In our October 2011 Newsletter we gave some background to our work to establish a way forward for broadband radio capacity for Public Protection and Disaster Relief (PPDR) services. This is particularly to bring high-quality video from large events and especially the scenes of major accidents. The existing robust and successful networks based on the TETRA technology in the 400 MHz band do not have the bandwidth to support this new and valuable requirement.

The train crash in July 2013 in Santiago de Compostela was an incident where high-resolution video could have been useful

As is usual with ECC project teams, the work of PT FM49, chaired by Peter Buttenschön (Germany) was conducted by member administrations and industry. Another central part of the team was national governmental emergency services organisations and European level associations in this sector. The work is shaped by the input contributions based on the shared knowledge and expertise of the participants.

FM 49 has now developed an ECC Report 199 which defines the user requirements, and therefore estimates the spectrum which a PPDR service would need in dealing with realistic scenarios. As always the figures have to be a compromise between adequacy of capacity but avoiding overstating the case through combining worst-case demands. Based on two independently conceived analyses, the group concluded that the sensible working dimension of this special requirement would be 2x10 MHz (that is 10 MHz each of a balanced uplink and downlink).

Now FM49 is developing a further report which will summarise the most suitable frequency bands and regulatory solutions for future BB PPDR networks, in each case envisaging the 2x10 MHz as a subset of the band concerned. The concept of a ‘tuning range’ is important here. Equipment could operate across a range of similar frequencies, but the precise range used could vary between countries. The options have now been narrowed to the following preferred bands: 

• from within the 400-470 MHz range;
• 1900-1920 + 2010-2025: the 2 GHz unpaired bands; FM 49 has considered these for ad-hoc PPDR networks; and
• 694-790 MHz: the same 700 MHz band which we discuss earlier in this Newsletter.

The 400 MHz range is already occupied by specialised private mobile networks, including the existing ‘TETRA’ PPDR networks, whose retention is expected for some time to come; these networks tend to have good coverage. Introducing BB-PPDR here would therefore be difficult.

The 2 GHz unpaired bands would tend to be a supplementary option, especially for air-ground-air PPDR services (i.e. helicopters at the scenes of disasters), rather than the main means of supporting PPDR video links close to the scene. There are also other candidate uses for these bands which are being reviewed by a correspondence group of the ECC's Working Group Frequency Management (WG FM).

The 700 MHz option comes onto the table because FM49’s working assumption is that the PPDR broadband networks would be based on the same technology (typically LTE) as for public mobile broadband; therefore even dedicated PPDR systems could be made less expensive.

At first sight there may seem to be an irreconcilable paradox between developing 700 MHz for public mobile broadband, and allocating it to the dedicated requirements of PPDR. Up to a point this is true, since there is certainly an opportunity cost in the spectrum for one use vis à vis the other.

The ability of governments and public authorities to invest in dedicated PPDR systems is likely to vary a lot between countries. A premise of the approach in 700 MHz is that PPDR would use public infrastructure if outside the coverage range of the dedicated networks. This would include a roaming principle between public and private networks similar to the arrangement between GSM-R used for railway signalling, and public GSM networks.

PT FM49 is now involving other groups: PT1 to take account of PPDR in its work on the 700 MHz mandate, and WG SE to improve knowledge of how BB PPDR would work compatibly with existing services in the 400 MHz range. The Group is also developing its work on the candidate bands, expecting a further ECC Report in April 2014.

Mark Thomas
ECO Director