Digital Advanced Mobile Phone System

Computer EngineeringComputer NetworkMCA

Digital Advanced Mobile Phone System (D-AMPS)is a digital version of Advanced Mobile Phone Systems (AMPS), the original analog standard for cellular phones. D-AMPS uses a combination of time division multiple access (TDMA) and frequency division multiple access (FDMA). It adds TDMA to get three channels per AMPS channel, thus tripling the number of calls on a channel.

Features

  • They are standardised by IS-54 and IS-136.

  • As in AMPS, D-AMPS also uses frequencies from 800 to 900MHz for transmission. Half of the spectrum is used for sending signals and the other half is used for receiving signals.

  • The frequency band is divided into 30KHz sub-bands, called channels, by FDMA.

  • The channels for uplink are called forward channels and the channels for downlink are called reverse channels.

  • TDMA is applied to each channel thus tripling the number of available channels.

  • Presently, all D-AMPS channels are replaced by GSM or CDMA technology.

raja
Published on 28-Sep-2018 14:58:46
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