Deployment of Reconfigurable Intelligent Surfaces for Beyond 5G Mobile Networks

The world of wireless communications is growing rapidly, with the number of devices connected to networks growing at an exponential rate.

Future sixth-generation (6G) networks are expected to provide smooth experiences for use in applications such as Virtual Reality and Artificial Intelligence.

To meet these requirements, compared to 5G, 6G is expected to provide peak data rates of 1,000 Gbps (50 times that of 5G's peak data rate), as well as vastly improve in other areas such as latency, spectral efficiency and energy efficiency [1]. Particularly, with the increase in required data rates, new challenges are met when coming from current 5G systems.

Where 5G networks typically use frequencies in the range of sub-1 GHz to 6 GHz, 6G will utilise more of the mmWave range of 30 GHz to 300 GHz to allow for the vastly higher data rates required [2].

These new frequencies pose challenges in populous areas such as cities where large infrastructure commonly blocks line of sight between large antennas (e.g. Base Stations (BSs) or Remote Units (RUs)) and the User Equipment (UE) - the creation of dead zones.

Lower frequencies are capable of penetrating and reflecting off surfaces whilst maintaining enough signal strength to maintain a connection with the end user, however, higher frequencies suffer more from propagation loss and cannot penetrate, nor reflect, as effectively. In these cases of high-frequency communications, a line of sight is required [3].

A proposed solution to this problem is the new concept of Reconfigurable Intelligent Surfaces (RIS).

A RIS consists of an inexpensive array of configurable elements that can be programmed in real-time to alter the properties of the surface and change how incident radio waves are reflected off them.

These surfaces can assist in the transmission of information over a wireless network and can mitigate the line-of-sight difficulties faced in high-frequency communications [4].