POLICIES :: eCommunications :: Collective use
Shared spectrum access
The Collective Use of Spectrum (CUS) model allows spectrum to be used by more than one user at the same time without the requirement for an individual exclusive licence. The CUS model can support improved access to radio spectrum as the entry barriers are low and is increasingly important for stimulating wireless innovations.
Under the CUS model an undetermined number of independent users and/or
devices is allowed to access spectrum in the same range of frequencies at the
same time and in a particular geographic area under a well-defined set of
conditions.
Although the CUS model is very much associated with spectrum used on a
licence-exempt basis, it should be seen in a broader context than merely
licence-exempted usage. The model covers also ‘Light licensing’ regimes
(registration or notification) as well as spectrum access approaches such as
underlay (via ultra-wide band (UWB) technology) and overlay (cognitive radio and
other white space technologies). The CUS model is also increasingly important
for stimulating wireless innovations, due to the potentially very low entry
barriers for technologies that can share spectrum bands with other users.
Different approaches
The main difference between the traditional spectrum
management approach that is based issuing individual licences to users and the
CUS model can be illustrated by the different concepts of usage rights and
interference management.
Under the CUS model all users have shared or "collective" usage rights to access
a particular frequency band. In order to manage interference the CUS users rely
on technical usage parameters that are specified in spectrum regulation in
combination with a degree of self-regulation for the sharing rules. These can
for example be specified in harmonised equipment standards. Legally based on the
concept of a
general authorisation, the CUS model therefore allows for a reduction of
regulatory constraints and increases the responsibilities of spectrum users to
share spectrum efficiently and to manage interference effectively.
In comparison to the CUS model, the traditional spectrum management approach is
based on individual (exclusive) usage rights that users need to receive before
they can access a particular frequency band. Under such a licensed-regime
interference management is the responsibility of the spectrum management
authority, which sets the spectrum access parameters through spectrum regulation
and licence conditions. A user that receives an exclusive usage right, for
example by acquiring a licence through a spectrum auction, is often also
entitled to be protected against harmful interference.
The CUS model in practise
Important advantages of the CUS model are the low entry
barriers, the certainty of access (which in turn can encourage wireless
innovations) and lower administrative burdens for both user and regulator. This
is particularly the case if shared spectrum bands are regulated on a
licence-exempt basis, i.e. if users do not have to acquire a licence to access
the spectrum.
A broad range of application and technologies currently benefit from CUS model
of spectrum regulation. Among those are most
short-range devices (SRD) with applications such as Radio Frequency
Identification Devices (RFID) that support supply chain automation and
machine-to-machine (M2M) applications. Emerging
intelligent transport systems and
automotive short-range radars (SRR) also depend on CUS bands as do Wi-Fi
routers.
Ultra wide-band (UWB) is another family of wireless technologies that
depends on the shared access to spectrum based on a CUS model. UWB transmits
low-power radio signals across a wide range of frequencies facilitating the
operation of different short-range applications including high-data
communications, location tracking and ground-penetration radar. UWB is a type of
‘underlay’ spectrum usage – in that it shares frequencies with other
applications but without causing harmful interference to these existing user
applications.
Current Development
In line with its proposal for a Radio Spectrum Policy
Programme (RSPP) the European Commission will publish a Communication in 2012
assessing the merits of innovative and flexible authorisation solutions that
allow the shared use of spectrum. These include approaches such as the
collective use of spectrum as well as dynamic access to spectrum in order to
increase efficiency. In doing so, the Commission's policy objective is to
maximise the socio-economic and environmental benefits that can be generated by
radio spectrum in support of the Digital Agenda for Europe.
In this context, the European Commission has commissioned an
independent study on shared spectrum access and the RSPG has recently
adopted a
Report on collective use of spectrum and other sharing approaches.