1

Presentation Outline

• Historical Overview• Radio Fundamentals• US Developments in PCS• Mobile Data• Satellite Systems• Problems with existing schemes• Wireless Overlay Networks• US Government Research Initiatives

2

ATM Switch

Local AreaBroadcast Network

Infopad Project

ComputeServer

BaseStation

VideoDatabase

SpeechServer

BaseStation

InfoPads

Backbone

BaseStation

BaseStation

Local AreaBroadcast Network

ATM Switch

Wide AreaNetwork

Server

Server

Server

3

Wide-Area Wireless Testbed

MultipleOverlayedWirelessNetworks

SeamlessMobilityAcross

Overlays

Integration with wide-area high performance networks (BAGNet)Bandwidth/latency aware APIs; Wide-area untethered applications

4

Wireless Overlay Concept

In-Building

Campus-Area Packet Relay

Metropolitan-Area

Regional-Area

Remote Clinics

Ambulance Dispatch

Hospital Campus

HospitalOperating RoomEmergency Room

5

Application: Emergency Response

St. Mary's Hospital

UCSFRegional PACS Center

ATMWireline

Infrastructure

In-BuildingWireless

Wide-AreaWireless

EmergencyRoom

DiagnosticCenter

(CAT/MRI)Operating Room

6

Overlay Internetworking

Gateway

LAN

HostSatNet

GatewayGateway

Internet Host

Host

NIUHost

PagingNetworks

Gateway-Centric

Approach

In-BuildingRF Network

In-RoomIR Network

Campus-AreaPacket Relay

Network

Cellular Packet

Data Net

GEO, MEO, LEO VSAT Nets

SatelliteDirect

Broadcast Net

Multi-HopPacket Radio

Network

Cooperative OverlayNetworks

Network CenteredWithin homogeneous netNo roam between nets

Gateway CenteredHeterogeneous netsRoam between them

7

Multimode “Radios”

PCMCIA #1: IR modemPCMCIA #2: RF modemAT Slot: Hughes DirectPCFloppy Slot: CDPD modemSerial Port: Metricom modem

ITU “Future Public Land Mobile Telecommunications System” (FPLMTS) -- Satellite -- GSM -- DECT

8

Mobility Challenges:Horizontal Roaming

Roaming within an administrative domain -- Mobile IP provides initial solution for the routing problem -- Single authentication with home domain

SingleAdministrativeDomain

9

Migrating Hosts

VideoServer

BaseStation

BaseStation

For continuous playbackwith real-time constraints,must readahead packets to the base station

10

Migrating Hosts

VideoServer

BaseStation

BaseStation

Leftover packets

Empty buffer?Retransmit from server?Retransmit from BS?

Infopad detects newbase station within range

Buffering affects hand-offdecision

11

Migrating Hosts

VideoServer

BaseStation

BaseStation

New idea: broadcastpackets to adjacentbase stations to smoothhand-offs

Multicast backboneeffect on bandwidth?

Mobile host communicatesseq. no. of last receivedpacket during handoffnegotiation

12

Migrating Hosts

VideoServer

BaseStation

BaseStation

Multicast backbone

BS-to-BS purge packet protocols

— or —sequence no.resolution in

Infopad

13

Mobility Challenges:Vertical Roaming

Multiple AdministrativeDomains-- Handoff-- Authentication-- Routing– Billing

14

BaseStations

InformationServer

In-Building Cooperative Networks: IR and RF

15

In-Building Cooperative Networks: IR and RF

651

611

600LC

600E

600N

600S

600W600SW

600SE

600NW

600NE

600EL

684

676

695

665

617

643

623

625

627

629

631

633

635

637

639

621

687

685

683

681

673

679

675

689

671

678

609

603

653

663D

655

053

697

697D

097

005

003

007

009

652

698

615

645

606

600LW

600LE677

634

604

602

682

626608

IR Room-sized Cells

RF CellBS

16

Application Support

Network of WorkstationServers

Base Station Mobile Node

Application Server Application ClientAgent

Foreign Agent

17

Application Support:Map Browsing

Low Resolution

Medium Resolution

High Resolution

Major Features

Minor Roads

Elevations

18

Applications Support Services

Audio Video Image Maps

Data-type Specific Data Transmissions

Processor Resource Allocation

NavigationCollaboration Image ExchangeAudio/Video Conferencing Digital Library Access

Mobile Multimedia Applications

Agent-based backend processing

Compression/Decompression Multi-layer representations

Session Management

Overlay Network Management

Transaction combining to reduce latency

Wireless TCPAdaptive QOS Support

ApplicationsQOS Needs

NetworkCapabilities

Wireless Overlay Subnets

SatelliteIn-building Campus-Area Wide-Area

Mobile IPUser Tracking Low Latency Handoff

Physical Layer

Data Link Layer

Network Layer

Transport LayerConnection-Oriented Mechanisms

Network load-balancing across cooperative overlays

Policy-based Network Selection Scalable Network Management

Layered Architecture

19

State-of-the-Art In-building Networking Infrastructure

Scalable, High BandwidthLow Latency Switches

InteractiveMedia Accessworkstations

Dedicated Computing Resources ~100 “dark” workstations+ mass store, special servers

OrganizedFiber PhysicalLinks

Computing / Interactive“Light” workstations

WirelessTransceivers

Cooperative In-building Wireless Overlays: • IR for offices, meeting spaces, classrooms • RF overlay for “between” spaces, connectivity load sharing

Integration with building-scale computing resources

Soda Hall

20

Wide-Area Wireline Infrastructure

Wireless-to-wirelinegateways in Berkeley

Possible explorationof wide-area medical dispatch applications

Integration withwide-area computingresources

Pacific BellATM switchOakland CO

LBLUC Berkeley

Pacific BellSan Ramon Valley

(Broadband Technology Group)

LLNL

Sandia Livermore

DEC - SRC

Pacific BellATM switchPalo Alto CO

ICSI

AppleNASAAmes

HP Labs

Xerox PARC

Lockheed

SFSU

Genetech

UCSF

VA Hosp.

Mt. ZionKaiser SF

Kaiser Oak

Kaiser DOR

Philips

BAGNet sites are indicated in a straight font.

Non-BAGNet sites are in italics.

StanfordSRI

SGI

SUN

0 5 Mi. 10 Mi.

21

UCB-Hughes DBS Testbed

Soda Hall

AccessPoint DirectPC

Basestation

InternetGateway

High Bandwidth, High Latency "Downlink"

Lower BandwidthUplink

WLAN

Hughes DBSBasestation

Gateway

22

BARWAN Testbed (June 95)

Soda Hall

AccessPoint DirecPC

Basestation

Gateway

ATTWaveLAN

(WLAN)

Hughes DirecPC DBS(Regional Area)

ExperimentalSubnet

Dell 486/Pentium PCsBSDI Unix

Metricom(WMAN)

IBM ThinkpadsBSDI Unix

Beta testers for: Metricom’s new Internet gateway ATT’s 2.4 Ghz WaveLAN IBM’s next generation IR devices

23

Satellite Broadcast Application

Frequently askedquestions periodicallyrepeated

IBM @ $82.875

Broadcast Queue

Traffic East Bay

Traffic North Bay

Traffic Peninsular

Traffic SF

Bay Area Weather

Traffic East Bay

… …

Filter "East Bay"

Filter "SF"

High Priority"IBM Stock Quotation"

Internet

Data filtering and query combining

24

Collaboration with UCSF

VAMedicalCenter

Golden Gate Park

SFMRC

Mt. Zion

University ofCalifornia,

San Francisco

OaklandPacBell

ATMSwitch

San Francisco General Hospital

San Francisco

Bay Bridge

Golden Gate Bridge

ACTS

VSAT

T1 T1T1

DocumentRequests

Radiographs

UCSF NLMPC/MS Windows

Sun WS/UNIX

Router

Ethernet Ethernet

DocumentViewing

RadiographTransmission

Ethernet/T1

Interface

Sun WS/UNIX

Sun WS/UNIX

Router

Ethernet/T1

Interface

Jukebox

VSAT

T1DocumentImages

DocumentTransmission

RadiographReceiving

Picture Archive and Communications System (PACS)

linking major hospitals in SFand the National Library of

Medicine

Laboratory for RadiologicalInformatics at UCSF

25

Research Issues

• Seamless connectivity over multiple overlays– Implementing low latency handoffs– Exploiting movement-tracking and geography– Performance characterization of channels– Authentication, security, privacy

• Scalable mobile processing– Hierarchical and distributed network management– Load balancing for network mgmt & application support– Integration with local- & wide-area networked servers– Application support for adaptive connections