The document summarizes a draft report on the use of license exempt frequency bands in the UK. It discusses the importance of license exempt bands, the status of these bands in the UK and Europe, managing interference and congestion, technology coexistence case studies, and provides initial conclusions and recommendations. The report aims to analyze license exempt spectrum use and demand to inform UK spectrum policy decisions.

1. Plum Consulting, London | +44 (0)20 7047 1919 | www.plumconsulting.co.uk
Study for UK Spectrum Policy
Forum on Use of Licence Exempt
Frequency Bands: Draft Report
John Burns, Selcuk Kirtay
Plum Consulting
Spectrum Policy Cluster 2 Meeting
27th May 2015

2. Report Structure
1. Introduction
2. What are Licence Exempt Frequency Bands and why are they so important?
- Definition; Benefits and Drawbacks; Economic and Social Value; Estimating
Spectrum Demand
3. Status of Licence Exempt spectrum in the UK, Europe and elsewhere
- Principal Bands and Technical Standards; Comparison of Licensed and
Licence Exempt allocations; Europe / US comparison
4. Managing Interference and Congestion in Licence Exempt Bands
- Interference mitigation techniques; Specific Licence Exempt technologies;
Examples of Interference and Congestion
5. Technology Co-existence Case Studies
- Wi-Fi and LTE-LAA at 5 GHz; Wide Area M2M and SRDs at 868 MHz
6. Conclusions and Recommendations
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3. Importance of licence exempt bands
 Can be used without any prior authorisation or right of use, so long as
any specified regulatory rules or technical specifications are complied
with
 Benefits include greater convenience and flexibility (e.g. WLANs),
ability to offload traffic from licensed networks, easier market entry,
ability to address niche applications quickly and cheaply
 Drawbacks include QoS and range limitations, more difficult to monitor
spectrum use and implement re-farming
 Market served is very diverse – wireless access, RFID, Medical
Devices, Intelligent Transport, Home and Business Automation, Smart
Cities, Security, Industrial Telemetry
 Economic Value difficult to quantify but estimated to be huge – Wi-Fi
alone up to €23 Bn in Europe by 2023, M2M potentially even greater
 Spectrum Demand likely to be driven mainly by broadband data traffic
in future – implications for existing Wi-Fi bands
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4. Licence Exempt Frequency Bands (UK / EU)
MeteringMedical
SRDs (non-spec)
0 100 200 300 400 500 600 700 800 900 1000 MHz
Wireless AVRFID
Alarms PMR446
0 1 2 3 4 5 6 7 8 9 10 GHz
Wireless BB Data /Access
RTTT/ITS
0 10 20 30 40 50 60 70 80 90 100 GHz
Radars
DECTKey:
2.4%
15.8%
17.4%
% licence exempt

5. Licence Exempt Bands in relation to other uses
Total bandwidths in MHz
Approximately 12% of available spectrum is licence exempt

6. Managing Interference and Congestion
Interference Mitigation techniques are widely deployed:
 Power Limits – apply to all licence exempt bands
 Duty Cycle Limits – generally apply to narrow band applications
・Must be very low (e.g. 0.1%) or combined with other techniques to be effective in
busy environments, but can be good low cost solution for less critical applications
 Listen Before Talk (LBT)
・Widely used in most licence exempt bands with varying degrees of complexity
・Requires receiver to detect other users
・Key requirement for wireless access systems such as Wi-Fi (CSMA/CA)
 Frequency Agility
・Often used in conjunction with LBT
・Many variants in use again with varying complexity
・Essential requirement for Wi-Fi in 5 GHz band
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7. Examples of licence exempt technologies
 Wi-Fi: Probably most widely used LE technology – success largely due to global
adoption and successful implementation of effective LBT protocol (CSMA/CA)
 Bluetooth: Increasingly used for wireless audio, shares spectrum with Wi-Fi and
other LE applications. Adaptive Frequency Hopping Spread Spectrum has improved
co-existence
 RFID: Widely used in various forms, mainly operates in designated bands but shared
with other SRDs. Low duty cycle, short range and enclosed environments help co-
existence
 Wireless Alarms: most now operate in designated bands where mandatory
interference mitigation requirements support reliable operation – but some concerns
raised about impact of LTE interference
 ZigBee – widely used for building automation, mostly at 2.4 GHz where interference
can be an issue
 Analogue AV links – legacy equipment widely used in 2.4 and 5.8 GHz has no
interference mitigation and can affect other applications
 Low Power Wide Area: Ultra narrow band M2M systems provide cellular-like
coverage with short range device technology
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8. LTE and Wi-Fi in 5 GHz band: the story so far
・ LTE Licensed Assisted Access (LAA) standards currently in development “to
opportunistically increase data rate” – primary focus on SDL at 5 GHz
・ Key benefit to operators is control channels retained in licence band
・ Key requirement (as for Wi-Fi) is to protect existing incumbent services - will
need to conform to existing regulations (e.g. LBT mandatory in Europe)
・ 3GPP technical report due in June 2015
- will be part of Release 13 with commercial products expected in the following 12 – 18 months
・ ETSI (BRAN) working in parallel to update EN 301 893 (5 GHz wireless access
standard) to meet requirements of new Radio Equipment Directive
・ Discussions currently focusing on optimum approach to LBT
- Concerns exist within Wi-Fi community - compromise proposals have been
made in 3GPP with aim of reaching consensus by June
- Any proposals must subsequently be agreed by ETSI
- Most concerns relate to pre-standard LTE-U deployment in US, which has
prompted a recent FCC notice
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9. LTE-LAA Time Frame
Note linkage between 3GPP and ETSI
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• 3GPP driven by Release 13 time frame
• ETSI driven by Radio Equipment Directive
• Key Event - 3GPP TSG RAN WG1 Meeting 25th - 29th May 2015

10. Meeting future spectrum demand
 Main bottleneck likely to be in wireless access bands (2.4 / 5 GHz)
 Fragmentation of 5 GHz band and need to protect incumbent radars limits
effective utilisation and constrains deployment of higher bandwidth systems
 Expansion is favoured but need to demonstrate can co-exist with aeronautical and
satellite services
 Greater use of spectrum around 60 GHz could relieve pressure on lower bands
 Recent expansion of licence exempt spectrum below 1 GHz (870-876 and 915-
921 MHz), emergence of new M2M-optimised technologies and potential use of
“white spaces” in UHF TV band should be sufficient to meet other foreseeable
licence exempt requirements, due to relatively small data volumes
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11. 5 GHz relative channel utilisation (central London)
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No DFS
Weather Radars

12. Initial Conclusions and Recommendations
1. Re-iterate importance of interference mitigation and receiver performance in
technical standards, e.g.
・ Mitigation already mandated for 868 MHz and 5 GHz – but not 2.4 GHz
・ Impact of legacy equipment (e.g. video links) at 2.4 GHz on Wi-Fi
2. Ensure long term benefit of licence exempt bands for broadband data traffic
・ Promote efficient use of 5 GHz band whilst retaining equitable access
・ Utilise higher bands (e.g. 60 GHz) where possible, e.g. for mesh networks or high
bandwidth indoor applications
・ Improve utility of 2.4 GHz to retain Wi-Fi coverage benefits (e.g. restrict analogue
video links and mandate digital with interference mitigation in future?)
・ Explore scope to improve co-existence with incumbents at 5 GHz (e.g. cognitive
techniques)
3. Consider most effective use of new licence exempt bands below 1 GHz
・ e.g. how best to accommodate emerging M2M applications including wide area
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13. Next Steps
 Investigate further co-existence between SRDs and wide area networks
・ Review experience at 868 MHz (Sigfox / Weightless)
・ Consider impact of new spectrum (870-876 MHz and 915-921 MHz)
 Consider utility of higher licence exempt bands e.g. 60 GHz to relieve pressure on
lower bands
 Review options for expansion of 5 GHz band to support long term growth
 Consider impact of Radio Equipment Directive, e.g. on tightening receiver
parameters or co-existence requirements
 Develop recommendations for industry and regulators
 Final report to be submitted during first half of June
 Presentation of final report to 14th July plenary
 Any feedback from today’s meeting welcomed!
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14. Acknowledgements
 We are grateful for inputs received from the following organisations in the
preparation of the report:
・ Arqiva
・ BSkyB
・ BT
・ Cisco
・ Intel
・ Ofcom
・ Qualcomm
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