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Frequency and transmitter network planning

“ARD and ZDF are planning to introduce DVB-T2 HD starting in 2017!” “The Federal Network Agency is preparing the auction of the 700-MHz band for mobile communication!” “Key points plan of Federal Economics Minister proposes ten thousand new wind turbines in the next ten years!” These are exemplary headlines from important media that immediately resonate with the experts of frequency and transmission network planning in the radio systems department of the IRT.

A wide range of questions in the field of terrestrial broadcasting supply is continuously being researched. In many cases, comprehensive studies have to be done in order to come up with sound answers. DVB-T2 alone compared with DVB-T offers magnitudes more possibilities for parameter selection. The evaluation between supply goal and area, data rate, spectral efficiency and cost has to be made very precisely. The above-mentioned project of the Federal Network Agency has to be accompanied by alternative planning. The implicit question of the transmission possibility of broadcasting content via mobile networks in particular has to be thoroughly questioned and examined – also in the light of new mobile communication technologies such as LTE-eMBMS with its declared single-frequency capacity. With regard to wind turbines systems, the potential interference with broadcast signals stands in the spotlight.

Compiling Frequency Allocation Plans . . .

The purpose of frequency planning is the provision of frequencies for all reception points such that broadcasting coverage is sufficiently extensive and of high quality. Frequency-allocation plans stipulate the rights to use a frequency in a specified area. The stipulated parameters for mutual interference must not be exceeded by broadcasting services and broadcast content transmitted on the same frequency or on neighbouring frequencies.

. . . a Matter of Combinatorial Optimisation
Frequency-allocation plans cover large geographical areas and thus typically govern thousands of instances of frequency usage. The synthesis of allocation plans compatible with interference thus presents a complex mission requiring combinatorial optimisation. IRT addresses such tasks by relying on modern and effective methods of stochastic optimisation. We also enhance these methods, which are ideally suited for synthesising modern frequency-allotment plans and conventional frequency-assignment plans for a large number of broadcasting services on the basis of cellular or broadcasting networks.

The Supplementing of Existing Frequency Allocation Plans
The synthesis of allocation plans not only results in the creation of new frequency plans, but also the addition of supplementary frequency use to existing plans. The same methods are employed in this case as during the compilation of new allocation plans. Thanks to modern planning tools and years of experience, IRT has the expertise necessary for investigating and demonstrating additional options for frequency utilisation in existing plans.

New Concepts in Network Structure
The growing demand for spectrum access has in recent years spawned new concepts which facilitate optimum spectrum use. Single frequency networks (SFNs), for example, offer broadcasters the unique possibility of utilising spectra far more efficiently. In terms of frequency planning, SFN technology is similar to the principle of allotment. The implementation of frequency-allotment plans stipulated in the GE06 agreement offers network operators considerable latitude to design their networks as they wish. Ultimately, these new possibilities constitute a significant step toward more flexible use of spectra.

IRT played a significant role in ensuring that SFN and allotment concepts were included in RRC-06 planning principles. Allotment planning and SFNs laid the foundation for realising an ambitious goal: the creation of seven wide-area coverage sectors for digital television in Germany.

New Approaches to Spectrum Allocation
IRT studies new concepts such as SDR (Software-Defined Radio), LBT (Listen Before Talk), DFS (Dynamic Frequency Selection) and cognitive radio before determining their suitability for broadcasting applications. Our experts also analyse interactions between broadcasting technology and new systems based on one of these concepts.

Developing Transmitter Networks

Transmitter networks constitute the foundation of terrestrial broadcasting, which continues to dominate the radio sector and is of renewed relevance for TV on account of digitalisation. Thanks to its consistently high quality and a wider selection of channels, digital transmission technology is replacing more and more analogue transmission systems. Reception on the go with portable devices will depend on terrestrial transmission networks in future, too. In fact, the potential for mobile reception opens up an entirely new market segment for terrestrial television.

Planning and Designing Transmitter Networks
The transition to digital technology has necessitated an overhaul of transmitter-network planning. IRT has performed a great number of jobs in Germany and abroad (analogue transmission but also DVB-T, T-DAB, DVB-H and T-DMB), which means that our specialists have the experience necessary to tackle such projects.

IRT experts not only deftly employ modern tools in planning transmitter networks; they also know the hitches and hindrances of frequency planning. After all, they themselves develop on-site propagation models and coverage tests. Our specialists furthermore know the ins and outs regarding regulatory and political boundary conditions of frequency planning, and maintain close ties with all the important contact people in Germany and abroad.

Wave Propagation

Predictions of coverage are essential for planning and preserving terrestrial broadcasting services. A prediction identifies a geographical area or a segment of the population which is considered to be covered by a transmitter network. In addition to the analysis, additional data are generated concerning aspects of coverage.

Predictions of coverage combine several components to provide reliable conclusions: a set of transmission data, wave-propagation models, the accumulation method, the synchronisation method, the protection-ratio method, reception scenarios and/or the Geographical Information System (GIS module). IRT relies on different experienced specialists for each of these approaches.

Data, such as received field strengths of various VHF and TV transmitters, must be gathered over a long period of time in order to improve predictions of brief intervals (interference). This is the only way to obtain statistically relevant information about short periods of time.

IRT has developed a large array of prediction methods; the proper model can be selected for any given task. IRT’s 3-D model delivers especially precise field-strength predictions since it considers digital terrain models, orographical data and explicit multipath propagation.

In order to analyse coverage areas and identify fringe areas, IRT experts rely on the “accumulation method” and the “synchronisation method” to investigate single frequency networks (SFNs) in the case of digital broadcasting services. Both of these methods represent a variety of coverage-analysis techniques which IRT had a leading role in creating. One example of our expertise in this field is FRANSY: frequency-planning software which enables the user to create predictions of coverage via an intuitive interface.

IRT utilises a specialised test vehicle to determine broadcasting coverage as well as various propagation parameters of transmission channels and transmitter networks (e.g. DAB, DRM and DVB-T). Our test vehicle enables us – in the experimental stage – to reliably evaluate the transmission quality of broadcasting systems and detect any malfunctions.

 

Assistance with Coordination Procedures

The Europe-wide digitalisation of broadcasting demands extensive coordination work to harmonise the frequency needs of individual countries. IRT has decades of experience in this context thanks to its role in coordination procedures with Germany’s public broadcasters.

Coordination work itself, however, is preceded by negotiations and agreements. Close working relationships with contact people in Germany and abroad are therefore a must for successful coordination. IRT’s experts know the people in charge of frequency planning in Germany and neighbouring countries. They also keep in close touch with the International Telecommunication Union (ITU), European Conference of Postal and Telecommunications Administrations (CEPT), and Germany’s Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railway (Bundesnetzagentur). Since our specialists themselves played an active role in drafting new coordination rules at ITU’s RRC-06 conference in Geneva in 2006, they are deeply aware of background issues and problems. And with planning tools and the appropriate database at their disposal, IRT’s experts can find optimum solutions to coordination problems. All in all, IRT provides comprehensive assistance on coordination matters thanks to its practical experience at all levels.

Compatibility Studies

In today’s wireless information society, spectrum access is a key prerequisite for introducing new services. Demand for access to the spectrum is all but certain to increase in the broadcasting frequency ranges, as well. The digitalisation of broadcasting kindled interest in utilising the broadcasting spectrum for other services. This has helped mould the new concept of “digital dividends” and has sparked efforts to introduce numerous supplementary broadcasting services.

The growing trend toward flexibility is evinced by spectrum trading, the WAPECS concept and the so-called mask concept (RRC-06), which enables practically any service to operate under the mask of a broadcasting service. These innovations hint at a great number of complex compatibility issues in future between broadcasting and other services. This tendency of increasingly complicated joint use of broadcasting frequency ranges constitutes an ever greater challenge for frequency-management experts. It is more important than ever to ensure that consumers enjoy problem-free reception of broadcast content.

IRT examines the impact of new services on the broadcasting spectrum. We also represent the interests of Germany’s public broadcasters on all key committees of the ITU, CEPT and EBU. In this regard, IRT is particularly committed to the World Radio Conferences (WRCs) and the preparations prior to them. These conferences take place every three years and are the best opportunity worldwide for administering and modifying spectrum utilisation.

IRT’s experience and extensive expertise enable it to investigate the compatibility of various systems with broadcasting technology. Moreover, our skills and contacts grant us an active role in defining spectrum utilisation on a global scale.

To name but a few examples, we examine compatibility between broadcasting applications and SRDs (Short-Range Devices), UMTS, BSS (Broadcast Satellite Service), air-ground communications, UWB (Ultra-Wide Band), military applications and wired communication networks.

Das IRT untersucht, wie sich die Einführung neuer Dienste auf das Rundfunkspektrum auswirkt. Es verfügt über die notwendige Erfahrung und das entsprechend breite Know-How, um die verschiedenen Systeme auf ihre Verträglichkeit mit Rundfunk zu untersuchen, aber auch über die Kenntnisse und Kontakte, um im internationalen Gestaltungsprozess der Spektrumsnutzung aktiv mitzuwirken. Deswegen vertreten wir in diesen Angelegenheiten den deutschen öffentlich-rechtlichen Rundfunk in allen wichtigen Gremien der ITU, CEPT und EBU. In diesem Zusammenhang ist das IRT insbesondere in die WRCs und ihre Vorbereitung stark involviert. Die in dreijährigem Turnus stattfindenden World Radio Conferences (WRC) bilden die wichtigsten Stationen bei der Verwaltung und Neugestaltung der Spektrumsnutzung auf internationaler Ebene.

Frequency Planning Software FRANSY

FRANSY is a frequency-analysis software tool used in planning terrestrial transmitter networks for DVB-T, T-DAB, analogue TV and VHF/FM.

IRT developed this Java-based software in conjunction with its partner con terra and public broadcasters.

Further information

Your contact

Dr. Khishigbayar Dushchuluun
Sachgebietsleiterin
Head of Department
Tel. +49 (0)89 32399-238