Licensed Spectrum Access opens new opportunities
Introduction
It is quite rare for the ECC to agree a harmonisation measure which designates spectrum more or less exclusively for a specific use. These measures will almost always include some provision for compatibility with identified incumbent services in the same band. These days ECC Decisions on harmonising measures focus on liberalisation of existing provisions (especially where technology neutrality is promoted), the exemption of devices from individual licensing, and how new services may be introduced on a shared-spectrum basis with existing ones.
Authorised Shared Access and Licensed Shared Access: licensed services in shared bands
During the 72nd meeting of the ECC's Working Group Frequency Management (WG FM) held in Miesbach, Germany, on 16 - 20 May 2011, industry stakeholders gave a presentation on 'An evolutionary spectrum authorisation scheme for sustainable economic growth and consumer benefit'. The Authorised Shared Access (ASA) concept was presented as an enabler to unlock access to additional frequency bands for mobile broadband under an individual licensed regime while maintaining incumbent uses. ASA has been developed with the aim of making the dynamic use of spectrum possible, whenever and wherever it is unused by incumbent users. Spectrum initially sought for mobile services on a shared allocation basis is in the 2.3 GHz band (mobile service sharing with military applications/wireless cameras) and the 3.8 GHz band (mobile with satellites).
In November 2011, the RSPGi finally adopted for publication a Report on collective use of spectrum and other sharing approaches which included consideration on the regulatory aspects of a Licensed Shared Access (LSA) concept similar to ASA. The extended LSA concept is not only limited to International Mobile Telecommunications (IMT) services. According to this RSPG Report, it can provide new sharing opportunities on a European scale under individual licensed regimes, while safeguarding current national spectrum usages which cannot be re-farmed.
In the broadest sense, LSA is nothing new: introducing new services which are compatible with existing ones has been the spectrum manager’s practice for decades. However, what is new is the possibility to apply smarter tools such as dynamic databases to track and define the opportunities for new services to share with incumbent users which may be quite specifically defined geographically, and limited in the time over which they need to be protected. From a European perspective, the LSA approach can address the market demand for the harmonised introduction of new applications, operated under an individual licensed regime, in specific bands characterised by fragmented incumbent uses which have to be maintained in different countries. Overall, this allows for more efficient spectrum use.
Scope of LSA
Following some initial investigations, in September 2012, CEPT established WG FM Project Team FM53, with the aim of providing generic guidelines on Licensed Shared Access (LSA). The RSPG established in parallel a working group to develop a response to the European Commission’s Request for an Opinion on spectrum issues concerning LSA.
The draft report, ECC Report 205, was developed by FM53 and adopted for public consultation by WG FM in October 2013 and is due for publication in February 2014. It provides an overview of the regulatory framework for the use of spectrum, current practices in terms of spectrum management and management of frequency authorisations. The report includes a detailed analysis of the application of LSA to mobile broadband services.
Taking into account the initial RSPG working definition of LSA and how it fits into the current regulatory framework, the report clarifies the concept in relation to supporting its potential for fostering spectrum sharing.
- LSA is a complementary spectrum management tool that fits under an 'individual licensing regime'. It aims to facilitate the introduction of new applications in a frequency band while maintaining incumbent services in the band.
- LSA, as a general concept, does not specify the nature of the incumbents and LSA users. LSA licensees and incumbents operate different applications and are subject to different regulatory constraints. They would each have exclusive individual access to a portion of spectrum at a given location and time.
- LSA impacts the national allocation of a frequency band, which is a sovereign decision on the destination of this public resource. The decision on the incumbent services to be protected within a 'sharing framework' is to be made by national administrations in light of national policy objectives, and taking into account international obligations and community law in the case of EU member states. The sharing framework shall give a certain level of guarantee (i.e. taking into account user requirements and sharing constraints) with respect to the spectrum that can be made available, with corresponding technical and operational conditions for alternative usage under LSA. Its development requires the involvement of all relevant stakeholders.
- LSA does not prejudge the modalities of the authorisation process to be set by Administrations/NRAs taking into account national circumstances and market demand. It is not a tool to regulate the spectrum market and is based on different principles to 'spectrum trading'.
From a European perspective, a CEPT harmonisation measure would designate a frequency band and define harmonised conditions of use (e.g. BEM, radio interface). Investigations at a European level on the various sharing constraints aim to ensure that corresponding harmonised standards include the necessary tools for implementation of sharing mechanisms required for operation in the band. Flexibility in the national implementation is required to enable the protection of incumbent services.
The report was also developed in conjunction with ETSI TC RRSii. As well as technical measures to support the implementation of LSA, the report considers an example of LSA functional architecture and identifies interfaces that would require standardisation.
Finally, it should be noted that LSA could be one solution for mobile network operators to access complementary spectrum for Mobile/Fixed Communications Networks (MFCN) and should not preclude efforts to secure exclusive access to spectrum for mobile broadband.
Frequency band 2.3-2.4 GHz
The frequency band 2.3-2.4 GHz was allocated to the Mobile Service and identified for IMT globally in the ITU Radio Regulations at the World Radiocommunication Conference in 2007. The band is suitable for application of TDDiii technology and is standardised by 3GPP as LTE Band 40. Based on this standardisation work, and driven by the growing developments in the Asia Pacific region, multi band equipment is already available in support of this LTE band.
The situation within CEPT countries is fragmented today: incumbent uses, such as military communications and cordless cameras – these are often limited in time and location, have to be maintained in certain countries, while in others the band may be unused and is attractive for MFCN.
The results from ECC Report 172 suggested that the introduction of MFCN may be possible on a shared basis with appropriate provisions. CEPT decided to study the applicability of LSA for MFCN in the 2.3-2.4 GHz band and established WG FM Project Team FM52.
The Draft ECC Decision for MFCN in the band 2.3-2.4 GHz developed by FM52 includes in particular the following provisions:
- harmonised frequency arrangement – 20 blocks of 5 MHz suitable for TDD;
- Least restrictive technical conditions developed as Block-Edge Mask, containing in-block and out-of-block power limits for both BS and UE. Currently under definition, taking into account recent activities, in particular in the 3.4-3.8 GHz band;
- administrations wishing to introduce MFCN in the band, and maintain the long-term incumbent use of the band in their territory, shall develop appropriate provisions based on LSA.
The ECC Decision is scheduled for consideration for adoption for public consultation by WG FM in February 2014. It will then be forwarded to the ECC for final adoption and publication in June 2014.
Emmanuel Faussurier
Chairman of the ECC’s Project Team FM53
i The Radio Spectrum Policy Group, a high level advisory group of EU member states to the European Commission
ii RRS = Reconfigurable Radio Systems
iii TDD = Time division duplex, as opposed to defining individual channels in each direction by frequency division duplex (FDD).