You are probably all using a radio every day. Not just the radio for listening to music, but your Mobile phone is a very cool two way radio (Transmits and Receives both voice and Data), and your TV receives radio signals over the air so you can watch your favorite programs all over the world.

Mobile Telecoms

When you are using your mobile phone, have you wondered how it all works? Well, although the Network your mobile phone talks to is very complicated, it can be simplified as shown below.

Basically your mobile phone is a Radio Transmitter and Receiver. So when you make a call, or surf the Net, your mobile phone will talk to the nearest Base Station and the Network will do all the clever stuff to route your calls or Data (for example Web sites), to the person you want to speak to or the web site you are surfing for information on.

A typical Mobile base station mast will have 3 directional antennas covering 120 degree sectors as shown below.

In towns and cities the mobile phone antennas maybe attached to high buildings. As you move around the country, your mobile phone will search for the strongest signal, and if you are in a call, it will handover to the next base station, seamlessly.

To separate the base stations, they will be on different channels (Dependent on the technology this maybe by Frequency or code). Picture below gives a rough idea of how this maybe done to cover a rural area.

For example on a 2G system where different frequencies are used, then a reuse pattern of 9 different frequencies could be used, as one base-station, is unlikely to have a radio range long enough to interfere with the next base-station on the same frequency. This is dependent on the terrain, and radio waves do not travel in hexagonal shapes (This is just for clarity).