Part%204%20Wireless%20Network

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Part 4 Wireless Network

• Wireless Technologies
• Wireless Networks
• Wireless Computer Networks
• Personal Mobile Networks
• Industry Use Wireless Networks

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Wireless Technology Basics

• Medium -- Air
• Types of Waves used for wireless communications
• Infrared
• Radio Wave
• Microwave
• Satellite

Wired communication, directions fixed between
sender and receiver
Wireless communication, goes to all directions
as long as there is an receiver configured with
the right frequency
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Comparison of wired and wireless comm.
Wired Wireless
Bandwidth Depending on the media used, can be large Narrow in general, regulated by FCC (Federal Communication Commission, US government agency.)
Signal reception Reliable due to dedicated link Unreliable, signal can be blocked, reflected
Security High, difficult to tap in Everyone within the range can intercept the message
Interference Very little Significant because all share the same medium air
Mobility No Yes
Cost Changes dramatically in recent years. Depending on the technology. Keep tracking. Changes dramatically in recent years. Depending on the technology. Keep tracking.
Expansion Add wires Adding relays, etc.
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Comparison of Different Wireless Wave

• Bandwidth a measure of frequency range and is
  typically measured in hertz. Central concept in
  data communication. Larger bandwidth more
  channel to communicate simultaneously ? faster

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Multiplexing Share communication channel

• TDMA Time Division Multiple Access
• CDMA -- Code division multiple access

Each can only talk in his assigned time slots.
Have to agree upon when to talk.
Both can talk together, using assigned codes,
which insure that the two signals are orthogonal.
So two can talk together. Complicated, but can be
more efficient.
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Wireless Computer Networks Radio Frequencies

• Wireless Personal Area Networks (WPANs)
• Wireless Local Area Networks (WLANs)
• Extension Wireless Mesh Network
• Wireless Metropolitan Area Networks (WMANs)
• Wireless Wide Area Networks (WWANs)
• Just Proposed. Wider

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Wireless Personal Networks

• Connecting Personal Devices
• Use Bluetooth Technologies
• Bluetooth IEEE 802.15
• Can connect up to 8 devices within 10-meter area
  (30 feet, 10.95 yard)
• Transmission rate 1Mbps

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Wireless LAN

• Wireless Local Area Network
• Mainly used for devices to communicate to
  Internet using hotspots access points (APs)
• Technology Wi-Fi IEEE 802.11 family
• Wireless-Fidelity Industry standards for WLANs
• 100 meters, 300 feet, 110 yards

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Wi-Fi Family

• IEEE 802.11 standards have a set of standards,
  use 2.4 GHz and 5 GHz frequency channel

Faster due to multi-channeling
Watch Microsoft video
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Problems with Wi-Fi

• Roaming currently hotspots are owned by a
  variety of vendors. Users cannot roam from
  hotspot to hotspot if use different Wi-Fi network
• Security radio waves, easy to intercept,
  difficult to protect
• Survivability currently intense competition. No
  viable and profitable business model yet.

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Wireless MAN

• Wireless Metropolitan Area Networks
• Technology Wi-Max IEEE 802.16
• 31 miles, 75 Mbps
• 349 per receiver
• Good for city-wide wireless deployment

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Summary of RF Wireless Standards
IEEE Standard A.K.A Range Speed
WPAN IEEE802.15 Bluetooth 30 feet 1Mbps
WLAN IEEE 802.11 Wi-Fi 300 ft 1154Mbps
WMAN IEEE 802.16 Wi-Max 30 miles 75Mbps
WWAN IEEE802.20 N/A gtgt30miles N/A
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Computation

• Company A is designing a new service used for
  travelers to download music to their handheld
  devices. They have the following choices of
  technologies to communicate between the music
  server and the personal handheld device.
• A) 10mbps Ethernet B) Bluetooth technology
  C) IEEE 802.11b
• D) IEEE 802.11g
• 1) Assume that the effective communication rate
  is 40 for all the above communication
  technologies. Also assume that the average size
  of a music file is 4MB per song. Estimate the
  time needed to download 15 songs.
• 2) Except for communication speed, discuss other
  pros and cons of implementing those technologies.
  Based on your discussion, give your choice.
• 3) Why Wimax is not being considered in this
  application?

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Extension Using Wi-Fi to Build WMAN

• Use Wi-Fi to create a Mesh Network
• What is mesh network? discuss how to form a
  mesh using cables.
• Compare to the current WLAN with wireless-mesh
• Less number of access points
• Economical solution for rural area
• and developing countries

Wired Network
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Mobile Wireless Devices

• Use telephone network, satellite network, and
  other channels
• Wireless Application Protocols (WAP)
• Application level (5th layer) protocol for small
  devices,
• Tiny screen
• Low bandwidth
• Minimal memory
• The new age of M-Commerce

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Industry Wireless Applications

• Telemetry sensor antenna, measure remotely
• Used in dangerous, remote, inconvenient areas.
• Mesh Wireless Sensor Networks
• RFID Radio Frequency Identification Tags
• http//www.youtube.com/watch?v4Zj7txoDxbE
• Future Fantasy mote/dust

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Business Telemetry Services
Information Right Where You Need It
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After class reading

• A) The Road to WiMax
• To get more business information about WiMax
  development
• (Optional) blog your knowledge of WiMax and your
  opinions on the future of this technology.
• B) Network Applications
• How many major categories of network applications
  have been discussed in this material?
• Pick one category you are the most familiar with
  or the most interested in (based on your reading)
  and write a paragraph to discuss your
  understanding. Post your writing on the blog
  site.