CHAPTER: 01-MOBILE COMPUTING Introduction to Mobile Computing

WIRELESS MOBILE OR MOBILE WIRELESS?

Wireless communication systems is type of

communication system.

Dimensions of mobility:

The set of properties that distinguishes the mobile

computing system from stationary computing system.

WIRELESS & CELLULAR COMMUNICATION

Transmitting voice, data, video and other servicesdata using electromagnetic waves in open space(atmosphere).

Cellular communication:

Wireless communication using unguided media, that is,radio and microwave frequencies or satellites, has foundwidespread use in mobile phones.

MOBILE NETWORK ARCHITECTURE

WIRELESS CHARACTERISTICS

Variant Connectivity

Low bandwidth and reliability

Frequent disconnections

• predictable or sudden

Asymmetric Communication

Broadcast medium

Monetarily expensive

Charges per connection or per message/packet

Connectivity is weak, intermittent and expensive

PORTABLE INFORMATION DEVICES

PDAs, Personal Communicators Light, small and durable to be easily carried around

dumb terminals, palmtops, wristwatch PC/Phone,

will run on AA+ /Ni-Cd/Li-Ion batteries

may be diskless

I/O devices: Mouse is out, Pen is in wireless connection to information networks either infrared or cellular phone

Specialized Hardware (for compression/encryption)

PORTABILITY CHARACTERISTICS

Battery power restrictions transmit/receive, disk spinning, display, CPUs, memoryconsume power

Battery lifetime will see very small increase need energy efficient hardware (CPUs, memory) andsystem software

planned disconnections - doze mode

Power consumption vs. resource utilization

PORTABILITY CHARACTERISTICS CONT.

Resource constraints Mobile computers are resource poor

Reduce program size – interpret script languages (MobileJava?)

Computation and communication load cannot be distributedequally

Small screen sizes

Asymmetry between static and mobilecomputers

MOBILITY CHARACTERISTICS

Location changes

• location management - cost to locate is added tocommunication

Heterogeneity in services

bandwidth restrictions and variability

Dynamic replication of data

•data and services follow users

Querying data - location-based responses

Security and authentication

System configuration is no longer static

WHAT NEEDS TO BE REEXAMINED?

•Operating systems - TinyOS

•File systems - CODA

•Data-based systems – TinyDB

•Communication architecture and protocols

•Hardware and architecture

•Real-Time, multimedia, QoS

•Security

•Application requirements and design

•PDA design: Interfaces, Languages

MOBILITY CONSTRAINTS

•CPU

•Power

•Variable Bandwidth

•Delay tolerance, but unreliable

•Physical size

•Constraints on peripherals and GUIs

•Frequent Location changes

•Security

•Heterogeneity

•Expensive

•Frequent disconnections but predictable

TYPES OF WIRELESS COMMUNICATION

Celullar Wireless computer

network

Radio service

WIRELESS TELECOMMUNICATIONS NETWORKS

WWAN communication bandwidths 1G

The first generation of wireless technology, which was analog based

2G

The second generation of digital wireless technology; accommodates voice and text

2.5G

An interim wireless technology that can accommodate voice, text, and limited graphics

WIRELESS TELECOMMUNICATIONS NETWORKS

3G

The third generation of digital wireless technology; supportsrich media such as video

3.5G

This generation was inserted into the ranks of cell phonegenerations; it refers to the packet-switched technologiesused to achieve higher transmission speeds

4G

The expected next generation of wireless technology thatwill provide faster display of multimedia

WIRELESS TELECOMMUNICATIONS NETWORKS

WWAN communication protocols Frequency Division Multiple Access (FDMA)

Time Division Multiple Access (TDMA)

Code Division Multiple Access (CDMA)

WWAN network systems Global System for Mobile Communications (GSM)

An open, nonproprietary standard for mobile voice and datacommunications

INTRODUCTION MOBILE COMPUTING

Introduction: Mobile computing is computing that allowscontinuous access to remote resources, even to small computingdevices such as laptops, palmtops and other handheld deviceslike personal digital assistants (PDAs) and digital cell phones.

Goal of Mobile Computing: “People and their machines shouldbe able to access information and communicate with each othereasily and securely, in any medium or combination of media –voice, data, image, video, or multimedia – any time, anywhere, ina timely, cost-effective way.”

MOBILE COMPUTING ISSUES

Basic issues of concern in physical mobility

Weak connectivity

Wireless connectivity

Ubiquitous computing

Mobile systems Technical issues for mobility

Security

Security infrastructure

Reliability

Naming and locating

MOBILE COMPUTING

Mobility of physical devices can be viewed at threedifferent levels:

Macro-mobility: This is mobility through a global network. While

moving in such a network, it should be possible to communicate withoutbreaking the existing access. mobile IP, which is the protocol that takes careof macro-mobility.

Micro-mobility: This is mobility of a device in one single

administrative domain of the global network. For cellular networks, this is thelowest level of mobility. Cellular IP is the protocol designed to take care ofmicro-mobility.

Ad hoc mobility: This is mobility within a mobile ad hoc network

(MANET), caused by device mobility constantly changing the networktopology.

MOBILE AGENTS

A mobile agent is a program that can movethrough a network and autonomously execute taskson behalf of the users.

Mobile agents are used to great advantage inapplications like e-commerce, software distribution,information retrieval, system administration,network management, etc.

CONTEXT-AWARE COMPUTING

A context-aware computing system is one which has user, deviceand application interfaces which enable it to remain aware ofvarious parameters like its surroundings, circumstances or actions.

The context of a mobile device represents the circumstances,situations, applications or physical environment under which it isbeing used. For example, the context is student when the device isused to download faculty lectures.

Context-aware computing leads to application-aware computingand pervasive or ubiquitous computing.

CONTEXT-AWARE COMPUTING

The five types of context-aware:

Physical context- The context can be that of the physical environment.

Computing context- Computing context is defined by interrelationships

and conditions of the network connectivity protocol in use

User context- The user context is defined as user location, user profiles,

and persons near the user.

Temporal context Temporal context defines the interrelation between

time and the occurrence of an event or action.

Structural context- It defines a sequence and structure formed by the

elements or records.

MOBILE COMPUTING DEVICES

Personal digital assistant/enterprise digital assistant

Smartphone

Tablet computer

Ultra-Mobile PC

Wearable computer

MOBILE COMPUTING LIMITATIONS

Range & Bandwidth: Mobile Internet access is generally slowerthan direct cable connections,

Security standards: When working mobile, one is dependent onpublic networks.

Power consumption: rely entirely on battery power

Transmission interferences: Weather, terrain, and the rangefrom the nearest signal point can all interfere with signalreception.

Potential health hazards: more likely to be involved in trafficaccidents.

Human interface with device: Screens and keyboards tend tobe small, which may make them hard to use.

NOMADIC, MOBILE & UBIQUITOUS

No

Network

Mobile ComputingNomadic

Computing

Wireless

Network

(B)

Fixed

Network

Wireless

Network

(A)

Fixed

Wireless

Network

Ubiquitous Computing

Ubiquitous computing (ubicomp) is a concept in software engineering and

computer science where computing is made to appear everywhere and anywhere.

WHAT IS PERVASIVE COMPUTING?

Pervasive computing is a term for the

strongly emerging trend toward:

Numerous, casually accessible, often invisible

computing devices

Frequently mobile or embedded in the

environment

Connected to an increasingly ubiquitous

network structure.

IMPRESSIVE WIRELESS INFRASTRUCTURE!

Satellite

Macro-CellMicro-Cell

Urban

In-Building

Pico-Cell

Global

Suburban

dik ©In-Room

(BlueTooth)

MOBILE APPLICATIONS

Expected to create an entire new class ofApplications

new massive markets in conjunction with the Web

Mobile Information Appliances - combining personalcomputing and consumer electronics

Applications: Vertical: vehicle dispatching, tracking, point of sale

Horizontal: mail enabled applications, filteredinformation provision, collaborative computing…

GENERAL EXAMPLES OF MOBILE COMPUTING APPLICATIONS

Vehicles

Emergencies

Traveling Salesman

Entertainment

Education

Location Dependent Services etc.

DIMENSIONS OF MOBILE COMPUTING

Location Awareness

Network Connectivity Quality of Service

Limited device capabilities

Limited power supply

Support for a wide variety of UI

Platform proliferation

Active transaction