Optimal Deployment Strategy for Reconfigurable Intelligent Surface under LoSD via Joint Active and Passive...

Area of Science:

• Wireless communication networks
• Metamaterials and intelligent surfaces
• Optimization theory

Background:

• Reconfigurable intelligent surfaces (RIS) offer a revolutionary approach to enhance spectrum efficiency (SE) and energy efficiency (EE) in wireless systems.
• Traditional deployment strategies for RIS may not fully exploit their potential in optimizing wireless network performance.

Purpose of the Study:

• To investigate an optimal deployment strategy for RIS in a line-of-sight domain (LoSD) considering practical deployment scenarios.
• To minimize transmit power by jointly optimizing RIS beamforming and phase shifts while satisfying quality-of-service (QoS) constraints.

Main Methods:

• The study formulates an optimization problem to minimize transmit power under QoS constraints (SNR).
• An efficient alternating optimization (AO) algorithm is proposed to solve the non-convex optimization problem.
• The proposed LoSD deployment is compared against conventional endpoint deployment strategies.

Main Results:

• The proposed LoSD deployment strategy significantly reduces transmit power compared to conventional methods.
• The optimization effectively utilizes line-of-sight (LoS) links for single RIS relaying.
• The impact of the number of reflecting elements on system energy efficiency (EE) is analyzed.

Conclusions:

• The optimal LoSD deployment strategy for RIS is effective in reducing transmit power and improving energy efficiency.
• The proposed alternating optimization algorithm provides an efficient solution for complex RIS deployment problems.
• Further analysis reveals the relationship between the number of RIS elements and overall system EE.