What is 4G: technology

The main reason 4G is faster than 3G is because of Orthogonal Frequency-Division Multiplexing (OFDM). It sounds complicated, but it’s the same technology used in Wi-Fi, ADSL broadband, digital TV and radio.

OFDM is a technique for squeezing more data onto the same amount of radio frequency. It also reduces latency and interference. Data is split up and sent via small chunks of frequency in parallel, therefore increasing the capacity of the network.

Multiple-input and multiple-output, or MIMO, is another reason 4G is able to provide faster speeds. It is simply the use of multiple antenna arrays at both the transmitter and receiver to improve communication performance.

This allows more data to be transferred without requiring additional bandwidth or drawing more power. The most common configuration currently is a 2×2 MIMO, found in many smartphones and some tablets. A 4×4 setup is also possible and promises even faster speeds but is still a little way off making its way onto devices. Since different setups are possible, one phone could provide faster 4G speeds than another.

With 3G handsets, most of us take roaming for granted. We take our phones travelling around the world, and expect to be able to pick up emails and browse websites as soon as we land. Things are different with 4G.

Although there are 4G networks in many countries around the world, your UK 4G smartphone won’t necessarily work wherever you go. The reason is that 4G doesn’t operated on the same frequencies in every country.

If your phone’s 4G modem doesn’t work on the same frequencies as those used in the country you’re visiting, then you’ll have to live with 3G instead. Even if the numbers do match, there needs to be a 4G roaming agreement between operators. Currently, there is no such agreement in place and even when there is, expect data prices to be high.