Transcription of CELLULAR MOBILE COMMUNICATION
{{id}} {{{paragraph}}}
CELLULAR MOBILE COMMUNICATION1 UNIT IINTRODUCTION TO WIRELESS MOBILE COMMUNICATION2 Introduction: In1897,GuglielmoMarconifirstdemonstrated radio sabilitytoprovidecontinuouscontactwithsh ipssailingtheEnglishchannel. Duringthepast10years,fueledby DigitalandRFcircuitfabricationimprovemen ts NewVLSI technologies Otherminiaturizationtechnologies( ,passivecomponents) Themobilecommunicationsindustryhasgrownb yordersofmagnitude. of MOBILE Radio Communications4 In1934,AMmobilecommunicationsystemsformu nicipalpoliceradiosystems. Vehicleignitionnoisewasamajorproblem. In1946,FMmobilecommunicationsforthefirst publicmobiletelephoneservice Eachsystemusedasingle,high-poweredtransm itterandlargetowertocoverdistancesofover 50km.
In late 1991, U.S. Digital Cellular (USDC, IS-54) was introduced. to replace AMPS analog channels 3 times of capacity due to the use of digital modulation ( DQPSK), speech coding, and TDMA technologies. could further increase up to 6 times of capacity given the advancements of DSP and speech coding technologies.
Domain:
Source:
Link to this page:
Please notify us if you found a problem with this document:
{{id}} {{{paragraph}}}