, etc.)

X10Module

X10Module

X10Module

X10Module

X10Module

X10Module

X10Module

Appliance orhome device

Proxy Software for X10,TINI, & Internet Services

RF1

RF2

TINI

TINI

TINI

TINI

AppClients

TINITini Internet Interface(Micro-controller)

Sample Applications

Location Tracker: elder finds her whereabouts

Security Alert: alerting the elder to security breaches

Unlocking Device: lock/unlock doors and windows

Intercom: elder talks to person at the door

Emergency Alert: phone alerts care giver

Reverse Locator: others find elder’s whereabouts

Mapmaker: elder finds directions to destinations

Pager for TV Remote: phone pages TV remote

Switch functions: turn on/off light, stereo, etc.

Sample Applications

Alert/Alarm: phone alarms elder to take medications

Weather Info: elder queries phone for weather conditions

Mail Notification: phone notifies elder of mail arrival

Grocery shopping assistant: phone as shopping assistant

Dictation: phone takes and organize notes from elder

On demand service ordering: elder shops (eg. order a pizza)

Remote monitoring: phone shows images of remote places

Bookkeeping of health measurements: taking blood pressure

ICTAPlanned

Renovation

Room 447, CSE Bldg.

Har

ris M

obile

Com

putin

g

Labo

rato

ry

Ser

vers

Elder HomeMockup

Storage Pins

Workshop Area

Wor

ksta

tions

Video Tele-conferencing Main Entrance to ICTA

Meeting Table

Window

Frontdoor

Early Prototyping

UnLatch

Client

Server

Response

Query

Reply

Request

ProxyHTTP Interface

Query

Response

Generated PulseData written to portUnlock request

CircuitTINI Board

Scanner

Medicine Bottle

Pharmacy

Video

802.11 Wireless Networking

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 Layers

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

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.

DSSS Channels

Channel Coordination

Vertical Channel Coordination

Basic Topology

UF CoreAuthentication Gateway

Access Point

Core POP

UF CoreAuthentication Gateway

Access Point

CORE POP

VPN Authentication

VPN Concentrator

VPN connection

VLAN Trunking

• 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.

VLAN Trunking Design

Authentication Gateway

CORE POP

BPOP Switch

802.11q Trunk

Access Point

Building Network(s)

Authentication VLAN

Building VLAN(s)

Authentication VLAN

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

Access Point Authentication VLAN

Area VLAN ImplementationCORE POP

802.11q Trunk

Building Network(s)

Access Point Access PointBuilding Network(s)

Authentication VLAN

Authentication VLAN

Authentication Gateway

UF CoreAuthentication VLAN

Problems/Issues• Departmental wireless networks• Rogue wireless networks• Interference from other devices• Security• Malicious interference• Interoperability• Competing technology• Emerging technology

Isolated Deployment

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.

Current Wireless Campus Coverage(Spring 2002)