Advancements in wireless communications could soon revolutionise indoor positioning, according to researchers from the University of Glasgow, alongside collaborators from the UK and Australia. 

Their findings involve refining Reconfigurable Intelligent Surfaces (RIS), a technology with potential to precisely locate people and objects indoors.

Published in the journal Communications Engineering, the research outlines how RIS utilises programmable elements to manipulate electromagnetic waves, enhancing the performance of wireless communications. 

By strategically placing RIS sheets on walls and ceilings indoors, these surfaces intercept external wireless signals, intelligently reflecting and directing them to optimise performance.

One of the most promising aspects of RIS technology lies in its ability to address longstanding challenges with established positioning technologies like GPS, particularly in indoor environments where signals can be weakened or interfered with.

“While GPS works very well outdoors, helping us to use mapping apps to find our way efficiently on foot or in a vehicle, it works considerably less well in indoor environments,” said Professor Qammer Abbasi, who is leading the research.

“Positioning communication signals can be weakened by thick walls or interfered with by other electronic signals, reducing the accuracy of GPS.

“RIS has the potential to greatly improve active location-finding indoors. It can do that by being aware of the communications signals being sent and received from devices like mobile phones at any given time, which allows them to precisely locate the device and its user.

“That opens up a wide range of possible applications, including tapping into RIS’ ability to focus signals to improve call quality by directing signals straight to mobile phones’ antennae, no matter where their user moves indoors.

“Our research is an important step forward in fine-tuning RIS technology’s ability to perform indoor localisation tasks in future comms networks.”

Dr Syed Tariq Shah, first author of the paper who worked on the research at the University of Glasgow said: “This research shows that RIS can be used to shape and direct wireless signals in ways that have a lot of exciting future applications once RIS devices evolve and become more widely-adopted across communications networks.

“The system we’ve prototyped could help with to develop improved management of crowds of people carrying mobile phones at large public events, or enable warehouse managers to keep better track of stock tagged with wireless transmitters. It could be applied to any situation where active positioning of signals from wireless devices is required.” 

Professor Muhmmad Imran, leader of the University of Glasgow’s Communications, Sensing and Imaging Hub, is another author of the paper said: “This work will be a major milestone for solving complex localisation problems in indoor environments. This will be one of the added benefits of 6G communications networks in the years to come.”