Mobile Computing A Brief Report

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Mobile Computing A Brief Report

• Shakir Ali Mohammed
• Dept. of Computer Science
• University at Albany.

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Mobile Computing

• Introduction
• Market of Mobile and Wireless Communication
• Difference between Mobile and traditional
  Computing.
• Network Architecture for Mobile Computing
• Applications and Products
• Challenges in Mobile Computing
• Some Useful Resources.
• Conclusion.

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Introduction

• Ubiquitous Computing i.e.
• Anywhere Anytime Computing
• Mobile Computing is
• Portable Computers Wireless n/w
• Portable Computers modem Telephone Network
• Workstation Wired n/w mobile users

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Computers Everywhere

• Vision of ubiquitous computing hundreds of
  computers per person, various sizes and
  capabilities
• Marc Weiser Scientific American article The
  Computer for the 21st Century

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Some Recent Outlook Numbers(Mid 2000)

• By the year 2004, Revenue from wireless data will
  reach 33.5 Billion Globally ( Source Strategies
  Group)
• By the Year 2010, there will one billion wireless
  subscribes worldwide on 3G Networks. ( Source
  Strategies Group)

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What does Mobile Computing Offer?

• Untethered and/or tiny computers yield
• A choice of work environments
• In your garden (but watch out for birds!)
• Coffee shops
• In the field
• Remote access to important data
• Clients office (no "can I borrow your
  computer")
• Meetings (e.g., quick access to statistics,
  reports)
• In the grocery store!

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Offerings Contd.

• Electronic note-taking
• While touring a new city
• Where am I? What is this building? How do I
  get to Lane Avenue? Im hungry!
• Diversion
• E-books stored, downloadable
• Games e.g., chess, solitaire, poker
• Ubiquitous communication
• email, Web
• voice
• video

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Mobile Devices

• A variety of computing and communication devices
  for mobile users
• Watch-sized devices (and usually a watch!)
• PDA (Personal Digital Assistants)
• Multifunction cellular phones
• Palm-sized computers
• Wearable computers
• Notebook computers

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Characteristics of Mobile Devices

• Resource-poor compared to their desktop
  counterparts
• Limited processing power
• Limited battery life
• Limited network connectivity
• Poor availabilitythey sleep a lot!
• Poor display resolution (except notebooks)
• Tedious data input (except notebooks

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Characteristics Contd.

• Limitations are a result of tradeoffs between
  portability and horsepower
• Very small size limits traditional I/O methods
• New ones handwriting recognition, voice input
• Must work well or extreme frustration...
• Notebook computers fare better in the comparison
  with desktops because they ride the edge
• Reasonable screen size
• Decent keyboards
• Mouse substitutes
• Ample memory

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Mobile System Architecture

• Mobile Computing System consists of Static Host
  and Mobile Host.
• Static Host have fixed geographical locations.
  Mobile host can move and have a Unique Network
  Address
• Some Static Host with required infrastructure are
  designated as Mobile Support Service MSS

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Mobile System Architecture

• Communication among the MSS is done using
  Backbone Network
• Communication between MSS and MH in its cell is
  done over wireless medium.
• Each MH has a Home agent (MSS) which maintains
  information such as current location, services
  subscribed, etc.

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Mobile System Architecture

• Each MSS is incharge of a Cell, Picocells (about
  100m in diameter), macrocells, or global cells
• - A Handoff is involved when a MH crosses
  cell
• boundary
• HANDOFF
• MSS Broadcasts MSS specific information, MH keeps
  track of this information and checks with the
  information previously stored, if the MH changes
  the cell, this information received from MSS is
  different from stored, thus MH knows about the
  change of MSS, and thus a Handoff is said to be
  taken place.

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Network Architecture for Heterogeneous Mobile
computing
A Paper presented by Eric A. Brewer, Radny H.
Katz summuarizes the resuts of BARWAN Project
which focused on enabling truly useful mobile
networks and mobile devices. Overlay Networks as
discussed in this paper shows that lower levels
are comprised of high bandwidth wireless cells
that cover a relatively small area, Higher levels
in the hierarchy provide a lower bandwidth per
unit area connection over a large geographic area.
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Vertical Handoff

• There is difference between Upward and downward
  Vertical Handoffs.
• Upward vertical Handoff is a handoff to an
  overlay with a larger cell size and lower
  bandwidth/area.
• Downward vertical Handoff is a handoff to an
  overlay with smaller cell size and higher
  bandwidth/area.

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Wireless Application Protocol WAP and wireless
markup language WML

• WAP allows mobile phones and other mobile devices
  to connect to the internet
• WAP and WML are extension to HTTP and HTML
  specially designed for the wireless technologies.
• Unlike pages in HTML WML has Cards, files in WML
  are called as Decks
• WML script is similar to Java script which can be
  used to validate User, send messages etc.

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Wml
lt?xml version"1.0"?gt lt!DOCTYPE wml PUBLIC
"-//WAPFORUM//DTD WML1.1//EN"    
"http//www.wapforum.org/DTD/wml_1.1.xml"gt
ltwmlgt   ltcard id"Hello" title"Hello"gt      ltpgt
Hello from WML! lt/pgt   lt/cardgt lt/wmlgt
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Applications

• Various Business Applications like for mobile
  computing both horizontla applications that are
  used by workers and professionals across the
  industries as well as specific to bussiness
  process in a vertical industry.
• Horizontal applications
• Internet messaging, Paging etc,
• Database Inquiry, File Transfer,
• Sales Force Automation.

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Applications Contd.

• Vertical Applications
• Airline and Railway Industries,
• Construction Industry,
• Distribution Industry,
• Electronic News Communication,
• Financial Industry.

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Mobile Computing Challenges

• Challenges in mobile computing directly related
  to the resource-poor nature of the devices
• Mobile computing isnt a simple extension of
  distributed computing
• Power-poor
• Hostile environment
• Poor (or no) network bandwidth
• Higher error rates
• Frequent disconnection
• Variable latency
• Mobility

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Challenges contd.

• Result Must rethink many issues cant just
  plug in classic distributed systems theory
• Adaptability to deal with varying conditions
• Transcoding proxies--scale content (e.g., images)
  to match available bandwidth
• Mobile proxies to convert content (e.g.,
  Postscript ASCII)
• More clever ways of checking for data consistency
• Application callbacks to monitor conditions
  (network, battery power, etc.)

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Challenges Contd.

• Prevalent network protocols require workor
  workarounds to give good performance for
  wireless
• Schemes for mobility
• TCP hacks
• Schemes for intelligent handoff between network
  interfaces
• Tradeoffs between cost, bandwidth, availability

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References and Resources

• www.mobileinfo.com
• Mobile computing An Introduction Sandeep Gupta
  Dept of Comp Science Colorado State University,
  Co.
• A Network Architecture for Heterogeneous Mobile
  computing, Eric A. Brewer, Randy H. Katz,
• Mobile Computing Prof. olden G. Richard III,
  University of New Orleans.

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Conclusion

• Mobile computing is the computing of 21 century
• Vision of ubiquitous computing Hundreds of
  computers per person, various sizes and
  capabilities
• Prevalent Network Protocols require work to
  improve performance
• Schemes for intelligent Handoffs required
• Development of Applications are done keeping in
  mind the limited resources of mobile devices.