There are plans to release more of the airwaves currently employed for digital television transmissions to enable mobile data services. This is in addition to the planned auction of spectrum released by the recently completed switch off of analogue television services in the United Kingdom. The latest proposals aim to draw on the 700 MHz band, currently used for digital terrestrial television, as part of future harmonised spectrum planning across Europe and the rest of the world.

At the 2012 World Radiocommunications Conference, Europe, Africa, the Middle East and Northern Asia passed a resolution signalling an intention to allow the 700 MHz band to be used for mobile broadband. A final decision will be taken at the conference in 2015.

Ed Richards, the chief executive of Ofcom, the communications regulator in the United Kingdom, said: “Within the coming months we will hold the UK’s largest-ever auction of mobile spectrum for 4G. However, that may not be enough to meet consumers’ future data demands, which is why we are already making significant efforts to prepare to go beyond 4G.”

“Our plans are designed to avoid a ‘capacity crunch,’ ensuring that the UK’s mobile infrastructure can continue to support the inescapable growth in consumer demand and economic growth more generally.”

Ofcom data suggests that mobile data network usage increased by nearly 120% between March 2011 and June 2012, to 19,700,000 gigabytes a month. That is around a quarter of a gigabyte of data a month per active SIM card, and that includes feature phones as well as smart phones. That is still 25 times less than carried over fixed broadband networks.

The rapid expansion in the use of mobile data services will inevitably put pressure on valuable spectrum currently allocated for broadcasting.

Ofcom says its plans seek to ensure the long-term future of digital terrestrial television by ensuring alternative frequencies are available for broadcasts when then next generation of mobile broadband is introduced towards the end of the decade.

These frequencies are likely to be in the 600 MHz band. The changes will require an international spectrum plan to be agreed and work on this is unlikely to be complete before 2018.

The regulator claims that moving terrestrial television to different frequencies will require a simple retune of existing receivers, although it concedes that a small minority of consumers may need to change their rooftop aerials.

In practice, more efficient compression and transmission standards may require millions of receivers to be replaced, yet again.

Charles Constable, the managing director of digital platforms at transmission services provider Arqiva, and the chairman of Freeview, said: “Ofcom has yet to make the case to justify today’s proposed long-term changes to allocate more spectrum to mobile use, especially given the disruption they will cause to Freeview viewers.”

“Despite its enduring popularity, television has been the poor relation in terms of spectrum allocation for the development of new services,” he said. He called for more spectrum to be made available to further enhance the high-definition channels offered on Freeview.

The lack of clear strategy for spectrum allocation is partly a result of the international collaboration required in frequency planning. Any changes of use necessarily need a long-term approach. It does not help that the major conferences to decide such matters only take place every three years.

Recognising the importance of digital terrestrial television in providing coverage for 98.5% of households in the United Kingdom, ensuring that public service channels are universally available in high quality, in high definition will remain a priority for many years.

However, the language that Ofcom is now using, to “seek to ensure the long-term future of digital terrestrial TV” falls short of guaranteeing the necessary spectrum, which is not necessarily within the remit of the regulator, which is required to ensure “optimal” use of spectrum, in line with international agreements.