How a Cellular Phone System Works

The cellular phone entered our lives in the 1980s, and improved communication between people in many countries. The device consisted of a copious amount of technical solutions, but the most outstanding innovation of these was the supportive cellular network.

When you talk to a friend from a different city, your mobile device converts the words you say into electrical signals. They become radio waves, reach your friend’s phone instantly, and then are converted back into sound waves so that the person you are talking to hears your voice. The first cellular phones were almost like hybrids of radio transmitters and receivers. A citizen-band radio and walkie-talkie are very much like them. The cellular network is what makes the difference between the phones and radios. It enables the phones to work between huge distances. A walkie-talkie has a large antenna and works within hundreds of meters, but thanks to technical innovations, a cellular network allows very compact antennas to make connections between very far distances.

The innovation involves the creation of hexagonal areas of land called ‘cells’. Each ‘cell’ has special equipment, each known as a base station. Base stations peak up the phone signals and relay them further so the signal reaches the next station. This step-by-step technique allows the signal to reach your friend’s phone in a flash. When people move, their phones switch cells and the calls do not get interrupted. Some cellular phones even provide information about the cell you are using at the moment.

The development of the cell system helped solve another problem – the availability of frequencies. Cellular networks usually use about 800 frequencies, so the amount is limited. Each conversation needs two frequencies: one frequency for speaking and another one for listening. In other words, both a transmitting and receiving frequency are required at the same time. Therefore, a whole broadband is needed for only 400 talks. However, cells re-use the same frequencies, and many more conversations can take place at the same time in even a very busy area. Engineers have further improved this technology, and they estimate the optimal number of base stations in these areas today. More stations can provide more frequencies, so everyone can make and receive calls and messages with ease.

However, there is still space for new ideas, because the available frequencies sometimes run out. This leaves people confused and frustrated, especially on busy days like Christmas Eve or Thanksgiving Day.