Elsevier

Computer Networks

Volume 121, 5 July 2017, Pages 1-12
Computer Networks

Radio Spectrum: Evaluation approaches, coexistence issues and monitoring

https://doi.org/10.1016/j.comnet.2017.04.017Get rights and content

Abstract

The explosive growth of wireless communications lately imposes novel challenges for radio spectrum usage and policing. Many new communication scenarios have emerged that necessitate techniques for precise spectrum availability estimation and subsequent optimal spectrum sharing. For this purpose, estimating and validating the spectrum availability and policing its appropriate usage represent very important aspects of wireless network planning and optimization. This article discusses various approaches for spectrum availability evaluation, calculation and correct usage combining several case studies developed in different countries. In particular, it offers insights into simulation, modeling and measurement-based methodologies related to spectrum utilization and appropriate usage focusing on the effects before and after the digital switchover (DSO) of the television system. We investigate the usability of the different propagation models for wireless systems modeling, including the measurement-based validation of their precision for different scenarios. The article, furthermore, presents laboratory experiments targeting various aspects of DVB-T and LTE-800 coexistence, as a cheaper alternative to the measurement campaigns for fast and satisfactorily accurate results in controlled laboratory environments. Finally, the article discusses an example of a nationwide monitoring system for intruder detection, comparing several applied methods and their precision, which is important for constant monitoring of the spectrum usage policies, set by the spectrum regulatory institutions.

Introduction

The continuous increase in data rates and new services and the growth of number of mobile users has been a trend over the last decade. The successful implementation of the Digital Television (DTV) and the emergence of the digital dividend (DD) are enabling penetration of broadband services in new bands The demand for wireless services will increase significantly, especially stimulated by new applications and the push towards the Internet of Things (IoT) [1], 5G mobile communications [2] and small cells [3]. The higher number of users and the diversity of the services operating in the same or adjacent bands, contributes to the increased interest in spectrum evaluation and optimization.

The planning and managing of the spectrum imposes a necessity for regulations on global, regional and national levels. The global radio services are regulated coherently for all countries worldwide under the auspices of the International Telecommunication Union. The rational usage and the optimization of the wireless spectrum is not a trivial task and needs some comprehensive research, applying a variety of methodologies. Moreover, the local regulators need accurate results for specific spectrum managements to monitor disturbances caused by the coexistence of different wireless technologies. The results for such analysis can be obtained by focused measurement campaigns, laboratory experiments and comprehensive calculations. Laboratory experiments are the cheaper alternative to the measurement campaigns and they can provide fast and acceptably accurate results in controlled laboratory environments. Finally, the maintenance and the protection of the spectrum impose a necessity for systems that can constantly monitor the spectrum usage policies. This becomes an increasingly complex task due to the development of many novel wideband technologies operating on high frequencies (above 1 GHz). As a result, there must be a comprehensive and integrated approach to providing modern spectrum monitoring solutions.

This article elaborates on spectrum evaluations and regulations and partly focuses on the coexistence of DVB-T and LTE-800 or WiFi-like devices operating within TV band. The article integrates several findings previously obtained by the authors, with new results developed in the context of spectrum evaluation, radio propagation, coexistence of wireless technologies and monitoring. It provides a wide platform for spectrum modeling, spectrum measurement, and spectrum availability assessment in different scenarios, as well as system's details for analysis of interference and intruder detection.

The reminder of the article is organized as follows: Section 2 describes the targeted scenarios; Section 3 presents several case studies on spectrum evaluation, detailing the results based on modeling and measurements; Section 4 introduces laboratory experiments for DVB-T and LTE-800 coexistence providing easy and rapid framework for laboratory evaluation of the aforementioned problem without the need for extensive on-field measurements; Section 5 analyzes the problems associated with spectrum monitoring and introduces a system for radio interference and intruder detection on a nationwide operational level; Finally, Section 6 concludes the article.

Section snippets

Usage scenarios

The radio spectrum became a sparse resource, which triggered a broad research towards its optimized consuming. Many of the solutions suggested re-usage of the spectrum dedicated to one incumbent communication system (called primary system) by an opportunistic communication system (called secondary system). In spectrum sharing scenario, the performance might be degraded by the reassignment of the spectrum between the primary and secondary users. The challenge is to maximize the overall system

DTV spectrum modeling and measurement

The radio signal coverage of different wireless technologies, especially with requirements for high level of precision, must engage multiple interleaved methodologies and approaches. That is crucial for comprehensive evaluation of radio spectrum availability. The analysis is significantly complex when we need to take into consideration the actual terrain of the target territory. The methodologies implemented in this research include: numerical calculations performed by multiple software

Laboratory evaluation of LTE-800 and DVB-T coexistence

The DSO led to operation in adjacent frequency bands of the DVB-T and the LTE services. This poses a major problem for the DVB-T service since most of the market available DVB-T receivers today still receive transmissions from the UHF band dedicated to the LTE. As a result, the DVB-T service may experience serious degradations.

The regulatory bodies worldwide are focused on deriving appropriate DVB-T service protection ratios for various market available DVB-T receivers. This sub-section

Analysis of interference and intruder detection

Even though Dynamic Spectrum Access (DSA) and Cognitive Radio (CR) techniques are popular in the research world, still the spectrum assignment worldwide is almost exclusively based on stakeholders paying licenses for usage of specific bands. Therefore, modern comprehensive radio spectrum evaluation frameworks also require effective methods for policing appropriate spectrum usage by all involved entities. This results in the need for monitoring of spectrum interference and intruders violating

Conclusion

This article discussed a plethora of possible methodologies and approaches in radio spectrum evaluation. These methods (including laboratory and field measurements, numerical and analytical calculations, simulations and modeling) need to be applied in combined manner in order to provide accurate results and mutual validations. The spectrum re-usage and co-existence are hot topics and above all an obvious necessity in the radio-communications today and it requires careful selection of tools and

Acknowledgment

The Public Diplomacy Division of NATO in the framework of Science supported this work for Peace through the SfP-984409 Optimization and Rational Use of Wireless Communication Bands (ORCA) project. The authors would like to thank to all partners and participants in the project.

Dr. Liljana Gavrilovska currently holds the position of full professor at the Faculty of Electrical Engineering and Information Technologies, Ss Cyril and Methodius University in Skopje. She is Head of the Center for Wireless and Mobile Communications (CWMC) working in the area of telecommunication networks and wireless and mobile communications. Prof. Gavrilovska participated in numerous EU funded projects such as ASAP, PACWOMAN, MAGNET, MAGNET Beyond, ARAGORN, ProSense, FARAMIR, QUASAR and

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    Dr. Liljana Gavrilovska currently holds the position of full professor at the Faculty of Electrical Engineering and Information Technologies, Ss Cyril and Methodius University in Skopje. She is Head of the Center for Wireless and Mobile Communications (CWMC) working in the area of telecommunication networks and wireless and mobile communications. Prof. Gavrilovska participated in numerous EU funded projects such as ASAP, PACWOMAN, MAGNET, MAGNET Beyond, ARAGORN, ProSense, FARAMIR, QUASAR and ACROPOLIS, NATO funded projects such as RIWCoS and ORCA and several domestic research and applicative projects, mostly as a leader of national team. Her major research interest is concentrated on cognitive radio networks, future mobile systems, wireless and personal area networks, cross-layer optimizations, broadband wireless access technologies, ad hoc networking, traffic analysis and heterogeneous wireless networks.

    Dr. Gavrilovska is author/co-author of more than 200 research journal and conference publications and technical papers and several books and books’ chapters. She is a senior member of IEEE.

    Dr. Pero Latkoski currently holds the position of associate professor at the Institute of Telecommunications, Faculty of Electrical Engineering and Information Technologies, Ss Cyril and Methodius University in Skopje. He is also head of the Telecommunications laboratory at FEEIT Skopje. He has received his B.Sc, M.Sc and Ph.D. from Ss Cyril and Methodius University in Skopje, in 2004, 2006 and 2010, respectively. Dr. Latkoski participated in numerous EU funded projects such as SEEFIRE, SEEGRID, QUASAR, and NATO funded projects RIWCoS and ORCA, as well as in several domestic research and applicative projects. Dr. Latkoski is an author of more than 60 research journal and conference papers and two books. His major research interests include communication protocol engineering, telecommunications software, antenna engineering, optical networking, software defined networking and information theory. Pero Latkoski is a senior member of IEEE.

    Prof. Vladimir Atanasovski currently holds the positions of associate professor at the Institute of Telecommunications and Vice Dean for Finances at the Faculty of Electrical Engineering and Information Technologies, Ss Cyril and Methodius University in Skopje. He has received his B.Sc, M.Sc and Ph.D. from Ss Cyril and Methodius University in Skopje, in 2004, 2006 and 2010, respectively. Prof. Atanasovski participated in numerous international and domestic projects in his areas of interest (e.g. FP5 PACWOMAN, FP6 MAGNET, FP7 ARAGORN, FP7 ProSense, FP7 QUASAR, FP7 FARAMIR, FP7 ACROPOLIS, FP7 eWALL, NATO funded SfP RIWCoS and ORCA projects etc.). He is currently involved in the SCOPES funded ERT-SEE projects. Prof. Atanasovski is an author/co-author of more than 130 research journal and conference publications and technical papers, co-editor of a book published by Springer and an author of a book published by Scholars’ Press. His major research interests lie in the areas of resource management for future wireless networks, cognitive radio networks, traffic analysis and modeling, cross-layer optimizations and wireless sensor networking.

    Dr. Ramjee Prasad is a Professor of Future Technologies for Business Ecosystem Innovation (FT4BI) in the Department of Business Development and Technology, Aarhus University, Denmark. He is the Founder President of the CTIF Global Capsule (CGC). He is also the Founder Chairman of the Global ICT Standardisation Forum for India, established in 2009. GISFI has the purpose of increasing of the collaboration between European, Indian, Japanese, North-American and other worldwide standardization activities in the area of Information and Communication Technology (ICT) and related application areas.

    He has been honored by the University of Rome ``Tor Vergata”, Italy as a distinguished Professor of the Department of Clinical Sciences and Translational Medicine on March 15, 2016. He is Honorary Professor of University of Cape Town, South Africa, and University of KwaZulu-Natal, South Africa.

    He has received Ridderkorset af Dannebrogordenen (Knight of the Dannebrog) in 2010 from the Danish Queen for the internationalization of top-class telecommunication research and education.

    He has received several international awards such as: IEEE Communications Society Wireless Communications Technical Committee Recognition Award in 2003 for making contribution in the field of ``Personal, Wireless and Mobile Systems and Networks”, Telenor's Research Award in 2005 for impressive merits, both academic and organizational within the field of wireless and personal communication, 2014 IEEE AESS Outstanding Organizational Leadership Award for: ``Organizational Leadership in developing and globalizing the CTIF (Center for TeleInFrastruktur) Research Network”, and so on.

    He has been project coordinator of several EC projects namely, MAGNET, MAGNET Beyond, eWALL and so on.

    He has published more than 30 books, 1000 plus journal and conference publications, more than 15 patents, over 100 PhD graduates and larger number of masters (over 250). Several of his students are today worldwide telecommunication leaders themselves.

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    Dr. Octavian Fratu received the Ph.D. degree in Electronics and Telecommunications from University Politehnica of Bucharest, Romania in 1997. He pursued a postdoctoral stage as senior researcher in 3rd generation mobile communication systems, based on a research contract between CNET-France, ENS de Cachan—France and Universite Marne la Vallee—France. He is currently professor at the Faculty of Electronics, Telecommunications and Information Theory. His research interests include Digital Mobile Communications, Internet of Things, Radio Data Transmissions, Mobile Communications and Wireless Sensor Networks. His publications include more than 200 papers published in national or international scientific journals or presented at international conferences. He participated as director or collaborator in many international research projects such as ’’eWALL for Active Long Living—eWALL’’ (FP7 IP project, 2013–2016), ‘‘Optimization and rational use of Wireless Communication Bands (ORCA)’’ (NATO Science for Peace research project, 2013–2016), ,,Reconfigurable Interoperability of Wireless Communications Systems (RIWCoS)’’ (NATO Science for Peace research project, 2007–2010), ,,REDICT—Regional Economic Development by ICT/New media clusters’’ (FP7 CSA project, 2008–2009), ‘‘ATHENA—Digital Switchover: Developing Infrastructures for Broadband Access’’, (FP6 STREP project, 2004–2006) and others.

    Dr Pavlos Lazaridis is a Reader in Electronic-Electrical Engineering and Communications at the University of Huddersfield, UK. He previously held positions at France Telecom, Paris, TDF, as Head of the Antennas & Propagation Laboratory, at TDF-C2R research centre, Metz, France, the European Patent Office, Den Haag, The Netherlands, as a senior examiner, Brunel University, London, and ATEI Thessaloniki, Greece, as a senior lecturer. He is a senior member of IEEE, member of the IET, and Fellow of the Higher Education Academy. His main research interests are antennas, wireless communications, RF electronics, and broadcasting. He has authored and co-authored around 100 research papers, as well as various patents, and book chapters. From 2012 to 2015 he was co-director of the NATO Science for Piece research project ORCA and in 2011 he obtained an EU Basileus III grant. From 2002 until 2016 he has obtained a number of national and international grants for research on digital TV broadcasting and coverage studies.

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