The defragmentation dividend

A more efficient use of the UHF band

Cambridge, November 2017

Digital UK requested Aetha to consider whether the existing allocations of the 694-960MHz band were fit for purpose in the longterm. This followed from a debate initiated at the European Spectrum Management Conference in Brussels in June 2017 over the potential use cases for the 470-960MHz band beyond 2030. A link to the report and a short summary of our findings are provided below.

Report download

The full version of the report is available for download on Aetha's website. Please follow this link.

Summary of report findings

In June 2017, at the European Spectrum Management Conference in Brussels, a debate was initiated regarding the long-term future of the 470-960MHz range and whether the existing allocations were fit for purpose. With an extensive debate already ongoing about the use of 470-694MHz, Aetha Consulting contributed to the wider debate about the use of the entire UHF band (470-960MHz) by specifically considering the 694-960MHz range.

The recommendations of the Lamy Report have locked in the current UHF allocations until 2030. This opens up the opportunity to take a more holistic approach when looking at future UHF allocations, by considering the full 470-960MHz range (rather than just looking at a part of the band). As any reconfiguration may take many years to complete, it is critical to consider potential options now such that decisions can be made that provide sufficient implementation time ahead of 2030.

Within the report, we have considered the option of creating a ‘defragmentation dividend’ by reconfiguring the existing band plan between 694-960MHz to make additional capacity available to mobile services and other spectrum users. Our analysis has found that there are potentially large benefits from defragmentation. Depending on the exact solution chosen, it could provide up to 70% additional downlink capacity for mobile-based services. Even in the most pessimistic case, we expect there to be scope for an increase in downlink capacity of 25%, which is not dissimilar to the capacity that would result from the creation of a 600MHz band. Naturally, carrying out a defragmentation would be a complex task, but our analysis of technical, regulatory and commercial constraints has not identified any unsurmountable issues. That said, a number of obstacles should be addressed ahead of any defragmentation. Notably, the UK is not a sufficiently large market to adopt a new mobile band plan in isolation. Therefore, the case for defragmentation is contingent on a substantial market (e.g. the EU) adopting the defragmented band plan. We have identified three different candidate band plans. Further study will be required to identify an optimal solution, which may vary from our proposals. However, our analysis has highlighted some key principles that we would expect to guide any defragmentation:

  • The capacity benefits are largest when the defragmented band plan is (largely) used for TDD, due to the asymmetric capacity this provides.
  • The costs for mobile services reduce with a staged implementation (e.g. where one of the existing bands is left undisturbed for a period of time), as the number of legacy mobile devices declines over time.
  • Any solution that requires the migration of SRDs/IoT devices in the 863–870MHz range substantially increases the cost of implementation for other, non-mobile, spectrum users.

In conclusion, we believe that a ‘defragmentation dividend’ offers an interesting and credible long-term solution to increase capacity for mobile-based services in the UK. Therefore, we recommend that further study is conducted to fully explore the defragmentation options available as well as the merits of each proposed solution.

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