Original URL: http://www.theregister.co.uk/2008/07/07/eu_rsgp_cus/
EU forms an opinion on CUS'ing
But wants to see more polite radios
Common Use of Spectrum such as the 2.4GHz band that makes Wi-Fi possible should become more prevalent to drive innovation and efficient spectrum use, the EU Spectrum body says. But legislation may be needed to ensure radio systems play nicely together.
The Radio Spectrum Policy Group (RSGP) was asked to look at Common Use of Spectrum (CUS) in May last year, and has now published a draft opinion for comment. The group recommends that more spectrum be allocated to CUS, but stopped just short of saying all spectrum should be available for common use.
Radio frequencies across Europe are either allocated or sold, and have historically been tied to a specific technology and application. The UK is leading the world in removing restrictions on what spectrum can be used for, but UK regulator Ofcom is firmly of the opinion that he who pays most for spectrum will use it most efficiently, so giving away chunks of bandwidth for free doesn't really fit the model.
Between the prime real estate of licensed frequencies are gaps where anyone is pretty much allowed to do anything. For example 868MHz is often used for wireless light switches and plugs, while 434MHz is a favourite for keyfobs. In these spaces radios are expected to play nicely with each other, adopting "politeness protocols", and implementing "politeness rules" set by the local regulator. The former could involve scanning for unused frequencies or hopping around the place like Bluetooth, while the latter might include restrictions on broadcast power or accuracy of tuning.
The nice thing about these gaps is that manufacturers can bring products to market really quickly. The bad thing is that there's no guarantee of service: the bands can become overcrowded and are almost impossible to clear if the regulator later decides to sell them off.
CUS isn't restricted to unused spectrum, the RSGP considered the potential of allowing anyone to use any frequency, as long as they avoid interfering with the licensed user. This is the way that Ultra Wide Band is permitted, between 4.2 and 4.8GHz, across Europe - UWB is very low power, and so shouldn't interfere with other uses.
The opinion formed by the RSGP (pdf ) is that CUS is a good thing, but within allocated bands, and they'd like to see more of those across Europe. The group would also like to see some of the less-populous areas in the EU used as wireless test-beds, as happens in Ireland, so new licensing models can be tried out.
In the meantime some more snippets across the dial could be allocated to CUS, and proper-sized chunks at the top of the dial where there's not a lot happening right now.
In this respect the RSGP is in agreement with UK-regulator Ofcom, which also sees such little value in the frequencies above 40GHz that it's prepared to give some of it away. Such high frequencies are hard to use, at least with today's technology, and the RSGP suggests that some EU money be spent finding ways to use it in a more productive fashion.
The opinion is still a draft, and comments  are welcomed until the fifth of September. ®