JOEL OPENS UP A PORTABLE COMMUNICATION SYSTEM.
A cellular mobile phone is a telecommunication devices which uses radio waves over a cell (networked area). it is served through a cell site or base station at a fixed location, enabling the calls to transmit wirelessly over a wide range to fixed the landline or via internet, In 1970, when he was working as an electrical engineer at Bell labs, in Murray hill, New jersey, Amos Joel came up with an idea that worked so well that many of us it today without noticing that anything has happened at all. Joel had invented the idea of the cellular mobile phone.
Cell phone existed prior to 1970, but they had problem. Since each call was made on a single
channel, the number of simultaneous call was limited to the number of available channels. additionally the cell phone could not leave the base station area of coverage in which the call was initiated or the connection to net work would be lost.
Joel's cellular mobile phone communication system proposed providing phone services to a geographic area by dividing up into many small, low powered base station or "cells." This network of the cell deal a greater number of simultaneous call by allocating a radio channels to a call in one cell and reusing the same radio channel in a number of other cells separated by enough distance to prevent interference. When a user traveled from the service area of one cell to another, the user 's phone call would not be disrupted as each cell would "hand off" to the other, switching cellular base station and radio channels without anyone noticing.
The key ingredient? A microprocessor that could make all the decision, find cellular base station, identify the phone , and control the connection as user moved through the network. Today's cell phone supports a number of additional services ,such as access to internet, messaging, and camera. mobile phone connected to a terrestrial cellular network of base station whereas the satellite phone connected to orbiting satellite.
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