Reconfigurable, Intelligent, and Sustainable Wireless Environments for 6G Smart Connectivity

Abstract

Various visions on the forthcoming sixth Generation (6G) networks point towards flexible connect-and-compute technologies to support future innovative services and the corresponding use cases. 6G should be capable to accommodate ever-evolving and heterogeneous applications, future regulations, and diverse user-, service-, and location-based requirements.A key element towards building smart and energy sustainable wireless systems beyond 5G is the Reconfigurable Intelligent Surface (RIS), which offers programmable control and shaping of the wireless propagation environment.Capitalizing on this technology potential, in this article we introduce two new concepts: i) wireless environment as a service, which leverages a novel RIS-empowered networking paradigm to trade off diverse, and usually conflicting, connectivity objectives; and ii) performance-boosted areas enabled by RISbased connectivity, representing competing service provisioning areas that are highly spatially and temporally focused. We discuss the key technological enablers and research challenges with the proposed networking paradigm, and highlight the potential profound role of RISs in the recent Open Radio Access Network (O-RAN) architecture.

Security Requirements and Challenges of 6G Technologies and Applications

“…RISE 6G seeks to improve 6G capabilities for a sustainable, flexible, and intelligent wireless environment by exploiting RIS. The project will face four challenges related to RIS [62]. First, the actual RIS-assisted signal propagation will be modeled.…”

Tensor-based Channel Tracking for RIS-Empowered Multi-User MIMO Wireless Systems

“…1, where M singleantenna UEs communicate with one BS equipped with N r antennas, with the assistance of a passive RIS. All nodes are considered synchronized and the RIS configuration control is handled by the BS [1]. The RIS contains K unit elements, each with a tunable impedance capable of configuring its reflection coefficient [2].…”

“…The technology of Reconfigurable Intelligent Surfaces (RISs) is currently considered as one of the most promising technologies for future wireless communications, due to its inherent capability to offer programmable signal propagation conditions [1]. RISs are artificial surfaces containing massive numbers of almost zero power consumption elements that have tunable impedance properties, whose joint configuration can dynamically adjust the phase of the impinging signals and thus shape the channel incurred [2].…”

“…RISs are artificial surfaces containing massive numbers of almost zero power consumption elements that have tunable impedance properties, whose joint configuration can dynamically adjust the phase of the impinging signals and thus shape the channel incurred [2]. The tunable signal reflections can realize more directive beams towards the desired receiver (and cancel the interference to undesired ones), resulting in improved Signal-to-Interference-plus-Noise Ratio (SINR) [1], or enable spatio-temporal signal focusing in rich scattering environments [2].…”

RIS-Aided Wireless Communications: Extra Degrees of Freedom via Rotation and Location Optimization

“…With the inherent ability in tailoring the radio propagation environment, reconfigurable intelligent surfaces (RIS) technology has overwhelmingly emerged as one of the most promising approaches for future wireless communications [1]- [3]. The RIS is a two-dimensional surface composed of a large number of passive units arranged mostly in sub-wavelength inter-element spacing with the property of manipulating the electromagnetic waves, such as scattering, reflection, and absorption [4]- [6].…”