4G is the fourth generation of mobile phone technology and follows on from 2G and 3G.
2G technology was suitable for making calls and sending text messages while 3G makes it possible to access the internet more effectively through your mobile phone.
4G services should make it much quicker to surf the web on your mobile, tablets and laptops - speeds will be nearer to those of home broadband.
As a result, 4G will be suited to services like video streaming, mapping and social networking sites.
For the typical user, download speeds of initial 4G networks could be around 5-7 times those for existing 3G networks.