Ofcom Warns Of TV Changes To Prevent 4G Clash

Tom Jowitt is a leading British tech freelance and long standing contributor to TechWeek Europe

The arrival of 4G services in the UK could well impact some digital TV signals Ofcom has warned

The introduction of 4G technologies into the UK’s airwaves from next year presents a potential problem for industry regulator Ofcom, as 4G technology may interfere with digital TV signals.

It is already known that the introduction of 4G technology such as Long Term Evolution (LTE) and WiMAX will improve the spectrum efficiency of mobile networks. For example, Ofcom research last month found that 4G would be (230 percent) more spectrally efficient than today’s standard 3G networks. This means that a user on an early 4G network will be able to download a video in around a third of the time it takes today on a 3G network.

But the arrival of 4G does present a few problems, especially as the 4G signal could provide interference to digital TV signals. This is because the 800MHz spectrum is adjacent to the frequencies used for digital terrestrial television (DTT) broadcasting.

More TV Changes

Due to its proximity, in a small number of cases this could cause the signals from mobile base stations to interfere with set top boxes and digital televisions in the future, Ofcom has warned.

The regulator believes this could potentially affect up to 3 percent of DTT viewers if no measures are put in place to solve the problem.

The UK switchover from analogue to digital TV is undoubtedly freeing up valuable spectrum space, but it is proving to be a lengthy process, and for certain members of society such as the elderly, it is also proving to be a fairly complex and daunting prospect.

Therefore, in order to ensure that digital TV delivered through a roof top aerial can function alongside the 4G, Ofcom has set out its proposals on how to reduce this interference.

And it seems that it could involve even more changes to people’s TV systems.

“In some cases viewers will have to fit a filter to their TV aerial. These filters block the signals that interfere with TV reception and should solve most of the interference cases,” said Ofcom. It is proposing a scheme to give information and help to consumers. “Further work is being carried out in conjunction with the government on the level and nature of consumer support,” it added.

Ofcom proposes that the majority of the costs should be borne by the future 800 MHz licensees.

Spectrum Issues

“In a very small number of cases – less than 0.1 percent of DTT viewers – filters may not solve the problem,” Ofcom warned, and said that it is considering a number of options to address the problem which may require some viewers to change platforms.

“Ofcom’s role is to ensure that mobile services can be used effectively in the 800MHz band and at the same time enable DTT broadcasting to function properly,” it said. Ofcom is carrying out more research into this issue and expects to publish a further consultation in the autumn.

The consultation, which closes on 11 August, can be found here.

Ofcom announced back in March its plans to auction 800MHz spectrum for 4G mobile services next year. It will also auction off some 2.6GHz spectrum, an event expected to take place in the first quarter of 2012. The auction will mark the arrival of 4G technology in the UK, and is expected to fuel an explosion of next-generation services and applications.

Ofcom has set strict maximum and minimum limits to the amount of spectrum which can be bought by any one operator, in an attempt to maintain competition in the market and allay fears that the auction could squeeze out smaller players.