Active RIS Versus Passive RIS: Which is Superior With the Same Power Budget?

Article Telecommunications

Active Reconfigurable Intelligent Surface: Fully-Connected or Sub-Connected?

Kunzan Liu et al.

Summary: To overcome the power consumption issue of the existing fully-connected architecture of active RIS, a sub-connected architecture is proposed. It reduces power consumption by sharing a power amplifier among multiple elements while sacrificing degrees of freedom for beamforming design. Analysis shows that the performance loss introduced by the sub-connected architecture is minimal, achieving higher energy efficiency.

IEEE COMMUNICATIONS LETTERS (2022)

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Article Telecommunications

Active Reconfigurable Intelligent Surfaces-Aided Wireless Communication System

Majid H. Khoshafa et al.

Summary: The use of active elements in RIS significantly reduces the size of the structure to achieve desired performance levels. A practical design for active RIS is proposed to overcome the double-fading problem in wireless communications systems.

IEEE COMMUNICATIONS LETTERS (2021)

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Article Engineering, Electrical & Electronic

Physics-Based Modeling and Scalable Optimization of Large Intelligent Reflecting Surfaces

Marzieh Najafi et al.

Summary: To optimize large intelligent reflecting surfaces (IRSs), a physics-based model and a scalable optimization framework are proposed in this article. By partitioning IRS unit cells into subsets and optimizing each subset in two stages, offline design and online optimization, efficiency can be improved for optimizing large IRSs.

IEEE TRANSACTIONS ON COMMUNICATIONS (2021)

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Article Computer Science, Information Systems

Wireless Communication Aided by Intelligent Reflecting Surface: Active or Passive?

Changsheng You et al.

Summary: The letter discusses the optimization of active and passive IRS placement in an intelligent reflecting surface (IRS)-aided wireless communication system. It shows that, with the same number of reflecting elements, the passive IRS generally outperforms the active IRS.

IEEE WIRELESS COMMUNICATIONS LETTERS (2021)

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Article Engineering, Electrical & Electronic

Active Reconfigurable Intelligent Surface-Aided Wireless Communications

Ruizhe Long et al.

Summary: The paper introduces a new type of RIS, called active RIS, which enhances the incoming signal by incorporating active loads to each reflecting element, in contrast to conventional passive RIS systems. However, this amplification may unintentionally boost RIS-correlated noise, requiring optimization of the reflecting coefficient matrix at the RIS and receive beamforming at the receiver to strike a balance between maximizing received signal power and minimizing RIS-related noise.

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS (2021)

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Article Computer Science, Information Systems