5G is not a single technology. Instead, it is a whole new generation of mobile network technology (the 5th generation) with new waves for sending data back and forth to your mobile device much faster than 4G LTE networks.
To understand the different 5G waves, such as sub-6GHz or millimetre wave (mmWave), you have to delve into the different frequencies or spectrums mobile networks use.
Mobile networks transfer data using radio signals, electromagnetic waves at radio frequencies. The radio spectrum is massive, going from 3Hz to 300GHz, and only small amounts are available for use by mobile networks.
Perhaps the most significant technological leap in the 5G network is gaining access to new higher frequency spectrums for transferring data. Whereas 5G networks can go as high as 40GHz, the maximum 4G frequency in the UK is 2.6GHz.
With higher frequencies come higher data rates.
Radio frequencies used for mobile networks are grouped into different bands or spectrums with similar properties. Technically speaking, mmWave refers to the radio frequencies above 24GHz (frequency at which the signal’s wavelength is 1mm). In the context of 5G networks though, 6GHz is the line used to describe the performance of different 5G waves. Anything above 6GHz is “mmWave”, and anything below is part of the “sub-6GHz” spectrum.
MmWave (above 6GHz), also referred to as 5G’s “high-band”, can deliver vast amounts of data with low latency over short distances. Theoretically, the mmWave spectrum can deliver speeds as high as 5Gbps. In practice though it is currently maxing out at roughly 2Gbps, with speeds varying based on the user’s position in relation to the nearest 5G tower.
The reason for this performance variation is its short-range and object penetration. mmWave is easily blocked, with windows, walls, and trees weakening or preventing the signal entirely. MmWave therefore requires a high number of 5G towers to be functional, making the infrastructure expensive to deploy.
The viability of the mmWave spectrum is therefore restricted to areas that need the highest network capacity, such as dense urban areas or locations where large numbers of people gather (stadiums, concerts, etc.). The low latency capabilities of mmWave also make it ideal for Extended Reality (XR) experiences, online gaming, and industrial applications such as smart factories with autonomous equipment. Many private 5G projects are looking to mmWave to deliver connectivity for such use cases.
The sub-6GHz 5G spectrum is on the other side of the speed vs coverage trade-off. Sub-6GHz signals it can travel much further and penetrate obstacles such as buildings, but without offering the same top-end performance as mmWave.
Sub-6GHz still offers better performance compared to 4G LTE though, and it is the 5G most of us will be using most of the time.
To find out more about the different spectrum layers, check out our earlier