Prospects of Flexible spectrum use in NonTelecommunication Actor's Spectrum
Licensed Approach (e.g. LSA), Unlicensed Approach (e.g. LAA) or both?
Supervisors: Ashraf A. Widaa (ahmed2@kth.se)
Examiner: Jan Markendahl (janmar@kth.se)
Background
The tremendous popularity of wireless technologies during the last decade has created a
considerable expansion of wireless networks both in size and use. This trend is expected to continue
in the future considering the emerging human and machine-centric applications along with the
advances in end-subscribers equipment and internet applications [1] [2]. These potential increases in
demand from different application and services, with different variants of quality of services (QoSs),
put more constraint on the design objective of the future wireless networks [1] [2] [3]. In this
respect, recent studies and extrapolations anticipated broad design targets for the future mobile
systems that include 10 to 100 times average date rate, 1000 times more network capacity, 10
times less energy consumption, and 10 to 30 times lower latency and yet at lower or same
deployment and operation cost as experienced in today network [1] [4].
Addressing the aforementioned technical challenges is closely related to the ability to manage and
utilize the spectrum resources in the most efficient way. Hence, the concerned regulatory
authorities, academia, industry and standardization bodies are currently exploring the transition
towards more flexible spectrum management regime [5] [6] [7]. From the technical perspective,
these increasing research activities are aiming at improving the efficiency in spectrum resource
usage focusing on three interrelated areas as follows: 1) improving the spectral efficiency at the link
level by adopting advanced radio access technologies 2) improve the radio resource reusability by
adopting effective network topology and architecture such as dense layers smallcell 3) increasing the
amount of spectrum resources per radio base station by enabling more cognitive and dynamic
spectrum use in favored spectrum bands (i.e. below 6 GHz), or identifying and using new spectrum
resources in higher spectrum bands (i.e. above 6 GHz)
From the policy maker perspective, the adoption of different variants of flexible spectrum
management regime can be discussed based on several dimensions: flexible use vs. exclusive use;
licensed vs. common authorization approaches (i.e. open entry); primary and secondary usage
rights; and technology-oriented or technology-neutral choice [5] [7]. In this context, various forms of
spectrum authorization and access options can be envisioned within the two traditional broad
authorizations approaches, i.e. exclusive use and common use, based on the primary and secondary
usage concepts. In the case of primary (horizontal) usage all the users have similar authorization
rights, while in the case of secondary (vertical) usage, at least one of the spectrum users (primary
user) has a higher authorization right and shall be protected from harmful interference caused by
the secondary users.
Under the exclusive use regime, a license is typically issued to specific actors by defining the
frequency ranges and geographic locations in which the spectrum can be utilized, the maximum
power level to be transmitted, technology to be used and type of service to be provision. In this
regard, the licensees have a primary usage right and can expect to be protected from interference
that would disrupt the normal operation within their licensed service areas. TV broadcasting,
commercial broadcast radio, and cellular voice and data services are examples of applications that
utilize licensed spectrum. While in the common use regime (i.e. open entry), a more technologyneutral and service-neutral spectrum use are allowed without any license fee if certain technical and
regulation conditions are met as experienced in the 2.4 GHz and 5 GHz ISM bands for example.
Literature Review
The licensed shared access is a proposing a spectrum authorization approach that has been received
with large interest from the telecom industry during last few years. The LSA scheme assumes some
guarantees for the secondary user compared to secondary access (TVWS) and unlicensed used
options. In the Licensed/Authorized Shared Access (LSA/ASA), the primary license holder
(incumbent, e.g. a military) will be allowed to grant spectrum access rights to one or more other
users who can use the band in accordance with a set of pre-defined conditions and regulations. A
number of research works have been focusing on identifying the services which could be based on
LSA – including both technical regulatory aspects. Moreover, a number of papers discuss the
potential business models for mobile network operators (MNOs) in view of LSA [8]. The prosed
business models in [8] indicate that the dominating MNOs could benefit significantly from the new
LSA bands which would enable dynamic traffic management to offer different service levels to
different customer segments. On the other hand [8], some other research works argued that the
flexible spectrum authorization schemes such as Licensed Shared Access (LSA) can reduce entry
barriers to the mobile market and allow other actors rather than MNOs to provision mobile services
in local areas [9], [10].
Another emerging approach is the Licensed Assisted Access spectrum sharing scheme, where the
unlicensed 5GHz (ISM) band is used as an additional spectrum resource for high capacity (typically
indoor) LTE systems. Due to the unreliability of the 5GHz spectrum band, which is heavily used by
Wi-Fi and other technologies, a licensed LTE band is always used in conjunction with the 5GHz
unlicensed band. The control signaling is thereby guaranteed, as well as a minimum data
throughput. In LAA, WiFi spectrum will be used to boost the downlink data channel, while the uplink
will reside within licensed spectrum only. On the downlink, carrier aggregation will be used between
the MNO (Mobile Network Operator) licensed band and the unlicensed 5GHz band. LAA is one usage
scenario of the more general LTE-U area, LTE for unlicensed spectrum, which has been studied for
many years [11] .LAA can typically be performed by a combination of macro cell in combination with
one or several small indoor cells using LTE on 5GHz [12].
Problem formulation and main task
The introduction of flexible spectrum use regime can lead to implication and disruption of the
traditional exclusive/common authorizations regime, and considerable push-back can be expected
from actors whose service operation and their competitive advantage in the market may be
threatened [8],[11]. The aim in this work is to have understanding and insights about the different
perspectives regarding the adoption of the flexible spectrum use concept in the nontelecommunication actor bands. Two flexible spectrum use approaches will be considered in the
scope of this thesis project; namely licensed shared access (LSA) approach and Licensed Assisted
Access approach aiming to answer the following research questions:
 What are the main drivers and obstacles for the adoption of LSA and LAA in future mobile
services market?


In which ways do the introduction of flexible spectrum concepts in non-tele-communication
bands (comparing both LSA and LAA) affect the existing business strategies of the mobile
network operators?
What are the potential business opportunities for the emerging actors (i.e. comparing both
of LSA and LAA) rather than the traditional mobile network operators?
Reference
[1] WP1, ”D1.1 : Scenarios, requirements and KPIs for 5G mobile and wireless,” METIS Project ,
Europe, 2013.
[2] J. Zander och P. MÄHÖNEN, ”Riding the Data Tsunami in the Cloud - Myths and Challenges in
future wireless acces,” Communications Magazine, IEEE, vol. 51, nr 3, pp. 145-151, 2013.
[3] CISCO, ”Visual Networking Index Report,” CISCO, US, 2014.
[4] METIS_D6.6, ”Final report on the METIS 5G system concept and technology roadmap,”
https://www.metis2020.com/wp-content/uploads/deliverables/METIS_D6.6_v1.pdf, Europe,
2015.
[5] P. L. Parcu, A. Nicita, G. Corda, M. A. Rossi och L. F. Bravo, ”Authorised Shared Access (ASA): An
Innovative Model of Pro-Competitive Spectrum Management,” 1 May 2011. [Online]. Available:
http://ssrn.com/abstract=2174518. [Använd 3 June 2013].
[6] METIS2020, ”D5.1: Initial description of the spectrum aspects of the selected scenarios,” METIS,
WP5, METIS Consortium, 2013.
[7] E. Commissioner, ”http://www.out-law.com/en/articles/2013/february/legal-action-threatover-single-eu-telecoms-market-risks-overshadowing-infrastructure-sharing-initiatives-saysexpert-/,” February 2013. [Online]. Available: http://www.out-law.com/en/articles/. [Använd 20
May 2013].
[8] P. Ahokangas, M. Matinmikko, S. Yrjola, M. Mustonen, H. Posti, E. Luttinen och A. Kivimaki,
”Business models for mobile network operators in Licensed Shared Access (LSA),” i IEEE
DYSPAN, McLean, VA, April 2014.
[9] A. Ahmed, J. Markendahl och A. Ghanbari, ”Evaluation of spectrum access options for indoor
mobile network deployment,” i PIMRC Workshops, London, 2013.
[10] J. Markendahl, A. A. W. Ahmed och B. G. Mölleryd, ”Business models and investment options
for use of licensed shared access of spectrum,” i 24th European Regional Conference of the
International Telecommunication Society,, Florence, 2013.
[11]Wi-Fi alliance (2015). Statement on License-Assisted Access (LAA). Available at: https://www.wifi.org/news-events/newsroom/wi-fi-alliance-statement-on-license-assisted-access-laa
[12] Nokia (2014). LTE for unlicensed spectrum White paper. Available at
http://networks.nokia.com/sites/default/files/document/nokia_lte_unlicensed_white_paper.pdf