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Upper band n77 (3.8 - 4.2 GHz) shared access spectrum: Is there a substantive supply & demand issue?

  • 9 minute read
  • Published by Vicki DeBlasi on 28 Jun 2022
  • Last modified 29 Jun 2022
Our Benefits Realised and Lessons Learned series aims to share learnings, disseminate actionable insights and enable others to subsequently fast-track their own 5G deployment plans.

Essential reading for anyone considering using shared access spectrum in the upper n77 band ( 3.8 - 4.2 GHz), in this article we explore some of the key findings and insights arising from a detailed piece of work undertaken by UK5G and Real Wireless on behalf of DCMS to explore challenges around the availability of chipsets and devices in this band. The full report can be read here.

What is n77?

n77 is one of the New Radio (NR) operating bands, covering the frequency range of 3.8GHz to 4.2GHz.  n78 is another NR band, covering the frequency range 3.3GHz – 3.8GHz, a subset of the n77 frequency range. The part of the n77 band that is not coincident with n78 (ie 3.8 - 4.2 GHz) is typically known as n77 upper band or just upper n77.

n77 band

In 2019, Ofcom announced that it would be making several frequency ranges, including n77 upper band, available under the UK’s Shared Access Licence Framework, with the intention of driving innovation beyond typical public mobile network models.  Put simply, this means service providers - typically new private mobile network operators - can apply to use spectrum in this range for deploying private networks. These networks might require a variety of equipment, ranging from phones and tablets to industrial routers, Mi-Fi devices, dongles, modems and Fixed Wireless Access equipment.

Whilst n78 is a globally harmonised band, and is fast becoming the primary 5G band in use globally, n77 upper band by contrast has the perceived disadvantage for private network deployment of potentially being a sub-scale niche market for equipment, as this spectrum band lacks European  take up and adoption. 

For example, Germany and the US have implemented spectrum sharing approaches in the mainstream 5G band: the US at 3.5 GHz, and Germany at 3.7 GHz. The lower part of the n77 band, namely 3.4 – 3.8 GHz, has been harmonised across Europe for mobile services. In the UK, this part is already awarded to Mobile Network Operators (MNO)s.

Might there be a potential problem? 

Throughout the course of 2020 and 2021, up to ten of the projects in the 5G Testbeds & Trials (5GTT) programme endeavoured to use the band and reported a number of challenges:

  • Testing revealed that devices billed as supporting n77 were actually only enabled for the n78 part of the band i.e. 3.3 to 4.2GHz
  • Support for Stand Alone networks was often built into products but not enabled 
  • General market immaturity issues such as failure to meet delivery timescales, technical design issues, general firmware instability and a lack of interoperability testing with a range of RANs

All of which led DCMS to ask: is there a substantive supply and demand concern in this band, or are we just seeing typical early-stage market issues?  DCMS commissioned UK5G, who partnered with Real Wireless, to explore this question and identify what options may be available to improve the situation.  A series of focus groups and interviews were then conducted with 5GTT stakeholders as well as both general and specialist device and chipset manufacturers.

Key findings around demand and supply challenges

The study identified low order volumes for upper band n77 devices as the key issue of concern in the UK market, and that this issue of concern is driven by 10 inter-related issues that the report explored further.

Whilst spectrum divergence in regards to bands set aside for sharing in different countries is one of the issues identified, it also ranked as the least critical issue – although the relative weighting of each issue was not widely different (with mean impact scores ranging from 2.6 to 3.6 on a 1-5 scale). The 10 ranked issues are as follows:

n77 challenges

Whilst 10 key issues were identified, there is a degree of interconnectedness between the issues. A group of four main systemic challenges were thus identified, which are - on the whole - consistent with early market dynamics:

  • Volume demand
  • Value chain fragmentation
  • System testing for operational readiness
  • The shared access spectrum licence framework

High levels of complexity in a target addressable market that is both hard to define and hard to serve, inevitably impacts on supplier willingness to invest in serving the upper n77 band.

Reassuringly, interviews with chipset manufacturers quickly indicated that all the major vendors are supporting the full n77 band as a standard capability and they do not believe that additional electronic components should be required as part of the design of a specific Original Equipment Manufacturer (OEM) device to support the upper n77 range.  This significant finding provides reassurance that the supply of upper n77 band devices into the UK is not being limited by the capabilities of chipsets typically used by device OEMs.

As a result of the study, it has become clear however that there are a number of other issues at play, the biggest of which is supplier estimates of the addressable market size of the UK for upper band n77 devices.  The majority of uses of upper n77 in the UK is expected to be through private network deployments, which is a limited market.  Critically, the wide array of use cases that exist within potential private networks - which from our interviews, range from video surveillance and analytics to workforce manager and connected tracking - all further fragment the market demand into various device form factors and different firmware configurations.

Can these challenges be overcome?

There are a number of steps that could be taken to help mitigate these risks and overcome the challenges the research identified.  A detailed package of recommendations has been provided to DCMS;these can be grouped into four core themes:

  • Market Formation - consolidation of use cases and device requirements, perhaps by an entity who can aggregate market and product needs across public and private sector, could help to counteract the effects of market fragmentation.
  • Architecture Harmonisation - adoption of a coopetition model between Mobile Network Operators and Mobile Private Network Operators could help to resolve some of the common issues around the Core (Stand Alone and Non Stand Alone) and standardise template architectures. The Joint Operators Technical Specification (JOTS) architecture could provide a useful jumping off point for this. 
  • Interoperability Testing - establishing a full telecom-grade “open networks” Interoperability Development Test lab that spans the 5G ecosystem but with a clear mandate around Mobile Private Networks.
  • Regulatory adjustments - An Ofcom-run industry consultation to explore topics such as higher Effective Isotopic Radiated Power (EIRP) limits.  Proactive engagement in the harmonisation efforts currently being underway in the European Conference of Postal and Telecommunication (ECPT) is also strongly encouraged.

It is recognised that DCMS’ planned UK Telecoms Innovation Network can play a pivotal role in facilitating and supporting the implementation of the above recommendations.

What does this mean for organisations looking to use upper band n77 spectrum?

We were pleased to find that the initial premise - that there was a fundamental challenge with OEM and chipset readiness for this band - was not borne out.  Instead, many of the issues we did identify appear to be more inline with typical early market dynamics and it is likely many will resolve or improve over time.  Indeed, it is clear that the situation has markedly improved since the first identification of challenges in 2020.  

For those looking to deploy in the short term, there are some recommendations we would make to organisations considering this spectrum band, most notably:

  • Buy off-the-shelf solutions from vendors for industrial products such as routers and modems wherever possible: this is likely to significantly improve aspects of supply such as delivery time and cost, due to the benefits of scaling. Although it is feasible to add custom features to some of these products in partnership with the vendor, this may significantly impact on delivery. If you must, engage in frank and open discussions with suppliers around the time and cost implications of specialist requirements or adaptations to devices.  Often what may seem like a seemingly small personalisation can have significant delivery impacts when suppliers are already encountering challenges around the size of this early stage addressable market.  Such early discussion can avoid frustration and disappointment during the procurement and installation process, and allow purchasers to make more informed decisions around the value of such requirements.
  • The shared access licence terms for upper band n77, require limitations on permitted power - in order to avoid the risk of spectral interference between geographically adjacent users of this shared spectrum. For “industrial islands” such as a factory or other sites with a largely contiguous indoor space, use of the upper n77 band can be very appropriate. However, large sites with a number of different locations requiring coverage within the site, may find the power restrictions of shared access spectrum could limit the viability of certain use cases.  So careful consideration is advised about whether this is the most appropriate option for your needs.
  • Cooperation and collaboration between the organisations and projects within the 5G Testbeds & Trials Programme demonstrated the benefit of sharing of insight and know-how amongst organisations seeking to deploy services in the upper n77 band, due to the early stage nature of the market for both products and use cases. There is a strong case for continued “co-opetition” between service and solution providers, and with the supply chain, to ensure that overall all players can move forward and deliver their propositions and end-user value.

It is clear that despite notable improvements over the past 12 months, potential users of the band may encounter challenges, in line with those often associated with being an early adopter.  The trade off however is that once past the deployment hurdles, 5G will offer more efficient and productive operations and potential sources of competitive differentiation and advantage.

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