A major step towards the harmonised use of the band 1452-1492 MHz: Mobile Supplemental Downlink is the way ahead

In the October 2011 Newsletter, we reported on the ECC's review of the 1452-1492 MHz band, sometimes referred to as the 'L-Band'¹. This frequency range has good propagation characteristics for many applications but currently configured, just as a broadcasting band, its usage has been very limited. We have now completed our review and reached an important conclusion about the future use of this promising band.

The September 2012 WG FM meeting in Minsk approved for public consultation the draft ECC Report 188 which identifies, through a detailed impact analysis, the most appropriate application and associated regulatory framework for the harmonisation of the band 1452-1492 MHz in Europe.

Impact analysis

The candidate applications considered for the future use of the band were:

  1. Terrestrial Broadcasting;

  2. Mobile Broadband;

  3. Mobile Supplemental Downlink;

  4. Satellite Digital Audio Broadcasting;

  5. Programme Making and Special Events;

  6. Public Protection Disaster Relief; and

  7. Broadband Direct Air to Ground Communication.

These applications have been assessed against a number of criteria, namely:

  1. compatibility with the existing regulatory framework (to facilitate a quicker time-to-market);

  2. possibility to share with other applications/uses (for flexibility and overall efficiency);

  3. extent of social and economic benefits;

  4. timeframe for availability of equipment on a large scale and for application deployment, status of standardisation; and

  5. potential for economy of scale (need and potential for harmonisation within and outside CEPT).

On this basis, three potential regulatory options have been identified and further assessed through a methodology specifically developed for this impact analysis.

Proposed regulatory framework

The conclusion of this extensive work is that the most appropriate regulatory framework for the future use of the 1452-1492 MHz band in CEPT is the harmonisation of this band for 'mobile supplemental downlink', while allowing individual countries to adapt to specific national circumstances in parts of the band for terrestrial broadcasting and other terrestrial applications. We believe that this regulatory framework will bring the highest overall benefits in the CEPT countries.

Mobile SDL

Mobile Supplemental Downlink (Mobile SDL) is a mobile broadband system, which by means of base station transmitters in the network, is able to use unpaired spectrum to provide a supplemental downlink capacity to carry efficiently comprehensive text, audio, images, sound and video content in unicasting, multicasting and/or broadcasting mode to mobile devices. Mobile SDL uses a wider channel for the downlink than for the uplink, by bonding the usual downlink of the paired (FDD) mobile bands with a supplemental downlink channel(s). The harmonisation of the 1452-1492 MHz band unpaired spectrum for Mobile SDL is important to enhance the downlink capability of mobile broadband systems and represents a strategic tool to tackle the growing mobile data traffic asymmetry.

With such an appropriate regulatory framework in place, the ECC intends to provide guidance and certainty to the industry so that the UMTS/HSPA (3GPP specification Release 9 and beyond) standard and LTE-Advanced (3GPP specification Release 10 and beyond) standard, that are capable of aggregating multiple downlink channels in multiple bands, thus allowing the use of an unpaired spectrum for SDL, specify the 1452-1492 MHz band as an SDL band to be implemented in chipsets, devices and equipment.

The next steps

FM50, the Project Team which carried out the impact analysis contained in the draft ECC Report 188, has recently been tasked to develop the required elements for this regulatory framework. This will consist in particular of a new ECC Decision designating the band for Mobile/Fixed Communication Networks (MFCN²) supplemental downlink (SDL), which should include:

  • a harmonised frequency arrangement, based on a block size of 5 MHz³, resulting in the following 8 frequency blocks in 1452-1492 MHz:
  • the least restrictive technical conditions (LRTC) related to the avoidance of interference between users of spectrum. It is anticipated that these LRTC would be in the form of block-edge masks (BEMs), to address the coexistence between MFCN SDL in neighbouring blocks, and out of band (OOB) emission limits to address compatibility between MFCN SDL in the 1452-1492 MHz band and other applications in adjacent bands. 

This new ECC Decision should also leave flexibility for administrations to adapt to specific national circumstances in parts of the band for terrestrial broadcasting and other terrestrial applications.

Under this new framework, it is also intended to:

  • suppress the ECC/DEC/(03)02, which currently harmonises the sub-band 1479.5-1492 MHz for Satellite Digital Audio Broadcasting within CEPT;
  • retain the MA02revCO07 Arrangement for administrations wishing to implement terrestrial digital sound broadcasting networks in part of the 1452-1492 MHz band.

We plan to make the final draft of the ECC Decision available to WG FM for adoption for public consultation in February 2013.

Bruno Espinosa
Deputy Director of the ECO

¹ In fact this frequency range is just a subset of the 'L-Band', terminology usually associated with satellite communications.
² Mobile/Fixed Communication Networks (MFCN) is a regulatory term, commonly used in recent ECC Decisions, which includes IMT and other communications networks in the mobile and fixed services.
³ This also allows for aggregation of adjacent 5 MHz blocks where national conditions allow.

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