Mobile /Wireless Communication

workablejeansMobile - Wireless

Nov 21, 2013 (3 years and 7 months ago)

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1

Mobile /Wireless Communication

What can change for Mobility?


Spring 2008

Instructor: Yuhao Wang

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What is Mobility?


A device that moves


Between different geographical locations


Between different networks


A person who moves


Between different geographical locations


Between different networks


Between different communication devices


Between different applications


3

Topics in Wireless Communication


Wireless Communications



Space
-
time, OFDM, MIMO


UWB and Impulse Radio


Channel Modeling and Characterization


Modulation/Coding/Signal Processing


B3G Systems, WiMAX and WLAN


Advances in Wireless Video


RFID Technologies


Mobility and Handoff Management

4

Topics in Wireless Communication


Services and Application



Wireless/mobile networked Applications


Multimedia in Wireless Ad
-
hoc Networks


Authentication, Authorization and Billing


Advances in Wireless Video


Location Based Services (LBS)


Applications and Services for B3G/4G era


Radio Resource Management

5

Topics in Wireless Communication


Networking and Systems



Wireless sensors networking


Security in wireless networks


Network measurement and Management


Ad hoc and sensor networks


Multimedia QoS and traffic Management


Network protocols for Mobile Networks


Internetworking of WLAN & Cellular Networks

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Device mobility


Plug in laptop at home/work on Ethernet


Occasional long breaks in network access


Wired network access only (connected => well
-
connected)


Network address changes


Only one type of network interface


May want access to information when no network is
available: hoard information locally


Cell phone with access to cellular network


Continuous connectivity


Phone # remains the same (high
-
level network address)


Network performance may vary from place to place

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Device mobility, continued


Can we achieve best of both worlds?


Continuous connectivity of wireless access


Performance of better networks when available


Laptop moves between Ethernet and Wireless LAN


Wired and wireless network access


Potentially continuous connectivity, but may be breaks in
service


Network address changes


Radically different network performance on different
networks

8

People mobility


Phone available at home or at work


Multiple phone numbers to reach me


Breaks in my reachability when I’m not in


Cell phone


Only one number to reach me


Continuously reachable


Sometimes poor quality and expensive connectivity


Cell phone, networked PDA, etc.


Multiple numbers/addresses for best quality connection


Continuous reachability


Best choice of address may depend on sender’s device
or message content


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Mobility means changes

How does it affect the following?


Hardware


Lighter


More robust


Lower power


Wireless communication


Can’t tune for stationary access


Network protocols


Name changes


Delay changes


Error rate changes


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Changes, continued


Fidelity


High fidelity may not be possible


Data consistency


Strong consistency no longer possible


Location/transparency awareness


Transparency not always desirable


Names/addresses


Names of endpoints may change


Security


Lighter
-
weight algorithms


Endpoint authentication harder


Devices more vulnerable

11

Changes, continued, again


Performance


Network, CPU all constrained


Delay and delay variability


Operating systems


New resources to track and manage: energy


Applications


Name changes


Changes in connectivity


Changes in quality of resources


People


Introduces new complexities, failures, devices


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Example changes


Addresses


Phone numbers, IP addresses


Network performance


Bandwidth, delay, bit error rates, cost, connectivity


Network interfaces


PPP, eth0, strip


Between applications


Different interfaces over phone & laptop


Within applications


Loss of bandwidth triggers change from B&W to color


Available resources


Files, printers, displays, power, even routing

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Summing up

Generally, mobility stresses all resources further:



CPU


Power


Bandwidth


Delay tolerance


Radio spectrum


Human attention


Physical size


Constraints on peripherals and GUIs (modality of
interaction)


Locations (body parts!) for device placement


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References


T. S. Rappaport, "Wireless Communications: Principles & Practice," 2nd
Ed., Prentice
-
Hall:Upper Saddle River, NJ, 2002, ISBN 0
-
13
-
042232
-
0.


Jon Mark, Weihua Zhuang, "Wireless Communications and Networking,"
Prentice Hall. ISBN: 0130409057; 2003.


David Tse, Pramod Viswanath, "Fundamentals of Wireless
Communications," Cambridge University Press, 2005.


Harri Holma and Antti Toskala (ed.), ``WCDMA for UMTS : radio access
for third generation mobile communications,'' Chichester ; New York :
Wiley, c2000.




John G. Proakis, ``Digital communications,'' 4th ed., Boston : McGraw
-
Hill,
c2001.


. D. Parsons, "The Mobile Radio Propagation Channel," 2nd Edition, Wiley,
2000.


G. L. Stueber, ``Principles of mobile communication,'' 2nd Ed., Norwell,
MA: Kluwer, 2001.


http://www.wu.ece.ufl.edu/books/EE/wireless/wireless.html