Reconfigurable Intelligent Surfaces (RIS)
A Reconfigurable Intelligent Surface (RIS) is a programmable surface structure that can be used to control the reflection of electromagnetic (EM) waves by changing the electric and magnetic properties of the surface.
These surfaces can be strategically placed in the radio channel between a transmitter and receiver to control the way the signal reflects off a surface in its propagation path.
Reconfigurable Intelligent Surfaces can be used to steer signals to the receiver resulting in better reception or link quality.
In conventional wireless systems, the radio channel is seen as an uncontrollable entity that usually distorts transmitted signals.
The transmitted signals usually interact with a wide range of surfaces in their propagation path and reflect off them in random directions resulting in random constructive and destructive interference.
RIS provides a way to control the surfaces found in radio channels by directing them in a specific direction to improve the reliability and energy efficiency of wireless systems.
This can increase the range of a wireless system and direct signals to hard-to-reach places.
There are two main approaches can be used to implement an RIS to control the characteristics of signals (e.g., reflection, refraction, absorption, focusing and polarization), namely, conventional antenna arrays and metasurfaces.
Working of RIS
Reconfigurable intelligent surfaces would first absorb a signal that is directed towards it, which then would be processed by a microcontroller and then reproduced again and transmitted in a specific direction using antenna arrays and metasurfaces.
Thus they can be used to increase availability of cellular or GNSS signals in areas where they are not naturally accessible.
Deflection of signals can also be used to shorten the path taken by the signals to reach the receiver so as to maximize efficiency of the network system.
As frequency bands used for 5G and 6G go into the mmWave and THz region, the need for Reconfigurable intelligent surfaces (RIS) will increase.
This is because signals in these frequency bands have can not propagate very far or penetrate walls like the sub-6 GHz signal used by most cellular technologies today (3G/4G/ sub-6GHz 5G).
Such high-frequency signals would need to be directed artificially using RISs to reach inside buildings and other structures.
The signals may also need to be modulated according to a specific algorithm mid-propagation which can also be done by using RISs.
Recently in news
The International Institute of Information Technology-Bangalore (IIIT-B) is involved in the development of Reconfigurable Intelligent Surfaces (RIS), which will have immense potential to extend the communication range and enhance the quality of base stations, in 5G-Advanced and also in the forthcoming 6G networks.
According to the Institute, RIS technology also enables the creation of Smart Radio Environments (SREs), which can be tailored to specific use cases such as the Industrial Internet of Things.
Furthermore, by combining RIS technology with other futuristic advancements, IIIT-Bangalore envisions significant enhancements in data rates, coverage, and energy efficiency.
In addition, IIIT-Bangalore is also actively engaged in the development and design of a novel prototype for RIS-aided communication.
Collaborating with multiple institutes to create a practical RIS-aided communication system. This involves working on both algorithmic and hardware aspects, including the Open Radio Access Network 5G base station.
5G use-case testbed lab:
IIIT-B is also leading the efforts to establish a 5G use-case testbed lab, focusing on Urban Management and Health.
This lab will serve as a learning environment for approximately 150 students and start-ups annually and will be integrated into advanced graduate-level courses covering various topics like Mobile Computing, Wireless Communication, and Network Function Virtualization.
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