VoLTE stands for voice over LTE and lets users make voice calls over a 4G LTE network, rather than 2G or 3G.

While 4G is currently used for downloading, streaming and web browsing, it will increasingly be used for making calls too, according to 4G.co.uk.

Its big advantage is call quality because more data can be transferred over 4G then 3G, for example so a person's tone of voice is clearer, for example.

VoLTE can also connect calls up to twice as fast as the current methods and will still be available when there’s no 4G signal.

The signals that 4G operates on, such as the 800MHz spectrum, have far greater reach than 2G or 3G spectrum, so users will be able to get signal further away from a mast or in buildings which other signals struggle to penetrate. (from dailymail.com)