Cellular Nation--The introduction of cellular devices
Cellular Nation--The introduction of cellular devices Com 2400
Popular in Intro to Media and Telecom
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This 7 page Class Notes was uploaded by Rio Frohriep on Friday November 6, 2015. The Class Notes belongs to Com 2400 at Western Michigan University taught by Kayany in Summer 2015. Since its upload, it has received 31 views. For similar materials see Intro to Media and Telecom in Communication Studies at Western Michigan University.
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Date Created: 11/06/15
Comm 2400 Intro to Media and Telecommunications Cell Phones Pointtopoint communication using radio waves Two way radios It was difficult to find unique frequencies for each user thus cell phones didn t take off for a while Mobile phones have been around since the 1950 s but only for a few people 24 channels were allowed for EMS Fire Police etc Cell System A cell is a small area of 10 square miles with a low power transmitter Frequencies can be reused in nonadjacent cells When Mobile phones started using this system the name changed to Cell Phone Mobile Telephone Switching Office The only wireless part of a cell phone is from the unit to the cell tower from there it travels by wire to the switching office where it then gets transmitted to wherever it needs to go MTSO Mobile Telephone Switching office Cell Phone Generations 16 One frequency per conversation Analog System Uses Bandwidth between 824894 MHz 26 One channel can be used for several conversations Digital System Two systems GSM CDMA 3G More conversations per channel Digital System Smaller cells 4G Faster Data Rates LTE is a technology that allows cell providers to provide 46 speeds GSM vs CDMA CDMA uses code division multiplexing VerizonSprint GSM Uses time division multiplexing ATampTT Mobile Used by 80 of phone systems On CSM Systems you can change the SIM cards Subscriber Identity Module And use it with any other GSM device Cell Phone Regulations Wireless Local Number Portability WLNP From 2003 FCC allowed subscribers to keep their cell phone numbers if they change service providers Cell Phone Consumer Empowerment act Would prohibit SIM locking DIED ON FLOOR AND NEVER BECAME LAW Unlocking Consumer Choice and Wireless Competition Act 2014 Unlocking of cell phones is now legal Smart Phones IBM Simon Introduced in 1992 Included a calendar address book fax modem calculator notepad email application and simple games Touch screen 900 Black Berry 850 1999 Research in Motion RIM introduced Black berry Android 2003 Andy Rubin Rich Miner Nick Sears and Chris White founded Android In 2005 Google bought the tech In 2007 Google and 34 other companies launched the open Handset alliance OHA to work together to create open mobile device standards First Android phone Gt or HTC device was released in 2007 Android Controls 85 of the smartphone market in the world iPhone Released in 2007 by Apple i a uo 739 a 0 I r H 1 ml a mmm The first Tablet PC was introduced in 2000 by Microsoft Was intended as a computer substitute Required a stylus 2000 Apple released iPad in 2010 Apple marketed it as a consumer product and a compliment to a computer The iPad exploded in popularity Voice Over Internet Phone VOIP Delivers voice communications over networks like the internet that uses packet switching eg VonageSkype etc Advantages of VOIP Transmit more than one telephone call over the same broadband connection Easily encrypt calls Loca onindependence Integration with other services available over the internet including video conversation messaging and data file exchange Disadvantages of VOIP Quality of service is unpredictable IP network doesn39t have it s own power system as regular phones do Emergency calls cannot be routed to the nearest emergency center Waves and Frequencies Waves used for radio waves are determined by The unique features of the wave and particulate frequency range The need for spectrum space in other applications National agencies FCC and international agencies ITU determine these two things Modulation the process of stamping information on electromagnetic waves There are two ways of modulation a carrier wave Amplitude and Frequency l39quotll quotlquot quotrm 39 lll39lrlllquotlllquot39 ll l39 391 U I U l39 391 l a U in l If U 39J l lquot U l l if U l l ll U l39l l l l r Nl39lIY 39ld39 H quot39l tll39l39ll w n 4 J J U HJ39JL39H KU g0 U U v f l 391 in U Ill Uquot h u ll ll JquotIndiaUnixIquotquotn Inlhjlk nbl39b J fluP 39l39lvquotquotulquot3939l39lb39 39Jii39JlJatiCl39 I ll Bandwidth AM signal requires 10 KHz of space FM signal require 200 KHz of space 20 AM stations Television requires 6 MHz of space 30 FM stations600 AM stations VHF vs UHF VHF Very High Frequency 54 MHz216 MHz Channels 213 UHF Ultra High Frequency 470 MHz870 MHz Channels 1483 Long Distance Relay of Signals Direct WavesSpace Waves Directly from transmitter to antenna Ground WavesSurface Waves Through the ground along the curvature of the earth Sky Waves Bounces off the ionosphere This is known as shortwave broadcasting Microwave relays Relay towers pick up incoming signals Amplify them Then Transmit them to the next tower Satellites Low Orbiting Medium orbiting GeoStationary What is used for Communication GeoStationary Satellites Placed in a position where the gravity is almost nonexistent so it does not fall to the ground They orbit the earth at the exact same speed the earth spins so they appear stationary Also called Geo synchronous satellites First communication satellite Developed by ATampT Launched by NASA in 1962 Named Telstar Footprint of a satellite The range of a satellite signal Uplink and Downlink Satellites require two different frequencies so the signals don t interfere with each other The signal beamed up to the satellite is called the Uplink The signal beamed down from the satellite is called the Downlink Transponders Receive amplify and change the frequency from the uplink and transmit it back to Earth A typical satellite has 2448 transponders Satellite Frequency Satellites operate in SHF Super High Frequency a range that is measured in GHz CBand 64 GHz KuBand 1411 GHz KaBand 3020 GHz International Telecommunications Union Apart of the United Nations Assigns specific slots in geostationary orbit and frequency Coaxial Cable Bandwidth typically up to 400 MHz Fiberoptics Strands of glass through with bits of laser beams are sent Bandwidth up to 2 GHz Immune to external interference Secure Almost impossible to tap into