G Rajesh [U4ECE 13117]

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Mobile Phones

Introduction

A mobile phone (also known as a cellular phone, cell phone, hand phone, or simply a phone) is a phone that can make and receive telephone calls over a radio link while moving around a wide geographic area.

History

The first official mobile phone used in Sweden by the Swedish police in 1946;

 could make 6 phone calls before car's battery was drained

John F. Mitchell and Martin Cooper of Motorola in 1973, - First Commercial Cell Phone.

 1983 Motorola DynaTAC 8000X made commercially available: 2 lbs, $3,500

1991 Motorola MicroTac Lite the lightest phone: $1,000 

Dr, Martin Cooper

Researcher for Motorola

Credited with inventing the first cellular phone

1973 made the first call to rival Joel Engel, Head Researcher from Bell Labs

Motorola first to use cell technology without the use of an automobile

Evolution

Manufacturers

Features of a Mobile Phone

A  modern day mobile phone has the following features(but are not mandatory or limited to) in common 

Screen

Battery

Processors

Operating System

Memory

Camera

Sound Output & Input

Sensors

Screen

Once Used only to display numbers

But then the trend changed:

8 bit games –Bigger

Camera – Sharper

Video- Refresh Rate

The first screen appeared in 1996 on Various phones ,slightly greater than 1 inch

Siemens S10 – the first mobile phone with a full colour screen (1998)

Now – Over 5.5 inch

Various Types of screens

TFT-LCD

(thin-film transistor liquid crystal display)

The only type used in phones now

need to have a light behind them,

hence not Thin

Used in Google Nexus 7,HTC Desire C

AMOLED(Active-matrix organic light-emitting diode)based on organic compounds high image qualityvery low power usageCostly ,Difficult to ManufactureUsed for HTC Desire ;replaced with LCD

Super AMOLED & Super AMOLED+

Derived form of AMOLED

Includes capacitive touch screen while mfg

doesn't have to be overlaid later

Increased Brightness & lower power usage

Used in Samsung Galaxy S2

Retina displaymarketing term created by Applepixel density high enough such that human eye is unable to make outNo pixilation Used in all apple devices

Platform

Platform- Operating System +Processors

Processors System-on-a-Chip (SoC) SoC is made of

CPU GPU sub-processors like video encoders & decoders

What’s a processor?

A processor executes what you want your Smartphone to do.

What’s a core?

Its an element found in the main processor that reads and executes instructions.

What’s the benefit of multiple cores?

The more cores, the faster they can divvy up the work

Is an octa-core smartphone twice as fast as a quad-core one?

No

What other factors are involved?

GPU,RAM,etc

Operating Systems

Interface between hardware and the User

The 4 main OSs are :

IOS – Apple Inc

Blackberry OS

Windows Mobile OS

Android OS

Other OSs :

Ubuntu Touch

Sailfish OS

Tizen

Android – Google

Unveiled in 2007Initially developed by Android Inc, bought by GoogleMost used OS till date

Versions:Android v1 2007 to Android 6 2015

UI flavors/ROMS:Cyanogen ModMIUIAOSPMokee

Connectivity

Few ways in which a phone can connect with other machines :

BluetoothWiFiUSB RadioInfrared

WiFi1st version of the 802.11 protocol in 1997,2 Mbit/sUpdated to 802.11b in 1999,11 Mbits/sLocal area wireless computer networking technologyUses the 2.4 ghz and 5 ghz radio bandsless secure than wired connectionsRange depends on

frequency band radio power output antenna gain and antenna type

WiFi –Protected System (WPS)Uses:

Internet access City Wide Connectivity Campus Wide Connectivity

Bluetooth

Invented by telecom vendor Ericsson in 1994Ideal for data exchange over short distancesUses short-wavelength UHF radio wavesoperates at frequencies between 2400 and 2483.5 MHz Managed by Bluetooth Special Interest GroupRange :Typically less than 10m, up to 100mLow power consumption compared to WiFiUses:

Phone to phone data transfer Wireless Controlling Bluetooth speakers,earphones

USB

Universal Serial Bus

developed in the mid-1990

currently developed by the USB Implementers Forum

designed to standardize the connection of computer peripherals

Size - Standard , mini, micro

USB 1.X , 1996 1.5 Mbit/s

USB 2.0 , 2000 480 Mbit/s

USB 3.0,2008 3.2 Gbit/s

Phone to Phone Call

Mobile Phones are ‘radio’ phones

Operating at microwave /radio frequencies

Handset power minimised by having a network of local transmitters and receivers

Each colour represents a base

station operating at a slightly different frequency

Making a mobile-to-mobile call

Network Control Knows in which cell every telephone is

Originating Telephone

Receiving Telephone

Screen

Linking to base stations

Mast power between

• 60 watts and 120 watts

•Handset power

• less than 1 watt

•Handset sends signals every few minutes to establish which is the nearest mast

Screen

Anatomy of a GSM Signal

2G or GSM phone

217 Pulses per second per telephone call

Each frequency channel can carry 7 calls

Thank You