Priorities for Making Best Use of 5GHz Spectrum
The report summarises the outcome of the UK Spectrum Policy Forum’s 2016 discussions regarding plans for future use of the 5GHz band and identifies 6 industry priorities. This report has been prepared by Analysys Mason on behalf of the UK Spectrum Policy Forum (SPF).
This report has been prepared in the context of the need for additional spectrum for radio local area networks (RLANs), for which Wi-Fi is the most common technology in use today. Consideration of the spectrum needed to support growth in RLAN use is relevant to agenda item 1.16 for the 2019 World Radiocommunication Conference (WRC-19). To inform the current debate and studies leading up to WRC-19, the SPF has held a series of workshops and discussions during 2016 to gather views on the key issues that are relevant to future use of 5GHz spectrum in the UK.
From these discussions, the SPF concludes that the UK industry as a whole – including the RLAN community and incumbent users of the 5GHz band in the UK – is willing to engage in further discussions to ensure the necessary sharing studies can be completed (including engaging in further discussions to develop representative UK-deployment scenarios for the various sharing scenarios as required). The ultimate aim of these studies is to ensure that policy decisions can be taken at the UK Government level to resolve the key question regarding competing spectrum demand between RLAN and incumbent uses.
A summary of the industry’s priorities derived from the conclusions [Figure 7] is as follows:
- If sharing with incumbent users can be achieved, the goal of the RLAN community is to work towards a core 5GHz band for RLAN use of 5150–5850MHz if feasible. Access for RLANs to spectrum in the 5350–5470MHz range is only feasible if it can be demonstrated through the conclusion of sharing studies that interference protection to incumbent uses including the space and science sector, and the MOD can be achieved. UK stakeholders in these communities have shown willingness to collaborate on conducting these studies to assess feasibility where needed.
- With an increasing range of technology and deployment options for 5GHz RLAN expected to emerge (including LTE solutions working in tandem with Wi-Fi), it will be important that regulatory restrictions in the different sub-bands are only those necessary to enable sharing with the incumbent primary users, while also enabling RLAN technologies to share spectrum co-operatively. Global harmonisation in operational requirements for RLAN use is to be encouraged where feasible. Conditions that appear to be unduly restrictive at present should be re-examined and amended where possible. Priorities in this regard would be to increase the 25mW limit on use of the 5725–5850MHz sub-band, which Ofcom is already proposing to amend, and removal of the indoor-only restrictions on use of the 5150–5250MHz and 5250–5350MHz sub-bands such that both can be used for indoor and outdoor RLAN deployments.
- The need for the DFS restriction across the different sub-bands in the 5GHz band should be re-examined with a view to improving its effectiveness if possible.
- The need to trigger DFS should be reconsidered if the signal detected is recognised as another RLAN rather than a radar.
- The possibility of another less stringent DFS detection threshold for even lower powered APs should be considered, and also the possibility of removing the need for DFS detection completely for extremely low powered APs (e.g. used for very short range tethering).
- The feasibility of alternative options, such as geo-location databases populated with details of some incumbent systems (where feasible), should be considered. However, it is hard to see that geo-location could be a feasible solution to enable RLANs to detect all incumbent uses – for example, radars in the weather radar network have a range of over 200km, each scanning 360 degrees at up to eight different elevation angles every five minutes, thus minimising the time available at any one location where RLANs could use the bandwidth available. However, experience from previous geo-location database development in the UK (e.g. TV white space) suggests that where very conservative protection requirements are proposed within geo-location, this can contribute to there being limited commercial interest in exploiting new commercial solutions.
In 2016 Cluster 1 held meetings on 5GHz in December, September and June. The slides from these meetings are available. techUK has also responded to Ofcom's consultation onImproving spectrum access for consumers in the 5 GHz band.
Launched at the request of Government, the UK Spectrum Policy Forum is the industry sounding board to Government and Ofcom on future spectrum management and regulatory policy with a view to maximising the benefits of spectrum for the UK. The Forum is open to all organisations with an interest in using spectrum and already has over 150 member organisations. A Steering Board performs the important function of ensuring the proper prioritisation and resourcing of our work.