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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
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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
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Wide-Area Wireless Testbed
MultipleOverlayedWirelessNetworks
SeamlessMobilityAcross
Overlays
Integration with wide-area high performance networks (BAGNet)Bandwidth/latency aware APIs; Wide-area untethered applications
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Wireless Overlay Concept
In-Building
Campus-Area Packet Relay
Metropolitan-Area
Regional-Area
Remote Clinics
Ambulance Dispatch
Hospital Campus
HospitalOperating RoomEmergency Room
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Application: Emergency Response
St. Mary's Hospital
UCSFRegional PACS Center
ATMWireline
Infrastructure
In-BuildingWireless
Wide-AreaWireless
EmergencyRoom
DiagnosticCenter
(CAT/MRI)Operating Room
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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
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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
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Mobility Challenges:Horizontal Roaming
Roaming within an administrative domain -- Mobile IP provides initial solution for the routing problem -- Single authentication with home domain
SingleAdministrativeDomain
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Migrating Hosts
VideoServer
BaseStation
BaseStation
For continuous playbackwith real-time constraints,must readahead packets to the base station
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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
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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
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Migrating Hosts
VideoServer
BaseStation
BaseStation
Multicast backbone
BS-to-BS purge packet protocols
— or —sequence no.resolution in
Infopad
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Mobility Challenges:Vertical Roaming
Multiple AdministrativeDomains-- Handoff-- Authentication-- Routing– Billing
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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
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Application Support
Network of WorkstationServers
Base Station Mobile Node
Application Server Application ClientAgent
Foreign Agent
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Application Support:Map Browsing
Low Resolution
Medium Resolution
High Resolution
Major Features
Minor Roads
Elevations
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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
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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
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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.
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UCB-Hughes DBS Testbed
Soda Hall
AccessPoint DirectPC
Basestation
InternetGateway
High Bandwidth, High Latency "Downlink"
Lower BandwidthUplink
WLAN
Hughes DBSBasestation
Gateway
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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
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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
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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
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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