Geographic Sharing in C-band Final Report
We commissioned this report from Transfinite Systems to provide an independent view of geographic sharing in C-band (between 3.6 GHz to 4.2 GHz) within the UK. The C-band is currently used by fixed satellite services and fixed links, as well as broadband services in limited locations by UK Broadband, and the report examined the opportunity for sharing these frequencies with new mobile services. The central scenario looks at an IMT-Advanced system deployed for capacity enhancement in high population density areas.
For the sharing analysis, suitable parameters were selected based on existing ITU-R studies of the Joint Task Group 4-5 6-7 (JTG), and satellite and fixed links sites were identified from incumbents’ licensing data held by Ofcom. This data was used to perform three levels of analysis:
- Spectrum availability analysis across the UK, in 5 MHz channels;
- Interference zone analysis, using terrain and land use databases; and
- High resolution analysis, to examine a detailed scenario in a dense urban area (London).
Options for mitigation were also investigated, and their impact on sharing scenarios assessed. Little difference was found between results for the whole frequency range and a separate analysis of 3.6 to 3.8 GHz and 3.8 to 4.2 GHz.
The principal conclusion is that there is scope for sharing spectrum in this band, the implication being that a managed approach to shared access of the band based on geographic sharing has great merit. Spectrum is available but the possibility of interference remains in some locations under all assumptions. The key findings are:
- half the existing spectrum is available to 65% of the urban+ population (urban+ means areas that are classified as urban, dense urban or hotspot), and this increases to around 90% if 20 dB of mitigation is applied;
- even in the baseline case, 80% of the 3.6 - 4.2 GHz spectrum band is available to 50% of the urban+ population;
- the constraint on operation of mobile in C-band is dominated by the need to protect fixed links deployed across urban areas (eg. Central London). Protection of satellite earth stations is much less constraining due to their location generally being in less populated areas, though some large urban areas may also experience interference.
We will use this report to inform our international discussions and engagement with CEPT and ITU-R, as well as advancing actions for further analysis, as identified in our Mobile Data Strategy (published in May 2014). The specific actions relating to shared use of C-band were:
- to establish feasibility / conditions for sharing as soon as possible (in the 3.6 to 3.8 GHz band); and
- to establish viability of shared access (in the 3.8 to 4.2 GHz band)
We will engage with relevant stakeholders on any future proposals in due course.
The assumptions, conclusions and recommendations made in this report are entirely those of Transfinite.
Full report
Geographic Sharing in C-band Final Report (PDF, 3.7 MB)
A report for Ofcom by Transfinite Systems