As we know, mobile data needs to travel on a frequency band and bands have different specialities as some of them carry the data for a longer distance and some are just better at passing through things like walls in the cities and obstacles in the nature.

 

So what would make an ideal band a technology like 5G will use? Firstly, it needs to be able to access a wide enough spectrum to cope with the high demands that 5G will potentially bring. Secondly, it needs to be as versatile as possible for the new and innovative 5G use cases that will most probably require combining more than one frequencies. For the moment, 5G bands are still being finalised and there is ton of research going on, nevertheless, judging by the current discussions there will be different frequencies in the millimetre wave (mmWave) spectrum ranging from very high to low.

 

 

So what are the bands we are likely to see used?

 

As we understand from the recent discussions between Ofcom and the EU regulators, there will most likely be 3 main bands that the 5G will sit on in Europe: 700 MHz, 3.4 - 3.8 GHz and 24.25 - 27.5 GHz.

 

Although the regulator in the UK is still trying to understand and explore the other bands for the initial technology roll out which is aimed in 2020. We are expecting that there will be an auction sometime this year for the 2.3 GHz and 3.4 GHz spectrum which was used by the Defence Ministry in the past. In parallel, Ofcom is willing to reclaim by 2020 the 700 MHz spectrum from Digital Terrestrial TV for 5G usage.

 

In the rest of Europe however, the International Telecommunication Union (ITU) has already successfully allocated around 200 MHz of the 3.4 - 3.6 GHz spectrum and we suspect that the 694 - 790 MHz band will likely to be available for 5G.

 

However, we think that the success of 5G lies in the millimetre wave where there is considerably more capacity. It is constantly being talked about that the 26 GHz will be the "pioneer band" which will be seen as a "Global 5G standard".

 

What are the challenges of working at the higher frequencies?

 

When we look at the low frequency bands, it is clear that the data can travel longer distances as the waves attenuate much less compared to the higher frequencies. But at the same time, it is very tricky to enable you to get the kind of bandwidth and capacity that the 5G will demand. And this is obviously to do with the laws of Physics.

 

Since there is a huge pressure on data capacity, we as operators should always be looking for ways to provide greater rates and better service to the users. When we get to milimeter wave, new parts of the spectrum is opening up for larger signals and peaks data rates at gigabit per second levels to enable things like beyond 4K, 8K videos at higher frame rates.

 

Theoretically, anything above 20 GHz will be called a millimetre wave and it has been traditionally in use for so-called "line of sight" communication in which there is ideally no obstacle and there is a direct path between the transmitter and the receiver so they can clearly see each other. But when you have a mobile environment, this becomes trickier as you need to look at and consider the changes in the structure of the map you are dealing with. There can be various obstacles that the millimetre wave will not like and these may have an impact on your planning. As an example, these waves can easily blocked by things like poles, trees or even a person walking by just like the light that the eye may sense. But the interesting thing is that in most of the scenarios, there are surfaces reflect the waves quite well such as the cars, surfaces of the building or even the poles and this may be seen as an opportunity for the following reason. Where longer paths are desired, the extremely short lengths of millimetre wave signals make it feasible for smaller antennas to concentrate signals into focused beams with high enough gain to overcome or minimise the propagation loss. As we follow from the lab tests of the antenna and chip-set providers, 5G devices will likely to have the adaptive beam-forming technology which mean that on the device side we will be able to get many high gain antennas (up to 48 according to Qualcomm) and on the base station we will be even a higher number of them (256 or even higher) which will then be responsible to collectively beam in a certain direction dynamically just like the spotlights that follow the performer who is moving around on the stage. And in parallel, the lower bands will most likely play a critical role both in fall back scenarios where coverage continuity decreases and also on control plane parts.

 

Conclusion

 

Technologies such as beam-forming and concentrated signals are a bit more complex and sophisticated than explained here in couple of sentences. But the key message here is that what we traditionally understand from the frequency range and bandwidth will be changing rapidly together with innovative new technologies making millimetre wave (non line-of-sight) fundamentally achievable.

 

Just a couple of years ago millimetre wave was not even being discussed in the Telecom world because almost none of the electronic components could receive these waves. Now, it is about to be an important part of the next-gen Networks. 

 

Sources: Qualcomm Lab, 3GPP, Ofcom, ITU