Secrecy Energy Efficiency Maximization in RIS-Aided Networks: Active or Nearly-Passive RIS?

TL;DR

This paper compares active and nearly-passive RISs in wireless networks to maximize secrecy energy efficiency, analyzing trade-offs with different channel information and proposing algorithms for optimization.

Contribution

It introduces SEE maximization algorithms considering both RIS types and channel information, providing insights into their energy efficiency trade-offs.

Findings

Active RISs have worse SEE with higher static power consumption.

Algorithms optimize transmit power, reflection coefficients, and receive filters.

Numerical results show trade-offs between RIS types in energy efficiency.

Abstract

This work addresses the problem of secrecy energy efficiency (SEE) maximization in RIS-aided wireless networks. The use of active and nearly-passive RISs are compared and their trade-off in terms of SEE is analyzed. Considering both perfect and statistical channel state information, two SEE maximization algorithms are developed to optimize the transmit powers of the mobile users, the RIS reflection coefficients, and the base station receive filters. Numerical results quantify the trade-off between active and nearly-passive RISs in terms of SEE, with active RISs yielding worse SEE values as the static power consumed by each reflecting element increases.