The 5G network is in the process of being rolled out worldwide, with countries such as South Korea, Switzerland and the USA leading the way. In the USA, 5G technology has often been used as a complement to fibre technology in residential areas. For various reasons, fibre is not as widespread in the USA as it is in Sweden, for example. What has been used is a high-frequency system at 26 GHz and upwards, which works well in homes.
“A base station is set up in a residential area to provide a fast connection in the home. But when you start moving around, problems arise, which means that it does not work very well for mobile telephones”, says Fredrik Tufvesson, professor of Radio Systems at LTH.
He and his colleagues in the communications technology research team are currently examining how to improve control of the signals from the base stations, so that the signal can follow the users more effectively when they move around. The problem is that the high-frequency systems now being developed have a far more focused signal than the older, slower low-frequency systems. This means that there are high requirements on the technology to reflect and bounce the signal, i.e. that the signal is to be just as focused even when the user goes around a corner and that the beam is able to follow the user.
To assist them, the research team has unique equipment, which has been developed in cooperation with Ericsson and Sony.
“It enables us to follow what happens in dynamic scenarios and examine what is going on when things move around and when the signal moves in the air. There is no comparable equipment anywhere else and it is the first time this has been studied”, says Fredrik Tufvesson, who adds that they have developed everything themselves, right down to the circuit boards and customised antenna elements.
It is hoped that understanding how the high-frequency signals behave will enable the development of a much more effective and stable system compared with that of today. The equipment makes it possible to follow the rapid course of events and subsequently analyse the data.
“I would like to call it second-generation 5G. Stability is extremely important, for example when the technology is to be used for industrial purposes. What will be particularly noticeable for the user is the improved stability and the incredible speed – which is needed if you are going to be able to control things in real time”, says Fredrik Tufvesson.
To achieve this, a signal is required that can use several alternative paths from the base station to the user. The system currently under development uses a totally digital solution that will work more effectively compared with today’s system, which is partially based on analog technology.