Wireless Networks

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Wireless Networks
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Outline

• Introduction From Wired to Wireless
• Wireless Devices
• Smart Phones, Handhelds, Pagers,
• Wireless Networks
• WAN, LAN, PAN
• How do they work?
• Wireless Internet Architectures
• 2G, 2.5G, 3G, 4G, Bluetooth, IR, Satellites?
• Wireless Internet Applications
• The Future of Wireless Technology

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Introduction

• 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

• First wireless experiments
• 1888 Heinrich Hertz spark generator
• 1894 Guglielmo Marconi send radio across
  across the Atlantic
• Broadcast radio 1920
• Photographs transmitted by radio 1924
• Mobile Radio to Police Cars 1926
• Broadcast Television (B/W) 1936
• The first automatic radiotelephone service - 1948

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Wireless History

• Satellite Systems for Telephony 1962
• The Shoe Phone - 1965
• First Cellular Mobile Phone 1973
• Pagers (widely used) 1985,

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Wireless History

• Mobile Phones 1987, ....

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Mobile Internet Nodes
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Wireless Network Applications

• Hardware Perspective
• The Equipments / devices
• Wireless Spectrum
• Architecture Perspective
• Informative Perspective
• Application Perspective

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The Equipments / devices

• What are the advantages and disadvantages of
  using the following devices?
• Web Phone
• Handheld
• Pager
• Web PC
• Appliance

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Web Phones Handhelds

• 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.
• 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

• 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.
• Web PCs
• PC and even laptop are poor mobile devices, need
  to put near a power supply.
• Tablet PC, lightweight, easy to hand over.

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Web PCs Appliance

• Appliance
• iAppliances stand for Internet appliances refer
  to specialized gadget designed as a single
  application.
• Webpad, WebTV,

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Wireless Spectrum

• Left long, low-power, low-energy waves

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Spectrum Allocation History
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AM FM Radio

• Two different methods to represent 1 0.

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Architecture Perspective

• Wireless Networks
• WAN Wide Area Network
• Ranged up to 2500 meters, GSM, GPRS,
• LAN Local Area Network
• Ranged up to 100 meters, 802.11b,
• PAN Personal Area Network
• Low-power, short-range network
• Ranged up to 10 meters
• Bluetooth, IR,

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Three Wireless Internets
Local Area Network
Wide Area Network
Personal Area Network
11-54 Mbps
9-144 Kbps
1-20 Mbps
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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 MHz9600 kbps2500 meters
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LAN PAN
LAN 2.4 GHz 11 Mbps100 meters
PAN 2.4 GHz 700 Kbps10 meters
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WPAN Comparisons
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Informative PerspectiveHow wireless works?

• Including Wireless network and Wired network

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Cellular Tower Grids

• Towers Power the Mobile Spectrum

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Cellular handoff

• Handoff is the process of automatically passing
  the call from one transmitter to the next.

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Wireless Standards

• IEEE 802.11 (Wireless LAN, a family)
• IEEE 802.11a (5 GHz band)
• IEEE 802.11b (the most common one)
• IEEE 802.11g (Fast)
• IEEE 802.11n (2.4-5 GHz range and Up to 200Mbps)
• Bluetooth
• HomeRF
• Infra-Red (IR)
• The main standards for WLANs is the IEEE 802.11
  standard.
• Other standards in the family (cf, hj, n) are
  service enhancements and extensions or
  corrections to previous specifications.
• The IEEE 802.15 is a standard for WPAN.
• Coming standard is IEEE 802.17 .

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IEEE 802.11b Standard

• 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

• Same as IEEE 802.11b
• Transmission rate 11 Mbps
• Bandwidth 2.4 GHz
• Coverage 300 m

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IEEE 802.11a

• IEEE 802.11a supports 54 Mbps
• Bandwidth 5 GHz
• gives 802.11a the advantage of less interference.
  
• Incompatible with Wi-Fi devices
• Expensive devices
• Use of 802.11a is almost limited to line of sight,

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IEEE 802.11g

• Introduced in 2003
• 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
• 802.11g hardware will work with 802.11b hardware.

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Speed / Distance
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Bluetooth

• Bluetooth is the name for a short-range radio
  frequency (RF) technology that operates at 2.4
  GHz and is capable of transmitting voice and
  data.
• Bluetooth is an industrial specification for
  wireless personal area networks (PANs).
• Connect and exchange information between devices
  like personal digital assistants (PDAs), mobile
  phones, PCs and printers via a secure, low-cost
  channel.
• The name Bluetooth was born from the 10th century
  king of Denmark, King Harold Bluetooth who
  engaged in diplomacy which led warring parties to
  negotiate with each other.

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Bluetooth (802.15)

• Bluetooth transfers data at a rate of 721 Kbps
  which is capable of transmitting voice, data,
  video and still images.
• Bluetooth 2.0 supports up to 2.1 Mbps.
• Bluetooth is designed for very low power use, and
  the transmission range will only be 10m, about
  30ft.
• High-powered Bluetooth devices will enable ranges
  up to 100m (300ft).
• Considering the design philosophy behind
  Bluetooth, even the 10m range is adequate for the
  purposes Bluetooth is intended for.

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HomeRF

• HomeRF is a personal area network (PAN) standard
  which was compared to Bluetooth in its early
  days.
• It is a wireless networking specification that
  uses 2.4 GHz frequency band and can achieve a
  maximum of 10 Mbit/s throughput and travel within
  a 50 meter range.
• However, after 802.11b networks became accessible
  to home users and Microsoft began including
  support for Bluetooth in its Windows operating
  systems. HomeRF became obsolete, and no group is
  developing the standard further.

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Infrared Technology

• 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
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802.16 Wi MAX

• Similar to 802.11 cellular base station model
• Transmissions to/from base station by hosts
• Different from 802.11
• Range around 6 miles (with in city, but out of
  the shop)
• around 14Mbps

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3G Network Evolution
3G 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.
2G TDMA GSM Time Division Multiple Access
Groupe Speciale Mobile 1990s callers timeshare
a frequency channel nine users use 3 channels
1G FDMA Frequency Division Multiple Access 1980s
each calling party is allocated a dedicated
frequency channel 3 users use three channels
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Cellular Family Tree

• 1G introduced by ATT in 1983, only analog and
  voice
• 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)
• 2.5G supports faster wireless data services, GSM
  extensions.
• 3G 4G provide wider bandwidth and higher data
  rates for mobile users (W-CDMA, CGMA2000).
• 2G (Voice) ? 2.5G (Data) ? 3G (Multimedia)
• The fourth-generation (4G) systems provides
  further improvements such as higher bandwidth,
  enhanced multimedia, universal access, and
  portability across all types of devices.

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3G Launching
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Spectrum Allocation
ITU-R holds auctions for new frequencies, manages
frequency bands worldwide (WRC, World Radio
Conferences)
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Bandwidth Time
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Wireless Generations
3G
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Wireless Generations
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CDMA Present and Future
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3.5G - HSDPA

• High-Speed Downlink Packet Access (HSDPA) is a 3G
  mobile telephony protocol which increase their
  data transfer speeds and capacity.
• Current HSDPA deployments now support 1.8 Mbit/s,
  3.6 Mbit/s, 7.2 Mbit/s and 14.4 Mbit/s in
  downlink.
• Currently Hong Kong operators support mobile
  broadband service at speeds of up to 3.6 Mbps
• Further speed grades are planned for the near
  future.

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3.5G - HSDPA

• HSDPA shortens round-trip time between network
  and terminals and reduces variance in downlink
  transmission delay.
• The combination of faster data rates and the
  increased spectral efficiency results in a lower
  cost per data bit transmitted.

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Application Perspectivei-mode Story

• 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?
• Constant connection
• Viable national technology
• Quality Handsets
• Mature commercial infrastructure

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Worldwide Wireless Application Forecast
SourceARC Group 2001
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Short Message Service SMS

• 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.

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Multimedia Message Service MMS

• The Multimedia Messaging Service (MMS) is, as its
  name suggests, the ability to send messages
  comprising a combination of text, sounds, images
  and video to MMS capable handsets.
• Media supported by MMS
• JPEG, GIF, text, AMR voice, video H263, and some
  other formats.
• Message Presentation
• The message viewer handles content in XHTML
  Mobile Profile or MMS SMIL.

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Wireless Application Protocol (WAP)

• WAP is an application protocol for cell phones.

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Microbrowser Markup Languages for devices

• HTML (HyperText Markup Language)
• The original web page
• XML (eXtensible Markup Language)
• A Universal web page
• HDML (Handheld Dynamic ML)
• WML (Wireless Markup Language)
• cHTML (Compact HTML)
• It was developed by Access Japan for i-mode.
• XHTML (eXtensible HTML)
• The Next Web Page

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Wireless Internet Application

• Messaging
• Use web phone to send SMS messages.
• Browsing
• Use wireless devices to read cHTML, WML, HDML and
  XHTML web sites.
• Interacting
• Use interactive applications for the client
  devices, such as wireless games.
• Conversing
• Use Voice portal for information delivery, such
  as Tellme to get information from the voice
  gateway.

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Summary