PPDR broadband spectrum: Watch this space
The pursuit of harmonised spectrum for public protection and disaster relief (PPDR) has been a long and painstaking endeavour, but is entering the end of the first stretch. Much of the remaining standardisation work is now in the hands of 3GPP. The struggle will then shift to those countries that have yet to auction off Band 28; where regulators have to weigh up the monetary value of the band against the benefits to society from reserving parts of it for PPDR.
The World Radio Conference 2015 Final Acts published the modification of International Telecommunication Union Radiocommunication Sector (ITU-R) Resolution 646, which (among other things) consolidates all the global spectrum issues related to PPDR. Resolution 646 keeps the 380 MHz to 470 MHz band for Europe, the Middle East and Africa intact. This is used by many of today’s PPDR networks.
The resolution encourages “administrations to consider parts of the frequency range 694 to 894 MHz, as described in the most recent version of Recommendation ITU-R M.2015, when undertaking their national planning for their PPDR applications, in particular broadband, in order to achieve harmonisation”.
“Whatever the ITU can agree upon is a strong statement in itself. Of the 198 countries, if just one country blocks or is against it then nothing is adopted,” says Jeppe Jepsen, TCCA board member (pictured right). “So the fact that it has said that we need to have PPDR equipment in the 700 and 800 MHz range and continues to encourage administrations to work with their PPDR colleagues is a very strong statement. In Europe we have narrowed it down further to only the 700 MHz band.”
The European decision
In June 2016 the Electronic Communications Committee (ECC) plenary meeting in Sweden approved ECC Decision (16)02, which narrows the 700/800 MHz option down to just the 700 MHz range for 48 European countries.
Options in Band 28 (2 x 30 MHz) between 703 to 733 MHz and 758 to 788 MHz are already covered by ECC Decision (15)01. Some countries have decided to auction this piece of spectrum for commercial use and some are willing to allocate it partly to PPDR organisations and services. 2x5 MHz and 2x3 MHz slots have been identified for PPDR and are illustrated by the figure below.
However, the 400 MHz range can offer national flexibility, allowing countries to allocate additional spectrum for broadband PPDR if they wish. They may allocate one of two sub-ranges in the 450 to 470 MHz range. The two defined ranges are 450.5 to 456 MHz/460.5 to 466 MHz and 452 to 457.5 MHz/462 to 467.5 MHz.
This ECC decision does not cover the 410 to 430 MHz range, despite co-existence studies having been performed. The sub-band was discarded because of a lack of technical conditions, despite some Eastern European countries indicating interest in its use.
Due to the adoption of ECC Decision (16)02 for broadband PPDR, the ECC has amended Decision (08)05 for PPDR in the spectrum range 380 to 470 MHz to restrict its scope to narrowband and wideband PPDR systems.
While France is particularly interested in the 400 MHz range to supplement the spectrum assigned to PPDR in the 700 MHz range, one potential issue is that existing devices for PPDR do not support broadband in this band. As few countries can allocate it to PPDR because they have auctioned it off already the size of the potential market might prove to be a stumbling block for device development.
EU activities and next steps
The 700 MHz band is used by broadcasting and will need to be vacated before PPDR or commercial use. To ensure an optimal transition process the European Commission has proposed draft Decision on the use of the 470 to 790 MHz frequency band in the European Union. The draft Decision covers two main issues:
- Switching off broadcasting no later than 30 June 2020. The parliament is suggesting a grace period of two years.
- National use of mobile downlink in 470 to 694 MHz when not disturbing digital terrestrial television reception. The Decision specifies the least restrictive technical conditions for using the 700 MHz band. PPDR is listed as a potential user of parts of the band 698 to 736 MHz paired with 753 to 791 MHz. This Decision does not recognise PPDR- specific spurious emission limits for digital terrestrial television protection in band 28 other than those in ECC Decision (16)02. Allocation of specific spectrum will be subject to national decision. Band 28 has been auctioned off in Germany and France. France has also granted its PPDR 2 x 3 MHz just above and 2 x 5 MHz just below it.
“The battle for dedicated spectrum is going on in pretty much all of the countries in Europe at the moment and it is most public in Sweden,” says Jepsen. “The Swedish government has tasked the country’s PPDR operator MSB [which runs Sweden’s TETRA network] to define what its needs for future broadband data would be, which it did in the Spring.”
Since then there has been quite an intensive lobbying campaign in Sweden. For example, the head of MSB, the head of national police and the head of the armed forces have said in a joint letter to the government that they really need 2 x 10 MHz in the 700 MHz band in Band 28.
“Even the secret service has gone semi-public and stated that the government needs to consider who actually controls the spectrum. This is because it sees a risk that if spectrum is out of the control of the government essential communication will be in the hands of people it doesn’t want... The user community is driving a strong campaign in Sweden, and other countries are following it closely to see what they can learn from it,” Jepsen concludes.
3GPP consideration and next steps
Band 28 is already standardised within 3GPP, and the European Conference for Postal and Telecommunications Administrations (CEPT) co-existence requirements are independent of usage – the same conditions apply for both commercial and PPDR use.
To cover the 700 MHz band extension for PPDR allocations, specifically by Middle East administrations, 3GPP Technical Specifications Group (TSG) Radio Access Network (RAN) has approved a new band (Band 68) addressing 698 to 728 MHz/753 to 783 MHz. Its co-existence requirements are not the ones expected within CEPT and included in ECC Decision (16)02. The only significant difference comes from the requested level of out of band emissions (OOBE) into broadcasting channel 48.
Based on theoretical co-existence studies and agreements between the various stakeholders, ECC Decision (16)02 specifies a level of -42 dBm/8 MHz in the 470 to 694 MHz band while the new 3GPP band 68 only provides -25 dBm/8 MHz. The ECC has asked 3GPP to take that difference into account in a future revision of the standard. A WID (Work Item Description) together with election of a rapporteur will be considered in TSG RAN4 and TSG RAN.
In the UAE and elsewhere throughout ITU-R Region 3 an OOBE level of -25 dBm/8 MHz is defined. Therefore, industry is now preparing field trials at several different OOBE levels. The aim is to demonstrate that the -25 dBm/8 MHz OOBE level could be sufficient for CEPT, now that this is the case in the Middle East region.
“Now the issue has moved to 3GPP we will want to see input from the filter vendors to hear what is and isn’t possible, because one of the concerns we had is now confirmed. 3GPP RAN4 has had an initial look and reported that to keep the -42 dBm we will need to reduce the output power of devices,” says Jepsen.
“Yet -42 dBM is a purely theoretical number that has been agreed as a compromise – nobody knows if that’s a good number. So until we have some trials with real filters we cannot really say anything. -42 dBm is very protective of broadcasting channel 48 and I’m not sure that’s necessary. It is only used in Europe; the Middle East uses -25 dBm and with that there’s the possibility to have the full power of LTE devices in band 68. So that’s basically what we must have or the only alternative that a regulator has on a national level is to allocate spectrum inside band 28.”
The additional ranges in ECC Decision 16(92) (450.5 to 456 MHz/460.5 to 466 MHz and 452 to 457.5 MHz/462 to 467.5 MHz) will also need to be worked by 3GPP as there is no existing 3GPP standard for them. As above, a WID together with election of a rapporteur should be considered in TSG RAN4 and TSG RAN.
“It is difficult to say how long this process will take. It would have to go into 3GPP Release 14 and I’m not sure whether there’s room left in 14 for this,” says Jepsen. “If there isn’t then it would have to wait until Release 15, but that’s a couple of years away.”
Once industry has done the standardisation works mentioned above, tenders launched by user organisations according to national regulations will determine if competitive markets exist.
- Final Acts WRC-15, November 2015. Available at: http://bit.ly/2d4ZEY6
- ECC. Harmonised technical conditions and frequency bands for the implementation of Broadband Public Protection and Disaster Reliefsystems. Available at: http://bit.ly/297yj3Q
- European Commission. Proposal for a decision of the European Parliament and of the Council on the use of the 470-790 MHz frequency band in the Union. Download from: http://bit.ly/2cDCAew
- European Commission. Commission implementing decision (EU) 2016/687 on the harmonisation of the 694-790 MHz frequency band for terrestrial systems capable of providing wireless broadband electronic communications services and for flexible national use in the Union. Read here:http://bit.ly/2cDCGTo