Lecture02-MobilePervasivecomputing

Mobile and Pervasive Mobile and Pervasive ComputingComputing

Mobile Commerce 2009 2

The Mobile Commerce The Mobile Commerce LandscapeLandscape


Mobile ComputingMobile Computing Mobile Computing Devices

Personal Digital Assistant (PDA)

A handheld computer principally used for personal information management

Smartphone

Internet-enabled cell phones that can support mobile applications

Blackberry

A handheld device principally used for e-mail


Mobile ComputingMobile Computing Mobile Computing Software

Microbrowser

Wireless Web browser designed to operate with small screens and limited bandwidth and memory requirements

Wireless Application Protocol (WAP)

A suite of network protocols designed to enable different kinds of wireless devices to access WAP-readable files on an Internet-connected Web server


Mobile Computing Mobile Computing LanguagesLanguages

Wireless Markup Language (WML) A scripting language used to create content in the

WAP environment; based on XML, minus unnecessary content to increase speed

Compact Hypertext Markup Language (cHTML)

A scripting language used to create content in i-mode

Extensible Hypertext Markup Language (xHTML)

A general scripting language; compatible with HTML; set by W3 Consortium

Voice XML (VXML) An extension of XML designed to accommodate voice


WAPWAP Fixed Internet protocol:

IP –Internet Protocol: controls movement of individual pieces of information (packets) by means of routers

TCP –Transmission Control Protocol: controls movement of messages consisting of multiple packets

TCP/IP –complete set of protocols used by the Internet Problems with using TCP/IP on wireless

internet: Not developed for wireless links or mobile devices IP: router assumes next network node is same area of

network; with mobile network this may not be the case TCP: deals with lost packets by requesting that lost

packet be resent; with wireless networks connections are lost regularly and packets need to be resent often, thus congesting the system

Solution: Wireless Access Protocol (WAP)


Wireless Application Protocol Wireless Application Protocol (WAP)(WAP)

WAP is the leading global open standard WAP is the leading global open standard

for delivery Information over wireless for delivery Information over wireless

networksnetworks

WAP provides a uniform technologies WAP provides a uniform technologies

platform with platform with consistent formatsconsistent formats for for

delivering Internet and Intranet based delivering Internet and Intranet based

Information and services to digital mobile Information and services to digital mobile

phones and other wireless devices such as phones and other wireless devices such as

pagers, smart phones and communicatorspagers, smart phones and communicators


What WAP Can Do?What WAP Can Do?

Wireless access to Internet contentWireless access to Internet content Wireless access to Corporate IT Systems Wireless access to Corporate IT Systems

and Extranetsand Extranets Wireless access to personal informationWireless access to personal information Individuals will be able to buy theatre Individuals will be able to buy theatre

tickets, book restaurants or place bets from tickets, book restaurants or place bets from anywhere, charged to a telephone account anywhere, charged to a telephone account (MC services)(MC services)

The main news items of the day can be The main news items of the day can be delivered to mobile users on the hour (Pull)delivered to mobile users on the hour (Pull)


WAP ArchitectureWAP Architecture


WAP Wireless Transaction WAP Wireless Transaction ModelModel


WAP Security ProblemWAP Security Problem

WAP gateway is weak link in security WAP gateway provides interface between WAP

protocol stack and regular internet protocol stack WAP uses WTLS (Wireless Transport Layer Security) for

security over wireless links Wired internet uses SSL (Secure Socket Layer) for

security WTLS and SSL are incompatible

Requires that wireless communication be decoded from WTLS and then encoded by SSL for communication to web server at WAP gateway

Creates potential security problem at WAP gateway

Solution: WAP 2Solution: WAP 2


WAP 2WAP 2 Supports an alternative protocol stack that uses

SSL, not WTSL Message is encoded using SSL from mobile

client to web server with not decoding/encoding required in between

WAP gateway not needed (in theory) Provides end-to-end security Only works with faster wireless services (2.5G,

3G) that use a type of IP designed for mobile devices called Mobile IP

Use eXtensibleHTML (XHTML)


Mobile Messaging Mobile Messaging ServicesServices

Short Message Service (SMS) A service that supports the sending and

receiving of short text messages on mobile phones

Enhanced Messaging Service (EMS) An extension of SMS that can send simple

animation, tiny pictures, sounds, and formatted text

Multimedia Messaging Service (MMS)

MMS is able to deliver rich media


Wireless Communications Wireless Communications TechnologyTechnology

Three main categories: WWAN - Technology that supports

wireless telecommunications or wireless wide area networks

WLANWLAN - Technology that supports wireless local area networks

WPANWPAN - Technology that supports wireless personal area networks


Wireless Communications Wireless Communications TechnologyTechnology


WPANWPAN Personal Area Networks

Personal Area Network (PAN)

A wireless telecommunications network for device-to-device connections within a small range

Bluetooth A set of telecommunications standards that enables

wireless devices to communicate with each other over short distances

Developed by Ericsson for short range communication

Maximum speed: 721 Kbps

Maximum range: 30 meters


WLANWLAN

Wireless Local Area Networks Wireless Local Area Network (WLAN)

A telecommunications network that enables users to make medium-range wireless connections to the Internet or another network

Wi-Fi (wireless fidelity)

The common name used to describe the IEEE 802.11 standard used on most WLANs


WLANWLAN

Wireless Local Area Networks 802.11b

The most popular Wi-Fi standard; it is inexpensive and offers sufficient speed for most devices; however, interference can be a problem

802.11aThis Wi-Fi standard is faster than 802.11b but has a smaller range

802.11gThis fast but expensive Wi-Fi standard is mostly used in businesses


WLANWLAN

Wireless Local Area Networks Wireless Access Point (AP)

An antenna that connects a mobile device to a wired LAN

Hotspot

An area or point where a wireless laptop or PDA can make a connection to a wireless local area network


WLAN: IEEE 802.11b, g WLAN: IEEE 802.11b, g (Wi-Fi)(Wi-Fi)

Designed originally for notebook and desktop computer wireless communication

Maximum speed: 802.11b: 11 Mbps 802.11g: 54 Mbps

Maximum range: 500 meters Can be extended with special antennas

Has become very popular in creating wireless "hot spots" where wireless users can connect within a small radius

Most laptop computers come with built-in Wi-Ficapability

Used for Commercial WLANs (e.g., Starbucks) Public neighborhood area networks (NANs)


How Wi-Fi WorksHow Wi-Fi Works


WMANWMAN

Wireless Metropolitan Area Networks (WMAN)

A telecommunications network that enables users to make long-range wireless connections to the Internet or another network

WiMax

A wireless standard (IEEE 802.16) for making broadband network connections over a large area


WMAN: 802.16e (WiMax)WMAN: 802.16e (WiMax) Proposed wireless technology for

distances within a metropolitan area (i.e., within a city)

Could be used for a metropolitan area network (MAN)

Maximum range: 5-15 km (50 km with reduced data rate)

Maximum speed: 75 Mbps Not widely available so far

Limited to telecommunications companies in France


Wireless Wireless Telecommunications Telecommunications

NetworksNetworks

Wireless Wide Area Networks (WWAN)

A telecommunications network that offers wireless coverage over a large geographical area, typically over a cellular phone network


Wireless NetworksWireless Networks


Wireless Wireless Telecommunications Telecommunications

NetworksNetworks Wireless Wide Area Networks

Physical Topology of a WWAN

subscriber identification module (SIM) cardAn extractable storage card used for identification, customer location information, transaction processing, secure communications, and the like


Cellular Telephone Cellular Telephone NetworkNetwork


Wireless NetworksWireless 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

3G - The third generation of digital wireless technology; supports rich media such as video

4G - The expected next generation of wireless technology that will provide faster display of multimedia


WWAN Network Systems – WWAN Network Systems – Mobile Phone TechnologyMobile Phone Technology

Many mobile phone technologies Not compatible Vary in speed

First generation (1G) mobile phone technology -analog: AMPS: Advanced Mobile Phone System

Second generation (2G) mobile phone technologies - digital: FDMA: Frequency Division Multiple Access (old fashioned) TDMA: Time Division Multiple Access (US) CDMA: Code Division Multiple Access (US, Japan, China) GSM: Global System for Mobile (US, Europe)


TDMA vs CDMATDMA vs CDMA

TDMA is slower than CDMA TDMA: 9.6 kbps CDMA: 64 kbps

CDMA is more complex than TDMA Requires code allocation, careful

synchronization CDMA is more secure than TDMA

Different codes are used by different users


GSMGSM

There are variations of TDMA in the world

GSM uses a sophisticated variation of TDMA in which users get very short time slots: 0.577 microseconds


Circuit switching vs. packet Circuit switching vs. packet switchingswitching

Circuit switching– User is assigned one circuit during the entire connect

time Requires long set up time (15-30 seconds) Inefficient use of bandwidth because communications

channel must be maintained for entire session duration

1G and 2G systems use circuit switching Packet switching

User sends voice/data in small groups called packets User does not have circuit assigned during entire

session duration Circuit is only used when a packet is sent More efficient use of bandwidth than circuit switching 2.5G and 3G systems use packet switching


WWAN - Mobile Phone WWAN - Mobile Phone TechnologyTechnology

Two-and-a-half generation (2.5G) mobile phone technology: HSCSD: High-Speed Circuit-Switched Data GPRS: General Packet Radio Service EDGE: Enhanced Data GSM Environment

Third generation (3G) mobile phone technology: WCDMA or UMTS: Wideband CDMA or Universal

Mobile Telecommunications System CDMA2000

Fourth generation (4G) mobile phone technology: –?


2.5G2.5G GPRS

Uses TDMA like GSM but channels can be allocated more than one time slot

Maximum speed: 100 kbps theoretically but 40 kbps in reality

Does not require hardware upgrade from GSM: relatively inexpensive upgrade

EDGE Uses TDMA like GSM/GPRS but uses a

technique that sends more data per time slot Maximum speed: 384 kbps Requires minor upgrades from GPRS system:

relatively inexpensive


3G3G WCDMA/UMTS (WidebandCDMA/Universal

Mobile Telecommunications System) Uses CDMA European standard Maximum speed: 2 mbps in theory, 400 kbps in

reality Requires new spectrum (license must be purchased) Requires new equipment

CDMA Uses CDMA US standard Maximum speed: 114 kbps to 2 mbps

LBS and Pervasive LBS and Pervasive ComputingComputing


Location-Based Service Location-Based Service (LBS)(LBS)

Location-Based Service (LBS)Delivery of m-commerce transactions to individuals in a specific location, at a specific time

The services provided through location-based m-commerce focus on five key areas:

Location Navigation Tracking Mapping Timing



Global Positioning System (GPS) A worldwide satellite-based tracking

system that enables users to determine their position anywhere on the earth

Geographical Information System (GIS)

An information system that integrates GPS data onto digitized map displays



Emergency Response Cell Phone Calls Wireless 911 (e-911)

In the United States, emergency response calls from cellular phones

Automatic Crash Notification (ACN)Device that automatically sends the police the location of a vehicle that has been involved in a crash



Telematics The integration of computers and wireless

communications to improve information flow using the principles of telemetry

Barriers to Location-Based M-Commerce

Accuracy of devices The cost-benefit justification Limited network bandwidth Invasion of privacy


Pervasive ComputingPervasive Computing

Overview of Pervasive Computing Invisible, everywhere computing that is

embedded in the objects around us Principles of Pervasive Computing

• Decentralization

• Diversification

• Connectivity

• Simplicity



Overview of Pervasive Computing Contextual Computing

The enhancement of a user’s interactions by understanding the user, the context, and the applications and information required



Pervasive Computing Initiatives Radio Frequency IDentification

(RFID)

Technology that uses radio waves to identify items

Electronic Product Code (EPC)An RFID code that identifies the manufacturer, producer, version, and serial number of individual consumer products



Pervasive Computing Initiatives Smart Homes

• Lighting• Energy management• Water control• Home security and communications• Home entertainment

Smart Appliances Smart Cars Smart Clothes



Pervasive Computing Initiatives Sensor network

A series of interconnected sensors that monitor the environment in which they are placed

Sensor networks can:• Protect the environment• Public safety• Monitor business and agricultural areas


Essay HomeworkEssay Homework

Find a recent research paper or case study in Journals about “Pervasive Computing” (Sciencedirect or Scopus)

1. Abstract – the section with title, author, journal name, and abstract

2. Description – the main findings and contribution of the article (paper/case study)

3. Conclusion – your comment about the article and suggested further research

Lecture02-MobilePervasivecomputing

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