Ubiquitous 5G wireless data coverage with speeds of up to 100 gigabits per second could be made possible by a European project developing technologies to exploit the millimetre wave spectrum.
The amount of data used by wireless devices such as tablets and smart phones already exceeds that of desktop computers, and is set to increase further as emerging technologies such as 4k video streaming, cloud gaming and augmented reality take off.
Increasing the amount of wireless data available will mean covering urban areas with dense grids of micro, nano and pico cells, each serving a small number of users.
But transmitting the data to these cells before it can be shared amongst users will be no easy task. Existing base stations are fed data through fibres, according to Professor Claudio Paoloni at Lancaster University. “But if the number of cells were to increase substantially, the fibre would be very difficult and expensive to install,” he said.
One option is to use millimetre wave frequencies, in the 30-300GHz range, to transmit data wirelessly.
However, millimetre wave signals are susceptible to attenuation, or weakening, by rain and fog, said Paoloni, who is leading a €2.9million European Union Horizon 2020 project aiming to develop technologies to exploit this part of the spectrum.
The project, known as ULTRAWAVE, will develop a system with sufficient transmission power to overcome this attenuation, based on a device called a millimetre wave travelling wave tube.
Travelling wave tubes are elongated vacuum tubes in which a high energy electron beam is sent along a tiny cylinder, through which the millimetre wave signal is also transmitted. The signal creates an electric field that alters the velocity of the electron beam, causing some electrons to speed up and some to slow down, and creating a bunching effect.
“At a certain point this dense mass of electrons is delayed, meaning it loses kinetic energy, and this energy is transferred to the signal,” said Paoloni. “As a result, the signal increases in power to a level that is impossible with any other technique,” he said.
The ULTRAWAVE consortium also includes Fibernova and the Universitat Politecnica de Valencia in Spain, the Ferdinand Braun Institute, Goethe University of Frankfurt and HFSE in Germany, OMMIC in France and the University of Rome Tor Vergata in Italy.