The NGMN recently produced a white paper outlining requirements for 6G from an operator perspective. Compared to some of the documents produced in the past year or so it makes interesting reading.

For example, countries around the world have published and combined their visions for what 6G could or should be, which culminated last year in a meeting to help set the direction within the ITU; while the details vary, there is a considerable consensus on solving social challenges:

• Reducing digital divides
• Providing access to broadband for all, regardless of location
• Improved trustworthiness of digital services
• Sustainable digital services, not just limited to energy reduction.

Released in November, the ITU’s technology trends paper tends in a very different direction as its focus is on technical solutions – mainly focussed on network capabilities and architecture. It necessarily skims over a good many commercial and operational considerations.  

Meanwhile the NGMN white paper really helps to identify more of the operator position on what 6G needs to be or do. Although couched in polite analyst-speak, it does not pull its punches. The outcome is a position on 6G which, if taken seriously, addresses some of the challenges of the past decade and stands a good chance of rebuilding the financial fortunes of the telecoms industry.

Graceful 6G

One of the very early points underlined within the paper is that the NGMN’s members don’t want 6G to be something completely new. This is hardly surprising, as the costs and returns of deploying fresh networks with every generation – and the related layering and management of ever more legacy systems – just are not working for operators. Even in Asia Pacific, where 5G deployments have been aggressive and ambitious, the ROI is hard to find. Instead, the report’s authors note that:

“This publication has been developed on the understanding that there will be a graceful evolution towards 6G, and at this stage we do not rule out the possibility that 6G is an evolution of 5G / 5G Advanced, either for the core network, the RAN, or both.”

The terminology is not entirely spelt out at that point and some people are no doubt wondering what a graceful evolution would look like. However, in their chapter on ‘Design considerations and trade-offs it becomes rather clearer.

“There is a desire for networks to become ‘simpler’ to operate and maintain, therefore 6G should not add complexity, while design paradigms should prioritise and ensure graceful introduction and easy operation. This means that the migration to 6G should avoid disrupting existing users and be software driven, taking advantage of concepts like virtualisation.”

We can see here that a graceful introduction of services and elements might involve the ability to upgrade components of existing networks piece by piece in response to market demands and the operators’ priorities. In fact, this would make sense given the NGMN’s definition of what 6G needs to be, according to operator consensus:

“A system solution that supports a broad range of use cases and use cases. As a result, 6G is best described as a non-unique system that builds upon the global harmonised standards for mobile networks and may include complementary components and differing implementations, selected to deliver capabilities that meet operational needs depending on specific deployments.”

This, in itself, is a far cry from previous generations of mobile technology which have tended to focus on the radio as a crucial element of the new generation’s identity. Indeed, the operator view of 6G downplays the air interface entirely.

“The design for 6G may include the specification of a new Radio Access Technology (6G-RAT),” the NGMN say, “But this is not yet assured and 6G becoming an evolution of 5G-NR cannot be discounted.”

Instead, the NGMN is looking at something that is much closer to the core architecture of 5G Standalone.

“5G Core Standalone functions can be moved to the edge of the network, satisfying the low latency demands of critical communication to fulfil the needs of new services and applications. For 6G, it is anticipated that the system architecture will inherit the same design principles ensuring a smooth evolution for new communication services.”

The implication of this for 6G deployment is clear. While previous generations of mobile have been welcomed with national races to deploy, with 6G the deployment strategy is likely to be both more nebulous and more gradual. Gradual as deployments are made according to demand, and nebulous insofar as the boundaries between a 5G, 5G-Advanced and 6G network will be blurry at best, both geographically and in terms of capabilities. It’s not yet clear, for example, that a new generation of consumer handsets would need to be deployed in order to start benefitting from network upgrades associated with 6G. This means that operators will have to focus on marketing new competencies, services, and capabilities to users rather than a ‘G’.

There is a second implication associated with this, which is spelled out starkly in the NGMN paper:

“There must be flexibility to make trade-offs for deployment. The reality is that a 6G network will not meet all performance goals and metrics for every subscriber at every location.”

This is a realistic admission – services in very remote areas, for example, may be drastically improved from their current state but they are unlikely to be the equal of an enterprise’s private 6G network unless it becomes clear that the need is there.

However, it does also mean that regulators may well need to rethink their approach to the next generation. Rather than stipulating a certain percentage of geographical or population coverage, the criteria that operators need to meet may be based on, for example, meeting minimum levels of service nationwide.

6G Economics

The NGMN vision is tied very closely to the practicalities of deployment in an environment where operators are not excited about a ‘build it and they will come’ approach to a new network. Indeed, the paper notes:

“Network Operators would need reliable sources of extra revenue coming from new services to fund the densification needed to maintain large increases in area capacity in the 6G era. Such densification therefore cannot be taken for granted today.”

This helps to explain the desire for a gradual deployment of 6G capabilities. Much of the paper, however, relates directly or indirectly to the prospect of either minimising new infrastructure build.

Indeed, when discussing the possibility of a new radio, the authors make a very plain stipulation:

“If a 6G-RAT is deployed in a new IMT band, then it should complement existing 5G deployments and avoid any spectrum efficiency reduction of 5G. For a 6G-RAT to displace incumbent 5G technologies in existing spectrum bands the threshold for relative improvement over 5G-NR should be greater to overcome the additional cost and complexity associated with technology migration.”

The paper highlights the lack of operator appetite for network densification as one of the key drivers of further cost. While the paper does emphasise the possibility that spectrum allocations in mid and low bands could reduce the demand for densification and advocates for finding more such spectrum, it concedes that these are liable to have only a limited impact, given the growth in demand for capacity expected. As a result, it notes that:

“Solutions that reduce the technical challenges and associated financial and energy cost of densification seem necessary to maintain area capacity growth in the long term.

“In parallel, alternative approaches that offload mobile data may be necessary such as self-provisioned Wi-Fi networks, dedicated private networks or hybrid private/public networks using shared access spectrum. All the above will require to be supported by 6G systems.”

On the other extreme, rural areas are a priority both for nations – in closing digital and economic divides – and for the operators. They are clear that the system solution that is 6G must “consider how economic solutions can be developed for hard-to-reach rural areas, and this may include non-conventional solutions such as non-terrestrial high-altitude-platforms or satellite-based services to deliver mobile services.”

As mentioned above, there is no expectation that a non-terrestrial rural service will deliver the same capabilities as fibre to the home, but it should close the gap. This may assist a virtuous circle, wherein the improved rural opportunities for employment, education and IoT stimulate demand for telecoms, thereby justifying further investment in rural areas.

Not surprisingly, energy consumption is also a priority; not only for cost reasons but also closely related to sustainability concerns. Strikingly, the NGMN calls out the challenge of measuring energy consumption in open networks.

“Energy consumption figures need to be comparable and interoperable between equipment suppliers and must be made available at all levels of the system to enable 6G system wide monitoring and optimisation.”

It also calls for features enabling end user devices to reduce their energy consumption and for IoT devices to harvest ambient energy.

Simple 6G  

Linked to both sections above – on a graceful introduction of 6G and its cost effectiveness – the NGMN underlines repeatedly that 6G must be simple to implement, which is a means of reducing the costs to operate.

“Managing the associated rising complexity is a challenge by itself,” the paper notes. “In this context, automation of service delivery is critical for network operators to enable them to efficiently manage large portfolios of services.”

The approach taken by the NGMN’s authors appears to be automation throughout the network, but combined with modular features and network functions which can essentially self-organise. For example:

“Reducing network complexity, including phasing out of legacy technologies such as 2G and 3G, provides an opportunity for future simplicity of communication networks. New features and network functions, should adopt self-contained modules that are managed through self-organising mechanisms to significantly reduce complexity.”

This theme echoes throughout the paper. For example, when speaking of service composition the paper requires “a framework for a simplified and trusted composition of services by establishing a federated control-plane between different networks (mobile and fixed access, Bluetooth, Wi-Fi, …).”

Elsewhere in the document we hear that “interfaces to 6G should be simple and support intuitive interactions,”

All of this suggests that, for operators, 6G needs to be a very different prospect from 5G. While many operators have been going on both a technology and mindset journey to adapt to open, cloud-native, software systems in 5G, the aspiration for 6G is to build on the lessons learnt. It should be a set of modular solutions and maybe radio technologies which are affordable, adaptable to local conditions and able to be implemented piecemeal.

The emphasis on energy reduction and sustainability, and the clear awareness of the need to reach everywhere and anywhere with some kind of solution, suggests that overall the NGMN is aiming to deliver outcomes which align closely with national priorities.

If the vendor community and standards organisations take on board the NGMN’s emphasis on building with commercial practicability from the start, then a 6G future that builds wealth both for the operators and for the countries where it’s deployed will be much more realistic.