Wireless Internet
Applications & Architecture
CSC1720 – Introduction to Internet
Essential Materials
Based on Wireless Internet App. and Arch.
© 2002 Mark Beaulieu.
Outline
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Introduction: From Wired to Wireless
Wireless Devices
– Web Phones, Handhelds, Pagers, …
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Wireless Networks
– WAN, LAN, PAN
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How do they work?
Wireless Internet Architectures
– 2G, 2.5G, 3G, 4G, Bluetooth, IR, Satellites? …
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Wireless Internet Applications
The Future of Wireless Technology
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Introduction
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The wireless Internet is the network of
radio-connected devices and servers
using voice, information and other
Internet services.
Two billion wireless mobile users will
exist by the year 2010.
Almost every Internet service is being
made ready for the wireless Internet.
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Wireless History
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First wireless experiments
– 1888: Heinrich Hertz – spark generator
– 1894: Guglielmo Marconi – Ring a bell 30 ft away
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Broadcast radio – 1920
Photographs transmitted by radio – 1924
Mobile Radio to Police Cars – 1926
Broadcast Television – 1936, Color – 1950
Satellite Systems for Telephony – 1962
Cordless Telephones – 1980
Pagers (widely used) – 1985, …
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Wireless History
Heinrich Hertz
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Guglielmo Marconi
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Hardware Perspective
The Equipments / devices
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What are the advantages and
disadvantages of using the following
devices?
– Web Phone
– Handheld
– Pager
– Voice Portal
– Web PC
– Appliance
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Web Phones & Handhelds
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Web Phones
– It is a modified cell phone with display hardware
and Internet access software.
– Japanese use color I-mode phones.
– Europeans use WAP phones for messaging.
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Handhelds / PDA
– It is a small computer with OS, storage, screen,
keyboard and wireless connection interfaces (IrDA
infrared) or Bluetooth (Short-range radio)
– With wireless modem, we can sync over the air.
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Pagers & Voice Portals
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Pagers
– A small wireless device that uses paging networks
to send and receive data.
– Paging belongs to messaging applications.
– Pagers are ideal as cheap and low-power.
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Voice Portals
– A natural voice interface that runs on a server to
give you a dialog. Listen your speech, calculate a
reply, synthesis a response.
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Web PCs & Appliance
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Web PCs
– PC and even laptop are poor mobile
devices, need to put near a power supply.
– Table PC, lightweight, easy to hand over.
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Appliance
– iAppliances stand for Internet appliances
refer to specialized gadget designed as a
single application.
– Webpad, WebTV, …
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Wireless Spectrum
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Left: long, low-power, low-energy waves
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1G
2G
Cellular Spectrum
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Spectrum Allocation
History
MHz
5.15 – 5.35
2400 – 2483
2400
1850
806
512
–
–
–
–
Spectrum Use
802.11a
Bluetooth (802.15)
Time
2002
2001
homeRF
PCS cell phone
AMPS cell phone
UHF TV
2000
1996
1980
1949
2483
1990
902
806
54 – 216
88 – 108
0.535
1.6 to Internet
CSC1720 ––
Introduction
VHF TV
FM Radio
AM Radio 12
1941
1935
1921
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AM & FM Radio
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Two different methods to represent 1 & 0.
demo
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Architecture Perspective
Wireless Networks
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WAN – Wide Area Network
– Ranged up to 2500 meters, GSM, GPRS, …
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LAN – Local Area Network
– Ranged up to 100 meters, 802.11b, …
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PAN – Personal Area Network
– Low-power, short-range network
– Ranged up to 10 meters
– Bluetooth, IR, …
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Personal Area Network
1-20 Mbps
Local Area Network
11-54 Mbps
Wide Area Network
9-144 Kbps
Three Wireless Internets
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WAN Topology
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LAN Topology
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PAN Topology
Wireless PAN module
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Wide Area Networks
WAN
800 to 1900 MHz
9600 kbps
2500 meters
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LAN & PAN
LAN
2.4 GHz
11 Mbps
100 meters
PAN
2.4 GHz
700 Kbps
10 meters
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Wireless data rates
Wireless data rate
Wireless device
9.6 kbps
Web phones
14.4 kbps
Pagers, Web phones
19.2 kbps
Pagers
128 kbps
Handhelds
11 Mbps
Handhelds using wireless LAN
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Informative Perspective
How wireless works?
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Including Wireless network and Wired network
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Cellular Tower Grids
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Towers Power the Mobile Spectrum
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Putting up Towers
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Antennas
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Omni-directional antennas
– The signal can be radiated out in all
directions
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Yagi antennas
– Provides a fairly focused beam
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Parabolic antennas
– The most powerful we can buy
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Dipole antennas
– Use to increase range indoors
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Antennas figures
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Cellular handoff
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Handoff is the process of automatically
passing the call from one transmitter to
the next.
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Wireless Standards
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IEEE 802.11 (Wireless LAN, a family)
IEEE 802.11a (5 GHz band)
IEEE 802.11b (the most common one)
IEEE 802.11g (Fast)
Bluetooth
HomeRF
Infra-Red (IR)
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IEEE 802.11b
standard
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Transmit and receive data at 11Mbps.
Include all the network overheads
Theoretically, real throughput: 7Mbps.
802.11b supports five speeds:
– 11M, 5.5M, 2M, 1M and 512k
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Wi-Fi Standard
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Same as IEEE 802.11b
Transmission rate: 11 Mbps
Bandwidth: 2.4 GHz
Coverage: 300 m
Support devices: 25
Any advantage & disadvantage?
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IEEE 802.11a
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IEEE 802.11a supports 54 Mbps
– Bandwidth – 5 GHz
– Incompatible with Wi-Fi devices
– Expensive devices
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IEEE 802.11g
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IEEE 802.11g also supports 54 Mbps
– Use 2.4 GHz
– Much cheaper than IEEE 802.11a devices
– Apple computers also support IEEE 802.11g
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Speed / Distance
Speed
Outdoor
Indoor
54Mbps
50m
20m
18Mbps
150m
75m
11Mbps
180m
125m
1Mbps
570m
125m
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Wireless network
connection
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Bluetooth
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It is a low-cost, low-power, short-range radio
link for mobile devices and for WAN/LAN
access points.
Both voice and data communications at about
70 kbps.
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HomeRF
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The network can accommodate a
maximum of 127 nodes.
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Infrared Technology
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It is a popular way for handhelds to exchange
data, typically range of 2M.
They are often used to manually exchange
information using strictly a point-to-point
connection.
IrDA v1.0 transmits data at 115 kbps.
IrDA v1.1 transmits data at 4 Mbps.
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Wireless Interference at
2.4 GHz
Wireless LAN 2.4 GHz Protocols
Table 14 (99)
IEEE 802.11b
HomeRF
Bluetooth
Speed
11 Mbps
1, 2, 10 Mbps
30 to 700 kbps
Use
Office or campus LAN
Home office, house and yard
Personal Area Network
50 meters
10 meters
Wideband frequency hopping
Narrowband frequency
hopping
100 meters
Range
Frequency Direct sequence spread
spectrum
sharing
Backers
Cisco, Lucent, 3Com, Apple, Apple, Compaq, Dell, Motorola, Ericsson, Motorola, Intel,
Proxim, HomeRF Working
Nokia, Bluetooth Special
Intel, WECA Consortium
Group
Interest Group
URL
www.wirelessethernet.com
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www.homerf.org
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www.bluetooth.com
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Break Time – 10 minutes
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Focus on the 3G
Network Evolution
1G
FDMA
Frequency Division
Multiple Access
1980s – each calling
party is allocated a
dedicated frequency
channel: 3 users use
three channels
CSC1720 – Introduction to Internet
3G
2G
TDMA & GSM
Time Division
Multiple Access &
Groupe Speciale
Mobile
1990s – callers
timeshare a
frequency channel:
nine users use 3
channels
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CDMA & WCDMA
Code Division
Multiple Access &
Wide CDMA
1990s – callers use a
shorter bandwidth
2000s – Each call is
spread, randomly
broken down and
mixed: ten callers
use one channel.
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1G, 2G, 3G Networks
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1G
– Circuit-switched, analog signals, Voice only
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2G
– Circuit-switched, digital signals, voice or
data overlay, 9 kbps or 19 kbps
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2.5G - GPRS, why it is called 2.5G?
3G
– Packet-switched, Transparent roaming,
2Mbps, Identification of caller location
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Cellular Family Tree
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1G introduced by AT&T in 1983, only analog
cellular telephony.
2G introduced in 1987 in Europe. Three
primary wireless standards:
– TDMA (Time Division Multiple Access)
– GSM (Global System for Mobile Communications)
– CDMA (Code Division Multiple Access)
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2.5G supports faster wireless data services,
GSM extensions.
3G & 4G provide wider bandwidth and higher
data rates for mobile users.
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Bandwidth & Time
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Frequency Divided Multiple Access
(Used in analog and digital systems)
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Time Divided Multiple Access
(Used in digital systems, FDMA is a foundation)
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Code Divided Multiple Access
(All Users talk on the SAME frequency. Digital codes divide the conversations)
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3G
Wireless Generations
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Forrester 12/1999
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3G Air Interfaces
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W-CDMA
CDMA-MC
TDMA
CDMA-TDD
FDD-TDMA
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1.25 MHz
CDMA2000
1xEV
5 MHz
up to 2.4
Mbps
1.25 MHz
DATA
DATA
up to 2.0 Mbps
1.25 MHz
1.25 MHz
DATA
Up to 307 kbps
DATA
Up to 115 kbps
14.4 kbps
VOICE
VOICE
95A
95B
cdmaOne
A
VOICE
INCREASED VOICE
CAPACITY
WCDMA /
CDMA2000
CDMA2000 1x/
1xEV
A B
A B 1x/
A B 1x/
World
1xEV Phone
1xEV
1995
1999
2000
2001
2002
2003
CDMA Present and Future
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3G Spectrum in different
Countries
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Using Satellites
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GEO – Geosynchronous Earth Orbiting
– Its orbital speed equals the earth’s rotation.
– Coverage: 35,785 km
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MEO – Medium Earth Orbiting
– Is not popular as GEO and LEO.
– Coverage: 10,000 km
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LEO - Low Earth Orbiting (1,000 km)
– Minimal delay, small, easy to launch
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GEO, MEO, LEO
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Application Perspective
i-mode Story
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The most popular wireless data service on
Earth is i-mode, developed by DoCoMo
formed in 1992 by NTT.
The no. of subscribers increases at the
rate of 50,000 new users per day.
Why success?
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–
–
–
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Constant connection
Viable national technology Enclave
Microbilling economy
Quality Handsets
Mature commercial infrastructure
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Worldwide Wireless
Application Forecast
Source:ARC Group 2001
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Short Message Service
SMS
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A messaging service supported by cell
phones that allows short text messages
to be sent between mobile devices.
All GSM phones support SMS, but not all
CDMA or TDMA cell phones support yet.
SMS teaches consumers to use wireless
devices for non-voice services.
SMS loses value as latency increases
– How to reduce the latency? Ans: SMSC
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General Packet Radio
Service (GPRS)
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GPRS is a the first available 2.5G
packet-switched standard.
It is the first packet data service on
wireless digital networks.
GPRS will be the backbone of GSM and
TDMA networks for wireless data packet
communications.
It can transfer data at 115 kbps.
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Wireless Application
Protocol (WAP)
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WAP is an application protocol for cell phones.
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Microbrowser Markup
Languages for devices
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HTML (HyperText Markup Language)
– The original web page
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XML (eXtensible Markup Language)
– A Universal web page
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HDML (Handheld Dynamic ML)
WML (Wireless Markup Language)
cHTML (Compact HTML)
– It was developed by Access Japan for i-mode.
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XHTML (eXtensible HTML)
– The Next Web Page
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Wireless Internet
Application
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Messaging
– Use web phone to send SMS messages.
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Browsing
– Use wireless devices to read cHTML, WML, HDML
and XHTML web sites.
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Interacting
– Use interactive applications for the client devices,
such as wireless games.
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Conversing
– Use Voice portal for information delivery, such as
Tellme to get information from the voice gateway.
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Summary
Devices
Web Phone
Handheld
Pager
Voice Portal
Web PC
Communicating
appliances
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Networks
WAN
LAN
PAN
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Applicatons
Messaging
Web Browsing
Interacting
Conversing
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Wireless flaws?
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Encrypted
password
Restricted
aces by MAC
address
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Wired Equivalent Privacy (WEP)
Disable WEP
Enable WEP
What is the
difference?
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The future of Wireless
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Faster and compatible: 802.11g
– Use the 2.4GHz band and reach 54Mbps
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Low price of wireless networking
equipment  community networks
– Public good or Theft of services?
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Many other extensions
– 802.11e, 802.11i, 802.11h
– 802.15.1-2002 (Bluetooth-like)
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References
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Wireless Internet Applications and
Architecture – Mark Beaulieu
Wireless Internet Crash Course – Roman
Kikta et al.
The wireless networking starter kit –
Adam and Glenn
Wi-Fi
The End.
Thank you for your patience!
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