As Ofcom publishes the rules for the auction of 4G mobile spectrum in the United Kingdom, there is continuing concern over possible interference with terrestrial television signals. This seems incredible given the efforts to ensure digital switchover to make the spectrum available for auction. In the longer term, some might suggest that even more spectrum should be released for mobile broadband applications, which broadcasters will no doubt protest to protect their existing services. What is needed is more long-term thinking about communications infrastructure strategy.

The communications regulator Ofcom has published the final regulations and timetable for the auction of 4G mobile spectrum, which it says will be the largest ever sale of mobile airwaves in the United Kingdom. The combined reserve prices for the spectrum being auctioned is £1.3 billion.

Prospective bidders will have to submit their applications by 11 December, with bidding taking place in January and the winners being announced and licences granted in February or March 2013, enabling services from a range of providers expected to launch from mid 2013.

So-called 4G or fourth generation services will enable mobile internet services around 5-7 times faster than existing 3G networks, using technologies such as WiMax and LTE or Long Term Evolution. Ofcom claims that as a result people will be able to stream high-quality videos and download large files to mobile devices in almost every home in the country, although this will presumably come at some cost to consumers.

The airwaves that are being auctioned will be equivalent to three quarters of the amount of spectrum currently in use for mobile services and 80% more than the auction at the height of the technology boom in 2000, which raised over £22 billion for the government in the United Kingdom. It seems unlikely that similar figures will be reached again.

Ed Richards, Ofcom Chief Executive, said: “Today marks an important shift from preparation to the delivery of the auction, which will see widespread 4G mobile services from a range of providers. The entire industry is now focused on the auction itself, with a shared goal of delivering new and improved mobile services for consumers.”

Everything Everywhere has already been given special dispensation to launch 4G services in its existing 1800MHz spectrum. However, there is continuing concern about the possible impact of the new services on digital terrestrial television reception. Some of the most valuable spectrum to be used is in the 800MHz band and was released through the switchover to digital television.

Following discussions with Ofcom and the government, four major mobile network operators, Everything Everywhere, Telefónica O2, Three and Vodafone, have got together to form a joint company, Digital Mobile Spectrum Limited, to ensure that all viewers continue to receive clear television signals.

This could involve fitting filters on aerial inputs in affected homes, in some cases requiring professional installation support. This may not be effective for some homes closest to the 4G base stations and it may be necessary to switch to satellite or cable. There is further concern about the impact on secondary televisions. It is estimated that there may be as many as 20 million second sets that rely on Freeview digital terrestrial television.

While there may be undoubted benefits of better mobile broadband, the potential impact of interference to digital terrestrial television has received limited coverage.

A significant proportion of the country relies upon digital terrestrial television for its reception on main sets, and even more on secondary sets. Having only just completed the transition to digital television, it seems incredible that apparently little thought has been given to the possible effects of interference from use of the spectrum released for other applications.

Ultimately, it makes more sense technically to employ radiofrequency spectrum that is particularly suited for terrestrial use for mobile applications, rather than distributing television signals to fixed displays in homes.

What seems to be missing is any long-term roadmap for this.

Any suggestion that it might be possible to release further spectrum from broadcast use to enable mobile broadband may be politically unacceptable and will face concerted lobbying from broadcasters. They rely upon terrestrial transmissions to reach a large proportion of the population and are keen to keep it that way.

However, a long-term vision for communications infrastructure is required and currently missing from the discourse of government, regulators and broadcasters.