Download - Wireless Networks
![Page 1: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/1.jpg)
1
Wireless Networks
Amit Jain and Petter KaralMedia Tech ClubSloan School of ManagementMay 2, 2000
![Page 2: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/2.jpg)
2
Mobile + Internet =
![Page 3: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/3.jpg)
3
The Mobile Internet
mCommerce
![Page 4: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/4.jpg)
4
The Mobile Internet
work anywhere
![Page 5: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/5.jpg)
5
The Mobile Internet
play anywhere
![Page 6: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/6.jpg)
6
The Mobile Internet
anytime
anytime
![Page 7: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/7.jpg)
7
MediaTech Wireless 101
Technical workshop
How wireless worksToday’s different
systemsThe future of
wireless technology
Business workshop
Markets and players
TrendsSuccess factors
Today
Today
May 9
May 9
![Page 8: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/8.jpg)
8
Technology enables marketing
Wireless technologies are very fancy, fun and intellectually exciting
Don’t fall into the tech trap
The business workshop is the “really” important part - this is preparation
WARN
ING
![Page 9: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/9.jpg)
9
Agenda
How does it work?
Today’s systems
Wireless technologies in the near future
![Page 10: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/10.jpg)
10
A wireless network
![Page 11: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/11.jpg)
11
Connects a mobile phone...
Mobiles send and receive radio signals to base stations (called BTS)
Each BTS has a service area
Several BTS are connected to a BSC over copper, fiber or microwave links
When a mobile moves from one service area to another, a handoff occurs
BSC directs the handoff, with or without the assistance of the mobile
![Page 12: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/12.jpg)
12
To the rest of the world!
BSCs are connected to Mobile Switching Center (MSC)
MSC connects mobile to other phones/devices in the world
MSC maintains subscriber database for Billing Roaming agreements Paging mobiles for incoming
calls
![Page 13: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/13.jpg)
13
Talking over the air
Bandwidth is limited (and expensive) FCC raised over $5 billion in PCS auction UK licenses recently auctioned for $35 billion Each operator has 5-10 MHz Each mobile call needs ~25KHz Frequency must be re-used
Wireless link unreliable Severe radio propagation losses Interference from other networks and users
![Page 14: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/14.jpg)
14
Air interface standards
Examples: FDMA, TDMA, CDMA Define how the phone talks to the network Determine how network solves the frequency
reuse, reliability, and voice quality problems Determine cost of a network and its capacity
Most phones are designed for one air interface and one frequency
Multi-mode phones work over multiple air interfaces but cost substantially more
![Page 15: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/15.jpg)
15
*DMA compared !
Consider a room with many people trying to have a conversation.
If they all speak at different frequencies, FDMA
If they take turns to speak, TDMA
If they all speak together but in different language, CDMA.
![Page 16: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/16.jpg)
16
Frequency Division Multiple Access (FDMA)
Spectrum is divided into channels
Each call takes one channel for the entire duration of a call
Geographical separation allows channels to be reused
Still used in US analog systems
16
5
23
4
7
1
4
47
23
12
7
….
Spectrum
![Page 17: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/17.jpg)
17
Time Division Multiple Access (TDMA)
Channels are divided into time slots
Each user gets a channel and a time slot
Uses digital modulation to improve voice quality and capacity
GSM is the leading TDMA based standard
![Page 18: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/18.jpg)
18
Code Division Multiple Access (CDMA)
All users use the same wide band channel
Users are separated by encryption or codes
Encryption/decryption needs huge computational power
Provides dramatically higher capacity
Well suited for transmitting packets i.e. data
Used by military since 50s, commercialized by Qualcomm in 90s
![Page 19: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/19.jpg)
19
Agenda
How does it work?
Today’s systems
Wireless technologies in the near future
![Page 20: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/20.jpg)
20
End-to-end mobile phone standards
Each standard covers air interface, mobility manage-ment, switching, inter-connectivity and other issues
AMPS : Advanced Mobile Phone System Established 1983 by AT&T
GSM : Global System for Mobile communications Established 1990, Europe Ericsson, Nokia, Omnipoint, Pacific Bell, all European carriers
cdmaOne Established 1995 Qualcomm, Motorola, Lucent, Sprint PCS
Others (D-AMPS, TDMA, N-TDMA, TACS, DECT...)
![Page 21: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/21.jpg)
21
AMPS
Still used in AT&T and AirTouch Networks in the cellular band
FDMA based air interfacePoor voice qualityHandoffs are done without the
assistance of the mobile, unreliable
![Page 22: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/22.jpg)
22
Higher capacity (2X over AMPS) TDMA air interface instead of FDMA
Better voice quality Digital voice encoding/decoding
Excellent roaming One phone, many networks
SIM cards Painless phone upgrades
![Page 23: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/23.jpg)
23
Higher capacity (5X over GSM) CDMA air interface instead of FDMA
Superior voice quality Digital encoding/decoding
Smooth handoffsSimpler network design
![Page 24: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/24.jpg)
24
GSM is predominant
67%
13%
11%8%
Total worldwide subscribers: 490 million
Share of digital mobile subscriber market
![Page 25: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/25.jpg)
25
Agenda
How does it work?
Today’s systems
Wireless technologies in the near future
![Page 26: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/26.jpg)
26
The MobileInternet vision
Any application...…on any device…anytime…anywhere
“The Network is the Computer”
- Scott McNeally
![Page 27: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/27.jpg)
27
The third generation of wireless (3G) is coming
Value to user
Introduction
1G: Analog voice
2G: Digital voice+
3G: High-speed multimedia internet access
~1980 1990 2002
![Page 28: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/28.jpg)
28
3G adds functionality and more connectivity
Multimedia capable Pictures Music Video
Internet connectedPacket-switched
(144 to >2000kps)Location sensitive
![Page 29: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/29.jpg)
29
Access by many different devices and technologies
Access from different devices (“terminals”) at different timesPhone deviceCarPDA/palmtop computerDesktopFridge?
![Page 30: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/30.jpg)
30
Today’s phones evolveinto funky devices
![Page 31: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/31.jpg)
31
3G must overcomeseveral challenges
Standardization Tug-of-War over technical aspects of global
standards waged in many forumsMigration
Old customers, networks and frequencies can’t simply be discarded
Technology High-speed data devours batteries, heats
handsets and uses a lot of spectrum
![Page 32: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/32.jpg)
32
Standardization for 3G
Three coinciding technologies DS-CDMA (UTRA FDD) MC-CDMA UTRA TDD
“Harmonization” - maximizing compatibilityDoesn’t matter all that much
Most consumers aren’t global Multi-band/multi-mode phones can roam the
world anyway
![Page 33: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/33.jpg)
33
Several step-stones for3G migration
Circuit-switched internet access WAP (discussed later)
Upgrades to 2G (“2.5G”) GPRS: Upgrades GSM to PS at 50-115kps cdma2000: High-speed data over cdmaONE
Upgrades to 3G of current networks EDGE: Upgrades GSM/GPRS and
TDMA/AMPS to 3G, with data rates of 50-473kps
![Page 34: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/34.jpg)
34
Related technologies
Operating systems (OS) for terminalsShort-distance wireless networkingApplications and servicesSecurity systemsLocation specificityNew input/output technologies
![Page 35: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/35.jpg)
35
Operating systemsBattle to become the “Windows of Wireless”Players come in at different angles
EPOC (Symbian) - the OS for the PSION PDA Palm OS Pocket CE - was: Windows CE, Microsoft’s “all
gadgets” OS Phone.com - WAP browser “all you need”? Mobile Linux - no position now, but potential Java - might make underlying OS “irrelevant”
![Page 36: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/36.jpg)
36
Widely adopted standardCheap chip that communicates via
microwave radioEnables devices within 30’ to
network spontaneously (forming “Piconets”)
Speed: 1mps, allegedly bound for 10mps
Short-distance wireless networking:
![Page 37: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/37.jpg)
37
Many kinds ofapplications
“Hardcoded” functionalityInstalled software (possible today on
PDAs, Palmtops; not on cell phones)Wireless-enabled web sitesNetwork applications - run them on
distant servers using browser
![Page 38: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/38.jpg)
38
Example applications
E-mail = instant messagingArrival services
Device knows you and your position - offers relevant booking services for transportation, as well as for dining and entertainment
Web-based enterprise systems Store and retrieve files, look up information
and perform transactions from anywhere, anytime
![Page 39: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/39.jpg)
39
Security systemsenable transactions
Main focus: To enable secure transactions
Key technology: Public Key Encryption (PKI)
Many players race to define industry standard
Strong contender: Hardware-based systems (smart-cards; chips)
![Page 40: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/40.jpg)
40
Your service will be tailored by your location
Location tracking required by US law for 9-1-1 purposes (“e911”)
Several technologies Analysis of signals and handoffs GPS (not used in mobile devices yet) Bluetooth (not sufficient for e911, though)
Current systems are not very precise; will improve
![Page 41: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/41.jpg)
41
New ways to operate your wireless device
New input technologiesPalm Grafitti (has been around for a while)Keyboard variantsIntegrated cameraSpeech recognition
New output technologiesNew screensScreen specs - glasses with display
Crazy stuff coming: Direct retinal projection, implants, AI, neural interfaces
HYPE?
![Page 42: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/42.jpg)
42
And the killer app is...
Voice!
![Page 43: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/43.jpg)
43
Wireless Application Protocol, W@P
Emerging standard for presentation and delivery of data on wireless phones
Designed to work within the constraints of existing wireless and phone technology
Standard initiated by Unwired Planet, now Phone.com, with the support of Nokia, Ericsson and Motorola.
Today WAP Forum has 100+ members
![Page 44: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/44.jpg)
44
W@P architecture
Phone
MicroBrowser- WML- WMLScript- WTAI
WAP Gateway
- Encode Reqs- Decode Reqs- DNS- Proxy Server- Optimization
CGI
ContentHTTPServer
WMLDecks
Java/ASP
Web Server
WAP ProtocolsWSP/WTP/WDP
StandardHTTP 1.1
![Page 45: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/45.jpg)
45
Why do we need W@P ?
Wireless devices are not PCs Devices are small Limited CPU, RAM Support Voice, Telephony
Wireless channel is not copper or fiber Unreliable Low Bandwidth High Latency
Standardization is essential for developing applications
![Page 46: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/46.jpg)
46
W@P protocols
Independent of wireless standards
Security
Micro-browser,WML, WMLScript,WTAI
![Page 47: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/47.jpg)
47
WML: Decks and cards
1> Pizza2> Chinese3> Indian
1> Pepperoni2> Meat Lovers3> Veggie
Cost $9Buy?
Cost: $8Buy?
Cost: $11 Buy?
1> Tandoori2> Naan Bread3> Dosa
1> Kung Pao2> Schezuan3> Fried Rice- Web servers
always send “decks”
- Decks contain “cards”
- Each card is ONE user interaction
- Decks maintain state information
One“deck”
One “card”
![Page 48: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/48.jpg)
48
WAP Gateway
Translates WAP requests to HTTP and TCP/IP
Encodes and decodes content to reduce size and number of over-the-air packets
Off-loads phone from computation intensive tasks
Maintains cookies / user informationCaches commonly accessed information
![Page 49: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/49.jpg)
49
Cellular Digital Packet Data (CDPD)
Technology currently used by Palm, RIMM Palm.net, GoAmerica (NASDAQ:GOAM) resells
service from ATT, Bell Atlantic, AmeritechUses a digital overlay of existing networkData sent using TCP/IPMaximum data rate = 19.2 kbpsBilled by the byte
![Page 50: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/50.jpg)
50
CDPD and WAP compared
CDPD Network Overlay
Required Uses TCP/IP Dedicated devices
like Palm, wireless modem
Packed-switched Charge by the byte
W@P Works on existing
network Own network
protocol Software upgrade
of phone Circuit and Packet Charge by the
minute
![Page 51: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/51.jpg)
51
i-mode
Wireless service launched in spring 1999 in Japan by NTT DoCoMo
“3G light”Web content based on subset of HTMLPacket-switched, multimedia enabledLow bandwidth (9.6kps), but improved by
compression and will move to 14.2kps
Extremely successful:6 .1M customers; growing at 200,000/weekThousands of services provided
![Page 52: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/52.jpg)
52
Q&A
![Page 53: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/53.jpg)
53
Conclusion
The main 2G standards are GSM and CDMA 3G standards are coming that will enable
consumer multimedia internet from any device
Many new dimensions to internet services (context-specific, on-the-spot, continuous)
Technological feasibility drives the evolution of the Mobile Internet (for now)
Be skeptical to hype
![Page 54: Wireless Networks](https://reader035.vdocument.in/reader035/viewer/2022062217/56814b99550346895db8794e/html5/thumbnails/54.jpg)
54
Resources
3G acronym expander: www.nokia.com/3g/acronyms/0,7076,,00.html Mobile commerce glossary: maffin.net/mobilecommerce/glossary.htm Great news compilation on wireless: www.mobic.com Ericsson background papers (pretty technical, but great):
www.ericsson.se/review/issues.taf Bluetooth homepage: www.bluetooth.com WAP Forum: www.wapforum.org Equipment providers’ homepages:
www.motorola.com www.ericsson.com www.nokia.com
Web site on wireless devices: www.allnetdevices.com Consultancy gives “teasers” on its reports: www.ovum.com