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Digital Dividend

Exploiting the benefits of UHF spectrum – what future allocations are needed?

Mobile broadband and terrestrial television jostle for spectrum

One of the most prominent changes to spectrum allocation worldwide in recent years has been the addition of mobile allocations to parts of UHF bands IV and V. This decision, taken at the World Radiocommunication Conference in 2007 (WRC-07), allocates the 698–862 MHz band in most of the Americas and Asia, and 790–862 MHz in most of Europe and Africa, to mobile services on a co-primary basis with terrestrial television.

The decision to introduce these new allocations was prompted by the switchover from analogue to digital terrestrial television broadcasting, and a recognition that the “digital dividend” frequencies released by the switchover are highly valuable for use by a variety of services, including mobile broadband networks and a range of other applications (for example, public safety communications, programme making and additional television programming). The new allocations therefore provide flexibility for countries to allocate digital dividend frequencies to mobile services, based upon market demand.

At the time the decision was made at WRC-07 to allocate parts of the UHF spectrum for mobile services, the process of switching from analogue to digital terrestrial television transmission was well under way in many countries, and had been completed in some. The WRC-07 decision prompted government action in many countries around the world to re-farm UHF frequencies (previously planned for digital terrestrial television use) for mobile services.

While this action resulted in additional costs for the replanning of spectrum for digital terrestrial television networks, the underlying rationale is that the benefits of making spectrum below 1 GHz available for use by mobile broadband services would outweigh the cost of replanning digital terrestrial television networks; that is, a change in the use of the identified frequencies would provide a net benefit to the national economy. The existence and amount of this net benefit will vary from country to country, depending on national market conditions, with the key variables being the relative importance of digital terrestrial television in the broadcast market of each individual country relative to other viewing platforms, and the demand, competition and pricing that exists within the mobile sector, as well as the need for additional frequencies either to accommodate growth in existing networks or to enable new networks to be rolled out.

Since WRC-07, the UHF band has been the focus of an intense harmonization effort around the world, to enable it to be used for mobile services. Its value for mobile use (and the reason it has received so much attention) is because UHF spectrum has one particular characteristic that makes it far more valuable than spectrum above 1 GHz: it propagates well over long distances and through barriers, and so provides better rural and deep indoor coverage.

As a result of this harmonization effort, a number of national regulators in Asia and the Americas have now allocated licences to use 698–806 MHz (“the 700 MHz band”) for mobile broadband services, and regulators in Europe and Africa are also allocating 790–862 MHz spectrum (“the 800 MHz band”) for mobile broadband use. As a result, mobile broadband devices that use the 700 MHz or 800 MHz bands are becoming widely available, although with marked differences in terms of the availability by region. Commercial services have been launched in a number of countries, and many more are expected to follow over the next year or two.

Since WRC-07, the telecommunications industry has moved on remarkably, with superfast broadband connectivity (providing speeds of 30 Mbit/s or more) now high on government agendas worldwide. A new wave of mobile services are now being delivered over a vastly improved range of devices, including advanced smartphones and tablet computers, and this is driving growth in mobile data traffic. Furthermore, government targets set in a number of countries to bring new superfast broadband services into widespread use have highlighted the fact that fibre broadband services will not be available in all regions, and that wireless services – including mobile broadband and satellite – will be increasingly important in delivering universal broadband service. A combination of these factors is creating demand in some countries for national regulators to release further spectrum for mobile services, in addition to spectrum that was made available as a result of the WRC-07 decision.

Accordingly, the need to identify additional spectrum for mobile services is high on the agenda for many governments. Estimates from some countries (including Australia, the United Kingdom and the United States) are that around 500 MHz of additional spectrum might be needed over the next ten years to accommodate anticipated demand for spectrum for wireless and mobile broadband services. This additional demand is both to accommodate the peak mobile data traffic being carried by mobile networks in some environments, and to provide improved network coverage and quality. This suggests that a combination of additional high (above 1 GHz) and low (below 1 GHz) frequencies will be needed to accommodate demand, depending on the particular network and user environments.

Given that spectrum is a finite resource, identification of this additional spectrum will inevitably involve re-farming of frequencies already occupied by other services, which will be difficult and costly to achieve. Re-farming of spectrum that is currently reserved for government use is one option that is being considered in some countries. Another option could be a second digital dividend – a further release of UHF spectrum for mobile use. With political debate on the balance of use of UHF spectrum already under way in some countries, it is expected that a future WRC (perhaps WRC-15) might be required to make further changes to spectrum allocations in the UHF band. Different stakeholders – notably the mobile sector and the broadcasting sector – have diverse views on the appropriate balance of spectrum between mobile and broadcasting in the UHF band, despite general agreement that mobile broadband services will grow significantly, and will also converge with the broadcasting sector by facilitating media services on the move.

From a mobile perspective

From a mobile perspective, a second digital dividend could provide further access to valuable frequencies below 1 GHz, which would have numerous benefits, such as increasing the speed, capacity and coverage of mobile broadband, enabling worldwide roaming, or potentially providing new harmonized mobile spectrum to accommodate the needs of specialist users such as public safety services. A second digital dividend could also help to align frequency bands released from the first digital dividend across different regions of the world, since the decision of WRC-07 placed new mobile allocations from the first dividend in different parts of the UHF band (790–862 MHz in Europe and Africa, 698–806 MHz in Asia and the Americas). Therefore, the creation of a second digital dividend in Europe and Africa, in the 700 MHz band, offers the prospect of alignment with other world regions.

However, offset against these benefits is the fact that there are already many non-UHF frequencies available for use by mobile network operators. In particular, the 2.5 GHz band (identified for IMT systems at WRC-2000) provides ideal capacity to accommodate the highest peaks of mobile broadband traffic demand anticipated in dense urban areas. The use of UHF spectrum, by contrast, is particularly suited to areas outside of dense urban environments, where peak traffic loads do not typically occur.

Demand for mobile spectrum is particularly high in countries where the use of mobile broadband has grown rapidly in the past few years. Worldwide, it has been estimated that mobile traffic volumes in 2010 were seven times higher than those previously forecast in 2005, in preparation for WRC-07, in ITU-R Report M.2072, World mobile telecoms market forecast . Both the volume and composition of mobile traffic have evolved considerably compared to industry expectations when ITU prepared M.2072. Despite regional variations, industry analysts are in broad agreement that global mobile traffic will continue to grow strongly, as a result of the combination of rising device penetration in emerging regions and take-up of secondary devices in developed regions. This growth represents a challenge for operators, who will need to adapt their existing networks to meet the new capacity requirements.

It should be noted, however, that one of the drivers of demand for mobile services is the availability of new devices such as smartphones and tablet computers, which consumers increasingly use to access a range of applications – including media – in the home. Video applications are widely expected to be one of the main content types consumed on devices connected to mobile networks, as illustrated in Figure 1. But within the home environment, where many of these applications are often used, there are typically alternative connection types (such as Wi-Fi), so the traffic generated by mobile applications in the home is not always carried over the mobile operator’s network.

It should also be noted that various market supply-side factors influence how users access mobile data services, including the affordability of mobile data services, and bundling of services. There are various techniques that can be used within mobile networks both to increase the efficiency of accommodating mobile data traffic and to reduce the cost of its carriage (the cost per bit). These include small cells (such as femtocells), adaptive antenna systems, video compression and optimization.

Taken together, this suggests that there will be significant regional and national variations in the need for additional spectrum for mobile services, primarily depending on: how demand for different mobile data services varies according to price and operator pricing policies; the cost that mobile operators incur to meet future traffic demand; and the availability of alternative solutions to reduce cost (such as offloading onto Wi-Fi).

From a broadcasting perspective

From a broadcasting perspective, a second digital dividend will be particularly problematic for digital terrestrial television channels, platforms and transmission/network providers, and in some cases may be costly to implement (if it is feasible at all). This is because many digital terrestrial television systems have already been replanned once to make way for the first dividend, and although there are options to improve the capacity of digital terrestrial television networks – such as the use of MPEG-4 coding and migration from DVB-T to DVB-T2 (the newer generation of digital terrestrial television technology) – access to UHF spectrum is still essential in maintaining existing digital terrestrial television networks and enabling services to expand (for example, by creating more multiplexes to carry additional digital channels).

A second digital dividend would be particularly problematic in countries where terrestrial television is the most important television distribution platform. Despite the availability of other platforms, terrestrial television remains a key platform for delivery of media services in many countries in Europe and the Americas, and in some countries there is evidence of demand for additional digital terrestrial television services to accommodate a growing number of national and local programmes and to exploit the availability of new technologies such as high-definition television and converged devices (including connected televisions that enable viewing via both digital terrestrial television and broadband networks). Digital terrestrial television is the key delivery platform for television in many European countries (see Figure 2), as well as in countries such as Brazil and Mexico (the two most populous countries in the Americas after the United States). In those countries, deployment of a wider range of digital terrestrial television services could require additional spectrum to be used.

It should also be noted that ancillary broadcasting services (often referred to as programme making and special events, or PMSE) currently make use of frequency gaps between UHF channels allocated for digital terrestrial television in many countries, by coordinating their transmissions with those of the television networks. Therefore, any replanning of UHF frequencies will affect the future availability of spectrum for those services, which include wireless microphones and other applications used in theatres, sporting events and media events.

There are a limited number of other frequencies that could be used by terrestrial broadcasting systems – VHF band III being the main alternative. It is not clear what alternative frequencies exist for use by PMSE. Although some countries have decided to use spectrum in VHF band III for the provision of additional digital terrestrial television services, others either already use VHF band III or plan to use it for other broadcasting services (such as digital radio), and so it is unavailable for digital terrestrial television (unless allocations to digital radio were to be reconsidered, and the spectrum reallocated to digital terrestrial television).

In contrast, television viewing using terrestrial platforms is relatively limited in some regions, particularly the United States, and some countries in Europe and the Middle East. Also, there are many countries in both the Middle East and Africa where analogue broadcasting switch-off may not occur for another five or more years.

Technical leadership and expertise from ITU

In the light of these very diverse national situations, any proposal for a second digital dividend is likely to be controversial. There would be a need for technical leadership and expertise from within the study groups of the ITU Radiocommunication Sector (ITU-R) to reconcile conflicting views from the different industry sectors and provide governments with a solid basis for policy development. Any policies that are developed must give national regulators sufficient flexibility to award valuable UHF spectrum for the appropriate services, based upon national demand.

Evidence-based spectrum policy, and regional and international coordination are critical. In particular, international harmonization of spectrum for mobile communications and content services has been shown to bring significant benefits to consumers through wider availability of a range of low-cost terminals and a greater variety of new and compelling mobile data services. Steps in this direction will be taken by WRC-12 delegates, who will determine the agenda for WRC-15, including the potential to consider allocating more spectrum for mobile broadband use.

Ultimately, ITU will play a key role in facilitating this debate, and providing guidelines for where the dividing line is drawn between the amount of spectrum retained by broadcasting services and that released for use by other services, including mobile. This is a decision which will have profound implications for the telecommunications and broadcast industry – and its consumers – for many years to come.

 

Figure 1 – Mobile data traffic, by application [Source: Cisco]

figure 1

 

Position of the digital terrestrial television platform in selected European countries

figure 21

 


This article was written by Analysys Mason, a consultancy and research firm with a focus on telecommunications, media and technology.

 

 

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Updated: 2014-08-27