Did you notice that 5G is everywhere? In 2014, 5G was identified as a major challenge in the Electronic Communications Committee’s (ECC) strategic plan. It has been listed as an objective in the International Telecommunication Union’s (ITU) roadmap for the standardisation of IMT-2020, the International Mobile Telecommunications system for 2020 and beyond.

In addition, 5G is expected to be high on the agenda at the 2019 World Radiocommunications Conference (WRC-19). It is also part of the Digital Single Market strategy, and 5G research will benefit from €700 million in EU funding.

While 5G will be a prominent feature in our daily lives after 2020, it is already in the daily lives of spectrum managers around the world, and here at the ECC.

What is 5G really?

Put simply, 5G is the next generation of broadband communication technologies. However, this concept of "generation" is misleading. Long-Term Evolution (LTE) has been commonly considered as 4G while some experts would tell you that, technically speaking, 4G corresponds to LTE-advanced technology.

Therefore, it is more convenient to refer to the ambitious efforts of ITU to specify 5G as IMT-2020. Also, we should recognise that there will be some “pre-5G” deployment even before 2020, at the 2018 Olympic Winter Games in South Korea, for example.

One of the main objectives of 5G is to increase the current data rates up to several gigabits per second (Gbit/s) with even more than 10 Gbit/s in hot spot environments. Today, carrier aggregation already enables us to increase data rates but its complexity is exponential with the number of possible combinations of frequency bands used. As a consequence, industry wants to consider the use of higher frequencies in order to increase the bandwidth available, which is necessary to achieve such speed.

This would be made possible using massive MIMO (multiple input and multiple output) solutions to compensate for the additional propagation loss in higher spectrum. Array antennas would be integrated in the terminal, which is made possible since the wavelength would become smaller.

Another option for increasing data rates, already envisaged for 4G, is the development of small cells and the combination of the capacity of unlicensed bands (e.g. 5 GHz) with the capacity of a licensed block. This will require technology development such as the Licensed-Assisted Access (LAA) approach, as well as smart networking for handover and switching between various technologies and frequency bands in heterogeneous networks.

In addition, 5G will offer many features such as improved connectivity, low-latency communication, prioritisation, energy optimisation and greater security. In particular, it aims to address the Machine to Machine/ Internet of Things challenge which will multiply the number of connected devices with very different requirements.

In the future, there will be a vast number of connected devices with very different requirements other than just personal mobile phone terminals. The overall objective will be to adapt the radio networks to the device and user needs. As a result, flexibility and scalability of the radio air interfaces will be essential.

This intrinsic flexibility and adaptability which will be part of 5G may offer side opportunities in terms of more efficient spectrum management. It will facilitate spectrum sharing with other users of the spectrum (e.g. under the Licensed Shared Access approach) or between access and backhauling networks. Also, the 5G waveform may be improved to reduce the unwanted emissions, improve the coexistence in adjacent bands or channels and remove the need for guard bands.

Although ECC harmonisation decisions for mobile broadband (designated as MFCN, mobile and fixed communications networks) are technology neutral, ECC will have to monitor carefully the development of 5G technology to fully understand the requirements and the associated opportunities around spectrum and regulations.

What spectrum are we talking about?

It is now recognised that the first 5G or pre-5G deployments are likely to occur in mobile broadband spectrum harmonised below 3.8 GHz.

In this respect, ECC has already harmonised more than 1200 MHz of spectrum for mobile broadband in the frequency range from 694 MHz to 3.8 GHz. This frequency range has been under permanent study for almost 20 years with a willingness to always increase the availability of bands for mobile broadband.

However, even if CEPT had developed proposals for additional bands for WRC-15, we have certainly reached a point where any additional bands would be under significant sharing constraints. There is a need to provide and secure spectrum access in the same range to other services and applications, i.e. radio-navigation (GPS/GALILEO/GLONASS), civil aviation, scientific /meteorological use of spectrum, satellite communications, safety, defence, etc.

Nevertheless, the current ECC harmonised framework for MFCN is providing 400 MHz of continuous spectrum in 3.4-3.8 GHz which already offers more opportunities for larger bandwidth than any other currently available band.

In the near future, there will be a need to adapt the harmonised regulatory framework in these existing frequency bands to account for 5G. But this is not likely to be the most significant challenge.

As explained above, 5G envisages very high data rates, which will need much larger bandwidths than ever before. Those high data rates may only be found in higher frequency bands.

CEPT is currently working on a proposal for a WRC-19 agenda item to respond to 5G spectrum requirements in frequencies above 6 GHz. This lower edge of 6 GHz was initially proposed to separate the existing spectrum for mobile broadband (including WiFi) and the new terra incognita for mobile broadband spectrum. It has become a debate in itself because increasing this lower edge would consequently exclude some bands from any consideration (though this may be welcome by the existing spectrum users!). Alternative lower edge put forward in the discussion is, for example, 24 GHz or 31 GHz.

Identifying suitable spectrums with all necessary studies beginning at 6 GHz will not be without its challenges. In order to simplify the task of preparing the WRC-19 agenda item within CEPT and ITU, several countries have investigated the possibility of limiting or focusing their scope to a list of most promising frequency bands.

The difficulty of the exercise already demonstrates that there is no easy solution to identify large bunches of spectrums (i.e. several GHz) in higher bands, at least up to 50 GHz. Compatibility studies must be carried out in each band, and each band must balance with the requirement of other existing services and applications such as satellite communications, scientific use of spectrum or radio determination.

Another important factor is the on-going technological development of 5G, with yet unknown characteristics. They may impact spectrum requirements and the possibility of coexistence with other spectrum users. Proposals are being discussed within CEPT but it is not clear yet what the final European proposal for WRC-15 will be.

The final text of the WRC-19 agenda item on 5G will be decided by WRC-15, but significant activity will be needed within ITU and CEPT in the meantime. Both organisations must work to understand which frequency bands could be used for 5G in Europe in the future, and also which could have the best potential for worldwide harmonisation, which remains key for 5G’s development to limit the complexity of terminals. As an illustration, one may imagine the design of a terminal where the lack of harmonisation would result in having to implement a dozen of array antennas.

This will require due attention to be given to the systems already using these frequency bands but also to get a good knowledge of technical and operational 5G requirements, in order to understand sharing possibilities as well as the impact of convergence between access and backhaul 5G networks.

Future spectrum opportunities and service innovation

5G is already attracting much attention and effort from spectrum managers and, indeed, from CEPT. Industry has been successful in demonstrating the potential of 5G in responding to the challenges already identified for the development of services, devices and networks. Likewise, it has identified new spectrum opportunities for broadband in higher frequency ranges.

The role of CEPT now is to find the suitable spectrum for making such opportunities a reality and to do this by working side by side with the mobile industry and the other users of the spectrum.

Eric Fournier
Chairman, CEPT/ECC