Can unused TV spectrum offer an inexpensive solution to satisfy escalating wireless connectivity requirements of UK consumers and businesses? That’s the charge given to some of the UK’s largest technology and media companies in a joint effort known as the Cambridge TV White Spaces Consortium.
The Consortium will undertake technology trials to explore how mobile devices can tap into unused television channels — TV “white space” — to supplement wireless broadband and cellular networks. The trial is designed to validate that white space can be used without affecting traditional broadcast television in the UK, a concept that’s already been successfully explored in the US and other European countries.
TV white space networks can provide wireless connectivity and work in much the same way as Wi-Fi. However, because TV spectrum signals travel farther and are more effective at penetrating walls than Wi-Fi, they require fewer access points. TV white space also could help bring mobile broadband to rural areas that aren’t served well by existing connections.
The range and mobile bandwidth offered by TV white space can also more easily support a variety of connected devices that offer different services. That idea is often referred to as the “Internet of Things.”
Consortium members include the BBC, BSkyB, BT, Cambridge Consultants, Microsoft, Neul, Nokia, Samsung, Spectrum Bridge, and TTP. They will test technologies under various scenarios, including streaming high-quality video and audio content from the BBC and BSkyB over the TV white space spectrum to a range of mobile devices, including some from Nokia and Samsung. White space hotspots will include local pubs and other leisure venues, as well as commercial and residential premises.
Cambridge Consultants has already announced a successful trial of its white space network. The company recently sent the first tweet over white space (from @CambConsultants), having set up a white space network between its headquarters in central Cambridge and the village of Cottenham, 6km away. This trial intended to demonstrate white space’s suitability for cost-effective rural broadband provision, as well as the network’s ability to avoid interference with residents’ TV signals and professional radio microphones.
To address the interference issue, Cambridge Consultants developed a database engine that accurately pinpoints unused frequencies available in each locality. The database works alongside InCognito, the company’s novel “spectral sensing” cognitive-radio technology platform. Spectral sensing enables white space radios to search the spectrum for channels that have interference.
In another development, Cambridge-based startup Neul claims it’s crafted the first production white space radio system, delivering up to 16Mbps at 10km (see the figure). Called NeulNET, the technology includes a basestation unit and portable battery-powered terminals. It’s aimed at machine-to-machine (M2M) communications in the Internet of Things (an application in which cellular 2G and 3G technology is often too expensive and power-hungry), as well as rural broadband provision.
Neul is also developing an open royalty-free wireless standard called Weightless for M2M communications over white space. According to the company, up to 150MHz of high-quality white space spectrum is available free of charge. Neul announced last month that it has secured £8.0million ($12.8million) in funding.
The Consortium chose Cambridge for the trial because of its long history in developing novel wireless communication technologies. Moreover, it offers an environment for testing diverse uses of the TV white spaces network. The city is distinguished by a dense mixture of buildings, including the historic stone buildings of its colleges, which offer a unique opportunity to demonstrate the penetration of TV white spaces signals when compared with other higher-frequency networks such as Wi-Fi.
On top of that, although Cambridge itself has good broadband access, some neighbouring villages suffer poor broadband service. This further helps demonstrate the advantageous range of TV white spaces communications.