Abstract
The usage of the electromagnetic spectrum is mainly managed by the international organizations and bodies described in Chap. 3. In the first place, spectrum usage is organized by allocating parts of the spectrum to particular services, i.e. broadcasting, mobile service, fixed service, aeronautical radionavigation service, or others. In most cases, a given spectrum range can be used by more than one service. This requires to properly define the characteristics of the systems providing these services and, very important, to specify the conditions under which spectrum can be shared.
Keywords
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The usage of the electromagnetic spectrum is mainly managed by the international organizations and bodies described in Chap. 3. In the first place, spectrum usage is organized by allocating parts of the spectrum to particular services, i.e. broadcasting, mobile service, fixed service, aeronautical radionavigation service, or others. In most cases, a given spectrum range can be used by more than one service. This requires to properly define the characteristics of the systems providing these services and, very important, to specify the conditions under which spectrum can be shared.
The allocation of the spectrum to particular services is a task that is typically fulfilled by a World Radiocommunication Conference (WRC) of ITU-R. These conferences are regularly held every 3–4 years. The conditions under which sharing is accomplished is passed on to the Study Groups of ITU-R by a WRC. Between two conferences relevant Study Groups then prepare ITU-R Recommendations and ITU-R Reports dealing with all these aspects.
However, allocating spectrum to services and specifying the sharing conditions if more than one service is allowed to use a given spectrum range, is just one side of the coin. The details of spectrum usage for each service need to be defined and agreed between the administrations of different countries. There are basically two ways of accomplishing this. The first possibility is to convene international frequency planning conferences that elaborate detailed plans about which country can use which frequencies under which conditions in order not to cause harmful interference to the radiocommunication services of its neighboring countries. As as a result of such a process an agreement is established that is to be signed by administrations. Usually, the Radiocommunications Bureau (BR) of the ITU-R will then be involved in terms of carrying out calculations regarding the requests to use particular frequencies. Furthermore, the BR has to maintain corresponding data bases such as the Master International Frequency Register (MIFR) to monitor the actual spectrum usage.
The second way of aligning the demands and requirements of different countries is two work on the level of bilateral or multilateral coordinations only. This means there is no superordinate international agreement that needs to be applied and respected by administrations. Rather, it is left to administrations themselves to take care of their interests with regard to their neighbors.
Both approaches to frequency planning are currently employed around the world. In ITU-R Region 1 except Mongolia but including Iran from Region 3, the so-called GE06 Agreement governs the usage of frequency Bands III, IV and V while in Regions 2 and 3 the bilateral approach is applied. They are both discussed in the following together with the WRC-07 which proved to be the key event with respect to the Digital Dividend issue.
4.1 The GE06 Agreement and Plan
If new broadcasting systems are to be introduced in a spectrum range that is allocated to the broadcasting service it is necessary to establish a corresponding detailed frequency plan. Such a plan contains a list of transmitters or equivalent planning objects together with a specification of their technical characteristics and the frequency that can actually be used. Moreover, a frequency plan needs to be amended with a technical and regulatory framework providing the means to modify or extend the plan. Typically, frequency plans are addressed as “Arrangements” or “Agreements” between administrations of a certain region of the planet which signed the corresponding Final Acts of a planning conference.
Several frequency plans for analogue broadcasting have been set up over the last 100 years. The most important for Europe relating to terrestrial television was the so-called Stockholm Plan (ST61) established on International Telecommunications Union (ITU) level by a corresponding conference that was held in Stockholm, Sweden, in 1961 [ITU61]. It governed the usage of spectrum for terrestrial television for more than 40 years. For Africa and the Arabic countries a corresponding frequency plan has been set up in Geneva, Switzerland, in 1989 (GE89) [ITU89]. With the advent of digital terrestrial broadcasting it became necessary to develop a new plan for the new digital broadcasting systems. This process culminated in the GE06 Agreement which contains a frequency plan for DVB-T and T-DAB in the VHF and UHF range [ITU06]. The new plan superseded ST61 in Europe and GE89 in the African Broadcasting Area (ABA). GE06 was established in terms of two planning conferences that were held in 2004 and 2006 in Geneva, Switzerland.
4.1.1 Regional Radiocommunication Conference RRC-04
At the end of the last century it became obvious that a new frequency plan for digital terrestrial broadcasting was needed. Therefore, in 2000 the CEPT administrations led by Germany requested the ITU to consider convening a Regional Radiocommunication Conference (RRC) for the revision of the Stockholm Agreement ST61. The main target was to pave the way for a rapid introduction of DVB-T in the European Broadcasting Area (EBA).
In 2001, the ITU Council agreed on Resolution 1185 aiming to convene such a RRC in the EBA. The frequency bands 174–230 MHz and 470–862 MHz were to be re-planned for DVB-T and T-DAB in terms of two conference sessions. Member States of the ITU from the planning area of the Regional Agreement for VHF/UHF television broadcasting (GE89) [ITU89] in the ABA and neighboring countries also expressed the wish to take part in such a RRC for digital terrestrial broadcasting. Hence, the decision was taken to convene a RRC for the “planning of the digital terrestrial broadcasting service in Region 1 (parts of Region 1 to the west of meridian 170 ∘ E and to the north of parallel 40 ∘ S) and in the Islamic Republic of Iran, in the bands 174–230 MHz and 470–862 MHz, in two sessions”. Figure 4.1 sketches the planning area.Footnote 1
Planning area of the RRC-06. It extends up to 170 ∘ E
The first session of the planning conference which is usually called RRC-04 was to lay the technical foundations in terms of setting up and agreeing on planning parameters and sharing criteria. The second part, referred to as RRC-06, was to draft a new agreement which together with a corresponding new frequency plan should be adopted by the conference. In order to prepare for these two conferences ITU decided to establish Task Group 6/8 (TG 6/8) to draw up a report for RRC-04. This report was to contain all relevant technical information which RRC-04 was invited to consider for integration into the new agreement. It covered planning concepts, technical criteria, compatibility issues between different types of services, and planning tools. This work was heavily supported both by CEPT and European Broadcasting Union (EBU) which both set up corresponding project teams dealing with these issues. The report was eventually submitted to the RRC-04 together with further independent contributions from CEPT and EBU.
On 10 May 2004, the RRC-04 started in Geneva [ITU04]. About 750 delegates from 95 countries participated in the conference lasting for three weeks. RRC-04 agreed on planning parameters and criteria such as minimum field strength values and protection ratios. However, planning principles have also been decided upon. First of all, it has been agreed that DVB-T will be the only standard to be dealt with in the conference as a representative for digital terrestrial television. Even though this decision reduces the planning effort significantly it is well known that DVB-T allows for a huge number of different system variants. All of them require different planning parameters which has a direct impact on the generation of a frequency plan.
This variety is a very important feature of DVB-T from which broadcasters are able to benefit when it comes to network planning. But on the other hand, it became clear during the preparations of the conferences that including every single detail of a system variant in a plan entry to a frequency plan constrains the freedom of network operators, in particular in view of the freedom DVB-T offers e.g. allowing Single Frequency Network (SFN) operation. Hence, in order to simplify the planning process as much as possible three so-called Reference Planning Configurations (RPC) have been developed. They were used as some kind of placeholders representing a large number of different system variants requesting similar planning parameters. The three RPCs represent fixed reception, portable outdoor or mobile reception and portable indoor reception. Furthermore, four different reference networks (RN) have been included which during the plan generation process allow the assessment of the interference a typical network would impose on other networks. By choosing an appropriate combination of RPC and RN intended coverage targets could be mapped to mathematical objects that could be appropriately dealt with by the frequency planning process of RRC-06.
Another important issue of the RRC-04 was to make appropriate provisions for T-DAB planning. CEPT had already made frequency plans for T-DAB in the years before and many T-DAB networks have been put into operation. The usage of Band III spectrum resources for T-DAB in Europe was governed by the so-called Wiesbaden Arrangement (WI95)[CEP95] which was revised in 2007 in Constanta (CO07)[CEP07d]. From a CEPT perspective it was important to ensure that this Arrangement could somehow be integrated into the new frequency plan for VHF. Initial resistance against allowing T-DAB to make use of “television frequencies” could be overcome. Similar to DVB-T two RPCs and two RNs were proposed for T-DAB in the report submitted to RRC-06. One of the RPCs corresponded to the planning scenario of WI95 referring to mobile reception while the new RPC reflected the fact that also portable indoor reception would be important for the future development of T-DAB [Bru05].
Soon it became clear that not only allotment planning as in WI95 was requested by administrations. ST61 was an assignment plan and there were many administrations in the planning area which wanted to base their input requirements to the new frequency plan on ST61. Basically, they were pursuing some kind of conversion strategy from analogue to digital broadcasting which nevertheless meant that they favored a planning approach based on assignments. Therefore, in the end it was decided that both types of requirements should be dealt with.
Bands III, IV, and V are not exclusively used for broadcasting. There are many other services which are listed in the Radio Regulations of ITU-R as primary services. Therefore, administrations have to coordinate with affected administrations whenever a broadcasting service or one of these other services is newly introduced or an existing station is modified. Thus, the plan generation process for digital terrestrial broadcasting had to take into account the protection of other services. Amongst them there are fixed services, mobile services, aeronautical radionavigation services, radio astronomy, broadcasting-satellite services, and others. During the RRC-04 interference and protection criteria between digital broadcasting and these services were developed but it was not possible to cover all sharing situations. Therefore, this work had to be left to the intersessional period between RRC-04 and RRC-06.
Frequency planning rests on predictions of interference levels at given geographical points. This calls for appropriate wave propagation methods to predict the field strength a transmitter produces at a given point. Shortly before the RRC-04 ITU-R published a new Recommendation, ITU-R Rec.P1546, for field strength prediction in the frequency range from 30 to 3000 MHz [ITU01]. The propagation method which was proposed to be used for the RRC-06 was based on that Recommendation. There were several deviations from the original version, in particular in relation to the treatment of negative effective transmitting antenna heights and the way in which mixed path propagations were taken into account.
The large planning area of RRC-06 quite naturally brought together many very differently developed countries. In Europe, digital terrestrial broadcasting had already been introduced to some extend while in Africa or the Arabic countries deployment of analogue television was still in full swing. Therefore, it is evident that there were different ideas about when and how the transition to an all-digital broadcasting world should be accomplished. During the so-called transition period existing and planned analogue station would need to be protected. After that date the protection rights of analogue services would cease. The date when the transition period should end caused some conflict even during the preparation of the RRC-04. It was not possible to come to a common view on this issue and hence RRC-04 identified two options for the end of the transition period. In particular, CEPT-countries favored to cease analogue transmissions as soon as possible but not later than 2015. The other option said that the end of the transition period should not be only before 2028 but also not later than 2038. It was left to RRC-06 to finally decide on the end of the transition period.
The clash about the transition period triggered the development of a new element to be included in the digital terrestrial broadcasting plan. It is what was later called the envelope concept. At the beginning it was referred to as mask concept which was later abandoned in order not to mix it with the idea of spectral masks for T-DAB or DVB-T emissions. Confronted with the fact that there was no consensus in sight in relation to the transition period, the question was asked within CEPT if some measure could be developed which would allow to continue the operation of analogue services even beyond the end of the transition period. The proposal was to operate the analogue station under the envelope of a digital plan entry. According to the planning principles, the technical characteristics of a plan entry precisely define the amount of interference that will be produced at any given point. Vice versa, it would be also clear how much interference this plan entry would have to accept at the boundaries of its own service area. The envelope concept simply stated that the operation of an analogue station would be feasible if not more protection is claimed nor more interference is produced as determined by the associated plan entry.
Finally, RRC-04 laid the foundations for the structure of the planning process itself. Basically, the same methodology as used in WI95 was adopted apart from necessary modifications due to the different systems that had to be taken into account. Therefore, the planning process consisted of the two steps compatibility analysis and plan synthesis which could be iterated if necessary. More details on the RRC-04 can be found in [Pui04] and [Beu04].
4.1.2 The Regional Radiocommunication Conference RRC-06 and the GE06 Agreement
The RRC-04 laid the foundations for RRC-06 by establishing the technical basis and providing the planning criteria and parameters for the new plan. Since during the RRC-04 not all tasks could be finished the two years between the two conferences were a busy time for frequency planners. The intersessional period was used by ITU, CEPT and EBU to fill those gaps that were left by RRC-04. At ITU level several working groups were established. This was foreseen by RRC-04 in terms of several Resolutions. Three of these group had particular importance, namely the Intersessional Planning Group (IPG), the Planning eXercise Team (PXT) and the Regulatory and Procedural Group (RPG). The IPG was to develop draft plans during the intersessional period, taking account of bi- and multilateral negotiations carried out by the administrations. PXT should test the planning software which was provided by the Technical Department of the EBU by carrying out planning exercises. Finally, RPG had the task to prepare the regulatory and procedural framework which was to be drawn up in the new agreement.
RRC-06 took place from 15 May 2006 until 16 June 2006. More than 1000 delegates from 104 different countries participated. The conference was structured by setting up six Committees dealing with different items. Committee 4 (Planning Committee) and 5 (Regulatory Committee) constituted the core of the planning conference. Committee 4 was subdivided into five so-called Coordination and Negotiation Groups (CNG) which were created to divide the entire planning area into smaller regions. They were defined in a way that these areas could be considered as more or less independent from each other. CNG1 covered Europe and the North Eastern part of the planning area. CNG2 represented Western and Central Africa. CNG3 was responsible for Eastern and Southern Africa, CNG4 covered the Red Sea area where extreme propagation conditions are encountered, while CNG5 contained countries around the Mediterranean Sea. Committee 5 was dealing with regulatory, procedural and technical aspects of using Bands III, IV, and V. In particular, the development of the agreement text was in the scope of Committee 5.
The Technical Department of the EBU had developed the software that was used for the planning process of the RRC-06. This covered both the compatibility analysis and the plan synthesis. The Radiocommunication Bureau of the ITU (BR) provided software tools to capture and validate the input data and to visualize the results of the planning process. A joined team of EBU and ITU experts carried out the intensive calculations during the conference. In particular, the compatibility analysis required so much computational power that the computing facilities of European Organization for Nuclear Research (CERN) [CER10] in Geneva had to be exploited.
The compatibility analysis was needed to identify whether two requirements for digital broadcasting could share a frequency or not. Furthermore, the impact of digital requirements on assignments to other primary services including existing or planned analogue television assignments to be protected had to be evaluated as well. These calculations resulted in a list of available frequencies for each digital broadcasting requirement. The results of the compatibility analysis were taken into account during the plan synthesis which was based on the implementation of several thousands of different graph theoretical algorithms for the frequency assignment process. They were run concurrently as much as possible by distributing the task onto the several hundreds of computers available at the CERN computer centre.
4.1.2.1 Overview of the Results of the RRC-06
A total of 118 administrations submitted requirements to be taken into account in the planning process. They were asking for frequencies, i.e. T-DAB blocks or TV channels, in the frequency ranges 174–230 MHz and 470–862 MHz. In the UHF Bands IV and V a channel raster of 8 MHz was used throughout the entire planning area. However, in Band III the situation was more complicated. A mixture of different raster schemes needed to be taken into account. T-DAB employs spectrum blocks of 1.75 MHz bandwidth. This was unique but for DVB-T both 7 MHz and 8 MHz had to be considered in Band III.
The first set of input requirements at the beginning of the conference comprised more than 80000 data sets out of which roughly a fourth referred to VHF. This pile of input data was the starting point for the planning marathon. Planning was carried out iteratively in terms of four iterations. The overall objective of the planning activities was to satisfy as many requirements as possible, i.e. to find frequencies for them. However, it turned out that the number of submitted requirements in connection with the constraints imposed by the other primary services to be protected was far beyond what could be accommodated in the spectrum at hand. Therefore, administrations were having extensive bi- and multilateral coordination meetings in order to figure out under which conditions the incompatibilities between parts of their requirements could be overcome.
The coordination efforts resulted in a very large number of so-called “agreements by administrative declarations” which became a crucial means for the successful plan generation. Providing an administrative declaration basically meant that two or more administrations carried out detailed geographically limited studies on the basis of more developed and sophisticated planning tools than those agreed to be employed by RRC-06. As a result of these investigations, requirements were declared mutually compatible thereby overwriting the formal findings of the compatibility analysis.
Very often it was clear for administrations and broadcasters that for digital terrestrial broadcasting networks the existing transmitters sites so far used for analogue broadcasting must be used for the implementation of the digital transmitter network due to economical reasons, too. In some cases where this led to obvious interference conflicts between transmitter sites, administrations simply agreed to accept higher levels of mutual interference. Hence, they provided corresponding administrative declarations.
It has to be borne in mind that in the context of RRC-06 the level of interference was evaluated on the basis of the wave propagation method adopted which was based on ITU-R Recommendation P.1546 [ITU01]. However, special topographic and morphologic conditions cannot be taken into account by that method. From their long-time experience of operating transmitters under very different conditions, broadcasters were quite aware of the mutual interference potential between different transmitter sites. For example, there are many cases in which terrain shielding basically leads to a decoupling of two transmitter sites so that they can share a channel in practice even though investigations based on ITU-R Recommendation P.1546 [ITU01] might indicate that spectrum sharing is not possible. Furthermore, detailed calculations employing more developed and sophisticated prediction methods showed that spectrum sharing could be envisaged if proper antenna design is considered.
In some regions of the planning area, like parts of Africa or the Arabic countries where no coordination had been carried out between administrations before the RRC-06 during the preparation phase, a general relaxation of the planning criteria by up to 5 dB was agreed in order to get requirements into the plan which otherwise would not have been assigned a frequency. In such cases, it was obvious that any implementation of a plan entry will need to be coordinated before bringing a station into operation.
One of the issues which lead to sometimes fierce arguments in the preparation of GE06 was the protection of analogue TV stations. RRC-06 was to draw up a frequency plan for digital terrestrial broadcasting in a spectrum range which was more or less fully occupied. The planning activities carried out by the PXT during the intersessional period clearly showed that there is no hope to establish a new frequency plan if the plan generation process would need to protect existing and planned analogue TV assignments. Consequently, RRC-06 quickly decided not to protect analogue stations during the plan generation process. This paved the way for a successful plan for DVB-T and T-DAB.
Even though analogue transmissions would not be protected by the final digital plan it was nevertheless clear that the introduction of digital terrestrial broadcasting would not be accomplished over night. A transition period during which analogue transmissions would be granted protection would be necessary. Basically, protection of analogue stations means that a digital station can only be put into operation after successful coordination with administrations whose analogue transmissions would be affected.
Opinions diverged heavily about the duration of the transition period. RRC-04 had already not been in a position to decide on the duration of the transition period. After very lengthy discussion it was finally decided by RRC-06 that 17 June 2015 should be the end of the transitions period. As an exception from this rule, it was agreed that for some non-European countries 2020 should be applied as the end of the transition period for VHF. CEPT was of the opinion that 2015 would still be too far away and decided that 2012 should be valid for its members. Administrations were in addition encouraged to go digital as fast as possible. It should be noted that other primary services than analogue TV were fully protected for the generation of GE06. Therefore, the term transition period exclusively refers to the protection of analogue terrestrial broadcasting.
In order to know which analogue stations would need to be protected during the transition period it was necessary to establish a reference situation for analogue television. It was decided that for the territories governed by ST61 and GE89 the reference situation should be given by the corresponding updated frequency plans. Thus, all assignments successfully coordinated until 15 March 2006 would be included in the reference situation. For assignments to other primary services also a reference situation was defined comprising all successfully coordinated assignments which have been notified to the ITU at the same date. This decision had already been prepared by RRC-04 and therefore administrations knew since then that if they wanted to claim protection for analogue stations or assignments to other primary services they had to take the effort to bring their notifications to the ITU up to date.
The digital switch-over, how the transition from analogue to digital broadcasting is also called, was and is still a very complex enterprise. In many cases, neighboring countries have entirely different ideas about the time horizon of the transition as well as the manner in which it could be accomplished. However, this poses a problem since along national borders the transition strategies need to be aligned. Some administrations are in favor of a hard changeover, i.e. switching off analogue transmission at a defined date and starting digital transmissions seamlessly. Others want to introduce T-DAB and DVB-T by gradually switching from analogue to digital broadcasting on a transmitter by transmitter basis.
Those digital plan entries which are not in conflict with any other co-channel users can be implemented in the short term without problems. For those plan entries whose operation is subject to the protection of analogue transmissions successful coordination between administrations has to be achieved prior to bringing digital plan entries into operation. However, it might nevertheless be possible to realize a partial network implementation. In the case of an assignment plan entry, this means to use reduced Effective Radiated Power (ERP) or specially adapted antenna patterns for the time when analogue stations need to be protected. For allotment plan entries there is more freedom. An allotment can be implemented in terms of building only part of a full SFN in a first step. This means not the whole allotment area will be covered but only that part which is far-off existing analogue transmissions. This way it is possible to limit the interference to analogue transmissions to an acceptable level during the transition period.
The key to achieve consensus amongst the administrations participating in RRC-06 concerning the duration of the transition period was the development of the envelope concept. This idea had been put forward by RRC-04 already. Basically, it allows to make use of a plan entry for DVB-T or T-DAB for another system as long as not more protection is requested and not more interference is produced than the underlying digital plan entry would do. Clearly, “another system” could also be analogue television. A digital assignment of the GE06 plan could be used as a “placeholder” under which an analogue station can be operated even beyond the end of the transition period when the protection of analogue transmission would have ceased.
The envelope concept is described in Article 5.1.3 of the GE06 Agreement [ITU06]. It states that a digital plan entry might be used for systems whose technical characteristics are different from those appearing in the plan. Both broadcasting services and also other primary services can be implemented. However, they need to be in conformity with the Radio Regulations (RR) of the ITU [ITU08]. This is in the first place a regulatory constraint which means that only those systems can exploit GE06 under the envelope concept which are defined as primary services in the Bands III, IV, or V already. From a technical point of view, the basic condition to be met is that the peak power density in any 4-kHz interval shall not exceed the spectral power density in the same 4-kHz as produced by the digital plan entry.
The generation of the GE06 frequency plan was accomplished after four planning iterations. Administrations had to submit their requirements at a given time usually before the weekend. They were given a bit more time to prepare the administrative declarations which were taken into account only after the full pairwise compatibility analysis had been carried out. This information was taken into account during the plan synthesis process. The large number of inputs to the first iteration resulted in only ca. 65% and 74% of satisfied requirements in VHF and UHF, respectively.
From one iteration to the next, administrations were urged to keep the number of changes of their input data to a minimum and for the fourth iteration only corrections of mistakes to the already existing input data sets like typos were accepted. The only modifications to the input that were always accepted was a reduction of the number of input requirements and the provision of more administrative declarations in order to make channel sharing possible. In the end, the total number of requirements for digital terrestrial broadcasting had dropped from roughly 80000 to about 72000 and the number of satisfied requirements increased to 93% and 98% in VHF and UHF, respectively.
The RRC-06 planning process provided three sets of results, namely a digital plan for T-DAB and DVB-T containing both allotments and assignments, a frequency plan for analogue television that need to be protected during the transition period and a list of assignments to other primary services in the frequency bands under consideration. In particular, in CEPT countries allotment planning was favored. In the end, the majority of CEPT countries obtained seven national coverages of DVB-T in UHF and three or four layers for T-DAB and DVB-T in VHF.
The majority of DVB-T plan entries, roughly 65%, refers to fixed reception which in the case of allotments is represented by RPC1. The rest corresponds almost entirely to portable outdoor reception (RPC2) because the number of portable indoor reception entries (RPC3) is almost negligible compared to the other two cases. For T-DAB, the situation is similar concerning the two possibilities, namely mobile (RPC4) and portable reception (RPC5). Also, here the number of mobile allocations is almost twice as large as that of portable indoor reception. Concerning the statistics of allocated frequencies it has to be noted that lower channels in UHF have been requested more often and subsequently allocated more frequently. In particular, starting with channel 61 the channel usage significantly decreases. This can very likely be addressed to the fact that in many countries of the GE06 planning area this spectrum range is allocated to other primary services as well. Therefore, this part of the spectrum was not available for digital terrestrial broadcasting. In the case of Band III, DVB-T allocations are primarily in channels 5–10 for the 7-MHz raster. This is due to the fact the WI95 allocations for T-DAB which most administrations wanted to be included in the new plan as well, were concentrated in channels 11 and 12.
As discussed above, administration provided a vast number of administrative declarations in order to get their requirements in the plan. As a consequence, implementation of these plan entries will be subject to the conditions agreed by the concerned administrations. Basically, there are three different types of conditions to be taken into account. For some entries coordination with respect to existing or planned analogue TV stations is explicitly required before the digital plan entry can be brought into operation. The second category refers to special conditions agreed by administrations in relation to other digital broadcasting plan entries. Actually, this corresponds to the standard case of getting broadcasting requirements into the plan which failed the compatibility analysis. Finally, there are cases where conditions have to be met relating to the protection of other primary services where administrations had agreed on special measures to be taken. In any case, the details of the agreement between administrations are not contained within the GE06 plan. It includes only remarks that there are some constraints to be considered. Administrations take the responsibility themselves to be able to retrieve the proper wording of their agreements. A more detailed analysis of the results of RRC-06 in terms of channel usage and geographical distribution of channels can be found in [Ole06]. Clearly, the most comprehensive source of information is the ITU-R website dealing with GE06 [ITU06].
4.1.2.2 GE06 Article 4: Plan Modification Procedure
Setting up the GE06 plan was certainly a big task. However, it was also clear that the new plan will not be static. There will be changes to it, either new plan entries need to be added, existing ones might be modified or some might even be deleted. In any case, it was one of the objectives of RRC-06 to provide the regulatory and technical means for all these intentions. Committee 5 took care of that very difficult and politically delicate task. To this end, Article 4 of GE04 was prepared to contain procedures which specify in detail what has to be done by an administration wishing to make a change to the GE06 plan. Any addition or modification will very likely have an impact on other digital plan entries, assignments to other primary services and during the transition period will need to protect existing and planned analogue TV assignments. Consequently, coordination with all affected administrations need to be sought.
Originally, it was intended to base the new frequency plan on two planning objects, namely assignments and allotments. Already, this decision had been an innovation since in the past either assignment plans have been drawn up (ST61 and GE89) or allotment plans were established (WI95). Therefore, mixing assignment and allotment planning was already a step into uncharted waters. However, during the preparation of the RRC-06 it turned out that administrations had very different demands that could only be satisfied by introducing a total of five different planning objects identified by five distinct plan entry codes.
The simplest planning object is a single assignment. This reflects exactly the same way of planning as in ST61 or GE89, i.e. an administration provides all technical characteristics of a transmitter site which are necessary to assess its interference impact at any given geographical location. A natural extension of a single assignment is a set of assignments which are combined by the same SFN identifier (SFN-ID). The intension is to use them in SFN mode, i.e. using the same frequency to broadcast the same content. Then, a single allotment could be provided as input to the planning process. It is given in terms of a set of geographical vertices defining an area to be covered by an appropriate transmitter network. An allotment is associated with a RPC and a RN. This information is sufficient to assess the interference produced by the allotment and the protection it needs to be granted. Plan entry code 4 refers to an allotment with linked assignment(s) and a SFN-ID. Linking assignments was invented to bring together the concept of allotment with existing transmitter sites. Employing such a construct allows to take into account the features of transmitters which are intended to implement the allotment but can however not be represented by the characteristics of the allotment, i.e. RPC and RN. Finally, a fifth planning object was introduced which consists of an allotment to which a single assignment is linked but no SFN-ID is provided. The intention of this was to combine the concept of a defined service area as given by an allotment area and special transmission characteristics which can be modelled by providing a corresponding assignment.
Since the five different plan entry codes have very different properties it is evident that they need to be treated differently. Both Articles 4 and 5 procedures require to calculate field strength values produced by these planning objects at given points. To this end, it has to be clearly defined what the source of interference for each of these cases is. For a single assignment and a single allotment the situation is obvious. The technical characteristics of the assignment and the RPC/RN combination will be used, respectively. However, for the mixed cases field strength values based on both information have to be calculated for a given geographical point. Then the larger value is defined as the field strength produced there by the planning object.
Another important aspect for both Articles 4 and 5 is the definition of a point of reference for each plan entry code. Both GE06 Articles 4 and 5 employ geometrical concepts on which their calculation methods are based. Depending on the task a set of geometrical contours has to be calculated. To this end, a geographical point of reference is needed. In the case of a single assignment it is straightforward to use the location of the transmitter site thereto. However, already for an allotment this becomes a tricky issue, in particular because a single allotment can consist of several distinct polygons. According to the GE06 rules this can be employed in order to more accurately treat main land and offshore islands as a single allotment. In principle, the centre of gravity of the allotment is used as the point of reference. In case of a set of assignments, more sophisticated rules apply. More details can be found in [EBU07].
The objective of the procedure anchored in Article 4 is to determine which services could be potentially affected by a proposed modification or addition to the GE06 plan. Clearly, this means to identify the administration to which a particular service is associated. In this context, the term services refers to both broadcasting services and other primary services. In order to limit the computational effort to a reasonable amount, first of all a contour separated by 1000 km from the location of the proposed addition or modification to the GE06 plan is constructed. Only administrations whose territory falls into the identified area will have to be considered during the Article 4 procedure.
Any modification to the GE06 plan has to refer to one of the five plan entry codes. Depending on that the corresponding point of reference is determined. In case of assignment(s) the distance is measured from the transmitter site(s), while for an allotment the 1000 km are taken from the allotment boundary. Any country whose border is intersected is taken into consideration. Furthermore, the frequency for the new or modified plan entry is important for the subsequent analysis. Figure 4.2 sketches the situation. It shows a broadcasting allotment to be added in country A. The 1000-km contour – from which only a small part is indicated here on top of the figure – intersects with countries B, C, and D, so they will have to be considered as potential candidates with whom coordination might be required. In countries B,C, and D, there are broadcasting plan entries and assignments to other primary services which are indicated in terms of their corresponding service areas.
1000 km contour derived from a broadcasting allotment that is to be added to the GE06 Plan according to an Article 4 procedure
The measure of Article 4 to decide if an administration needs to be approached for agreement or not is to calculate so-called coordination contours. In principle, a coordination contour represents a curve along which the proposed plan modification will create a certain field strength level, namely the so-called coordination trigger value. The actual value of the trigger field strength depends on the technical characteristics of the intended plan modification and the type of service potentially affected. Therefore, the identification of affected administrations has to be carried out in relation to broadcasting plan entries in GE06 and against assignments to other primary services contained in the list attached to the GE06 Agreement. Actually, this might require to construct several different coordination contours.
In any case, there will be a contour relating to the broadcasting service. Different trigger field strength values for T-DAB and DVB-T are given in GE06. Until the end of the transition period analogue television will need to be considered as well. The trigger values differ according to the frequency band, i.e. III, IV, or V. In order to simplify the calculations only the most critical, i.e. smallest trigger value is employed to construct a single broadcasting coordination contour. If this contour intersects or encloses the national boundaries of a country which is located within the 1000 km contour coordination with the corresponding administration is required.
In the case of other primary services, the details of the identification process are different. In a first step, those other services are identified whose assignments are located within the 1000-km contour. From these only those will be taken into consideration which are contained in the list attached to the GE06 Agreement. Then, it is checked whether there is a frequency overlap between the intended plan modification and the frequency used by the assignments to other primary services. Only if there is an overlap these assignments will be taken into account. It is important to note that this constitutes a significant difference between the treatment of broadcasting and other primary services. For the latter basically only co-channel usage can trigger coordination between administrations. In the case of broadcasting, the frequency is actually not taken into consideration.
Once the assignments to other primary services have been identified the relevant trigger field strength values are extracted from the GE06 Agreement and the corresponding coordination contours are generated. In contrast to the broadcasting case the national boundaries are not relevant, but coordination with an administration is required if the locations of the receiving stations or the service areas of these other primary services are intersected or enclosed by the coordination contour. For further details refer [EBU07].
Article 4 of GE06 contains the regulatory framework according to which an administrations has to act when wishing to modify the GE06 Plan. All technical issues in relation to Article 4 are given in Sect. I of Annex 4 to the GE06 Agreement. It specifies in detail how the coordination contours are constructed for a given assignment or allotment. Apart from the explanation given in the GE06 Agreement, a very good description of the relevant technical issues seen from a practical point of view can be found in [EBU07]. Figure 4.3 illustrates the different coordination contours.
Two coordination contours derived from a broadcasting allotment that is to be added to the GE06 Plan according to an Article 4 procedure
It is assumed in Fig. 4.3 that there is only one type of other primary service inside the 1000-km contour. In that case two coordination contours have to be constructed, one for broadcasting and one for the other service. The broadcasting contour intersects with countries B and C. Therefore, coordination concerning broadcasting services is required with these two countries. In the case of other primary services, the service area or the location of the transmitter site is relevant, not the national border. This means that coordination is required with country B in relation to other primary services and not with country D.
4.1.2.3 GE06 Article 5: Notification Procedure
Setting up a frequency plan and having the means to modify existing plan entries gives administrations and broadcasters the possibility to operate transmitter networks for broadcasting services. However, it is necessary to introduce rules which guarantee that the implementation of a network is carried out in conformity with the characteristics of the plan entries. This means that the network implementation must not produce more interference than the associated plan entry will do. To this end, Article 5 has been included in the GE06 Agreement which contains the technical details how the conformity check between plan entry and network implementation has to be carried out.
The operation of a transmitter under the GE06 Agreement calls for two requirements to be fulfilled, namely there must be a plan entry in GE06 with which the operational transmitter can be associated and furthermore an assignment corresponding to the technical characteristics of the transmitter has to be recorded in the ITU-R MIFR. The latter process is called “notification”.
Basically, there are three cases in which an Article 5 procedure is needed. Two of them refer to particular modifications of plan entries resulting from an Article 4 procedure and one is a “true” Article 5 issue. The latter refers to the straightforward intention of an administration to use a particular plan entry in order to implement a transmitter network. An implementation can be accomplished in terms of one or several assignments. The technical characteristics of the assignment(s) are fed into the machinery of the conformity check in order to prove that the intended network will not produce more interference than is calculated on the basis of the plan entry characteristics.
Furthermore, Article 5 has to be employed in relation to a modification of an allotment plan entry under Article 4, i.e. the conversion of an allotment plan entry into a set of assignments. This idea was taken over from the WI95 [CEP95] and CO07 [CEP07d] Arrangements of CEPT relating to T-DAB. In principle, this means to substitute the original allotment plan entry by a number of assignments which then will become part of the plan. Such a plan modification is only allowed if the aggregated interference of the set of transmitters does not exceed the limits imposed by the allotment plan entry. This is assessed by applying the conformity check defined by Article 5 of GE06.
The second Article 4 case where reference to the conformity check is made concerns a plan modification which claims to produce less interference than the original plan entry it refers to. Also, in such a situation a check is needed in order to confirm this claim.
As in the case of Article 4 of GE06 concerning an intended plan modification, the regulatory framework an administration has to apply when submitting a notification to the ITU is given in the main body of the GE06 Agreement under Article 5 while all technical issues are presented in Sect. II of Annex 4 to the Agreement.
Application of an Article 5 procedure starts with the submission of administration of a set of assignments whose technical details have to be specified. Then, the conformity check of Article 5 comprises two examinations. First of all, the frequency and the location of the submitted assignments are checked. Clearly, the frequency has to be the same as that of the plan entry. Moreover, the location of the transmitter sites have to be close to the location of the plan entry. For an allotment this means that they are allowed to lie inside or outside the allotment area. The latter case is only acceptable if the transmitter sites are separated from the allotment boundary by not more than 20 km. In the case of an assignment, the transmitter location may deviate by 20 km from the geographical location recorded in the plan.
The second examination of the conformity check relates to the technical characteristics of a plan entry which allow the calculation of a corresponding interfering field strength value at an arbitrary geographical point. The field strength values at all possible points define an interference envelope of the plan entry. An implementation is considered as being in conformity with GE06 if the network implementation stays below that interference envelope.
As already mentioned in the previous section, the GE06 comprises five different types of plan entries distinguished by their plan entry codes. Thus, it comes as no surprise that all of them require a slightly different treatment for this comparison. For any type of plan entry it is possible to calculate a field strength value at any arbitrary geographical point. Therefore, the concept of an interference envelope is naturally a two-dimensional concept. In other words, the interference envelope of a plan entry can be imagined as a two-dimensional surface above a given area. This is just like a mathematical function of two independent variables x and y corresponding to geographical latitude and longitude. The height of the surface above any point represented by a pair of longitude and latitude values is then given by the field strength value produced there by the plan entry. Checking if a network implementation is in conformity with a plan entry would consequently require to check any point throughout a given area. Since this is not feasible from a practical point of view, a set of calculation points is defined where a comparison of the field strength produced by the plan entry and by the intended network implementation is carried out.
In order to limit the amount of computational effort, the area in which calculation points are located is bounded by a so-called cut-off contour. The cut-off contour is basically a trigger field strength contour similar to those used in the application of the Article 4 procedure. However, in contrast to these there is only one cut-off contour which takes into account both broadcasting and other primary services appropriately. The first step of the construction of the cut-off contour is the determination of the point of reference of the plan entry for which a particular implementation is to be assessed. For a single assignment, this point corresponds to the location of the assignment. In case a set of assignments is dealt with, the centre of gravity of all locations is chosen while as soon as an allotment is involved the centre of gravity of the allotment area is used. Then, radials are drawn every 1 ∘ starting at the point of reference and extending to infinity. Along these radials the point is identified where the field strength produced by the actual implementation of the plan entry reaches the broadcasting trigger field strength as defined in Article 4. Just to avoid any misunderstanding, the cut-off contour is calculated on the basis of the technical characteristics of the transmitter(s) submitted for notification. In the case of an allotment, already notified assignments that have already been entered into the MIFR have to be included too, since they make part of the network implementation of the allotment. Clearly, this is also valid for the comparison in each calculation later in the process.
All points found that way are subsequently connected and the resulting polygon defines the cut-off contour. However, there are additional conditions to be taken into account. If the constructed contour lies entirely inside the territory of the administration whose plan entry is considered then other primary services have to be accounted for as well. This might lead to a modified cut-off contour whose calculation is then based on the trigger values of other primary services. Annex 2 of [EBU07] explains in details all possible implications of different conditions on the construction. Figure 4.4 sketches a simple layout for the case of a single assignment and a single allotment plan entry.
An assignment and an allotment plan entry together with the corresponding cut-off contours needed for the application of an Article 5 procedure. The cut-off contours are meant as examples. They depend on the technical characteristics of the plan entries, i.e. RPC/RN or ERP, antenna height and antenna diagram, respectively
Once the cut-off contour has been generated the calculation points have to be identified. As a general rule, calculation points must lie inside the area delimited by the cut-off contour. At the same time only those calculation points are considered which are located outside the territory of the administration whose Article 4 or 5 request initiates the conformity check. This means that there can be cases where no calculation points are found at all. In that case, conformity with the GE06 plan is granted by definition.
If the cut-off contour extends beyond the national boundary the location of the calculation points have to be determined. To this end, a set of geometrical contours are generated. They constitute contours which are separated from the location of the plan entry by a constant distance; in particular the distances 60 km, 100 km, 200 km, 300 km, 500 km, 750 km, and 1000 km are employed. For assignment plan entries the contours are concentric circles around the geographical location of the assignment which at the same time acts as point of reference. In the case of an allotment, the geometrical contours correspond to buffer zones around the allotment area. Figure 4.5 shows some geometrical contours.
An assignment and an allotment plan entry together with the corresponding cut-off contours and geometrical contours. The dark area on the lower left represents sea
The point where the radials emerging from the point of reference of the plan entry under consideration and the geometrical contours intersect are the locations of potential calculation points. The word “potential” is to indicate that not all intersection point are employed. Rather, only those points lying outside the national territory of the notifying administration and inside the cut-off contour are utilized as calculation points. Whether they are located on land or above water is not important, both are taken into account. Due to the fact that the radials are separated by 1 ∘ and that there are seven geometrical contours the maximum number of calculation points that ever might need to be considered is 360 ×7 = 2520. However, it can be expected that in practice the number will be significantly less. Figure 4.6 presents the locations of the calculation points for the examples considered here.
An assignment and an allotment plan entry together with the corresponding cut-off contours, geometrical contours and calculation points. The dark area on the lower left represents sea
The technical implementation of Article 5 as given in Sect. II of Annex 4 of GE06 exhibits one very important feature. The location of the calculation points is derived exclusively from characteristics of the plan entry. Both point of reference and circular contours or buffer zones are calculated from the geometrical features of the assignments or allotments in the plan, respectively. However, the cut-off contour is determined on the basis of the technical characteristics of the intended network implementation by calculating field strength levels and comparing them with trigger field strength values. This is reasonable from the point of view that e.g. a high power assignment plan entry could be implemented in terms of low power station. This will certainly have a rather limited impact on other plan entries or already existing networks. Consequently, it is not relevant to carry out intensive calculations at distances where the field strength values produced by the intended network implementation has fallen already below irrelevant levels.
Once the location of the calculation points has been determined, the actual assessment if the network implementation is in conformity with the characteristics of the plan entry can be accomplished. To this end, two calculations are carried for each calculation point. Firstly, the field strength value is calculated that will be produced by the plan entry at the given calculation point. Then, the technical characteristics of the assignment(s) representing the intended network are used to evaluate the field strength which is produced at the same point. All calculations are based on the wave propagation model described in Chap. 2 to Annex 2 of the GE06 Agreement. Aggregation of several signal contributions is based on the application of the power sum method as described in Sect. 3.5 of Chap. 3 to Annex 2. The network implementation is considered as being in conformity if the field strength of the plan entry is larger than that of the implementation at each calculation point. If only at a single point this condition is not met the notifying administration has to modify its network implementation and re-submit the new technical characteristics. In case this is not feasible, a plan modification procedure according to Article 4 could be envisaged in order to match plan entry and network implementation.
For an assignment plan entry which is to be implemented in terms of a single assignment the calculations are pretty straightforward. For each calculation point only two calculations need to be carried out. However, it should be borne in mind that even that simple case allows for relatively much freedom when it comes to implementation. First of all, the location of the assignment in the plan and the actual location of the transmitter site may differ by up to 20 km. This might lead to different efficient heights that have to be taken into account when calculating the field strength according to the wave propagation model of the GE06 Agreement. Moreover, both ERP and the antenna height above ground of the real transmitter can be different from what is recorded in the GE06 plan. But then it is obvious that a conformity check is mandatory in order to guarantee that the implementation stays below the interference envelope of the plan entry at every single calculation point. Figure 4.7 illustrates the situation.
Characteristics of a plan entry and an intended implementation of an assignment can differ significantly which calls for an appropriate conformity check even for this simple situation
The situation becomes more complex in the case of an implementation of an allotment plan entry. Still the same principle applies, namely to compare the interference produced by the plan entry with that of the intended network implementation. However, due to the larger freedom allotment planning offers the computations are more elaborate. An allotment is represented by a combination of RPC and RN. They define the interference envelope of an allotment. At any arbitrary point a field strength value can be calculated by properly adjusting the RN along the allotment boundary. It is positioned at each vertex of the allotment polygonFootnote 2 and the aggregated field strength produced by the set of transmitters in the RN is computed at the point of reception under consideration. Then, the maximum value obtained is defined as the field strength the allotment produces there. These calculations are repeated for each vertex. Figure 4.8 visualizes the layout.
Calculation of the interference of an allotment plan entry by positioning of a RN along the vertices of an allotment boundary. The orientation of the RN varies depending on the direction of the connecting line between calculation point and vertex
It has to be noted that the orientation of the RN relative to allotment boundary depends on the direction of the line connecting the calculation point and the vertices of the allotment. As a consequence, there are situations where the transmitters of the RN will lie outside the allotment area. They might be located in the territory of an adjacent country or in the sea. This caused a lot of heated discussion during the RRC-06. In the end, administrations could agree to that concept notifying that the same mechanism is used in the plan generation process during the compatibility analysis and therefore plan generation and conformity check are consistent.
Allotment planning gives the freedom to use as many transmitters for the network implementation as considered appropriate by an administration. From a principle point of view there is no limit as long as the total interference of such a network stays below the interference envelope of the corresponding allotment plan entry. Nevertheless, at the stage of implementation the technical characteristics of the transmitters need to be specified so that they can be used for the conformity check under Article 5. The set of notified transmitters is employed to calculate the aggregate field strength produced at the same calculation points as before. Figure 4.9 shows the scenery corresponding to the computation of Fig. 4.8.
Calculation of the interference produced at given calculation points by transmitters implementing an alltoment plan entry
Already during the preparation of the RRC-06 and during the RRC-06 there were heated discussions about the conformity check. It was considered as too complicated and computationally challenging. Even if this might be true, it has to be noted that the decision to base the plan generation on assignments and allotments enforced the development of a methodology which is flexible to cope with all potential implementation situations. The idea of an interference envelope under which administrations can virtually do whatever they like seemed to be very attractive in view of the rapidly changing digital telecommunications and broadcasting sector leaving enough freedom to adapt to future demands. In the first place, this required to replace the one-dimensional analysis along a given curve or polygon as included for example in the WI95 Arrangement of CEPT by a two-dimensional approach.
However, the issue became complicated when some administrations demanded the introduction of a cut-off contour. This led to plenty of conceptional problems. Still it has not been fully proven that the way the cut-off contour is now calculated does indeed properly cover any eventuality. The original proposal not to use a cut-off contour, i.e. not to reduce the number of calculation points by suppressing some of them might have established a more sound and transparent basis for the conformity check. However, any measure included in the GE06 Agreement has undergone a lengthy and tedious political consensus building process. So, it should not come as a surprise that technical shortcomings have to be borne as a consequence.
4.2 Bilateral Frequency Planning in ITU-R Region 3
The GE06 Agreement for digital terrestrial broadcasting is an example for formalized frequency planning. Over several years the planning conference has been prepared by ITU and regional organizations such as CEPT. The usage of a certain part of the electromagnetic spectrum is governed by formal rules laid down in the GE06 Agreement and to be supervised by the Radiocommunication Bureau of ITU-R. A corresponding data base, i.e. the GE06 Plan and the List, are maintained to keep track of all individual spectrum usages.
However, such an approach is not the only possibility to cope with spectrum usage issues on an equitable access basis. In ITU Region 3, no equivalent formal frequency planning framework exists. Frequency planning for all kind of services is carried out by means of bi- and multilateral coordination only. It has to be noted that such coordination activities nevertheless need to be embedded into the general framework of the ITU-R Radio Regulations (RR) together with the Table of Frequency Allocations (TFA)forming a part of the RR. They contain articles that in general terms govern the spectrum usage and in particular specify measures in order to avoid harmful interference into other telecommunication services.
Any spectrum usage needs to be in accordance with the rules of the RR and the entries of the TFA in first line and secondly any such usage has to be notified to the ITU-R Bureau. The Bureau assesses the conformity of the request with respect to the TFA and other relevant provisions of the RR. In case of a so-called favorable finding the request for spectrum usage is included as an assignment into the MIFR.
Clearly, administrations wishing to use a frequency for a particular service will seek the agreement of their potentially affected neighbors before sending a notification to the ITU-R. Therefore, administrations of neighboring countries are negotiating about their rights to use spectrum along a common border between themselves without taking into account anything else than their needs and the requirements of their neighbors. Neither there are procedures to be followed as in the case of GE06 nor are administrations bound to given calculation methods in order to assess the consequences of an intended spectrum sharing scenario between the same or different services.
In order to put the ITU-R Bureau in the position to carry a proper assessment of the potential interference of a new station administrations are requested to provide all relevant technical characteristics of the new station. Based on this information the Bureau can then assess whether the use of the frequency, under the notified conditions, could cause interference to stations of any other administrations whose assignments are recorded in the MIFR.
In Region 3, the UHF band has been used for broadcasting, mobile and fixed services on a primary basis already for a long time. A quick look to the TFA of the RR of the ITU e.g. in the case of the band 470–890 MHz illustrates the situation (see e.g. Table 4.1 in Sect. 4.4 below).
4.3 World Radiocommunication Conference 2007
WRCs are conducted by ITU every three to four years. Usually, each WRC has to review, and, if necessary, revise the ITU-R Radio Regulations (RR). The RR constitute the international framework for the usage of the radio-frequency spectrum and all satellite orbits. WRCs are conducted on the basis of an agenda determined by the ITU Council. This agenda is prepared several years in advance by relevant ITU groups such as the Conference Planning Meeting (CPM).
Under the terms of the ITU Constitution, the competence of a WRC comprises revisions to the RR and any associated frequency plans. It shall identify issues (called “Questions” in ITU terminology) which should be studied by corresponding Study Groups of ITU. Results of these technical and regulatory studies are presented to subsequent WRCs and may influence decisions on frequency allocations to particular services and sharing between services. Different ITU-R Study Groups are usually tasked to gather information on different WRC agenda items.
As a matter of fact, spectrum usage is not globally harmonized around the planet. This is due to a certain amount of historical legacy in different regions but also because different regions obviously have different needs in relation to radio- and telecommunications services. However, in order to confine fragmentation of spectrum usage the spectrum management is organized at ITU level in terms of subdividing the world into three ITU Regions. Basically, Region 1 covers Europe, Africa and the former Soviet states now forming what is called Commenwealth of Independent States (CIS). Region 2 corresponds to the Americas and Region 3 comprises the Asian-Pacific area. These geographical regions are considered independent so that different spectrum allocations can be made, if necessary.
Between 22 October 2007 and 16 November 2007 ITU conducted the WRC-07 in Geneva [ITU07]. More than 2500 representatives from ITU Member Sates, Regional Organizations, and other organizations and companies participated in the conference. By definition, the entire electromagnetic spectrum range relevant for telecommunication services ranging from 9 kHz up to 1000 GHz is under review during a WRC. In order to structure the whole process the agenda of a WRC contains many items which either refer to particular spectrum ranges or to services. With regard to the Digital Dividend the most important agenda item (AI) of WRC-07 was AI 1.4 “Candidate Bands for IMT” [IMT00]. The term IMT (International Mobile Telecommunication)describes a global broadband multimedia communication system. ITU has supported the development of the such a system for a long time, in particular with a focus on the global harmonization aspect. In the meantime, the next step called “IMT-advanced” has been made. This system is to provide a global platform on which to build the next generations of mobile services paving the way to fast data access, unified messaging and broadband multimedia consumption.
Before the WRC-07 CEPT was passing through a preparation process which is followed before any important event at ITU level. Several groups had been established to prepare European Common Proposals (ECP) and CEPT Briefs. ECPs contain explicit proposals for modifications of the RR or they call for adoption of ITU Resolutions in which tasks for ITU Study Groups are formulated or other general regulatory measures are put forward. Briefs provide the background information relating to ECPs.
Hence, CEPT submitted a set of ECPs referring to the different agenda items. Concerning AI 1.4 the European proposals consisted of two fundamental statements. Firstly, CEPT was proposing no change to the RR in the band 470–862 MHz at the WRC-07. Furthermore, it was proposed to foresee an agenda item for the next WRC in 2011Footnote 3 by which allocations to the mobile service in relevant parts of the band 470–862 MHz should be considered. If appropriate, the need for the identification of a sub-band for IMT should be envisaged, as well as a Resolution to invite studies on the potential use of the band 470–862 MHz by new mobile and broadcasting applications on a co-primary basis. Clearly, this also calls for consideration of any relevant harmonization measures an identification of a sub-band for IMT would require.
The justification for such an approach was that Europe at that time had started to investigate the use of the upper part of the band 470–862 MHz for mobile applications after digital switch-over from analogue to digital terrestrial broadcasting. Since the technical studies were still ongoing and no final decision had been taken yet, CEPT felt it would be pre-mature to request the frequency allocation for mobile services in the UHF band. Rather, CEPT explicitly declared that they would prefer to take a decision on this issue at WRC-11, after studies have been completed. Nevertheless, a fall back position had been slipped into the proposal by saying that Europe would be prepared to consider proposals from outside CEPT at WRC-07 and take appropriate action.
The CEPT proposal at WRC-07 for an agenda item at WRC-11 read in detail that Europe proposes [ITU07c]
to consider allocations to the mobile service in the band 470–862 MHz, taking into account the current and planned use of this band by services to which this band is allocated, and to consider the need for the identification of a sub-band for IMT, in accordance with Resolution [EUR/10A4/17–UHF] (WRC-07).
A corresponding draft for the Resolution mentioned in the text was attached to the ECP as well.
Even though this was the official course of action of CEPT, at the end of WRC-07 it was decided to accommodate a new allocation in the band 790–862 MHz in Region 1 already during the 2007 conference. Mobile services would be allowed to use that band on a co-primary basis together with broadcasting and fixed services. In Regions 2 and 3, such an allocation existed already before the WRC-07. Moreover, in Region 2 mobile services could be accommodated down to 614 MHz while in Region 3 the entire UHF band 470–862 MHz was allocated to the mobile service.
The allocation of UHF spectrum to the mobile service is subject to several footnotes to the TFA of the RR. Some of these footnotes were existing ones that were modified at WRC-07, others were newly introduced. The first important aspect of this new spectrum allocation is that the spectrum was identified for IMT services. This is expressed by the modified footnote 5.317A which refers to the band 790–960 MHz for Regions 1 and 3 and to the band 698–960 MHz. However, no priority is given to IMT with respect to other services. Secondly, footnote 5.316B essentially says that the allocation is effective as of 17 June 2015. For Region 1, this is a special date since it coincides with the end of the transition period of GE06. Clearly, since the band 790–862 MHz is governed by GE06 in Region 1 any base station of a mobile service network introduced in that spectrum range is subject to successful application of the GE06 procedures, i.e. Articles 4 and 5.
Furthermore, for Region 1 footnote 5.316 was modified and a new footnote 5.316A was added. They govern the usage of the upper UHF band for mobile services even before 17 June 2015 on a no-interference-no-protection basis. These immediate allocations end by 16 June 2015 when footnote 5.316B comes into effect. The two footnotes were introduced to find a work-around allowing to include a long list of countries in a footnote of the RR. However, since still many European countries did not ask for inclusion in the list of the footnotes coordination according to GE06 will be required for the introduction of mobile services. This might lead to delays for the roll-out of mobile services in the band 790–862 MHz.
Due to the fact that in the other two ITU-Regions a mobile allocation had already existed before the WRC-07 the situation was easier to resolve. First of all, there is no regional agreement like GE06 that governs the usage of the UHF bands by broadcasting and other services, neither in Region 2 nor in Region 3. Therefore, any spectrum usage has to be addressed on the level of bi- and multilateral coordination. To support this approach, for Region 2 just a reference to the modified footnote 5.317A was necessary to identify the range from 698 to 862 MHz for IMT. In Region 3, the same reference was included which means that similar to Region1 the band 790–862 MHz was opened for mobile services. Furthermore, a footnote 5.313A was also added which extends the allocation down to 698 MHz for a list of nine countries in Region 3.
In addition to these modifications, WRC-07 adopted two Resolutions, both calling for sharing studies between IMT and those services to which the bands under considerations are allocated. ITU-R Resolution 224 [ITU07a] requested to
study the potential use of the band 790–862 MHz in Region 1 and Region 3, the band 698–806 MHz in Region 2 and in those administrations mentioned in No. 5.313A in Region 3 by new mobile and broadcasting applications, including the impact on the GE06 Agreement, where applicable, and to develop ITU-R Recommendations on how to protect the services to which these bands are currently allocated, including the broadcasting service and in particular the GE06 Plan, as updated, and its future developments;
while ITU-R Resolution 749 [ITU07a] declares to
invite ITU-R to conduct sharing studies for Regions 1 and 3 in the band 790–862 MHz between the mobile service and other services in order to protect the services to which the frequency band is currently allocated.
The studies called for in Resolution 224 were carried out by ITU-R Study Groups 5 and 6 while in order to carry the investigations resulting from Resolution 749 the Joint Task Group 5–6 [ITU10a] was established. In summer 2010, the group delivered its results.
The question how it came to be that the initial CEPT intention not to change the RR, i.e. not to allocate the band 790–862 MHz to mobile services in Region 1, was abandoned and who initiated the process is a delicate one. It can be speculated that this has been the unofficial objective of CEPT from the very beginning. It might well be that at the time of the WRC-07 European administrations felt that little more than just one year after the assembly of the GE06 broadcasting plan it was too risky to openly go for an allocation of the upper UHF band to the mobile service. However, a WRC is autonomous in its decisions. To plant the seed at the conference itself probably seemed to be more promising.
During the conference this change of mind caused a lot of tension between broadcasters in Europe and their administrations. Apart from the fact that some broadcasters felt that CEPT had double-crossed them, this decision on a new allocation constitutes some kind of precedence. Usually, a frequency range is identified for allocation to a service. Then during the following study cycle the sharing conditions are investigated and corresponding sharing parameters are defined e.g. in terms of ITU Recommendations. Only after this is accomplished the frequency allocation is adopted and coming into effect. This time the process was turned upside down, first came the allocation and then the definition of the circumstances under which sharing between services would be feasible should be tackled. Such a course of action clearly shows that the political and economical pressure to open a new band for mobile services must have been tremendous.
4.4 Frequency Allocations for Broadcasting and Mobile Services
After the WRC-07 an updated version of the ITU-R Radio Regulations (RR) was published including a modified TFA [ITU08]. Modifications relating to any of the services dealt with at a WRC such as broadcasting, mobile, fixed, aeronautical, and other services had been included. However, for the discussion about the Digital Dividend and its impact on terrestrial broadcasting only a small part of the TFA is relevant. In the first place, only those entries referring to the mobile service are interesting at all.
The term mobile service encompasses many different applications at ITU level such as individual communication systems, military mobile services or Public Mobile Radio (PMR). They can have very different technical characteristics. Only a subset of all those mobile applications make up IMT, for example GSM, UMTS, LTE, or WIMAX. It is important to note that the RR only contain allocations to services and not to applications.
In order to harmonize the spectrum usage and to give clear indications to the industry ITU-R identifies part of the frequency ranges allocated to the mobile service for IMT usage. In the first place, this constitutes a kind of recommendation that the considered frequency ranges should be used for IMT rather than for other applications of the mobile service. However, it does not exclude the usage of these frequencies for other applications of the mobile service because if an application is part of a certain service it can be brought into operation within any spectrum range that is allocated to this service as long as the corresponding constraints and conditions for the spectrum usage are met. Obviously, by means of footnotes additional restrictions can be imposed by mentioning them explicitly.
Therefore, administrations can in principle ignore the identification for IMT expressed by ITU. But it is evident that as soon as applications are likely to have an impact on spectrum usages in neighboring countries it starts to become unattractive not to harmonize the usage of applications. Only in exceptional cases of very large countries such as the US or Russia this might be a viable option.
Before the WRC-07 several frequency bands had already been identified for IMT. These were the bands 806/860–960 MHz, 1710–2025 MHz, 2110–2200 MHz, and 2500–2690 MHz. In 2007, WRC-07 has identified additional spectrum for IMT in the following bands:
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450–470 MHz on a global level
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698–790 for nine countriesFootnote 4 in Region 3
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698–806 MHz for Region 2 (Americas)
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790–862 MHz for Region 1 (Europe, Middle-East and Africa)
-
790–960 for Region 3 (Asia-Pacific)
-
2300–2400 MHz on a global level and
-
3400–3600 MHz in 82 countries
It has to be noted that these identification do not in all cases properly reflect the availability of the spectrum due to special national arrangements in some of the countries.
Directly relevant for the broadcasting service are only the identifications in the UHF bands. Table 4.1 gives an overview about the frequency allocations in the frequency range between 470 and 862 MHz in the three different ITU Regions. Services written in capital letters have primary status in a given frequency range while standard notation refers to secondary status. In some cases, additional text is provided to highlight constraints on the usage of the spectrum by the corresponding service. Also, footnote labels are given wherever they apply.
The Digital Dividend discussion focuses on the UHF range. However, a sound assessment of the way in which IMT services are exploiting frequency resources has to take into consideration all frequency allocations across the entire electromagnetic spectrum range. This is, in particular, important in relation to addressing the issue of future spectrum requirements of IMT.
Notes
- 1.
This figure has been produced with ArcGIS based on the world map contained therein.
- 2.
The details about the positioning of the RN at a given vertex can be found in [ITU06] in Appendix 2 to Sect. II of Annex 4 to the GE06 Agreement.
- 3.
At the time of the WRC-07 it was foreseen to convene the conference in 2011. However, due to other big events being scheduled in Geneva in 2011 there was no possibility to find a large enough time slot to host the WRC. Therefore ITU decided to postpone the conference to February 2012.
- 4.
These countries are Bangladesh, China, Korea (Rep. of), India, Japan, New Zealand, Papua New Guinea, Philippines and Singapore.
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Beutler, R. (2012). Frequency Planning Frameworks. In: The Digital Dividend of Terrestrial Broadcasting. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-1569-5_4
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