Coexistence of DTT and Mobile Broadband: A Survey and Guidelines for Field Measurements
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paper_title: Process model for recent spectrum sharing concepts in policy making

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Regulatory authorities globally are looking for new policy making solutions to achieve more efficient spectrum usage by allowing multiple systems to share the same spectrum bands with the aid of cognitive techniques. This quest has led to the development of different spectrum sharing solutions in different parts of the world for optimising spectrum use in various spectrum bands. Despite the active widespread research on spectrum sharing over nearly two decades, only a few solutions have attracted the interest of industry and regulators as potential concepts for adoption. Though the selected solutions offer great promise, none have proven commercially successful at the time of the writing of this document. The process to introduce and adopt a new sharing concept in a specific spectrum band is very complex and the manner in which this introduction can take place varies considerably based on the regulation structure and the cultural norms of the nation where the deployment takes place. However, some general principles can be found and established for the process. Knowledge of these principles will allow researchers to develop their approaches taking into account requirements arising from different stakeholders in various phases of this process. In this paper, the spectrum sharing ecosystem and three prominent and most recent regulatory spectrum sharing concepts from Europe and US are introduced. Based on an analysis of these concepts, a general process model for spectrum sharing is introduced covering the roles and tasks of different stakeholders and emphasizing the need for seamless cooperation and interactions between them at different phases of the process. The general process model that is presented here can serve as a guideline for the development of new spectrum sharing models and help regulatory authorities to optimize the existing processes by pinpointing tasks for each stakeholder as providing a guide for the critical information that is needed for each phase of the process. Moreover, for academic and industry research and especially those involved with entrepreneurial endeavours, the paper gives a useful overview of the complicated administrative process behind and factors that contribute to the regulatory acceptance of a sharing concept.
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paper_title: Licensed Spectrum Sharing Schemes for Mobile Operators: A Survey and Outlook

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The ongoing development of mobile communication networks to support a wide range of superfast broadband services has led to massive capacity demand. This problem is expected to be a significant concern during the deployment of the 5G wireless networks. The demand for additional spectrum to accommodate mobile services supporting higher data rates and having lower latency requirements, as well as the need to provide ubiquitous connectivity with the advent of the Internet of Things sector, is likely to considerably exceed the supply, based on the current policy of exclusive spectrum allocation to mobile cellular systems. Hence, the imminent spectrum shortage has introduced a new impetus to identify practical solutions to make the most efficient use of scarce licensed bands in a shared manner. Recently, the concept of dynamic spectrum sharing has received considerable attention from regulatory bodies and governments globally, as it could potentially open new opportunities for mobile operators to exploit spectrum bands whenever they are underutilized by their owners, subject to service level agreements. Although various sharing paradigms have been proposed and discussed, the impact and performance gains of different schemes can be scenario-specific, and may vary depending on the nature of the sharing players, the level of sharing and spectrum access scheme. In this survey, we study the main concepts of dynamic spectrum sharing, different sharing scenarios, as well as the major challenges associated with sharing of licensed bands. Finally, we conclude this survey with open research challenges and suggest some future research directions.
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paper_title: A survey of cognitive radio access to TV White Spaces

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Cognitive radio is being intensively researched as the enabling technology for license-exempt access to the so-called TV White Spaces (TVWS), large portions of spectrum in the UHF/VHF bands which become available on a geographical basis after digital switchover. Both in the US, and more recently, in the UK the regulators have given conditional endorsement to this new mode of access. This paper reviews the state-of-the-art in technology, regulation, and standardisation of cognitive access to TVWS. It examines the spectrum opportunity and commercial use cases associated with this form of secondary access.
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paper_title: Study on Coexistence between Long Term Evolution and Digital Broadcasting services

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Korea has made a plan to transfer from analog television to Digital Television (DTV). Therefore, TV White Spaces (TVWS）are the unused TV broadcast channels which can be available for wireless communication systems. This paper assumes that DTV operates on Channel 34 and Long Term Evolution (LTE) is assumed that it uses Frequency Division Duplexing (FDD), and then upper 4 MHz of Channel 32 and channel 33 are assumed to allocate to LTE Uplink, and channel 35 and lower 4 MHz of channel 36 are assumed to allocate to Downlink. However, the interference effect of LTE on DTV has to be taken into account. Therefore, according to the interference probability of 5% required by DTV receiver and the allowable transmit power of LTE Base Station (BS) and Mobile Station (MS), the protection distance from the reference LTE BS and MS to DTV receiver and the guard band will be analyzed by using Spectrum Engineering Advanced Monte-Carlo Analysis Tool (SEAMCAT). As a result, in the case that 8 MHz guard band is required and the assumed emission mask of LTE BS is used, the required protection distance between the LTE BS and DTV receiver is about 2 km. In the case of interference between LTE MS and DTV receiver considering the assumed emission mask of LTE MS, the protection distance is negligible above 8 MHz of guard band. The results can be as a guideline and reference in making plan for the coexistence of LTE and DTV.
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paper_title: Interference measurements for Licensed Shared Access (LSA) between LTE and wireless cameras in 2.3 GHz band

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This paper presents interference measurements for spectrum sharing between Long-Term Evolution (LTE) network and wireless cameras in the 2.3–2.4 GHz band under the new Licensed Shared Access (LSA) concept. The introduction of wireless broadband (WBB) communications services in this band is currently under study in European regulation and standardization. If the band cannot be cleared, a potential implementation option is the LSA approach, which maintains the protection of the current incumbents while introducing WBB as an additional licensed system within the band. Defining the incumbent protection criteria is critical and will require field measurements. The incumbents operating on the band in Finland and many other European countries are Programme making and special events (PMSE) wireless cameras. This paper presents results from an interference measurement campaign conducted in Ylivieska, Finland, where the aim was to study the interference from real LTE WBB system to a professional level wireless camera link on the 2.3 GHz band using the Finnish LSA trial environment. The measurements were planned to reproduce the cordless camera link scenario in ECC report 172, which provides compatibility studies with respect to the potential usage of the 2.3 GHz band for WBB systems. The results indicate that coexistence between LTE and wireless camera link can be feasible in the measured cordless camera link scenario in adjacent or larger separation channels. The measurement results are slightly less restrictive than the theoretical results in the ECC report, which came to the same conclusion about the feasibility. However, further study is required to derive actual incumbent protection criteria.
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paper_title: Optimization of Spectrum Usage and Coexistence Analysis of DVB-T and LTE-800 systems

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This paper investigates the possible coexistence issues between the digital video broadcasting-terrestrial (DVB-T) system and the long term evolution (LTE) that operate in adjacent frequency bands. The proposed methodology for interference assessment evaluates the DVB-T performance degradation in presence of aggregate LTE-800 interference targeting the territory of Macedonia as evaluation area. The simulation analysis quantifies the percentage of interference degraded pixels and obtains the probability of pixel DVB-T service degradation. Furthermore, a measurement trial complements the simulation analysis through the evaluation of the influence of active antenna usage by the DVB-T receivers. The simulation and measurement results in this particular case confirm that the alignment of the active DVB-T receiving antenna towards the LTE-800 base station can substantially increase the degradation whereas aligning of the active DVB-T receiving antenna towards the DVB-T transmitter maintains the efficient TV reception. Finally, this paper proposes a simple algorithm for optimal LTE frequency arrangement, resulting in significant reduction of the LTE interference towards the DVB-T system.
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paper_title: Database-Assisted Television White Space Technology: Challenges, Trends and Future Research Directions

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Television white space (TVWS) technology is approaching the potential roll-out phase for commercial deployment, supported by recent pilot projects being conducted globally. Undeniably, TVWS technology is faced with daunting challenges that require attention. To enable an ecosystem in which TVWS technology can flourish, there is a need for a complete analysis of the challenges, trends and future research direction related to this technology. Database-assisted TVWS technology is market driven, geared toward the spectrum reuse paradigm, and faces fewer technical hurdles. Our goal in this paper is to present a tutorial review of the challenges related to database-assisted TVWS networks using the SLEPT (social, legal, economic, political, and technological) analysis framework. The SLEPT framework is a management model that is extensively used for quantitative analysis. A brief review of TVWS technology using the SLEPT model reveals that the technology has been socially accepted, legal challenges are evident in some countries, economic models are the way forward and are main focus of current research trends, TVWS technology cannot be implemented without political will emanating from spectrum reforms, and there are many coexistence-motivated technological issues confronting TVWS technology. In summary, this paper provides an up-to-date survey on TVWS and presents current trends and future research directions in the TVWS context.
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paper_title: Protection Ratio and Antenna Separation for DVB—T/LTE Coexistence Issues

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This paper concerns the analysis of adjacent channel interference of the 3GPP Long Term Evolution (LTE) E-UTRA (Evolved Universal Terrestrial Radio Access) mobile systems into Digital Video Broadcasting - Terrestrial (DVB-T) systems. The simulated performance of both systems allows us to define recommendations for minimizing the interference effects. The subjective quality of the received TV signal has been evaluated experimentally in terms of picture failure (PF). We also investigated the importance of the selection of suitable Spectral Emission Masks (SEMs) of the LTE downlink transmission. Results show that, by using the ECC 148 SEM, both the protection ratio and the minimum distance between LTE towers and DVB-T receivers can be significantly decreased.
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paper_title: Field measurements of WSD DTT protection ratios over outdoor and indoor reference geometries

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A currently prevalent view of the operation of white space cognitive radios is that they should use geolocation databases to determine their frequency band and maximum transmission power in any given location so that interference radiated to broadcast receivers is negligible. To estimate the level of such interference, physical reference geometries and path loss estimates have been proposed between co-located devices. In this paper we present results of a measurement campaign conducted over indoor and outdoor reference geometry scenarios in a digital terrestrial television test network. Applying a subjective error criterion, we provide practical estimates on the maximum relative transmit powers for white space devices in order to avoid visible interference in television reception. The study applies to various primary and secondary transmission and reception scenarios, and its results can be extended also to estimate protection ratios for signal configurations not considered in the reported measurements.
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paper_title: Co-Channel and Adjacent Channel Interference and Protection Issues for DVB-T2 and IEEE 802.22 WRAN Operation

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This paper presents a study on the coexistence issue of digital terrestrial TV broadcasting and cognitive broadband access operation in the TV white spaces (TVWS). Extended measurements were performed to evaluate the protection of the existing Second generation of digital video broadcasting terrestrial standard (DVB-T2) services in the presence of IEEE 802.22 WRAN co-channel and adjacent channel interference. The absence of picture failure over 30 consecutive seconds on decoded DVB-T2 streams has been monitored to obtain the maximum tolerable level of IEEE 802.22 WRAN interference, which ensures the protection of the primary broadcast system. This paper considers practical DVB-T2 system configuration options by varying parameters of the standard, such as constellation and code rate, FFT size, pilot pattern and guard interval, and rotated constellations and compares them in terms of robustness with respect to the interference generated by IEEE 802.22 WRAN operation. The goal is to provide cognitive broadband operators in the TVWS with guidelines to optimize their network by choosing the parameters that best fit their needs in case of coexistence with DVB-T2 broadcasting services.
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paper_title: Experimental evaluation of wireless simulation assumptions

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All analytical and simulation research on ad~hoc wireless networks must necessarily model radio propagation using simplifying assumptions. We provide a comprehensive review of six assumptions that are still part of many ad hoc network simulation studies, despite increasing awareness of the need to represent more realistic features, including hills, obstacles, link asymmetries, and unpredictable fading. We use an extensive set of measurements from a large outdoor routing experiment to demonstrate the weakness of these assumptions, and show how these assumptions cause simulation results to differ significantly from experimental results. We close with a series of recommendations for researchers, whether they develop protocols, analytic models, or simulators for ad~hoc wireless networks.
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paper_title: Spectrum Sharing for LTE-A and DTT: Field Trials of an Indoor LTE-A Femtocell in DVB-T2 Service Area

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In the near future, many applications such as environmental sensors, smart objects, health sensors, and personal devices will be connected to mobile networks requiring additional spectrum. Studies have been made to demonstrate a low occupancy time and locations on the digital terrestrial television (DTT) band. This available or unused spectrum have been called “TV-White-Spaces.” In the 2015 World Radiocommunication Conference, the ITU decided to re-allocate the 700 MHz band (694-790 MHz) for International Mobile Telecommunications (IMT) services and also emplaced the discussion of the future use of the DTT band (470-694 MHz) to 2025, for which studies have been requested. In this paper, we study a particular case which goes a step beyond the previous ones, as it aims at sharing the same frequency band in the same area between long term evolution-advance (LTE-A) and digital video broadcasting-terrestrial second generation (DVB-T2) technologies. Those geographical areas that are not covered because the useful DTT signal is obstructed by the environment or it has a limited coverage by the network design can be called “micro-TVWS.” We assume that a DVB-T2 transmitter provides coverage for fixed rooftop reception as a primary service, to a building in which a LTE-A femtocell is installed indoors for local coverage, as a secondary service. The results have been obtained by laboratory emulation and validated through field measurements using professional equipment. Our results provide the technical restrictions of the LTE-A femtocell, mainly on the maximum allowable effective isotropic radiated power that could transmit on the DTT band in terms of carrier separation, from co-channel to adjacent band. These results meet the need of spectrum for IMT-Advanced technologies, so spectrum sharing is proposed in this paper as a new solution to make an efficient use of this resource.
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paper_title: Coexistence: The Theory and the Practice

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RF coexistence, the ability of one piece of equipment to tolerate signals from another piece of equipment, is an often debated topic. Organizations from standards bodies to manufacturers to operators debate how to determine the ability to share spectrum with different technologies (CDMA, WiMAX, LTE, etc.), different duplexing schemes (FDD and TDD), and different deployments (public safety and cellular operations). Most often theoretical models are used, as measurements are often not practical. This article has performed both a theoretical and a practical (measured) analysis of CDMA-LTE coexistence in the U.S. PCS band (1850–1915/1930–1995 MHz), the result of which indicates that calculations based on standards or regulatory specifications are only directionally correct and that measurements, whenever possible, can provide a better picture of coexistence. This article validates theoretical coexistence calculations using real-world measurements and provides the methodology under which more detailed coexistence analysis can be performed. The methodology presented can be used to determine the coexistence of various wireless technologies, the results of which are directly translatable to field performance and thus practical network design. This leads to a better understanding of the challenges and solutions when disparate technologies and different network architectures attempt to share the same spectrum band.
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paper_title: Interference Issues for VANET Communications in the TVWS in Urban Environments

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Within the scenario of the proliferation of smart vehicles, a novel tendency is to exploit the cooperation between vehicles to create vehicular ad hoc networks (VANETs) using the IEEE 802.11p standard. IEEE 802.11p includes dedicated short-range communications (DSRC) between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed intelligent transportation system (ITS) band at 5.9 GHz. At such frequencies, fading problems caused by the Doppler effect and/or multipath adversely affect propagation, particularly in dense urban environments. To reduce such propagation impairments, the use of lower frequencies has been proposed in literature, namely the TV white spaces (TVWS) in the ultrahigh-frequency (UHF) band. TVWS is the part of the spectrum licensed to broadcasters that is not occupied at a given time in a given geographical area on a noninterfering/nonprotected basis with regard to primary services. This paper analyses coexistence issues between digital video broadcasting—terrestrial (DVB-T)2 and IEEE 802.11p transmission in the TVWS. The aim of this paper is twofold: to evaluate the protection of DVB-T2 broadcasting services interfered by IEEE 802.11p communications and the impact of adjacent DVB-T2 services on IEEE 802.11p communications in the TVWS. The main outcomes of this paper are the maximum transmission power level and bandwidth configuration of an 802.11p signal in the adjacent channel (i.e., TVWS) of an active DVB-T2 system while protecting the broadcast service, as well as the error rate curves for each allowed mode of IEEE 802.11p in the TVWS to evaluate the performance of VANETs communications coexisting with DVB-T2 regular services in the licensed TV band.
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paper_title: Next-generation digital television terrestrial broadcasting systems: Key technologies and research trends

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In the last two decades, digital television terrestrial broadcasting (DTTB) systems have been deployed worldwide. With the approval of the fourth DTTB standard called Digital Television/ Terrestrial Multimedia Broadcasting (DTMB) by International Telecommunications Union (ITU) in December 2011, the research on first-generation DTTB standards is coming to an end. Recently, with the rapid progress of advanced signal processing technologies, nextgeneration DTTB systems like Digital Video Broadcasting-Terrestrial-Second Generation (DVB-T2) have been extensively studied and developed to provide more types of services with higher spectral efficiency and better performance. This article starts from the brief review of the first-generation DTTB standards and the current status of emerging second-generation DTTB systems, then focuses on the common key technologies behind them instead of describing the specific techniques adopted by various standards. The state-of-the-art, technical challenges, and the most recent achievements in the field are addressed. The future research trends are discussed as well. In addition, the scheme of integrating DTTB and Internet is proposed to solve the crucial problem of information expansion.
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paper_title: Design considerations of IEEE 802.15.4m low-rate WPAN in TV white space

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This article provides an overview of technical design considerations for IEEE 802.15.4m LRWPAN operating in TVWS. We summarize and discuss TVWS regulatory requirements and LRWPAN applications, the two major driving forces motivating the formation of the new IEEE 802.15.4m standard. These forces define the criteria necessary for consideration during IEEE 802.15.4m system design to meet regulatory requirements and optimize performance. First, system design is presented from the perspective of LR-WPAN channelization with reference to the TV channel plan. Next, design considerations for network architecture and topology are discussed by relating the architecture requirement in TVWS regulations to that in the legacy IEEE 802.15.4 standard. Third, the PHY and MAC layer designs, which are crucial for meeting the criterion of optimizing LR-WPAN performance to support potential applications, are studied. In the PHY layer, the existing design in IEEE 802.15.4 is listed and discussed with regard to its applicability and reusability in TVWS. In the MAC layer, two functional entities, the TVWS operation-enabling feature and the dynamic frequency-band switching mechanism, are discussed with respect to their necessity and practicality for performance enhancement.
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paper_title: Some Are Born With White Space, Some Achieve White Space, and Some Have White Space Thrust Upon Them

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A few steps from Shakespeare's spiritual home The Globe Theatre in London, the U.K. regulator Ofcom is formulating its own well-crafted play based on TV white spaces (TVWSs). Such work comfortably fits into the Shakespearean analogy of “some achieve white space” through implementation of clever twists to make white space available while not causing harmful interference to incumbents, noting that the U.K. is extremely busy in terms of spectrum usage. This paper reports on some of the work of by our trial within the Ofcom TVWS Pilot, building key observations on beneficial usage scenarios for TVWS through link testing examples. It also particularly investigates performance of TVWS in terms of availability and capacity, through these scenarios and more generally, strongly focusing on aggregation of TVWS resources. A number of key observations result from this paper, some of which we highlight here. First, in the U.K., and in Europe in general where local DTT deployment characteristics and landscapes are similar to the U.K., TVWS has most benefit potential in below-rooftop receiver and indoor deployments. This is even more so if local white space device (WSD) deployment is extensive. Given this, we define and assess key baseline scenarios that we term as “mobile broadband downlink” and “indoor broadband provisioning” (akin to Wi-Fi or small cells in TVWS). We also argue comparison with other scenarios/topologies through parameter changes, and we further demonstrate the strength of TVWS for the indoor case through link performance tests. A second key observation is that good TVWS availability is achieved through the sophisticated regulatory approach of Ofcom, noting that the same approach to TVWS is harmonized across Europe through the ETSI EN 301 598 standard. However, this is affected by scenario: high power, high transmitter (e.g., 30 m above ground level) scenarios have a particularly reduced and variable availability. Further, high capacities are achieved by aggregating TVWS channels, especially if non-contiguous aggregation is supported; and moreover, profound implications for WSD RF design are derived based on such results, particularly under contiguous aggregation or channel bonding. A third key observation is that TVWS yields significant future potential, despite headwinds such as the WRC 2015 decision to allocate 694-790 MHz to mobile broadband on a co-primary basis in ITU region 1.
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paper_title: On the feasibility of unlicensed communications in the TV white space: Field measurements in the UHF band

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In practical unlicensed communications in TV band, radio devices have to identify, at first, the transmission opportunities, that is, the portion of the spectrum licensed for broadcasting services unoccupied in a certain region at certain time, that is, the so-called TV white space. In this paper the outcome of field measurements in the UHF TV band (470–860 MHz) conducted in EU is presented. To obtain empirical values for the parameters upon which unlicensed radio devices are able to distinguish in a real scenario between empty and occupied TV channels, signal power measurements have been performed in Italy, Spain, and Romania on rural, suburban, and urban sites, at different heights over the ground by using different analysis bandwidths. The aim of this work is to provide a set of practical parameters upon which harmless unlicensed communication in the UHF TV white space is feasible. The results have been analyzed with respect to the hidden node margin problem, spectrum sensing bandwidth, and occupancy threshold.
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paper_title: A survey of cognitive radio access to TV White Spaces

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Cognitive radio is being intensively researched as the enabling technology for license-exempt access to the so-called TV White Spaces (TVWS), large portions of spectrum in the UHF/VHF bands which become available on a geographical basis after digital switchover. Both in the US, and more recently, in the UK the regulators have given conditional endorsement to this new mode of access. This paper reviews the state-of-the-art in technology, regulation, and standardisation of cognitive access to TVWS. It examines the spectrum opportunity and commercial use cases associated with this form of secondary access.
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paper_title: Broadcast television spectrum incentive auctions in the u.s.: trends, challenges, and opportunities

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This article presents an overview of the upcoming television broadcast spectrum incentive auction in the U.S., which will be the first ever attempted worldwide, and discusses the main business, regulatory, and technical challenges of a successful incentive auction. The process combines two separate but linked auctions: a reverse auction, which will identify the prices at which broadcasters are willing to relinquish their spectrum; and a forward auction, which will determine the price mobile network operators are willing to pay to acquire the new frequencies. The two auctions will determine the buyers and sellers and also the amount of spectrum to be cleared in the 600 MHz band after reorganizing the television stations that remain on air. This process is known as repacking and will create contiguous blocks of cleared spectrum at the high frequency side of the UHF band for mobile use. The article also reviews the potential plans for the 600 MHz band and discusses the opportunities that could bring about the new digital terrestrial television standard known as “ATSC 3.0.”
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paper_title: Reducing Complexity of TVWS Operation: Complying with European Regulations

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License-exempt operation is considered to be a promising solution for spectrum-resource scarcity. Incumbent protection and coexistence management constitute two fundamental aspects of the successful operation. Under regulations for TV white space (TVWS), WS devices (WSDs) are required to access a WS database (WSDB) every time their individual location changes by >50 m. If the aggregate-interference effect is considered, one WSD's location change can incur frequent adjustment of the available spectrum for other WSDs. In this article, we present a practical low-complexity WSDB-assisted TVWS operation complying with the current regulatory progress in Europe. First, we propose a new procedure of setting emission limits for WSDs. By modeling the WSD distribution as the Poisson point process (PPP), we obtain a percentage emission limit valid for a WSD mobility region. By using the proposed procedure with the percentage emission limit in an example scenario, we reduce the complexity by 90% compared to the exiting procedure. Second, we present a succinct scheme to achieve the efficient coexistence of WSDs by deducing an upper bound on the number of cochannel WSDs over a given region.
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paper_title: A Survey of the DVB-T Spectrum: Opportunities for Cognitive Mobile Users

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Cognitive radio (CR) systems are designed to utilize the available radio spectrum in an efficient and intelligent manner. Terrestrial Digital Video Broadcasting (DVB-T) frequency bands are one of the future candidates for cognitive radio applications especially because after digital television transition the TV white spaces (TVWS) became available for radio communication. This paper deals with the survey of the DVB-T spectrum; wideband measurements were performed on mobile platform in order to study the variation of the radio signal power in city area aboard a moving vehicle. The measurement environment was a densely built-in region where the proper DVB-T receiving was guaranteed by three TV transmitters, utilizing three central channel frequencies using 610, 746, and 770 MHz. In our paper the methods, the applied antenna, and measurement devices will be presented together with simulated and measured fading statistics. The final result is an estimation of the cognitive DVB-T spectrum utilization opportunity; furthermore a scenario is also proposed for secondary channel usage.
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paper_title: Incentives for the key stakeholders in the hybrid use of the UHF broadcasting spectrum utilizing Supplemental Downlink: A dynamic capabilities view

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This paper investigates key stakeholders' incentives for the hybrid use of the Ultra High Frequency (UHF) spectrum for broadcasting and mobile broadband using novel Supplemental Downlink (SDL) Carrier Aggregation (CA) technique from the dynamic capabilities perspective of strategic management. So far broadcaster (BC) community has lacked true incentives for sharing the spectrum they currently use and have seen sharing only as unilateral repurposing act from regulatory bodies and Mobile Network Operators (MNO). In this paper we focus on key stakeholders capability to deal with combined internal and external resources and capabilities in doing business, refered as Dynamic Capability (DC). Spectrum sharing introducing a rapid change in the stakeholders business environments requires dynamic capabilities of hybrid use from both spectrum offering and spectrum utilization perspectives. We focus on identifying and discussing broadcaster incumbents' and MNO licensees' key antecedents, processes, and outcomes related to hybrid use of UHF spectrum using the supplementary downlink (SDL) carrier aggregation (CA) concept. Based on our DC analysis, we found incentives that could motivate both the incumbents and licensees to consider the hybrid use of UHF spectrum as a co-creation opportunity, and provide viewponts for the regulatory bodies to be considered when developing new regulatory models for accessing UHF spectrum.
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paper_title: IEEE Standard 802.19.1 for TV white space coexis tence

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Understanding of the need to provide coexistence solutions for different cognitive radio systems operating in white space frequency bands, in December 2009 the IEEE 802 Executive Committee started project 802.19.1 to develop a standard for "TV White Space Coexistence Methods". This standard, published in June 2014, specifies radio technology independent methods for coexistence among dissimilar or independently operated TV band networks. In this article we present the key concepts of the IEEE 802.19.1 coexistence system, its architecture, and protocol. We also provide an example of the IEEE 802.19.1 coexistence system implementation and operation.
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paper_title: IEEE 802.11af: a standard for TV white space spectrum sharing

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Spectrum today is allocated in frequency blocks that serve either licensed or unlicensed services. This static spectrum allocation has limited resources to support the exponential increase in wireless devices. In this article, we present the IEEE 802.11af standard, which defines international specifications for spectrum sharing among unlicensed white space devices (WSDs) and licensed services in the TV white space band. Spectrum sharing is conducted through the regulation of unlicensed WSDs by a geolocation database (GDB), the implementation of which differs among regulatory domains. The main difference between regulatory domains is the timescale in which WSDs are controlled by the GDB, resulting in different TVWS availability and WSD operating parameters. The IEEE 802.11af standard provides a common operating architecture and mechanisms for WSDs to satisfy multiple regulatory domains. This standard opens a new approach to treat spectrum as a single entity shared seamlessly by heterogeneous services.
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paper_title: LTE broadcast and supplemental downlink enablers for exploiting novel service and business opportunities in the flexible use of the uhf broadcasting spectrum

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This article reviews technology and business enablers for future flexible use concepts of the UHF broadcasting spectrum (470-790 MHz) by digital terrestrial TV and MBB. Flexible use of the UHF band aims to increase the efficiency of spectrum use in delivering fast-growing and converging mobile broadband, media, and TV content to meet changing consumer needs. Enabling technical factors are presented, and potential services are compared in order to identify similarities and differences in possible business model designs and scaling factors for developing successfully deployable services and regulatory concepts. The results indicate that several services meet basic requirements to scale, leveraging key existing assets and capabilities of LTE technologies and the business ecosystem while extending current business models beyond connectivity. Regulation and standardization forums can utilize the developed use case and service scenarios in analyzing the future of UHF spectrum and LTE broadcasting evolution. Furthermore, the flexible use concept has the potential to transform the business ecosystem around both BC and MBB by introducing new convergence opportunities for LTE's development toward 5G.
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paper_title: On using white space spectrum

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Use of the "white spaces" in the UHF TV band has been identified as an important spectrum resource, providing new unlicensed spectrum access in frequency bands with excellent propagation characteristics. As a result, regulators around the world have been working on technical measures that will allow the use of this spectrum without interfering with incumbent licensed users. Defining these measures is complex and can have major implications on the amount of white space actually available. This article looks at a number of aspects of defining, using and regulating white space and shows which parameters are critical. It compares regulatory approaches put forward in the UK and US and demonstrates how the current US approach results in much restricted spectrum access. It also assesses key factors for the technologies using white space and shows how all these factors influence the applications most likely to succeed.
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paper_title: RECENT TRENDS ON TV WHITE SPACE DEPLOYMENTS IN AFRICA

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In this paper, we presented the effects of Television White Space (TVWS) on digital divide in Africa. The trends in digital divide are found to be wide in most African countries, which are characterized with low internet penetration. Perhaps this is expected because over 60 % of people in Africa reside in the rural area and these areas are characterized with low literacy, poverty level and limited telecommunication infrastructure supports. There have been research efforts and regulations towards the secondary use of TV frequencies. However, findings indicate that there are limited opportunities for such system in Europe: This is due to high internet penetration in Europe, but the situation may be quite different in other part of the world like in Africa. Therefore, the TVWS could be used to provide affordable universal access in rural Africa. The paper also presents some benefits developing countries in Africa will incur from utilizing the TVWS solution. Also, recent trend in the deployment of TVWS and experiences got from African countries that embrace the solution are presented. http://dx.doi.org/10.4314/njt.v34i3.19
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paper_title: The Effectiveness of Opportunistic Spectrum Access: A Measurement Study

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Dynamic spectrum access networks are designed to allow today's bandwidth-hungry "secondary devices" to share spectrum allocated to legacy devices, or "primary users." The success of this wireless communication model relies on the availability of unused spectrum and the ability of secondary devices to utilize spectrum without disrupting transmissions of primary users. While recent measurement studies have shown that there is sufficient underutilized spectrum available, little is known about whether secondary devices can efficiently make use of available spectrum while minimizing disruptions to primary users. In this paper, we present the first comprehensive study on the presence of "usable" spectrum in opportunistic spectrum access systems, and whether sufficient spectrum can be extracted by secondary devices to support traditional networking applications. We use for our study fine-grain usage traces of a wide spectrum range (20 MHz-6 GHz) taken at four locations in Germany, the Netherlands, and Santa Barbara, CA. Our study shows that on average, 54% of spectrum is never used and 26% is only partially used. Surprisingly, in this 26% of partially used spectrum, secondary devices can utilize very little spectrum using conservative access policies to minimize interference with primary users. Even assuming an optimal access scheme and extensive statistical knowledge of primary-user access patterns, a user can only extract between 20%-30% of the total available spectrum. To provide better spectrum availability, we propose frequency bundling, where secondary devices build reliable channels by combining multiple unreliable frequencies into virtual frequency bundles. Analyzing our traces, we find that there is little correlation of spectrum availability across channels, and that bundling random channels together can provide sustained periods of reliable transmission with only short interruptions.
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paper_title: Digital video broadcasting

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A new kind of "wireless video" is currently entering consumers' homes-digital television. The term digital video broadcasting (DVB) is used as a synonym for digital television in many countries of the world. Whereas one may tend to think that digital television means just a new, digital, form of signal representation not necessarily affecting the information content of what one has always called TV, the truth is that digital television becomes multiple-channel data broadcasting. This article reviews some of the results of the work in the worldwide DVB Project and explains some of the fundamental concepts behind the work of this group. It then concentrates on the terrestrial transmission system (DVB-T) as one example of the many transmission technologies DVB has developed over the last few years. The COFDM modulation scheme which is a key ingredient of DVB-T is described in some detail. The performance of the system is presented. The use of DVB for data broadcasting and the accompanying return channel technologies are explained.
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paper_title: WIB: a new system concept for digital terrestrial television (DTT)

paper_content:

A new system concept for DTT, called “WiB”, is presented, where potentially all frequencies within the Ultra High Frequency (UHF) band are used on all transmitter (TX) sites (i.e. reuse-1). Interference, especially from neighbouring transmitters operating on the same frequency and transmitting different information, is handled by a combination of a robust transmission mode, directional discrimination of the receiving antenna and interference cancellation methods. With this approach DTT may be transmitted as a single wideband signal, covering potentially the entire UHF band, from a single wideband transmitter per TX site. Thanks to a higher spectrum utilisation the approach allows for a dramatic reduction in fundamental power/cost and about 37-60% capacity increase for the same coverage as with current DTT. High speed mobile reception as well as fine granularity local services would also be supported, without loss of capacity. The paper also outlines further possible developments of WiB, e.g. doubling the capacity via cross-polar Multiple In Multiple Out (MIMO), backward-compatible with existing receiving antennas, and adding a second, WiB-mobile, Layer Division Multiplexing (LDM) layer within the same spectrum, either as mobile broadcast or as mobile broadband.
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paper_title: Location estimation-based radio environment map construction in fading channels

paper_content:

Latest regulations on TV white space communications and trend toward spectrum access through geolocation databases relax the regulatory constraints on cognitive radios. Radio environment map REM is a kind of improved geolocation database and an emerging topic with the latest regulations on TV white space communications. It constructs a comprehensive temperature map of the cognitive radio network operation area by utilizing multi-domain information from geolocation databases, characteristics of spectrum use, geographical terrain models, propagation environment, and regulations. REMs act as cognition engines by building long-term knowledge via processing spectrum measurements collected from sensors to estimate the state of locations without any measurement data. Active transmitter LocatIon Estimation based REM construction technique is proposed and compared with the well-known REM construction techniques such as Kriging and inverse distance weighted interpolation in shadow and multipath fading channels. The simulation results suggest that the LocatIon Estimation based REM construction outperforms the compared methods in terms of RMSE and correct detection zone ratio by utilizing additional information about channel parameters that can be estimated by classical least squares method easily.Copyright © 2013 John Wiley & Sons, Ltd.
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paper_title: Field measurements for practical unlicensed communication in the UHF band

paper_content:

This paper presents the result of a measurement campaign conducted in Italy, Spain, and Romania to obtain empirical values for the parameters upon which unlicensed devices could distinguish in a hidden node scenario between empty and occupied TV channels. Signal power measurements in the UHF frequency band (470---860 MHz) have been carried out on rural, sub-urban, and urban sites, at different heights over the ground by using different analysis bandwidths. The results have been analyzed with respect to the hidden node margin problem, spectrum sensing bandwidth, and occupancy threshold, to produce a set of practical parameters upon which harmless unlicensed communication in the UHF TV bands is feasible.
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paper_title: Database-Assisted Television White Space Technology: Challenges, Trends and Future Research Directions

paper_content:

Television white space (TVWS) technology is approaching the potential roll-out phase for commercial deployment, supported by recent pilot projects being conducted globally. Undeniably, TVWS technology is faced with daunting challenges that require attention. To enable an ecosystem in which TVWS technology can flourish, there is a need for a complete analysis of the challenges, trends and future research direction related to this technology. Database-assisted TVWS technology is market driven, geared toward the spectrum reuse paradigm, and faces fewer technical hurdles. Our goal in this paper is to present a tutorial review of the challenges related to database-assisted TVWS networks using the SLEPT (social, legal, economic, political, and technological) analysis framework. The SLEPT framework is a management model that is extensively used for quantitative analysis. A brief review of TVWS technology using the SLEPT model reveals that the technology has been socially accepted, legal challenges are evident in some countries, economic models are the way forward and are main focus of current research trends, TVWS technology cannot be implemented without political will emanating from spectrum reforms, and there are many coexistence-motivated technological issues confronting TVWS technology. In summary, this paper provides an up-to-date survey on TVWS and presents current trends and future research directions in the TVWS context.
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paper_title: Cellular-Base-Station Assisted Device-to-Device Communications in TV White Space

paper_content:

This paper presents a systematic approach to exploiting TV white space (TVWS) for device-to-device (D2D) communications with the aid of the existing cellular infrastructure. The goal is to build a location-specific TVWS database, which provides a lookup table service for any D2D link to determine its maximum permitted emission power (MPEP) in an unlicensed digital TV (DTV) band. To achieve this goal, the idea of mobile crowd sensing is first introduced to collect active spectrum measurements from massive personal mobile devices. Considering the incompleteness of crowd measurements, we formulate the problem of unknown measurements recovery as a matrix completion problem and apply a powerful fixed point continuation algorithm to reconstruct the unknown elements from the known elements. By joint exploitation of the big spectrum data in its vicinity, each cellular base station further implements a nonlinear support vector machine algorithm to perform irregular coverage boundary detection of a licensed DTV transmitter. With the knowledge of the detected coverage boundary, an opportunistic spatial reuse algorithm is developed for each D2D link to determine its MPEP. Simulation results show that the proposed approach can successfully enable D2D communications in TVWS while satisfying the interference constraint from the licensed DTV services. In addition, to our best knowledge, this is the first try to explore and exploit TVWS inside the DTV protection region resulted from the shadowing effect. Potential application scenarios include communications between internet of vehicles in the underground parking and D2D communications in hotspots such as subway, game stadiums, and airports.
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paper_title: TV White Space in Europe

paper_content:

In this paper, we study the availability of TV white spaces in Europe. Specifically, we focus on the 470-790 MHz UHF band, which will predominantly remain in use for TV broadcasting after the analog-to-digital switch-over and the assignment of the 800 MHz band to licensed services have been completed. The expected number of unused, available TV channels in any location of the 11 countries we studied is 56 percent when we adopt the statistical channel model of the ITU-R. Similarly, a person residing in these countries can expect to enjoy 49 percent unused TV channels. If, in addition, restrictions apply to the use of adjacent TV channels, these numbers reduce to 25 and 18 percent, respectively. These figures are significantly smaller than those recently reported for the United States. We also study how these results change when we use the Longley-Rice irregular terrain model instead. We show that while the overall expected availability of white spaces is essentially the same, the local variability of the available spectrum shows significant changes. This underlines the importance of using appropriate system models before making far-reaching conclusions.
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paper_title: Improving LTE ${e}$ MBMS With Extended OFDM Parameters and Layered-Division-Multiplexing

paper_content:

The evolved multimedia broadcast multicast service ( ${e}$ MBMS) system was developed to achieve higher spectrum efficiency on video traffic delivery over the long term evolution (LTE) networks. As an integrated component of the LTE, ${e}$ MBMS can be deployed with great flexibility using the existing LTE infrastructure. However, the current ${e}$ MBMS was designed as a supplementary subsystem, and has limited capability to deliver high-quality broadcast-type video services in a spectrum efficient manner. This paper first studies the capability and limitations of the current LTE ${e}$ MBMS system to deliver broadcast services when deployed as single-frequency-network (SFN). Next, potential physical-layer enhancements are investigated for future ${e}$ MBMS systems to achieve enhanced broadcast service delivery capability, higher spectrum efficiency, improved service quality, and more efficient SFN deployment options. These include wideband transmission, non-orthogonal multiplexing, e.g., layered-division-multiplexing technology, and more flexible orthogonal frequency division multiplexing system configurations, such as longer cyclic prefix and smaller subcarrier spacing. Other technologies defined in the latest next generation digital television system are also discussed that might be applicable to the development of a more capable standalone future ${e}$ MBMS system.
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paper_title: Multilevel Protection to Broadcaster Contour and Its Impact on TV White Space Availability

paper_content:

In light of recent regulations from the Federal Communications Commission (FCC) governing the very-high-frequency/ultrahigh-frequency band sharing, we consider the database as a tool to plan the utilization of this spectrum by unlicensed wireless devices. Our approach, however, differs from that adopted by the FCC in the sense that it exploits the ability that white space (WS) devices have in controlling their effective isotropic radiated power through the transmit power control technique when concomitantly operating in a cochannel or in an adjacent channel to a TV station. We derive equations for the expected interference level generated by WS devices with antenna heights ranging from a few meters (portable devices) up to a 1000 m (fixed devices) based on very recent TV white space (TVWS) propagation literature and regulatory requirements. Additionally, we also provide exact and numerical methods to calculate the critical distance that prevents interference to primary contours, thus enabling fast identification of regions where operation is harmless to incumbents in the presence of shadowing and multipath fading. These equations reveal the intrinsic relationship between system design parameters, environmental parameters, and country regulations with TVWS availability. Finally, we provide an analysis that indicates notable enhancements in the expected TVWS availability through the use of a multilevel method while obtaining the same desirable degree of protection required by the current FCC regulation based on the single-level methodology. The analysis is divided in two parts: theoretical evaluations to obtain insights into the potential of multilevel protection in recovering TVWS-less regions from a single exclusion zone and extensive computations to obtain the expected TVWS availability yielded by both protection methodologies and primary-contour determination techniques across the Japanese territory. Specifically, multilevel protection is found to have the effect of doubling the TVWS bandwidth, as compared with single-level protection. On the other hand, diffraction methods used to determine the primary contour nearly triples the bandwidth, as compared with the height above average terrain (HAAT) technique. The combined effect of multilevel protection and diffraction-based primary contours is TVWS availability on 98.76% of the Japanese territory with a bandwidth expansion six times of that inherent to single-level protection and HAAT-based contours.
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paper_title: Layered-Division-Multiplexing: Theory and Practice

paper_content:

As the next generation digital TV (DTV) standard, the ATSC 3.0 system is developed to provide significant improvements on the spectrum efficiency, the service reliability, the system flexibility, and system forward compatibility. One of the top-priority requirements for the ATSC 3.0 is the capability to deliver reliable mobile TV services to a large variety of mobile and indoor devices. Layered-division-multiplexing (LDM) is a physical-layer non-orthogonal-multiplexing technology to efficiently deliver multiple services with different robustness and throughputs in one TV channel. A two-layer LDM structure is accepted by ATSC 3.0 as a baseline physical-layer technology. This LDM system is capable of delivering robust high-definition (HD) mobile TV and ultra-HDTV services in one 6 MHz channel, with a higher spectrum efficiency than the traditional time/frequency-division-multiplexing (T/FDM)-based DTV systems. This paper presents a detailed overview on the LDM technology, and its application in the ATSC 3.0 systems. First, the fundamental advantages of the LDM over the traditional TDM/FDM systems are analyzed from information theory point of view. The performance advantages of the LDM are then confirmed by extensive simulations of the ATSC 3.0 system. It is shown that, LDM can realize the potential gain offered by superposition coding over the TDM/FDM systems, by properly configuring the transmission power, channel coding, and modulation, and using different multiple antenna technologies in the multiple layers. Next, the efficient implementation of LDM in the ATSC 3.0 system is presented to show that the performance advantages of the LDM are obtained with small additional complexity. This is achieved by carefully aligning the transmission signal structure and the signal processing chains in the multiple layers. Finally, we show that the LDM can be further integrated with different multiple antenna technologies to achieve further transmission capacity.
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paper_title: Study on Coexistence between Long Term Evolution and Digital Broadcasting services

paper_content:

Korea has made a plan to transfer from analog television to Digital Television (DTV). Therefore, TV White Spaces (TVWS）are the unused TV broadcast channels which can be available for wireless communication systems. This paper assumes that DTV operates on Channel 34 and Long Term Evolution (LTE) is assumed that it uses Frequency Division Duplexing (FDD), and then upper 4 MHz of Channel 32 and channel 33 are assumed to allocate to LTE Uplink, and channel 35 and lower 4 MHz of channel 36 are assumed to allocate to Downlink. However, the interference effect of LTE on DTV has to be taken into account. Therefore, according to the interference probability of 5% required by DTV receiver and the allowable transmit power of LTE Base Station (BS) and Mobile Station (MS), the protection distance from the reference LTE BS and MS to DTV receiver and the guard band will be analyzed by using Spectrum Engineering Advanced Monte-Carlo Analysis Tool (SEAMCAT). As a result, in the case that 8 MHz guard band is required and the assumed emission mask of LTE BS is used, the required protection distance between the LTE BS and DTV receiver is about 2 km. In the case of interference between LTE MS and DTV receiver considering the assumed emission mask of LTE MS, the protection distance is negligible above 8 MHz of guard band. The results can be as a guideline and reference in making plan for the coexistence of LTE and DTV.
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paper_title: Optimization of Spectrum Usage and Coexistence Analysis of DVB-T and LTE-800 systems

paper_content:

This paper investigates the possible coexistence issues between the digital video broadcasting-terrestrial (DVB-T) system and the long term evolution (LTE) that operate in adjacent frequency bands. The proposed methodology for interference assessment evaluates the DVB-T performance degradation in presence of aggregate LTE-800 interference targeting the territory of Macedonia as evaluation area. The simulation analysis quantifies the percentage of interference degraded pixels and obtains the probability of pixel DVB-T service degradation. Furthermore, a measurement trial complements the simulation analysis through the evaluation of the influence of active antenna usage by the DVB-T receivers. The simulation and measurement results in this particular case confirm that the alignment of the active DVB-T receiving antenna towards the LTE-800 base station can substantially increase the degradation whereas aligning of the active DVB-T receiving antenna towards the DVB-T transmitter maintains the efficient TV reception. Finally, this paper proposes a simple algorithm for optimal LTE frequency arrangement, resulting in significant reduction of the LTE interference towards the DVB-T system.
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paper_title: Protection Ratio and Antenna Separation for DVB—T/LTE Coexistence Issues

paper_content:

This paper concerns the analysis of adjacent channel interference of the 3GPP Long Term Evolution (LTE) E-UTRA (Evolved Universal Terrestrial Radio Access) mobile systems into Digital Video Broadcasting - Terrestrial (DVB-T) systems. The simulated performance of both systems allows us to define recommendations for minimizing the interference effects. The subjective quality of the received TV signal has been evaluated experimentally in terms of picture failure (PF). We also investigated the importance of the selection of suitable Spectral Emission Masks (SEMs) of the LTE downlink transmission. Results show that, by using the ECC 148 SEM, both the protection ratio and the minimum distance between LTE towers and DVB-T receivers can be significantly decreased.
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paper_title: A framework for calculation of TV white space availability subject to the protection of DTT and PMSE

paper_content:

The UK/European framework for access to the UHF TV band by white space devices (WSDs) is predicated on the communication of information on TV white space (TVWS) availability from white space databases (WSDBs) to WSDs. This information is in the form of location- and frequency-specific maximum permitted WSD radiated power levels. These levels are calculated in such a way so as to afford protection to the two incumbent (licensed) uses within the band, namely Digital Terrestrial Television (DTT), and Programme Making and Special Events (PMSE), as well as users of spectrum outside the band. In this paper we first outline the proposed framework for access to TV white spaces in the UK, describing the interactions between the regulator, WSDBs and WSDs. We then present the calculations required for the computation of maximum permitted WSD radiated power levels, accounting for nationwide DTT coverage and PMSE assignments.
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paper_title: Local-area field strength variation measurement of the digital terrestrial television signal (COFDM 8K) in suburban environments

paper_content:

This paper presents the results of a field measurement campaign at the experimental COFDM 8K digital terrestrial television network developed by the partners of the VIDITER project in Madrid (Spain). This article focuses on the field strength spatial variation distribution inside small coverage areas. Due to the fact that the distribution parameters strongly depend on the survey area type, during this first stage the only environments taken into account have been those traditionally considered as suburban.
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paper_title: Coexistence of Digital Terrestrial Television and 4G LTE Mobile Network Utilizing Supplemental Downlink Concept: A Real Case Study

paper_content:

This paper contributes to the studies for long-term evolution (LTE) deployment into the ultrahigh-frequency (UHF) broadcasting spectrum (470–790 MHz) utilizing the supplemental downlink (SDL) concept and its coexistence with the digital terrestrial Television (DTT) service. The performed real and practical coexistence scenario studies were based on the modeling and simulation of the LTE and DTT systems in order to assess potential interference between systems and the availability of the spectrum for the LTE SDL services. Simulations were aligned with the scenarios and assumptions agreed to in the European regulation complemented with real case study parameters from Finland: the early adopter of the digital dividend II. The results lead to some conclusions about the LTE SDL-DTT coexistence and indicated availability of the complementary LTE SDL services on the lower UHF spectrum. Flexible use of the UHF band aims to increase the efficiency of spectrum use in delivering fast growing and converging mobile broadband, media, and TV content to meet the changing consumer needs. Simulated scenarios can be utilized by regulation and standardization forums for studying the future of UHF spectrum and LTE broadcasting evolution in mobile communications toward fifth-generation (5G).
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paper_title: On the feasibility of unlicensed communications in the TV white space: Field measurements in the UHF band

paper_content:

In practical unlicensed communications in TV band, radio devices have to identify, at first, the transmission opportunities, that is, the portion of the spectrum licensed for broadcasting services unoccupied in a certain region at certain time, that is, the so-called TV white space. In this paper the outcome of field measurements in the UHF TV band (470–860 MHz) conducted in EU is presented. To obtain empirical values for the parameters upon which unlicensed radio devices are able to distinguish in a real scenario between empty and occupied TV channels, signal power measurements have been performed in Italy, Spain, and Romania on rural, suburban, and urban sites, at different heights over the ground by using different analysis bandwidths. The aim of this work is to provide a set of practical parameters upon which harmless unlicensed communication in the UHF TV white space is feasible. The results have been analyzed with respect to the hidden node margin problem, spectrum sensing bandwidth, and occupancy threshold.
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paper_title: The future of spectrum sensing

paper_content:

Even though databases are currently favored in spectrum sharing scenarios, sensing is still needed. Spectrum sensing has a future in several existing and novel situations and applications. Those include crisis situations, local and indoor networks like wireless local area networks (WLAN) and battery-oriented applications like future intelligent Internet of Things (IoT). In this paper, the future of spectrum sensing is covered. Spectrum sensing properties are discussed and a short review about the most recent spectrum sensing methods is presented. The focus of this paper is on analyzing and defining conditions when spectrum sensing is a reasonable and justified choice. Our analysis showed that there are a lot of situations and applications when spectrum sensing is a practical and cost-effective choice. The advantages and disadvantages of sensing have to be in balance. The situation, application and used sensing method including their restrictions, requirements and needs have to be taken into account.
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paper_title: Wideband spectrum sensing for cognitive radio networks: a survey

paper_content:

Cognitive radio has emerged as one of the most promising candidate solutions to improve spectrum utilization in next generation cellular networks. A crucial requirement for future cognitive radio networks is wideband spectrum sensing: secondary users reliably detect spectral opportunities across a wide frequency range. In this article, various wideband spectrum sensing algorithms are presented, together with a discussion of the pros and cons of each algorithm and the challenging issues. Special attention is paid to the use of sub-Nyquist techniques, including compressive sensing and multichannel sub- Nyquist sampling techniques.
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paper_title: Field measurements for practical unlicensed communication in the UHF band

paper_content:

This paper presents the result of a measurement campaign conducted in Italy, Spain, and Romania to obtain empirical values for the parameters upon which unlicensed devices could distinguish in a hidden node scenario between empty and occupied TV channels. Signal power measurements in the UHF frequency band (470---860 MHz) have been carried out on rural, sub-urban, and urban sites, at different heights over the ground by using different analysis bandwidths. The results have been analyzed with respect to the hidden node margin problem, spectrum sensing bandwidth, and occupancy threshold, to produce a set of practical parameters upon which harmless unlicensed communication in the UHF TV bands is feasible.
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paper_title: Spectrum Sharing for LTE-A and DTT: Field Trials of an Indoor LTE-A Femtocell in DVB-T2 Service Area

paper_content:

In the near future, many applications such as environmental sensors, smart objects, health sensors, and personal devices will be connected to mobile networks requiring additional spectrum. Studies have been made to demonstrate a low occupancy time and locations on the digital terrestrial television (DTT) band. This available or unused spectrum have been called “TV-White-Spaces.” In the 2015 World Radiocommunication Conference, the ITU decided to re-allocate the 700 MHz band (694-790 MHz) for International Mobile Telecommunications (IMT) services and also emplaced the discussion of the future use of the DTT band (470-694 MHz) to 2025, for which studies have been requested. In this paper, we study a particular case which goes a step beyond the previous ones, as it aims at sharing the same frequency band in the same area between long term evolution-advance (LTE-A) and digital video broadcasting-terrestrial second generation (DVB-T2) technologies. Those geographical areas that are not covered because the useful DTT signal is obstructed by the environment or it has a limited coverage by the network design can be called “micro-TVWS.” We assume that a DVB-T2 transmitter provides coverage for fixed rooftop reception as a primary service, to a building in which a LTE-A femtocell is installed indoors for local coverage, as a secondary service. The results have been obtained by laboratory emulation and validated through field measurements using professional equipment. Our results provide the technical restrictions of the LTE-A femtocell, mainly on the maximum allowable effective isotropic radiated power that could transmit on the DTT band in terms of carrier separation, from co-channel to adjacent band. These results meet the need of spectrum for IMT-Advanced technologies, so spectrum sharing is proposed in this paper as a new solution to make an efficient use of this resource.
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paper_title: Field measurements of WSD DTT protection ratios over outdoor and indoor reference geometries

paper_content:

A currently prevalent view of the operation of white space cognitive radios is that they should use geolocation databases to determine their frequency band and maximum transmission power in any given location so that interference radiated to broadcast receivers is negligible. To estimate the level of such interference, physical reference geometries and path loss estimates have been proposed between co-located devices. In this paper we present results of a measurement campaign conducted over indoor and outdoor reference geometry scenarios in a digital terrestrial television test network. Applying a subjective error criterion, we provide practical estimates on the maximum relative transmit powers for white space devices in order to avoid visible interference in television reception. The study applies to various primary and secondary transmission and reception scenarios, and its results can be extended also to estimate protection ratios for signal configurations not considered in the reported measurements.
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paper_title: Bounding the error of path loss models

paper_content:

In this paper we analyze the efficacy of basic path loss models at predicting median path loss in urban environments. We attempt to bound the practical error of these models and look at how they may hinder practical wireless applications, and in particular dynamic spectrum access networks. This analysis is made using a large set of measurements from production networks in two US cities. We are able to show quantitatively what many experienced radio engineers understand: these models perform poorly at predicting path loss in even relatively simple outdoor environments and are of little practical use aside from making crude estimates of coverage in the least demanding applications. As a solution, we advocate a renewed focus on measurement-based, adaptive path loss models built on appropriate statistical methods.
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paper_title: Spectrum Occupancy Measurements: A Survey and Use of Interference Maps

paper_content:

In order to provide meaningful data about spectrum use, occupancy measurements describing the utilization rate of a specific frequency band should be conducted over a specific area instead of a single location. This paper presents a comprehensive methodology for the measurement and analysis of spectrum occupancy. This paper surveys spectrum measurement campaigns and associated interference maps, introducing the latter as a tool for spectrum analysis and management based on measurement data. An interference map characterizes the spectrum use by defining the level of interference over an area of interest in a certain frequency band. Building on findings from practical measurement studies, guidelines for spectrum occupancy measurements are given. While many scientific spectrum occupancy measurement papers tend to be too optimistic about the significance and generality of the results, we propose a cautionary perspective on drawing strong conclusions based on the often limited amount of data gathered. The different phases of the spectrum occupancy measurement and analysis process are described and a thorough discussion of interpolation methods is provided. Means to improve the measurement accuracy are discussed, especially regarding spatial domain considerations and the impact of the sampling interval on the results. A practical example of an improved measurement system design covering all the phases of the measurement process and used at the Turku, Finland; Blacksburg, VA, USA; and Chicago, IL, USA, spectrum observatories is given. Using the improved design, more realistic spectrum occupancy data can be obtained to lay the foundation for spectrum management decisions.
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paper_title: Coexistence of digital terrestrial television and next generation cellular networks in the 700 MHz band

paper_content:

With the spectrum liberation obtained by the deployment of digital terrestrial television and the analog TV switch-off, new bands are being assigned to IMT LTE. In the first cellular deployments in the digital dividend at the 800 MHz band, problems emerged due to the interference cellular networks can cause to DTT signals. Possible solutions imply either an inefficient use of the spectrum (increasing the guard band and reducing the number of DTT channels) or a high cost (using anti-LTE filters for DTT receivers). The new spectrum allocated to mobile communications is the 700 MHz band, also known as the second digital dividend. In this new IMT band, the LTE uplink is placed in the lower part of the band. Hence, the ITU-R invited several studies to be performed and reported the results to WRC-15. In this article, we analyze the coexistence problem in the 700 MHz band and evaluate the interference of LTE signals to DTT services. Several coexistence scenarios have been considered, and laboratory tests have been performed to measure interference protection ratios.
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paper_title: Propagation measurements and models for wireless communications channels

paper_content:

The authors describe the type of signals that occur in various environments and the modeling of the propagation parameters. Models are essentially of two classes. The first class consists of parametric statistical models that on average describe the phenomenon within a given error. They are simple to use, but relatively coarse. In the last few years a second class of environment-specific models has been introduced. These models are of a more deterministic nature, characterizing a specific street, building, etc. They are necessarily more time consuming to use, but are also more revealing concerning physical details and hopefully more accurate. Some key parameters and the measurement of them are discussed and then the different wireless environments are treated. The latter topic is divided into outdoor environments, indoor environments, and radio penetration from outdoor to indoor environments. >
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paper_title: Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands: Advanced Co-Existence Scenarios

paper_content:

The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co- existences between still used and upcoming mobile net- works (from GSM to LTE) and digital terrestrial television broadcasting (DVB) systems. For all of these measure- ments and their evaluation universal measurement testbed has been proposed and used. Results presented in this paper are a significant part of our activities in work pack- age WP5 in the ENIAC JU project "Agile RF Transceivers and Front-Ends for Future Smart Multi-Standard Commu- nications Applications (ARTEMOS)".
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paper_title: Exploring and Measuring Possible Co-Existences between DVB-T2-Lite and LTE Systems in Ideal and Portable Fading Channels

paper_content:

From the point of technical innovations the development and standardization of Digital Video Broadcasting - 2 nd Generation Terrestrial (DVB-T2) and Long-Term Evolution (LTE) systems are definitely the most significant results in the last decade. These systems have a very high potential to fulfill the highest user requirements, but they can operate in the same frequency spectrum. As a result, different co-existence scenarios can occur. In this paper, we explore and measure the co-existence between DVB-T2-Lite (e.g. portable TV) and LTE multimedia services in ideal and portable fading channel models. Theoretical backgrounds of the investigated co-existence scenarios, proposal and realization of an appropriate workplace for their measuring and evaluation are presented and described. Moreover, deeper investigation of the mutual influence of the DVB-T2 system on the LTE one is also explored and graphically illustrated. The obtained results show that these co-existences could be critical for both systems from the point of providing multimedia services with a constant level of Quality of Services (QoS).
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paper_title: Interference Analysis Between Digital Terrestrial Television (DTT) and 4G LTE Mobile Networks in the Digital Dividend Bands

paper_content:

With the introduction of digital terrestrial television (DTT) and the analogue television switch-off, terrestrial broadcast spectrum in the UHF band is being released for mobile communications, in particular for fourth generation (4G) long term evolution (LTE) mobile services. This spectrum is known as digital dividend. An impending problem when deploying 4G LTE mobile networks in the digital dividend bands is that interferences may appear in the adjacent radio frequency channels used for DTT. In this paper, we analyze the adjacent coexistence of DTT and 4G LTE networks in the digital dividend bands at 700 MHz and 800 MHz. A generic framework is adopted such that results can be easily extrapolated to different scenarios and bands. Results are presented as a function of the guard band between technologies, for both LTE uplink and downlink adjacent to the DTT signals, and for fixed outdoor and portable indoor DTT reception. Also, the effect of using anti-LTE filters is studied.
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paper_title: Comparative study of Radio Mobile and ICS Telecom propagation prediction models for DVB-T

paper_content:

In this paper, a comparative study between the results of a measurement campaign conducted in northern Greece and simulations performed with Radio Mobile and ICS Telecom radio planning tools is performed. The DVB-T coverage of a transmitting station located near the city of Thessaloniki is estimated using three empirical propagation models (NTIA-ITS Longley Rice, ITU-R P.1546 and Okumura-Hata-Davidson) and one deterministic model (ITU-R 525/526). The best results in terms of minimum average error and standard deviation are obtained using the deterministic model and the NTIA-ITS Longley Rice empirical model. In order to improve the results, the tuning options available in the ICS Telecom software are used on the Okumura-Hata-Davidson model, leading to a significant increase in accuracy.
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paper_title: Interference measurements for Licensed Shared Access (LSA) between LTE and wireless cameras in 2.3 GHz band

paper_content:

This paper presents interference measurements for spectrum sharing between Long-Term Evolution (LTE) network and wireless cameras in the 2.3–2.4 GHz band under the new Licensed Shared Access (LSA) concept. The introduction of wireless broadband (WBB) communications services in this band is currently under study in European regulation and standardization. If the band cannot be cleared, a potential implementation option is the LSA approach, which maintains the protection of the current incumbents while introducing WBB as an additional licensed system within the band. Defining the incumbent protection criteria is critical and will require field measurements. The incumbents operating on the band in Finland and many other European countries are Programme making and special events (PMSE) wireless cameras. This paper presents results from an interference measurement campaign conducted in Ylivieska, Finland, where the aim was to study the interference from real LTE WBB system to a professional level wireless camera link on the 2.3 GHz band using the Finnish LSA trial environment. The measurements were planned to reproduce the cordless camera link scenario in ECC report 172, which provides compatibility studies with respect to the potential usage of the 2.3 GHz band for WBB systems. The results indicate that coexistence between LTE and wireless camera link can be feasible in the measured cordless camera link scenario in adjacent or larger separation channels. The measurement results are slightly less restrictive than the theoretical results in the ECC report, which came to the same conclusion about the feasibility. However, further study is required to derive actual incumbent protection criteria.
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paper_title: Spectrum Occupancy Measurements: A Survey and Use of Interference Maps

paper_content:

In order to provide meaningful data about spectrum use, occupancy measurements describing the utilization rate of a specific frequency band should be conducted over a specific area instead of a single location. This paper presents a comprehensive methodology for the measurement and analysis of spectrum occupancy. This paper surveys spectrum measurement campaigns and associated interference maps, introducing the latter as a tool for spectrum analysis and management based on measurement data. An interference map characterizes the spectrum use by defining the level of interference over an area of interest in a certain frequency band. Building on findings from practical measurement studies, guidelines for spectrum occupancy measurements are given. While many scientific spectrum occupancy measurement papers tend to be too optimistic about the significance and generality of the results, we propose a cautionary perspective on drawing strong conclusions based on the often limited amount of data gathered. The different phases of the spectrum occupancy measurement and analysis process are described and a thorough discussion of interpolation methods is provided. Means to improve the measurement accuracy are discussed, especially regarding spatial domain considerations and the impact of the sampling interval on the results. A practical example of an improved measurement system design covering all the phases of the measurement process and used at the Turku, Finland; Blacksburg, VA, USA; and Chicago, IL, USA, spectrum observatories is given. Using the improved design, more realistic spectrum occupancy data can be obtained to lay the foundation for spectrum management decisions.
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paper_title: Interference measurements for Licensed Shared Access (LSA) between LTE and wireless cameras in 2.3 GHz band

paper_content:

This paper presents interference measurements for spectrum sharing between Long-Term Evolution (LTE) network and wireless cameras in the 2.3–2.4 GHz band under the new Licensed Shared Access (LSA) concept. The introduction of wireless broadband (WBB) communications services in this band is currently under study in European regulation and standardization. If the band cannot be cleared, a potential implementation option is the LSA approach, which maintains the protection of the current incumbents while introducing WBB as an additional licensed system within the band. Defining the incumbent protection criteria is critical and will require field measurements. The incumbents operating on the band in Finland and many other European countries are Programme making and special events (PMSE) wireless cameras. This paper presents results from an interference measurement campaign conducted in Ylivieska, Finland, where the aim was to study the interference from real LTE WBB system to a professional level wireless camera link on the 2.3 GHz band using the Finnish LSA trial environment. The measurements were planned to reproduce the cordless camera link scenario in ECC report 172, which provides compatibility studies with respect to the potential usage of the 2.3 GHz band for WBB systems. The results indicate that coexistence between LTE and wireless camera link can be feasible in the measured cordless camera link scenario in adjacent or larger separation channels. The measurement results are slightly less restrictive than the theoretical results in the ECC report, which came to the same conclusion about the feasibility. However, further study is required to derive actual incumbent protection criteria.
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paper_title: Flexible 5G below 6GHz Mobile Broadband Radio Air Interface

paper_content:

Abstract-In November 2015 the latest world radio conference took place and as a result the below 6 GHz RF bands have become more important for 5G in the foreseeable future. In the 5GPPP project Fantastic5G options for higher spectral efficiency based on massive MIMO, joint transmission cooperative multi point and interference mitigation are being investigated. Most of these concepts have been already developed in previous projects like Artist4G or METIS, but now it is important to integrate these into a flexible framework supporting a rudimentary phase I as well as a future proof phase II system. Interference mitigation might become the main differentiator to LTE and the inevitable enablers will be shortly highlighted. According to current results the novel 5G system has the potential to increase spectral efficiency by roughly a factor of ten compared to a 4x2 LTE system, thereby significantly outperforming also latest LTE results for full dimension MIMO.
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Title: Coexistence of DTT and Mobile Broadband: A Survey and Guidelines for Field Measurements

Section 1: Introduction
Description 1: Provide an overview of DTT-MBB coexistence, reallocation of DTT spectrum, study methods, and the importance of field measurements.

Section 2: The Utilization of UHF TV Broadcasting Spectrum in Europe
Description 2: Discuss the use and reallocation of UHF TV broadcasting spectrum in Europe, including TVWS and regulatory decisions.

Section 3: Definition of Protection Ratio and Picture Quality Criterion
Description 3: Define protection ratio (PR) and picture quality criteria for DTT reception, and PR values for cochannel and adjacent channel operations.

Section 4: DTT Receiver and Interfering Transmission Characteristics
Description 4: Explain the characteristics affecting DTT-MBB coexistence, including adjacent channel selectivity, ACLR, and DTT receiver overload conditions.

Section 5: Standardization in DTT Receivers and DTT Reception Installations
Description 5: Describe the standardization requirements for DTT receiver performance and the importance of EN 303 340 Harmonised Standard.

Section 6: Simulations to Determine Compatibility with DTT Broadcasting
Description 6: Outline simulation methodologies to determine compatibility between DTT and MBB, including location probability and interference analysis.

Section 7: Simulations to Assess the Compatibility with GE06
Description 7: Describe how simulations are used to assess compatibility with GE06 requirements and use measurement results to improve their accuracy.

Section 8: Guidelines for Conducting Field Measurements
Description 8: Provide detailed guidelines on conducting field measurements for DTT-MBB coexistence studies, including determining scenarios, obtaining licenses, and analyzing results.

Section 9: Determining Field Measurement Scenarios for DTT-MBB Coexistence Studies
Description 9: Discuss how to choose field measurement scenarios that represent worst-case interference situations and the importance of reference geometries.

Section 10: Interference from a Mobile Terminal
Description 10: Explain how to study interference from mobile terminals to DTT reception, including calculation of minimum coupling loss (MCL).

Section 11: Interference from Mobile Network Base Stations
Description 11: Detail the interference effects from MBB base stations on DTT reception and how to establish reference geometries for these scenarios.

Section 12: Obtaining Radio Licenses and Building Test Network Infrastructure
Description 12: Describe the steps to obtain necessary licenses and build test networks for field measurements.

Section 13: Determining the Field Measurement Locations
Description 13: Explain how to select appropriate locations for field measurements based on signal level requirements.

Section 14: Building the Measurement Setup in Laboratory Environment
Description 14: Outline the importance of verifying the measurement setup in a lab environment before conducting field measurements.

Section 15: Initial Measurements at the Field Measurement Locations
Description 15: Discuss the initial measurements to validate signal levels and assess receiver sensitivity at field locations.

Section 16: Conducting the Field Measurements
Description 16: Provide detailed procedure for conducting field measurements, including data recording and ensuring measurement repeatability.

Section 17: Initial Analysis of the Measurement Results
Description 17: Explain the importance of initial analysis during field measurements to identify unexpected phenomena and adjust the measurement plan accordingly.

Section 18: Conclusions
Description 18: Summarize the findings, contributions, and future steps for DTT-MBB coexistence studies and spectrum sharing frameworks.