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MOBILE COMPUTING SEMINAR By : Rounak Jain SOE, CUSAT

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Mobile Devices - Mobile Computing

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Page 1: Mobile devices

MOBILE COMPUTING SEMINAR

By : Rounak Jain

SOE, CUSAT

Page 2: Mobile devices

2. MOBILE DEVICES

1.Mobile Phones

2.Digital Music Players

3.Handheld Pocket Computers

4.Operating System used in Mobile Devices

5.Smart Systems

6.Limitations of Mobile Devices

Page 3: Mobile devices

2. Mobile Phones

Communicate with other phones using a cellular service-

provider network.

Packed with smart functions and are available in smaller sizes.

Applications of mobile phones no longer confined to telephonic

communication.

Can synchronize and upload and download data to and from

PCs.

Provides e-mail and Internet connectivity.

Even click pictures and prepare albums.

Includes a personal information manager (PIM), a handheld

computer, and an entertainment device.

Page 4: Mobile devices

New Generation Mobile Phones

Pack in everything from a computer to

an FM radio and from video recording

to TV viewing.

Smart Phones

Multimedia Phones

Apple iPhones

Page 5: Mobile devices

2. Digital Music Players

Revolutionized the way people listen to music

Includes software that play music files encoded in

formats such as MP3, WMA, Realmedia etc. on mobile,

PCs, and laptops.

Windows Media Player, QuickTime Player are some

examples of media-playing software.

Also include media-playing hardware or handheld (

portable ) music players that can play media file formats

such as MP3, AAC, WMA, WAV etc.

Page 6: Mobile devices

Such Players use flash Memory

Capacity may vary from 128 MB to 80 GB

Present day media players enable video as well as audio

Playback

Market Leader – Apple iPods

Page 7: Mobile devices

Popular Audio File Formats1. WAVE

Short for Waveform Audio, is a Microsoft and IBM audio

format

Audio format standard for storing audio .

Usually contains uncompressed audio in the PCM ( Pulse-

code Modulation ) form but they are also capable of holding

compressed audio.

Used by professionals for maximum audio quality and can

manipulated quite easily for storing compressed audio.

Supports a variety of bit resolutions, sample rates, and

channels of audio

Page 8: Mobile devices

2. RealAudio

Format developed by RealNetworks

Uses both low-bitrate formats for use over dial-

up modems and high-fidelity formats for music

Also serve as a streaming audio format which

can be played while it is being downloaded

Official playing software for RealAudio file format

is the RealPlayer

Page 9: Mobile devices

3. MP3

MP3 ( MPEG-1 audio layer 3) is one of the most

popular digital audio encoding and compression

format.

Uses lossy data compression

Designed to reduce the size of audio files to about

10% of the original uncompressed files without

compromising too much on sound quality.

Became an ISO/IEC standard in 1991.

Some Other Audio Formats are WMA, AAC etc.

Page 10: Mobile devices

3. Handheld Pocket Computers

Handheld Computers or Palmtops Come in many manifestations

For example, the smart phone

Pocket-sized PCs

Differ from smart phones and multimedia phones in that they can be

programmed for customized applications

Offer a variety of application and programming tools not included in new

generation mobile phones

Unlike smart phones, which usually use the text-on-nine-keys format,

handheld computers have full text keypad or a touch screen keypad.

Stylus generally used to enter data into handheld devices such as PDAs

and palmtops.

Some allow the user to write on the screen using a stylus and

incorporate special software for handwriting recognition

Page 11: Mobile devices

Palmtops

Programmable pocket computers

Include word processors and spread sheet software as

well as PIM software

QWERTY keyboards or touch screens with stylus for data

inputs

Page 12: Mobile devices
Page 13: Mobile devices

Difference b/w Pocket Computers and Laptops, notebooks

Pocket PCs no CD drives and hard disks

Use flash memory

Allow the insertion of a memory stick (A memory stick is a

removable flash memory card.)

Clock speeds of pocket computer processors are limited up to

200 MHz due to considerations about battery life

Unlike laptops and notebooks, which use regular

microcomputer operating systems, pocket computers have

specially designed operating systems which are scaled to the

requirements of the software, hardware, and peripherals used

in handheld computers

Page 14: Mobile devices

4. Operating Systems in Handheld Devices

Windows CE

Palm OS

Symbian OS

Linux for Mobile Devices

Android

iOS

Blackberry

Etc.

Page 15: Mobile devices

Windows CE

An operating system from Microsoft

Support multitasking on handheld devices

Real-time operating system meant for handheld computers and

embedded systems

Kernel different from the kernel of the desktop versions of Windows

Computing devices with low storage and can be run in about 1 MB

of memory.

But the Windows CE OS memory needs are larger as compared to

Palm OS

Support a wider range of hardware than Palm OS.

Support different CPUs such as NEC MIPS, Intel StrongARM, AMD

X86, etc.

Page 16: Mobile devices

Features in Windows CE Devices

High resolution colour/ display, touch screen and stylus keypad

Complex APIs

Gives the user a PC like feel and Windows like GUIs

PIM, MS Office, Internet Explorer features on handheld mobile system

The CompactFlash card slots to extend memory and extension card

slots

OS memory requirement is large but scales to the requirement of the

device peripherals

Digital camera card

Games

Microsoft Windows Media player and other media players

Page 17: Mobile devices

Palm OS

An operating system from Palm Inc

Used in smart phones and handheld computing devices

Optimized to support a very specific range of hardware ─ CPU,

controller chips

Screens of Palm OS based devices cannot be much different from

the hardware reference platform designed by Palm Computing

without major changes in the operating system itself

Advantageous in that that, because it is compiled for a specific set

of hardware, its performance is very finely tuned

Inability to adapt to different sorts of hardware

Page 18: Mobile devices
Page 19: Mobile devices

Does not support multitasking

Is definitely not a great platform for running multimedia

applications

Works efficiently when running small productivity

programs but doesn’t offer much expandability.

Palm OS devices usually have wide screens and input of

data is facilitated by a touch screen

PalmOne tungsten T5 Handheld

Page 20: Mobile devices

Symbian OS Was one of the most widely used operating system for smart

phones

Runs exclusively on ARM processors

Structure much like that of some desktop operating systems

Offers pre-emptive multitasking, multithreading

Memory protection

Initially designed for handheld devices with limited resources,

strongly emphasizes on memory conservation

Embodies event-based programming and when applications are

not directly concerned with events, the CPU is switched off

Such techniques are very useful in conserving battery life

Page 21: Mobile devices
Page 22: Mobile devices

Linux for Mobile Devices

Linux can be modified easily to suit different sorts of

hardware and software applications

Being an open source OS, it enables the user to customize

their device to suit their specific needs

Considered to be more secure than most other operating

systems.

Linux support is easily available from the many forums and

associations that promote this OS

Many international mobile phone manufacturers turning to

Linux for their OS requirements

Page 23: Mobile devices
Page 24: Mobile devices

5. Smart Systems

Smart cards

Sensors and Actuators ..

Already Taken

Page 25: Mobile devices

6. Limitations of Mobile Devices

1. Quality and Security of service Constraints

Technical restrictions and practical considerations─ difficulties in mobile device

uninterrupted operations

Maintaining quality of service along with the provisioning of seamless access to all

users

2. Accessibility constraints

Smart labels on packages limited access─ transmitted signals low power

Labels can only be read from very short ranges

RFID access limited to ranges within line of sight

RFID transmissions require hotspots close by due to low transmitted signal

strength. (A hotspot is an access point an interface for mobile systems, sensing

systems, and embedded systems to connect to a mobile network, wireless LAN, or

the Internet.)

Page 26: Mobile devices

3. Range Constraints

Signal strength inversely proportional to the square of the distance

Degradation of signal quality due to reflection, scattering, and diffraction

Access range limited to the range up to which the signal strength is such

that it can be separated from the noise and up to which multi-path delays

can be compensated for by digital signal processing techniques to restore

signal quality

4. Connectivity

Connectivity loss or intermittent connectivity in certain situations

The atmospheric conditions changes in environment affect signal strength

Water attenuation of UHF and near microwave

For example, in the event of heavy rain, there may be complete loss of

connectivity

Page 27: Mobile devices

5. Security constraints

Unsolicited advertisements and unwanted messages

Virus attacks

Hackers render it functionless or threaten integrity and

security of the data stored on the device

Noise signals transmitted by an attacker can jam a mobile

device

Repeated transmission of unwanted signals by an attacker

can drain the resources of the device

Energy resources depleted fast when computations are

forced and authentication algorithms are run repeatedly

Page 28: Mobile devices

6. Mobility Constraints

Non-availability of an access point or base station

Infrastructural issues

No base stations or Wi-Fi hotspots providing connectivity and

access to the Internet to sensors, labels, automotive systems,

RFID tags, and cell phones

Use of different standards in different regions limits the

operability

A GSM phone may not be operable in all continents hence

hampering global roaming for the user

Some service providers may not be able to provide connectivity

in all parts of the country or in other continents, etc.

Page 29: Mobile devices

7. Energy Constraints in Devices

Limited energy in battery. Battery size and power limited due to

considerations such as size, weight, and bulk of mobile devices

The devices need to be recharged after short periods of time. In this way

energy availability also limits device mobility.

Some devices such as smart cards, smart labels, remote sensors, and

actuators do not even have a battery of their own. They derive their

energy from the radiation received from a wireless source in vicinity. Such

devices, therefore, require these sources to Operate

Some devices such as smart cards, smart labels, remote sensors, and

actuators do not have a battery of their own.

They derive their energy from the radiation received from a wireless

source in vicinity. Such devices require these sources

Page 30: Mobile devices

8. Hardware Limitations

Constraints on memory

Innovative forms of memory designed and are continuously improved

upon.

Internal flash drives and the card slots for external memory used

Memory stick used to enhance the memory in the device

Large memory capacity─ 30GB video memory in mobile devices in a

recent enhancement of the Apple iPod

9. Bandwidth Limitations

Limited by the frequency spectrum that a regulator allots to a service

provider

The service must use the frequency spectrum allotted to it in an

efficient manner

Page 31: Mobile devices

University Questions

Operating Systems used in Mobile Devices ( 15 Marks) –

April 2010

What are the features desired in Mobile OS as compared

to desktop PCs ( 7 Marks ) – Sep 2011 Supplementary

Different types of audio file formats ( 5 Marks ) – Sep

2010 Supplementary

Page 32: Mobile devices

References

[1] Mobile Computing by Raj Kamal

[2] Xiang Yang, Yuanyi Zhang, Qinzhou Niu, Xiaomei

Tao, Luo, “A Mobile-Agent-Based Application Model

Design of Pervasive Mobile Devices”, Pervasive

Computing and Applications, 2007, ICPCA 2007.

[3] http://en.wikipedia.org/wiki/Audio_file_format

Page 33: Mobile devices

Thank You .. Questions ??