Allen Software

Cellular Telephony

The use of an only transmitter taking care of an area of very great service, with this to the measure that the subscriber arrived at the limit of the service area the signal went if vanishing until at last, if to lose thus falling the linking. One was not possible ‘ ‘ hand off’ ‘ , that is the impossibility of the linking to be transferred to one another area of service, was plus one of the limitations of the system. The overlapping of the attendance areas would provoke a mutual interference, since they were used transmitters of high power. Moreover the price of the services was carssimos. All these disadvantages in the systems of mobile telephony, had taken the adoption of a more efficient system for the mobile communication, were implemented then the System of Telephony Cellular Radio. The Cellular Telephony At the beginning the cellular system existed only in the concept (virtually), since the fulfilment of some criteria was necessary, more specifically three criteria, so that the system if became reality: 1 – To allow that a radio telephone syntonized hundreds of canals was first obstacle for the cellular telephony.

At the time already the canal element existed, but it was very great to be used in a mobile telephone. A lesser and more practical element was necessary. 2 – The commutation mechanism, that is the essence of the cellular service, was as the obstacle for the implementation of the system. The commutation mechanism is the responsible one for the management of the existing tasks in the cellular one. At the time technology was not advanced the sufficient to create a computerized central office to co-ordinate these tasks. 3 – The third obstacle was the specter of available frequency. The band of 800MHz in which it operates a cellular telephone had been placed for use. Surpassed these obstacles the phase of implementation of the system started, that is the subject of my next article.


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