11

Weightless-W promotes itself as a "low power wide area (LPWAN) star network architecture operating in TV white space spectrum", and seems to suggest that this method of transmission has several favourable characteristics:

At the terminal level data rates from 1kbit/s to 10Mbit/s are possible depending on link budget with data packet sizes from 10 bytes and no upper limit with an extremely low overhead - 50 byte packets have less than 20% overhead. [...]

An extremely wide range of modulation schemes and spreading factors provides flexibility in network design enabling 5km coverage to indoor terminals.

On the Which Weightless Standard page, it also states:

If TV white space spectrum is available in the location where the network will be deployed and an extensive feature set is required, use Weightless-W

The problem comes with determining if white space spectrum is available; how can I check where white space is open for IoT use with Weightless-W? Is there a tool I can use to determine this or a map? Also, would it be necessary to consider whether other IoT networks occupy some of the white space frequencies and the possibility that they could interfere?

If it is useful in your answer, you can specifically focus on determining TV white spaces in the UK, although a more general solution would be interesting to read too.

6

Wikipedia's article on Weightless states that the base station will determine an appropriate frequency to use by querying a database:

In networks using Weightless-W technology a base station queries a database which identifies the channels that are being used for terrestrial television broadcast in its local area. The channels not in use – the so-called white space – can be used by the base station to communicate with terminals using the Weightless-W protocol.

To mitigate interference from other IoT networks, Weightless-W can perform frequency hopping:

Operation in unlicensed spectrum requires good interference tolerance. Weightless employs a frequency hopping regime at a frame rate of 2s to avoid interference on congested networks and to limit the impact of interference to a single hop rather than degrading the entire transmission.

In the UK, Ofcom (the communications regulator) have published guidance on how to access approved TV white space databases for use with IoT devices, though this will be different in other countries.

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