Hybrid Active-Passive RIS Transmitter for Energy-Efficient Multi-User Communications

Core Concepts

The author proposes a novel hybrid active-passive RIS transmitter design to maximize energy efficiency in multi-user communications by optimizing RIS element scheduling, beamforming coefficients, and power allocation. The approach involves transforming complex optimization problems into tractable forms and utilizing alternating optimization methods.

Abstract

The content explores a novel hybrid active-passive RIS transmitter design for energy-efficient multi-user communications. It discusses the challenges in wireless networks, the benefits of reconfigurable intelligent surfaces (RISs), and prior works in the field. The proposed algorithms aim to optimize system performance while minimizing complexity and energy consumption.

Stats

"Numerical results validate that: 1) The proposed hybrid RIS scheme yields higher EE than the baseline multi-antenna schemes employing fully active/passive RIS or conventional radio frequency chains; 2) Both proposed algorithms are effective in improving the system performance, especially the latter can achieve precise design of RIS elements with low complexity; and 3) For a fixed-size hybrid RIS, maximum EE can be reaped by setting only a minority of elements to operate in the active mode."

Quotes

"The proposed hybrid RIS scheme yields higher EE than the baseline multi-antenna schemes."
"Both proposed algorithms are effective in improving system performance."
"For a fixed-size hybrid RIS, maximum EE can be reaped by setting only a minority of elements to operate in the active mode."

Key Insights Distilled From

Hybrid Active-Passive RIS Transmitter Enabled Energy-Efficient Multi-User Communications

by Ao Huang,Xid... at arxiv.org 03-05-2024

https://arxiv.org/pdf/2403.01956.pdf

Deeper Inquiries

How does the use of hybrid active-passive RIS impact overall network coverage

The use of hybrid active-passive RIS can significantly impact overall network coverage by enhancing the flexibility and adaptability of the transmitter system. By allowing each element to switch between active and passive modes, the RIS can dynamically adjust its configuration based on varying propagation environments. This capability enables better signal alignment, improved beamforming gains, and enhanced signal coverage for users within the network. The ability to optimize both amplitude and phase-shift coefficients at individual elements results in more precise control over signal transmission, leading to optimized coverage patterns tailored to specific user requirements.

What potential drawbacks or limitations might arise from implementing this novel transmitter design

While implementing a novel hybrid active-passive RIS design offers numerous benefits, there are potential drawbacks or limitations that may arise. One limitation could be related to increased complexity in managing the switching mechanisms between active and passive modes for each element on the RIS. This complexity could lead to higher hardware costs, increased power consumption due to additional control circuits, and potentially more challenging maintenance procedures.
Another drawback could be related to interference management within the network. With a more dynamic transmitter architecture like hybrid active-passive RIS, there might be challenges in mitigating interference among multiple users or neighboring cells effectively. Ensuring seamless coordination between different elements operating in various modes is crucial for maintaining optimal network performance without causing detrimental interference issues.
Additionally, as with any new technology deployment, there may be initial integration challenges or compatibility issues with existing infrastructure or devices in the network when transitioning to a hybrid active-passive RIS setup.

How could advancements in transceiver architectures impact future wireless communication technologies beyond 6G

Advancements in transceiver architectures have the potential to revolutionize future wireless communication technologies beyond 6G by introducing innovative capabilities that enhance efficiency, performance, and scalability. Some key impacts include:

Improved Energy Efficiency: Advanced transceiver architectures can enable energy-efficient designs by optimizing power consumption at both transmit antennas (such as feed antenna) and intelligent surfaces (RIS). This optimization leads to reduced energy usage while maintaining high data rates and reliable connectivity.

Enhanced Spectral Efficiency: Future transceiver advancements can support higher spectral efficiency through advanced modulation techniques, multi-user MIMO systems utilizing intelligent surfaces for spatial multiplexing, and adaptive beamforming strategies that maximize spectral utilization.

Low-Latency Communication: Transceiver innovations can reduce latency levels significantly by enabling faster data processing speeds at both ends of communication links. This improvement is crucial for real-time applications like autonomous vehicles or augmented reality/virtual reality experiences.

Increased Network Capacity: By leveraging sophisticated transceiver architectures incorporating intelligent surfaces like hybrid active-passive RISs into networks' infrastructure design allows for scaling up capacity efficiently without requiring extensive hardware upgrades or costly installations.

These advancements pave the way for ultra-reliable low-latency communications (URLLC), massive machine-type communications (mMTC), holographic telepresence applications using volumetric displays enabled by advanced beamforming techniques from intelligent surfaces.