Mobile computing

Q . Is one of the

most fascinating things for people of all ages these days? Can you guess? A. Chat rooms B. Trendy dresses C. Mobile D. Hip-hop music

ANSWER: Of course Mobile.1

Mobile computingMigration is important for survival. Mobility originated from the desire to move either towards resources or away from scarcity. Mobile computing is about both physical and logical computing entities that move. Physical entities are computers that change locations. Logical entities are instances of a running user application. Mobile agents can migrate any where over internet.2

BuzzwordsNomadic, mobile, ubiquitous, untethered, pervasive and any time, any where, any person computing are used by researchers to refer to computing. Nomadic computing refer to limited migration. - Migration is within a building at a pedestrian speed. - Interleaved pattern of user relocation and indoor connections -In the same vein, users carrying laptop with DIAL-UP modems are engaged in nomadic computing.

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Buzzwords

Mobile computing requires wireless n/w to support outdoor mobility and handoff from one n/w to the next at a pedestrian or vehicular speed. Traveller in car using laptop connected with a GSM phone - engaged in mobile computing. Ubiquitous computing or pervasive computing refers to access to computer network all the time at any location by any person. Ubiquitous computing can not be realized unless mobile computing matures.4

Relationships: NomadicMobile

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Portable Computing Devices

A keyboard-less tablet PC

The Compaq Portable

A Portable computer -easily moved from place to place - cannot be used while in transit, usually because it requires some "setting-up" and an AC power source. -example: Osborne 1. -also called a transportable or a luggable PC. A Tablet PC -lacks a keyboard -also known as a nonconvertible Tablet PC -shaped like slate or a paper notebook -features a touch screen with a stylus and handwriting recognition software. -Tablets may not be best suited for applications requiring a physical keyboard for typing, -carry out most tasks that an ordinary laptop would be able to perform.

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Portable Computing Devices

An Internet tablet is an Internet appliance in tablet form. - can not replace a general purpose computer. - Internet tablets typically feature an MP3 and video player, a web browser, a chat application & a picture viewer. A Personal digital assistant (PDA) is a small, usually pocket-sized, computer with limited functionality. - It is intended to supplement & to synchronize with a desktop computer, - giving access to contacts, address book, notes, e-mail and other features. An Ultra Mobile PC is a full-featured, PDA-sized computer running a general-purpose operating system. A Smart phone is a PDA with an integrated cell phone functionality. Current smart phones have a wide range of

A Palm TX PDA

A Nokia N800 Internet tablet

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Cell phones

Millions of people in the India and around the world use cellular phones. They are such great gadgets -- with a cell phone, you can talk to anyone on the planet from just about anywhere! These days, cell phones provide an incredible array of functions, and new ones are being added at a breakneck pace. Depending on the cell-phone model, you can: Store contact information Make task or to-do lists Take pics and video clips Keep track of appointments and set reminders Use the built-in calculator for simple math Send or receive e - m a i l Get information (news, entertainment, stock quotes) from the Internet Play games Watch TV Send t e x t m e s s a g e s Integrate other devices such as P D A s, M P 3 p l a y e r s and GPS receivers8

How a cell phone works?

Combination of wireless communicating radio and normal telephone Earlier--radio-telephone system - one central antenna tower per city, - and perhaps 25 channels on that tower. Need of a powerful transmitter to transmit about 70 km. Not many people could use radio telephones-coz lack of enough channels. Division of city into small cells Extensive frequency reuse

Problems:

Solutions:

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Comparing cell phone with CB radio & walkie-talkie Full-duplex vs. half-duplex

- Both walkie-talkies and CB radios are half-duplex devices - A cell phone is a fullduplex device. Channels -A walkie-talkie(1 channel) ,CB radio (40 channels) but a cell phone communicate over 1,664 channels or more! Range - A walkie-talkie transmit about 1.6 km using a 0.25-watt transmitter. - A CB radio transmit about 8 km using a 5-watt transmitter. - Cell phones operate within cells, and they can switch cells as they move around. Cells give cell phones incredible range.

In half-duplex radio, both transmitters use the same frequency. Only one party can talk at a time.10

How a cell phone works? When someone tries to call you. When u turn on, it listens for an SID on the control channel compares it to the SID programmed into the phone, If

match, the phone is part of home system. Also transmits a registration request, Through this, MTSO keeps track of your phone's location in a database when called, it tries to find you in its database to see which cell you are in. The MTSO picks a frequency pair that your phone will use in that cell to take the call. The MTSO communicates with your phone over the control channel Tells it which frequencies to use, and once your phone and the tower switch on those frequencies, the call is connected. Now, you are talking by two-way radio to a friend.

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How a cell phone works? When u move towards the

edge of your cell your cell's base station notices diminishing signal strength The base station in the cell you are moving towards notices increasing signal strength. The two base stations coordinate through the MTSO your phone gets a signal on a control channel telling it to change frequencies. This hand off switches your phone to the new cell.12

How a cell phone works? If the SID on the control channel does not match the SID

programmed into your phone, then the phone knows it is roaming. The MTSO of the cell that you are roaming in contacts the MTSO of your home system, Which checks its database to confirm that the SID of the phone you are using is valid. Your home system verifies your phone to the local MTSO, which then tracks your phone as you move through its cells. And the amazing thing is that all of this happens within seconds. The less amazing thing is that you may be charged insane rates for your roaming call. And More than one person has been unpleasantly surprised by the cost of roaming. So, Check your service contract carefully to find out how much you're paying when you roam. Note that if you want to roam internationally, you'll need a phone that will work both at home and abroad. Different countries use different cellular access technologies.13

Cell phone towers

A cell-phone tower is a steel pole or lattice structure that rises hundreds of feet into the air. This cell-phone tower near Hanuman Nagar is typical in the Mysore:14

Cell phone towers

The box houses the radio transmitters and receivers that let the tower communicate with the phones. The radios connect with the antennae on the tower through a set of thick cables:15

Cell-phone Network Technologies: 3G

Latest mobile communication. Stands for 3rd generation Intended for true multimedia cell phone The International Telecommunications Union (ITU) defined the third generation (3G) of mobile telephony standards IMT-2000 - to facilitate growth -increased bandwidth and transfer rates to accommodate web based applications and phone-based audio and video files. - But to support mobile multimedia applications, 3G had to deliver packet-switched data with better spectral efficiency, at far greater speeds.

Usage:- ideal for downloading information from the Internet and sending and receiving large, multimedia files coz of high data rates - 3G phones are like mini-laptops. - can accommodate broadband applications like 1) video conferencing 2) receiving streaming video from the Web 3) sending and receiving faxes 4) instantly downloading e-mail messages with attachments.

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Latest 3g phone

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Cell-phone Network Technologies: 3G

3G comprises several cellular access technologies. The three most common ones as of 2005 are: CDMA2000 - based on 2G Code Division Multiple Access (see Cellular Access Technologies) WCDMA (UMTS) - Wideband Code Division Multiple Access TD-SCDMA-Time-division Synchronous Code division Multiple Access

Some facts:GSM could deliver not only voice, but also circuit-switched data at speeds up to 14.4 Kbps. 3G networks have potential transfer speeds of up to 3 Mbps (about 15 seconds to download a 3-minute MP3 song). For comparison, the fastest 2G phones can achieve up to 144Kbps (about 8 minutes to download a 3-minute song).

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Problems with Cell PhonesNon-repairable internal corrosion of parts as phone wets Extreme heat in a car can damage the battery or the cell-phone electronics. Extreme cold may cause a momentary loss of the screen display. Analog cell phones suffer from a problem known as "cloning." A phone is "cloned" when someone steals its ID numbers and is able to make fraudulent calls on the owner's account19

GPS Navigation everywhere

GPS Navigation stands for the determining of position and direction on or near the surface of the Earth with the help of the Global Positioning System (GPS). A GPS chip is a small radioreceiver that can capture the signals of several GPS satellites simultaneously. It can compute its Position, Velocity and the exact Time. These information are given out in encoded form.

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Technical and other limitations of mobile computing

In su fficie n t b a n d w id th M o b i e i te rn e t a cce ss i g e n e ra l y sl w e r th a n d i ct l n s l o re ca b l co n n e cti n s, u si g te ch n o l g i s su ch a s G P R S and e o n o e E D G E , and more recently 3 G networks . These networks are u su a l y a va i a b l w i i ra n g e o f co m m e rci lce l h o n e l l e th n a lp to w e rs. H i h e r sp e e d w i l ss LA N s are inexpensive , but g re e h a ve ve ry l m i d ra n g e . i te S e cu rity sta n d a rd s W h e n w o rki g m o b i e o n e i d e p e n d e n t o n p u b l c n l s i n e tw o rks, re q u i n g ca re fu lu se o f V P N s. ri P o w e r co n su m p tio n W h e n a p o w e r o u tl t o r p o rta b l g e n e ra to r i n o t e e s a va i a b l , m o b i e co m p u te rs m u st re l e n ti l o n b a tte ry l e l y re y p o w e r. C o m b i e d w i th e co m p a ct si o f m a n y m o b i e n th ze l d e vi s, th i o fte n m e a n s u n u su a l y exp e n si b a tte ri s ce s l ve e m u st b e u se d to o b ta i th e n e ce ssa ry b a tte ry l fe . n i21

Technical and other limitations of mobile computing

Transmission interferences Weather, terrain, and the range from the nearest signal point can all interfere with signal reception. Reception in tunnels, some buildings, and rural areas is often poor. Potential health hazards More car accidents are related to drivers who were talking through a mobile device. Cell phones may interfere with sensitive medical devices. There are allegations that cell phone signals ] may cause health problems.[citation needed Human interface with device Screens and keyboards tend to be small, which may make them harder to use. Alternate input methods such as speech or handwriting recognition require training.

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Challenges 23

Cellular community's effort

is based on location management of cellular phone users. deals with connection oriented communication, since it is motivated by issues in call-setup in telephony. Main problem in mobility management is to find an appropriate trade between searching and informing. Searching is performed when address of the message recipient is not known - at least not known precisely.

Challenges 24 Security is a major concern. Authentication schemes. Encryption schemes. Payment schemes.

- E-tickets - getting a service by producing a ticket. - E-currency - issues like anonymity, creditworthiness, nonrepudiation, etc. Mobile agent security.

QUERIES?25

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