The Public Protection and Disaster Relief (PPDR) community and CEPT, the European Conference of Postal and Telecommunications Administrations, have been working for a number of years to advance the migration towards broadband radio capacity for PPDR services (BB-PPDR). As its campaign nears its conclusion, bringing broadband application coverage from large events - especially the scene of major accidents - could soon become a reality.

In our August 2013 Newsletter we gave some background to our work.

The PPDR user community has said that BB-PPDR, from a technical standpoint, wants to be part of the global LTE ecosystem. This, they say, will bring several advantages including a wider choice of terminals and potentially lower equipment prices such as lower costs for chipsets and duplex filters. It could also benefit roaming over commercial networks, whereby end user radio terminal equipment can obtain mobile communication services under the coverage of another radio communication network (the “visited network”).

Work on developing the LTE technology to support BB-PPDR specific functionalities has already started in international standardisation organisations. Support has come from the mobile industry, while PPDR stakeholders have also been involved. However, it is expected to take several years before key features and facilities identified by the PPDR community are fully specified, implemented, tested and integrated into LTE solutions.

European countries are increasingly experiencing the need to give and receive PPDR assistance within areas such as international crime and trafficking, near-border accidents, natural disasters, terror attacks etc.

Different national choices within CEPT will require - within an implementable tuning range - multiple band BB-PPDR user equipment. Such equipment can be used in either dedicated, commercial or hybrid LTE-based networks.

The required level of interoperability is to be realised on multiple layers through the availability of multiple band PPDR user equipment, the adoption of common technical standards (i.e. LTE and its evolutions), utilising different PPDR network types, and also by standard conformance and interoperability specifications.

In CEPT, the new ECC Report 218 on the 'harmonised conditions and spectrum bands for the implementation of future European broadband PPDR systems' has been published. This is an important step towards a CEPT harmonisation measure on spectrum for BB-PPDR. It is most likely to be approved by the Electronic Communications Committee (ECC) in 2016.

This Report proposes the concept of “flexible harmonisation” to enable an efficient implementation of BB-PPDR within CEPT. This includes three major elements:

• a common technical standard (i.e. LTE and its evolutions);
• national flexibility to decide how much spectrum and which specific frequency ranges should be designated for BB-PPDR networks within harmonised tuning range(s), according to national needs;
• national choice of the most suitable implementation model (either dedicated, commercial or hybrid BB-PPDR network solution).

Based on the above, it is not necessary to designate a single frequency band for BB-PPDR.

ECC Report 218 is complementary to the ECC Report 199 on ‘User requirements and spectrum needs for future European broadband PPDR systems (Wide Area Networks)’, approved in May 2013. This Report calculates a capacity need of 2x10 MHz for BB-PPDR spectrum.

Conclusions on spectrum compatibility of the options included in the ECC Report 218 are derived from ECC Report 239 and ECC Report 240.

The new ECC Report 218, meanwhile, addresses spectrum options for the implementation of BB-PPDR services in CEPT countries in the 400 MHz and 700 MHz frequency ranges:

The 400 MHz Range

Tuning ranges in the 400 MHz frequency bands for BB-PPDR Uplinks (UL) and Downlinks (DL) are considered (the duplex spacing is always 10 MHz) as shown in Figure 1:

Figure 1: 400 MHz BB-PPDR tuning range and other primary use

ECC Report 218 concludes that the 400 MHz range can offer national flexibility for BB-PPDR, e.g. in the context of additional spectrum beside the 700 MHz range. The spectrum compatibility with, among other things, the radio astronomy service, radiolocation service and the terrestrial broadcasting service, has been assessed in ECC Report 240, indicating the technical measures needed to ensure their co-existence. A spectrum of up to 2 x 5 MHz could be realised in the band 410-430 MHz, as well as in 450-470 MHz.

The 700 MHz Range

The following options have been considered within the 700 MHz range (the duplex spacing is always 55 MHz) as shown in Figure 2:

Figure 2: 700 MHz Options for BB-PPDR

1. CEPT Report 53 considers alternative options (M2M, SDL, PMSE, BB-PPDR) for this part of the band and these have been listed in ECC/DEC/(15(01). The Supplementary Downlink (SDL) option is one of them and uses zero up to four blocks of 5 MHz. Thus this approach provides flexibility for combining different options.
2. CEPT Report 53 considers Machine to Machine (M2M) as an alternative national option for 733-736 MHz UL / 788-791 MHz DL. Synergies with BB-PPDR could be explored in the 733-736 MHz and 788-791 MHz.
3. BB-PPDR usage could be anywhere within the harmonised MFCN band plan using a 55 MHz duplex spacing.
4. The use of the 2x2x5 MHz into a combined 10 MHz duplex channel arrangement in 698-708 MHz paired with 753-763 MHz has not been studied.

BB-PPDR can be accommodated within the 700 MHz range by either designating spectrum for dedicated BB-PPDR, use of a commercial mobile fixed communication network (MFCN)¹ or a combination of both to fulfil national PPDR requirements. Harmonised technical requirements for the use of MFCN in the 700 MHz band (703-733 MHz and 758-788 MHz) already exist in ECC Decision (15)01.

The spectrum compatibility with the MFCN (see Figure 2) and the terrestrial broadcasting service below 694 MHz has been assessed in ECC Report 239, indicating the technical measures needed to ensure their co-existence.

Project Team FM49 within the ECC Working Group on Frequency Management will continue to work on the harmonisation deliverable for BB-PPDR in the near future. This deliverable will cover the flexible harmonisation concept according to ECC Report 218 and the technical conditions to be defined for dedicated BB-PPDR spectrum in the 700 MHz and 400 MHz ranges.

Further investigation is needed on some additional aspects of future spectrum use for BB-PPDR such as direct terminal-to-terminal communications (off-network working), Air-Ground-Air, ad-hoc networks, critical voice communications over the BB-PPDR Wide Area Network and cross-border coordination.

Finally, the assumption is that mission critical voice (and narrowband data) will continue to be carried in most CEPT countries by the existing dedicated TETRA, Tetrapol and DMR networks until 2025 to 2030. The spectrum for these networks have been designated in the ECC Decision (08)05. However, in some CEPT countries, PPDR agencies could migrate all of their mission critical voice and data services into networks using broadband technology such as LTE. And they may do so in a shorter timescale.

Thomas Weber and José Carrascosa, ECO Experts - Spectrum Management

¹ For those countries opting for a commercial or hybrid BB-PPDR solution, any Mobile Fixed Communication Network (MFCN) band harmonised in CEPT may also be used for BB-PPDR meeting the specified requirements. Such use is also subject to BB-PPDR equipment roaming capabilities