Realizing the 6G vision - Why is spectrum fundamental?

The technological possibilities within mobile communication have accelerated over the last few decades. What began with analogue voice services in 1G, has now progressed to 5G and a cyber physical world where people and machines can be connected through digital technologies based on enhanced mobile broadband (eMBB) and ultra-reliable and low latency communications (URLLC). Beyond 5G, ICT industries have already begun to develop the next generation of limitless wireless possibilities: 6G. This vision is taking shape as you read this, both internally here at Ericsson and also across the many diverse 6G partnerships and initiatives.

The increase of spectrum availability is a fundamental criteria to expanding mobile network capabilities and ensuring that the required coverage, bitrates and latency demands of future diverse 6G use cases can be met.  Whereas 30 kilohertz (kHz) channels were sufficient in the early days of mobile networks, today’s 5G benefits from hundreds of megahertz (MHz) of bandwidth that can be deployed in frequency bands from sub-1 gigahertz (GHz) all the way up to the millimeter wave (mmWave) range above 24 GHz.

To realize the vision for 6G and deliver its full potential, there is a continued need to further increase spectrum availability. Given the time it takes to secure additional spectrum through regulatory deliberations in ITU or regional groups and to avoid delaying initial 6G commercial deployments starting around 2030, it is now the time to start the process to ensure timely availability of 6G spectrum.  

The journey from 2022 to 2030 and beyond

With 5G commercial networks now deployed worldwide and further expansion on the way, the research and development of 6G is also gaining momentum. Typically, it takes around ten years from early research to commercialization of new generational cellular systems. So it’s expected that, by 2030, the first 6G networks will be deployed. By this stage, 5G and its advanced technologies will already have transformed our societies, serving as the communication and information backbone which can support the daily needs of humans, enterprises and intelligent machines.

The 6G vision is manifested through a plethora of envisioned use cases and many more are still to emerge as we move closer to 2030. Some of the visionary 6G breakthroughs are described in Ericsson’s 6G whitepaper, for instance by 2030 it will be possible to move in a cyber-physical continuum between the connected physical world of senses, actions, and experiences and its programmable digital representation. Future network services will require omnipresent connectivity.

Above: 6G - Connecting a cyber physical world

With 6G, there will be requirements to support trillions of embeddable devices and provide trustworthy connections that are available everywhere. Immersive communication will deliver the full telepresence experience, removing distance as a barrier to interaction. To support such use cases and further develop existing ones, 6G would require a combination of new spectrum bands along with existing spectrum.

Spectrum is key to move from a 6G vision to a 6G reality

In recent years, local regulatory agencies across the world have gradually been releasing spectrum in low-band, mid-band and mmWave spectrum as part of the drive to 5G. While the pace has been uneven and even slow in some markets, by 2030, we expect that enough spectrum within these frequency ranges will have been allocated or auctioned to achieve the full potential of 5G/5G-Advanced.

We also expect these frequencies to play a role as part of the broader 6G spectrum context:

• Spectrum in the sub-1 GHz, such as the 600 MHz or 700 MHz frequency bands, will remain the basic coverage layer and will continue to help bridge the digital divide.
• Spectrum in the mmWave range, for instance 26/28 GHz or 40 GHz, will continue to provide high capacity in crowded environments as well as deliver the low latencies and high reliability required by enterprises.
• Mid-band spectrum, including 3.5 GHz, 4.5 GHz, and 6 GHz, will continue to address wide-area use cases that require capacity.

Indeed, this spectrum will help to address the spectrum needs for mobile communication, however the spectrum requirements for the new generation will be even higher than those of the previous generations due to the emergence of new use cases as well as the need to enhance existing ones. An example of the latter is videoconferencing; while 5G allows for high quality video conferencing on the move and 5G-Advanced will enhance this experience, 6G is expected to deliver a full telepresence experience.

The need for additional spectrum

The indisputable need for additional spectrum to cope with the emerging services and applications, to enhance existing ones, and to support the futuristic life that we envision, has led us to the challenging question: While maintaining and enhancing the 2022 capabilities and services in the 6G era, how can we also enable the new use cases?

6G use cases demand capacity. And this requires large spectrum bandwidth which typically is easier to find the higher the frequency is. On the other hand, the higher the frequency, the lower the coverage will be. As a result, similar to previous generations, different spectrum ranges become necessary.

This includes:

• existing spectrum
• additional spectrum in the essential centimetric (7-20 GHz) and the complementary sub-THz (92-300 GHz) ranges

Above: 5G spectrum ranges and possible new 6G spectrum ranges

The centimetric range 7-20 GHz – Why is it essential?

Spectrum from within the 7-20 GHz range is essential to realize the capacity-demanding use cases in future 6G networks. The lower the frequency bands are, the wider the area that can be covered.  

The coverage requirement that will allow for mobility and “on the move” applications of many 6G use cases across a wide area brings us to consider this range. To be even more specific, what value would for instance the large-scale metaverse and holographic use cases add if only enabled at home? Mobility and coverage restrictions would deprive such use cases of their full potential and value. This naturally rules out higher frequency bands and points us in the direction of centimetric waves where the envisioned futuristic life can be made mobile.

Above: The centimetric range is key to making powerful, immersive 6G use cases more mobile

At Ericsson, we have carried out an analysis of the current usage and future trends in these bands and evaluated the characteristics of the different frequency ranges to better understand their respective capabilities and limitations. These investigations have led us to initially focus on the lower part of the 7-20 GHz range, i.e. 7-15 GHz. Co-primary allocations to the mobile and fixed services in the 7-20 GHz range exist today in the ITU Radio Regulations, though noting that the existing use of this same spectrum by other services requires careful consideration. Hence, studying co-existence with these co-primary incumbent services will be an important task in the coming years.

Above: ITU-R RR (Radio Regulations) frequency allocations for 7-20 GHz, a simplified view

The complementary role of the sub-THz range (92-300 GHz)

This very high frequency range has the potential to provide wide blocks of lightly used, or even unused spectrum, which contributes to its unique yet challenging nature: The sub-THz range can uniquely offer the Terabits per second (Tbps) speeds and extremely low latencies that will be key enablers for 6G niche use cases, however this benefit comes with some limitations in terms of coverage and mobility. Such extreme performance (e.g. Tbps) will be required in certain areas and scenarios, e.g. direct device to device communications and extreme gaming. The characterictics of this range makes it  complementary and, thus it cannot substitute the need for lower frequencies (e.g. centimetric waves) to enable the coverage and mobility that will be the prime requirements for most 6G use cases.

Which frequencies to focus on within the sub-THz range?

It is all about physics and technological development. The former drives us to favor the lowest possible frequencies and their advantageous propagation characteristics and to preclude frequencies associated with atmospheric attenuation peaks. The attenuation factor is crucial to consider in a frequency range where the size of the wavelengths is close to that of most rain drops.

The technological development and component maturity factors also indicate yet another advantage of the lower edge of the sub-THz range. Use of the sub-THz frequency range relies on the development of components and an equipment ecosystem. This of course will need time to reach maturity, starting from the lowest sub-THz frequencies and slowly moving upwards in frequency.  

Combining the above facts, we see the emergence of two bands, the W and D bands. In fact, these bands are of interest for both 6G access and Xhaul (e.g. Fronthaul, backhaul) networks.  A solution that accommodates the needs of both services and ensures an equally powerful Xhaul development to support future access networks and their extreme requirements is to be considered.

Above: ITU-R RR (Radio Regulations) frequency allocations for the W and D bands, a simplified view

The pathway to 6G spectrum

Timely availability of sufficient spectrum for 6G will require contributions from and cooperation between several stakeholders, including spectrum regulators, research organizations, vendors of mobile equipment and CSPs (Communications service providers).  

Standardization work is already on its way both in 3GPP and ITU-R. ITU-R is currently working on the trends for technology development and the ITU Vision for IMT-2030/6G. We expect that the 3GPP specification of 6G will be finalized by 2028, and the ITU IMT-2030 standardization by 2030, thus spectrum should become available accordingly.

Spectrum availability can be achieved in different ways; through ITU World Radiocommunication Conferences, regional decisions or decisions on a per country basis. Whichever method is pursued, harmonization of the selected frequency bands on a global or regional basis could be key to unlocking economies-of-scale and provide numerous benefits to consumers and enterprises across many markets. This blueprint has been demonstrated by the success of previous generations of mobile networks.

In the process of making available new frequency bands, it is important to ensure that performance requirements of 6G applications such as security and reliability are enabled, an area where authorization regimes play a crucial role.

Ericsson proposed ITU-R and 3GPP timeline, simplified view

Conclusion

Spectrum is the oxygen of both technological success and the evolution of society, and regulators play a key role to unleash these benefits. For now, the timely availability of spectrum in the sub-1 GHz (e.g. 600, 700 MHz), mid-band (e.g. 3.5, 6 GHz) and mmWave (e.g. 26 GHz, 28 GHz, 40 GHz) continues to remain critical to unlocking the full potential of 5G and 5G-Advanced.  

As technologies and market needs develop, we expect the use of spectrum to be upgraded to 6G accordingly. However, additional spectrum in the essential centimetric range (7-20 GHz) and the complementary sub-THz range (92-300 GHz) is needed, the lower the frequency, the better. By ensuring timely availability of this additional spectrum, key stakeholders can essentially contribute to the realization of the 6G vision.

Ericsson is committed to taking a leading role in the 6G journey and supporting regulators facing the recurring challenge of finding an equitable balance in allocating spectrum resources to different services.

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Learn more  

Visit our public policy and government affairs page to get more spectrum insights, including socio-economic benefits, licensing principles and our vision for future spectrum.

Catch up on the latest 6G insights and trending topics on our 6G homepage.

Find out more about our vision for 6G in our research outlook white paper: 6G – Connecting a cyber physical world.

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