1. MOBILE AND WIRELESS
COMPUTING

2. Mobile Computing
 Also called nomadic, tetherless, wireless,
ubiquitous, remote computing
 User does not need to maintain a fixed
position in the network
 Useful for persons who travel away from
their primary work place

3. Mobile Computing
 Mobile computing is "taking a computer
and all necessary files and software out
into the field.“
 Mobile commerce is any transaction,
involving the transaction having
monetary value, which is initiated and/or
completed by using wireless electronic
device such as mobile phones, PDAs,
pagers etc. and mobile telecommunication
network. It is subset of e-commerce.

5. Mobile & Wireless Computation
 Wireless & Mobile are not synonymous
 Wireless
 Isa transmission or information transport
method that enables mobile computing
 Communication is without wires
 MobileComputing focuses on the
applications side .
 Ability to compute no matter where the
user is
 Infrared, cellular, radio waves, microwave,
satellite services

6. Mobile Computing Framework
 Wireless delivery technology
 Mobile Information Access Devices
 Mobile Data Internetworking standards
and equipment
 Mobile computing based business
applications

7. Wireless delivery technology
1. Radio-Based Systems
2. Infrared or mobile based computing

8. Radio-Based Systems
 Thesesystems use radio frequency (RF)
signals that range from 100 KHz to 20
GHz
 RF communication is of 3 types
 One way
 Two way
 Local way

9. Cont…
 Radio-Basedservices can be grouped in
two main categories
1. Land Based
 Cellular Communications
 Wireless Packet Data networks(GPRS)
1. Satellite Based(Satellite Networks)
 Very Small Aperture Terminals(VSATs)
 Paging and Satellite networks

10. Cellular Communications
 In cellular system, the area of coverage is
divided in to hexagonal cells that overlap
at the outer boundaries
 Communication takes place with the help
of transceivers
 A signal from the handset goes to nearest
cell through telephone lines
 The size of cell is 2-10 miles
 Working

11. Wireless Packet data networks
 Uses packet techniques for transferring
data
 Packet radio is a communication method
used to transmit packets of data over
network via RF signals
 These services were designed with data
only in mind
 Working

12. Satellite Networks
 Used for global communication(broadcast)
 Useful where data need to be dispersed or
gathered from many remote nodes and
end to end delay is not of concern
 Cost effective
 Reliable
 Suitable for remote areas where poor or
non existent phone services
 Disadv: poor choice for systems where a
high degree of security is required

13. Very small aperture
terminals(VSATS)
 Uses a large no. of small dishes called
VSATS for outlying nodes and one central
hub with a big dish.
 This approach causes additional delay
 Typically used by the organizations that
require data or voice communication
between sites distributed over a wide
geographical area

14. Paging and satellite networks
 Oldest form of mobile communication
(1949)
 One way mobile communication services
 Wireless communications
 Working
 Used for news, sports, weather, stock
information etc at scheduled intervals

15. Infrared or light based mobile
computing
 Works by sending pulses of light from a
LED to a photo sensor that diverts signals
 Computing devices can send as well as
receives signals
 Types of infrared equipments
 Low speed (115 kbps- 250 kbps)
 High speed (about 1.25 mbps)
 There should not be any physical
obstructions between sending and
receiving
 Cost effective

16. Mobile Information Access
Devices
 Portable Computers
 Laptops,Notebooks,Handhelds
 Hybrid Pen Computers
 Personal Digital Assistants(PDAs)

17. Mobile Data Internetworking
standards and equipment
Reasons for analog to digital transition:
 Limited available bandwidth
 Overcrowding
Current analog system divides the available
spectrum into 30 KHz wide channels.

18. Cont…
Technologies for multiple Channel Access
 CDMA(Code Division Multiple Access)
 Isa wideband spread-spectrum technology
 Uses specialized codes as the basis of
channelization(division of the frequency
spectrum into multiple channels)
 TDMA(Time Division Multiple Access)
 GSM(Global
System for Mobile
Communications ) is a type of TDMA
 Addsa time sharing of 3 users on each
frequency)

19. Mobile computing based business
applications
It is resulting in two changes:
 Remote Communications
 Remote data access
Applications:
 Health care
 Retail
 Field service
 Traveling professionals
 Sales and service

20. Cont…
Applications:
 Members of work groups
 Stock and commodity training

21. Technical and other limitations of
mobile computing
 Insufficientbandwidth
 Security standards
 Power consumption
 Transmission interferences
 Potential health hazards
 Human interface with device
(http://en.wikipedia.org/wiki/Mobile_comput
ing)

22. Mobile Data Internetworking
standards and equipment
 Consider a room (channel) in which people wish to
communicate with each other.
 To avoid confusion,
 people could take turns speaking (time division),
 speak at different pitches (frequency division),
 or speak in different directions (spatial division).
 In CDMA, they would speak different languages. People
speaking the same language can understand each other,
but not other people. Similarly, in radio CDMA, each
group of users is given a shared code. Many codes
occupy the same channel, but only users associated with
a particular code can understand each other.
http://www.broadbandreports.com/faq/5668