France wishes to keep an option that leaves space for high speed security network communications (“PPDR”), because the band seems specially suitable for personal portable devices. Several possibilities are under study, of which some could be combined with the use of additional frequency blocks to provide downwards capacity to commercial networks (SDL technology, “supplemental downward link”). The other options under study at the European level are wireless microphones that currently use blank television space in the 470-790 MHz band and the commercial networks for M2M applications.
In France, the perspective of the assignment of the band to mobile operators starting from 2015 brought the Agency, supported by the countries with the same ambitions such as Germany, to launch thought processes aiming to revise the border agreements with neighbouring countries in order to be able to transfer television below 694 MHz in the calendars being considered.
When the 800 MHz band was reassigned, these negotiations took over three years. If the geography of our borders with Italy and Spain make coordination easier, the situation is much more complicated in northern France considering the number of countries involved (Belgium, Luxembourg, Netherlands, Germany, United Kingdom) and a more unfavourable topography encouraging long distance radio routes.
The informal WEDDIP group (Western Europe Digital Dividend Implementation Group) that gathers together these countries now has a key role in preparing the scenarios for the fast migration of television out of the 700 MHz band. An inventory has been made: all the WEDDIP administrations, except for Switzerland, now want to sign most of the required agreements by 2016.
The next step will be to propose concrete solutions to our neighbours based on the national frequency plan drawn up by the CSA. Transitory plans will probably also be implemented to take into account the calendar to free up the 700 MHz band which will remain specific to each of our neighbours.
The major increase in mobile traffic is certain: from now until 2030 the most conservative forecasts show traffic multiplied by 30 and the least conservative by 300. Therefore, it is probable that new spectrum needs will appear.
In order to fulfil this demand, the State can, as it has done until now, release new frequency bands and exclusively assign them to very high speed mobile. Considering the increasing cost of this method, it must be combined with new spectrum management modes, in particular the use of dynamic frequency band sharing.
The possibility of sharing frequency bands already exists: for example, the regulator can issue separate, static licences for separate geographical zones. Open frequencies, such as Wifi, are usually shared by type. However, between these two extremes, dynamic frequency sharing mechanisms can also be designed. This is how the LSA (Licensed Shared Access) appeared. The RSPG defined it in its November 2013 opinion: to facilitate the introduction of radiocommunications systems operated by a limited number of licence holders (“licensees”), the LSA allows them to use a band that has already been assigned “under an exclusive licence scheme” to one or more initial users (“incumbents”). In brief, new users are assigned authorisations on frequencies that remain assigned to someone else, subject to the explicit condition of not creating interference for them: the new arrival must comply with the precise rules that guarantee that the initial occupant’s services are not deteriorated.
This peaceful coexistence can be adjusted over time. The LSA can, in fact, be implemented dynamically: for example, using a geolocated database, the holders of an LSA authorisation will only use the band in the areas that will not interfere with the initial user. Limitations can also be in time and modulate station power. The originality of the LSA is in the fact that these restrictions must first be accurately defined by the administrations and recorded in written form. The services previously deployed in the band thus obtain guarantees as to their operational continuity, whereas the new arrivals have sufficient legal security to justify their investments in the band.
In Europe, the 2.3 GHz band quickly became the main candidate band for LSA experimentation as the RSPG had underlined in its 2013 opinion on wireless high speed. This is a band that had already been identified in 2007 in the radiocommunications regulations for possible use by mobile systems benefiting from standardisation (3GPP). LTE TDD equipment therefore exists for this range of frequencies. It is already used as an exclusive LTE TDD mobile band, in particular in Australia, Hong King, India, Russia, South Africa or China. Since 2013, a CEPT work group (FM52) chaired by the ANFR has been studying the implementation of the LSA in the 2.3 GHz band and an ECC decision in the same vein was adopted in 2014. The ETSI has developed an SRD (System Reference Document) for mobile services using the LSA in the 2.3 GHz band to supplement the CEPT initiatives..
In France, this band is currently used by the Ministry of Defence for certain applications, in particular remote aeronautical measurements. The transfer of these applications to another frequency band in the near future cannot be envisaged. The ARCEP also uses the 2,290 2,310 MHz band for video reporting links. These two types of use are specific in that they do not cover the entire territory and are not permanent. Prior studies have been started at the national level under the ANFR’s control to contribute to European work.
Currently, French businesses such as Alcatel-Lucent alongside start-ups such as Red Technologies are at the cutting edge of LSA. The French public authorities support this innovating regulatory solution which has also been the subject of preparatory European work.
Sharing this band would make it possible for the Ministry of Defence to carry on using it wherever it is essential to its activities and where it cannot be freed up at a reasonable cost. The LSA approach applied to this band would then provide mobile operators additional capacity for very high speed services on most of the territory.
The implementation of the LSA system approach will require the regulator to precisely define the conditions for sharing and coordination of the initial and additional uses, by completing the conditions defined in the ECC decision.
Following the proposals by the ministerial report “A dynamic spectrum management for innovation and growth” by Joêlle Toledano, the work of the Agency’s Electromagnetic compatibility commission (CCE) has made it possible to look deeper into the compatibility between the different envisaged uses for the 2.3 GHz band. At the request of the minister Axel Lemaire, the National frequency agency, in collaboration with the ARCEP, the Business department and the Ministry of Defence, will now indicate the technical conditions that would make it possible to initiate experimentation of the LSA in this band. This initiative will open up the route to a more dense spectrum use while increasing capacity open to mobile high speed.