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Reader Forum: U.S. sees reason on unlicensed spectrum

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While the United States has long been in the lead in enabling white space access to TV bands there has been substantial longer-term uncertainty over just how much white space there might be in the future with some concerns that the amount might fall so low as to render access unviable.

In the short term white space access in the United States is unnecessarily constrained by simplistic database rules that, for example, do not take account of terrain when calculating TV coverage and have no flexibility in the power levels that white space devices can use. Rules proposed by Ofcom enable much greater white space access and there is some hope that the United States will adopt similar rules in due course.

The longer term access to white space in the United States has been blighted by two concerns. Firstly that much of the TV band would be vacated by broadcasters and sold, leaving little behind and secondly that legislation would effectively prohibit unlicensed access in an attempt to squeeze as much revenue as possible from the sale and usage of the frequencies. Let’s take each of these in turn.

The move from analogue to digital broadcasting brings opportunities to consolidate multiple transmissions onto multiplexes. This has happened in much of the world but not in the United States due to the historical structure of its broadcast industry. If U.S. broadcasters were to consolidate then there could be a significant “dividend” – perhaps as much as 100 megahertz. However, the politics, engineering issues and spectrum regulations are horrifically complex. The Federal Communications Commission plans to use an “incentive auction” where broadcasters offer up spectrum which can be bought by entities such as cellular operators while hoping the market results in a sensible outcome. It might work, but has never been tried before, is very uncertain and is liable to be delayed for myriad reasons. Were it to happen, it would take spectrum out of the “TV white space pot,” but the resulting band is likely to be structured as an FDD pair with a central guard band which could be available for white space access. Indeed, the central guard band might provide better access than current TV white space because the rules for access and nationwide availability will be favourable. So this is one to keep an eye on over the coming years but not a cause for concern.

More concerning was the idea that all spectrum, even unlicensed spectrum, should be auctioned. This was an idea put forward to maximize the revenue raised from spectrum in an effort to help reduce the U.S. budget deficit. But auctioning unlicensed spectrum is near impossible – there is just no practical way to do it. Despite this there was legislation proposed to make the provision of unlicensed spectrum illegal. If passed, it was far from clear what impact it might have but it would have at least caused delay to the planned unlicensed use of TV white space. Happily, it has just been announced that the legislation wasn’t passed – the “payroll tax extension bill” approved in late February confirms that the FCC can “create” white space spectrum.

This process, and the recent World Radiocommunication Conference allocation of the 700 MHz band in Europe for cellular does show that the TV bands are not fixed for all time and there will likely be occasional proposals around the world for alternative uses. Equally, change can bring new opportunities, sometimes better. The best strategy is to start using the white space, demonstrate the great value it can provide and then influence politicians and regulators through evidence rather than ideology.

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