May 4, 1996 - GSIC, Samsung, Sony, US West, Sprint ... 17. Mobile Computing is the. Natural Evolution of Computing ... Laptop Sales, Jan-Sept 1995. 0.
Is Wireless (Data) Dead? Randy H. Katz Computer Science Division, EECS Department University of California, Berkeley, CA 94720-1776 © 1997
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Heilmeier’s Vision “People and their machines should be able to access information and communicate with each other easily and securely, in any medium or combination of media -voice, data, image, video, or multimedia -- any time, anywhere, in a timely, cost-effective way.” G. Heilmeier, 1992
• Access – Internet connectivity
• Anytime, Anywhere – – –
• Securely – Global Authentication
• Any Medium
Wide-Area Coverage – Multimedia: AV/Graphics Scalable Processing Highly Available Operation • Timely – Performance
• Easily
– Transparent Access – Localized Service
• Cost Effective – Heterogeneous Support via Proxies 2
Marconi’s Vision “It is dangerous to put limits on wireless.” Guglielmo Marconi (1932)
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Presentation Outline • • • • •
Wireless Definitions and Trends Wireless Telephony Quo Vadis Wireless Data? Access is the Killer App! Summary and Conclusions
4
The Wireless Universe Wireless Communications Amateur
Industrial
Automotive
Monitoring
— IVHS — GPS
Consumer
Business
Military/Aero
Long-Haul
— AMR — Control
Residential Cordless Analog
Digital
— CT-0 — CT-1 — CT-300
— DECT — CT-2 — PHP — USCT — ISM
Cellular Analog
Digital
— AMPS — ETACS — NMT450 — NMT900 — NMT-O — Comvik — JTACS
— GSM — IS-54 — IS-95 — RCR-27
Paging — POSCAG — ERMES — SSB
WPABX — DECT — CT-2 — PHP — USCT — ISM
WLAN — 802.11 — DECT — HiPerLAN — ISM
PMR/SMR Mobile Data Conv ESMR — MIRS — TETRA
— ARDIS — Mobitex — Omnitracs — Cellular/CDPD
PCN/PCS — DCS1800 — PHP — US?? — LEO
— FPLMTS — UMTS — RACE — Others
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Radio Basics Wavelength (m) 10 4 10 2
10 0
10 -2
Frequency (Hz) 10 4 10 6
10 8
10 10 10 12 10 14 10 16 10 18 10 20 10 22 10 24
Radio Spectrum
10 -4
IR
10 -6
10 -8
UV
10 -10 10 -12 10 -14 10 -16
X-Ray
Visible Light ROYGBIV Speed of Light = λ * ƒ = 3 x 108 < 30 KHz 30 - 300 KHz AM Radio 1 MHz 300 m ≈1000 ft 300 KHz - 3 MHz FM Radio, TV 100 MHz 3 m ≈10 ft 3 - 30 MHz Cell Phone 1 GHz 30 cm ≈1 ft 30 - 300 MHz Satellite 10 GHz 3 cm ≈1 in 300 MHz - 3 GHz 3 - 30 GHz > 30 GHz
Cosmic Rays
VLF LF MF HF VHF UHF SHF EHF 6
Radio Basics Ionosphere HF Transmission Reflected
Absorption
Directional Antenna
VHF Transmission
Line of Sight
Reflected wave interferes with signal
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Wireless Spectrum CT-0 (US)
0
CT-1 (Japan)
200
LMR (US)
400
NMT-450
600
CT-2 ISM (Eur, SEA) (US) SMR CT-1/CT-1+ (US) (Eur)
GPS
DECT (Eur)
PHP (RCR-28) (Japan)
ISM
800 1000 1200 1400 1600 1800 2000 2200 2400
AMPS GSM ETACS NMT-900 RC2000 ...
PDC (RCR-27)
DCS-1800 (Europe)
PCS (US)
PCS Bands 8
Presentation Outline • • • • •
Wireless Definitions and Trends Wireless Telephony Quo Vadis Wireless Data? Access is the Killer App! Summary and Conclusions
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Wireless Telephony not Dead! • Exploding Cellular Voice Services – Approximately 40 million subscribers in US – Roughly half of the world’s cellular users – Similar number of paging subscribers in US – $7 billion in primary PCS license auctions – $10.2 billion in secondary PCS auctions
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Proliferation of Wireless Telephony 100 90 80 70 60 50 40 Millions of 30 Subscribers 20 10 0
Yankee Group Forecast
PCS Cellular+PCS
19 19 19 19 19 19 20 20 20 20 20 94 95 96 97 98 99 00 01 02 03 04 You are here!
28000 new AMPS subscribers per day
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Cellular Phone Growth Economist 4 May 1996
45 40 35 30
% of main lines that are mobile 25 20 phones 15
Europe Unites States Japan
10 5 0 1990
1995
2000
Year 2000: Mobile phones will reach 42% of fixed-line subscribers 12
Japan Unplugged 16 14 12 10 # Subscrib PHS
8 6 4 2 0 86
87
88
89
90
91
92
93
94
95
96 Oct
Number of mobile phone subscribers in Japan, in March of each year — N.Y. Times, 20 January 1997 13
The Lessons of the Japanese Cellular Phone System • Unexpectedly Rapid Growth – 1995: ten years to 5.4 million subscribers – March 1996: 10 million – October 1996: 21 million
• Why? – Rapidly declining prices for cell phones & services – Deregulation of Japanese cellular telephone market – Recent introduction of personal communication services: portable handiphone system
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PCS = “Pretty Crazy Situation”?
• • • •
Proposal CDMA (IS-95)
Mobility High
PCS1900 IS-54 Omnipoint WACS
High High High/Low Low
DECT PHS 5 MHz CDMA
Low Low Low
Supporters Qualcomm, AT&T, Motorola, ALPS, GSIC, Samsung, Sony, US West, Sprint Bell Atlantic, Time Warner Pac Bell, Nokia, MCI, Siemens, Kycom AT&T, McCaw Omnipoint, Rockwell Bellcore, Motorola, Panasonic, US West, Sprint, Bell Atlantic, Time Warner Ericsson NEC, Panasonic, Hitachi, Toshiba, PCSI Interdigital, Oki
PCS Primeco (Nynex/Bell Atlantic/US West/Airtouch): CDMA Wirelessco (Sprint, Comcast, Cox, TCI): CDMA AT&T Wireless: TDMA Other RBOCs (e.g., PBMS): PCS 1900 (Upbanded GSM) 15
Presentation Outline • • • • •
Wireless Definitions and Trends Wireless Telephony Quo Vadis Wireless Data? Access is the Killer App! Summary and Conclusions
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Mobile Computing is the Natural Evolution of Computing More Flexible Resource Usage
Mobile Computing LANs + WSs Networking Timesharing Batch Single User OS
Freedom from Collocation 17
Global Markets for Portable Computers $ Billions 60 50 40 30 20 10 0 90
91
92
93
94
95
96
Total PC Market: approx. $150 billion
97
98
99
0
You Are Here! 18
Laptop Sales, Jan-Sept 1995 AT&T
46
AST
68
Texas Instr
72
Zenith
75
Dell
Unit Sales (Top 10) From NYTimes 17 Jan 96
97
NEC
Approx. 20% of units are laptop computers
137
Apple
203
IBM
301
Compaq
331
Toshiba
556 0
200,000
400,000
600,000 19
A Short History of Wireless Data • Wireless LANs – late 1970s » IBM Research--IR for factory apps ( 1 Mbps
Latency Mobility < 3 ms
Comm’l RF: 2 Mbps Research IR: 50 Mbps
Campus-Area Packet Relay Network Metro-Area (Wireless Cable) Wide-Area Regional-Area (LEO/DBS/VSAT)
≈ 64 Kbps
Typ Video Performance
Typ Audio Performance
Pedestrian 2-Way ’ractive Full Frame Rate (Comp)
High Quality 16-bit Samples 22 KHz Rate
≈ 100 ms Pedestrian
10-30 mbps (one way, LOS)
< 10 ms
19.2 Kbps
> 100 ms
4.8 kbps–10+ Mbps > 100 ms (asymmetric)
Med. Quality Slow Scan
Med. Quality Reduced Rate
Stationary 2-Way 'ractive Full Frame Rate (Compressed) Vehicular Freeze Frame
High Quality 16-bit Samples 22 KHz Rate Asynchronous “Voice Mail”
Vehicular Seconds/Frame Stationary Freeze Frame
Asynchronous “Voice Mail”
Latency as critical as bandwidth in wireless networks Wide diversity of network performance parameters Competing infrastructure providers Pedestrian vs. vehicular mobility
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Application Support Challenge Device High-end PC Low-end PC High-end notebook Low-end notebook PDA
Bandwidth, bits/sec Ethernet (10Mbits), ISDN (128K)
CPU 266 Mhz Pentium Pro 150 Mhz Pentium
Mem/ Disk 64/4G 16/1G
Cellular (9600) or wireline (28.8K) modem 100 Mhz 486 2400-14.4K modem
20+ Mhz RISC or x86
2/0
Screen Bits/ size pixel 1280x1024 16-24, color 1024x768 8-16, color 800x600 8, color 640x480
4, gray
320x200
1–2, gray
Client variation spans an order of magnitude 35
Wireless Overlay Networks Satellite Regional Area Low-tier
High-tier
Local Area Wide Area High Mobility
Low Mobility
• Wireless internetwork: stacked networks providing wide area coverage and the best possible bandwidth and latency 36
Proxy Architecture • Proxy – Mediates between wireless and wireline environment – Ideally executes at “well-connected” boundary – Manages caches & chooses representations on-the-fly – Trade transcoding time against communications time
Well Connected Proxy
Poorly Connected 37
BARWAN Architecture Horizontal Handoff
Basestations
Foreign Agent
Server (Correspondent Host)
Local Proxy Host
GW Proxy Host
Local Services
IP Internet
GW
Overlay IP GW Vertical Handoff
Wireless Subnets Home Agent
• Overlay IP extends Mobile IP • Proxy/Forwarding Agent Interaction • “Vertical” Handoffs between subnetworks
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Mobile Applications “Sessions”
Proxy Agents Transport (Asymmetric, Heterogeneous, Lossy Links) Overlay IP (Mobile IP + Overlays) Snoop Agent Link Scheduling Net Connection Monitoring; Net-Appl Interface; ELN;
Wireless LAN
WirePacket Less Radio Cable
Location-Dependent Services
BARWAN Architecture
IP DBS SubNet
CDPD Sub- ATM Net
Mobile IP Beacons
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Presentation Outline • • • • •
Wireless Definitions and Trends Wireless Telephony Quo Vadis Wireless Data? Access is the Killer App! Summary and Conclusions
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Summary • Wireless data is not dead – Very successful vertical applications like UPS – Wide-Area: ISP model vs. “pipe” provider, GPRS – Local-Area: Higher b/w, 802.11 standards, etiquette
• Access is the killer app – Connectivity through wireless overlays – Adaptivity through proxy services
• IP “Dial Tone” – IP to the pager, phone, PDA, laptop, etc. – Internet service integration » A phone is not a workstation: limited b/w, storage, display 41
Conclusions • Promising Developments: – Overlays and Proxies – New spectrum allocations for serious bandwidth
• Many of these ideas apply equally well in today’s heterogeneous network environments – Asymmetries in satellites and cable modem links – Transport over high bandwidth-delay networks – High loss links: bandwidth achieved? – Adapt representations to the quality of the end device and its network connectivity 42
