More activities with mobile phones Not a word was said. Since 1947, some scientists at Bell Laboratories have been thinking of new ways to design mobile telephones. They realized that the way transmitters are used in general radio services, that is, huge power transmitters whose transmitted radio messages travel mile after mile, is not suitable for mobile phones. Mobile phone service must be provided using a very low-powered transmitter – so that the transmitter’s ability to send messages is limited to one-and-a-half miles.
What are the benefits? The advantage is that the same frequency can be used again one and a half miles away from that transmitter (frequency reuse) – without any interruption or interference in the message sent by the first transmitter. There are two benefits to this. Because the same frequency (or channel) can be used over and over again, there will be no need for multiple channels, and because the power of the transmitter will be very low, there will be no difficulty in making transmitter-receivers and working them together.
This time they divided a city into many smaller cells to provide services. Each cell will have a small transmitter-receiver tower and a specific number of channels for that cell – which will then be used in another cell far away. The telephone connection will take place through the cell tower through any one of the channels specified for the cell in which the mobile telephone will be located.
When the mobile phone moves from one cell to another, just before the first tower the tower next to it will ask the visitor to arrange a channel for the mobile, so that the mobile ‘call’ from the previous channel to the new channel without cutting off the connection. -T is transferred (hand off). This technology is called cellular technology. This is why in many countries mobile phones are replaced by cell phones, and services are called cellular services.
Although it is excellent in the pen, no one bothered about it for many days. This is because in order to use it, the radio receiver has to automatically tune itself to the new frequency in a matter of moments as it moves from cell to cell; You will need powerful computers and complex software. But everything developed slowly. The first cellular service was launched in 1983 in Chicago. This technology is called Advanced Mobile Phone Service (AMPS).