Wireless Data Communication and Networking

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Wireless Data Communication and Networking

• Introduction and Overview

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Know your units . . .

• 10x Abbrev. Symb.
• -18 atto a
• -15 fempto f
• -12 pico p
• -9 nano n
• -6 micro µ
• -3 milli m
• -2 centi c
• -1 deci d

• 10x Abbrev. Symb.
• 1 deca da
• 2 hecto h
• 3 kilo k
• 6 mega M
• 9 giga G
• 12 tera T
• 15 peta P
• 18 exa E

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Important relationships

• c ?f
• C speed of light (meters/second)
• 186,000 miles/second
• 3 108 meters/second
• ? wavelength in meters (meters/cycle)
• f frequency in Hertz (Hz) (cycles/second)
• Q Wavelength corresponding to 2.4 GHz?

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Wireless Advantages

• Mobility and increased reach
• Ease and speed of deployment
• Flexibility and ease of configuration
• Cost savings (sometimes)
• New business opportunities (m-commerce)

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Wireless Challenges

• Scarce total bandwidth available
• Compared to wired, generally
• Slower
• Less reliable
• Less secure
• Less able to ensure QoS

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Electromagnetic Spectrum
Details at http//www.ntia.doc.gov/osmhome/allochr
t.html
ACPower
Voice
ISM
VHFTVFMRadio
UHFTV
AM Radio
IR, Visible Light, UV
PCS
Hearing
Satellite
AnalogCell Phone
ISM Industrial, Scientific, Medical (allows
unlicensed but not unregulated uses).902-928
MHz, 2.4-2.48 GHz, 5.x GHz
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IEEE 802 Standards
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802.11 LAN Components
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Independent and Infrastructure BSSs
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Extended Service Sets (ESSs)
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Overlapping Network Types
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Network Services
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Mobility Support Transitions