Does white space need to be Weightless?

Next Friday, all the major companies in the UK white space business will be gathered in Cambridge to talk about which protocol should fill the airwaves where television isn't. Alongside the traditional options there's a new contender - Weightless - being proposed as a machine-to-machine standard that could evenly fulfil other white space roles.

The constant comparisons to Wi-Fi - encouraged

Despite the constant comparisons to Wi-Fi - encouraged by Google, Microsoft et al - and in spite of the fact that the FCC keeps calling it "Super Wi-Fi", white space is only similar to Wi-Fi in the manner that the M1 bears a striking resemblance to the Highway Code: in other words to say, on no account.

For that reason many devices will incorporate sensing research to avoid other users, such as the most-modern Wi-Fi routers will find the least cluttered channel in which to operate. However that's a lot easier if the majority of users have settled on a single communications standard, as the Wi-Fi band has done - yet in white space the options are all in all very open.

What straightway week's meeting is all about

Which is what straightway week's meeting is all about, with the world's first manufacturer of white space kit, Neul, proposing a Special Interest Group be created to endorse its "Weightless" standard for white space communications.

The standard was developed for machine-to-machine communications, and Neul has made noises about building a national network connecting up electricity meters, cars, and anything else which requires low-power connectivity, however the company reckons the standard can cope with high-speed internet access too.

That means a single Weightless hub can run connections to hundreds devices, across a network spanning 10km or so. Those devices could easily have a battery life measured in years, and be capable of responding with megabytes of data within 15 minutes.

A device which wants to connect to the network won't want to wait that long, and neither will one with something to report. In such circumstances the client can pick up a transmitted frame, which comes every second or two, and register an interest in sending some data upstream.

The network

Once on the network, a device has to wait for the hub to say when it can talk, even though it has the chance to request communication slots. The speed of transmission is dependent on the quality of the signal. Each frame is addressed in a really encoded header; all other devices can switch off their radios once they know the frame isn't addressed to them, and if the receiving device is nearby at the time the rest of the frame can be tightly encoded in the knowledge that little will be lost en route.

That means a Weightless hub can speak to hundreds of devices on the same network, with the speed of connection varying between devices. A receiver nearly the hub might in short get 10Mb/sec or better, nevertheless one operating on the same network, from the same hub, could be running at a few hundred Kb in the same timeframe.

The only contender vying to fill the white spaces

Weightless isn't the only contender vying to fill the white spaces. The strict out-of-band restrictions imposed by the FCC make white space unsuitable for LTE (Long Term Evolution, latest standard in the mobile network technology) nevertheless Xg Innovation is pushing into the space with a credible protocol, and there are other contenders waiting in the wings.

A global standard is a laudable aim, even if wireless internet providers decide to adopt something else for their higher-speed connections and Weightless ends up as a M2M standard. Bluetooth and Wi-Fi happily coexist in 2.4GHz, along with the occasional baby-listener and not forgetting the microwave ovens which originally rendered the band worthless, so even if Weighless doesn't become the standard for all white space communications, it is all in all a valuable development.

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