Joint Power Allocation and Phase-Shift Design for Beyond-Diagonal Stacked Intelligent Metasurfaces-Aided ISAC Systems

2026-08-19

AI Summary

本文提出了一种超越对角堆叠智能超表面（BD-SIM）架构，通过可重构阻抗网络增强波域处理灵活性，并开发了统一的交替优化框架来解决多用户通信和感知性能平衡问题。

Abstract

Stacked intelligent metasurfaces (SIM) provide an efficient architecture for integrated sensing and communication (ISAC) with few radio-frequency (RF) chains. However, diagonal SIM provide only element-wise phase control, so balancing multiuser communication and sensing performance may require additional layers. In this letter, we propose a beyond-diagonal SIM (BD-SIM) architecture for ISAC, enabling controllable intra-layer coupling through reconfigurable impedance networks, thereby enhancing wave-domain processing flexibility. We develop a unified alternating optimization framework applicable to fully-connected, group-connected, and diagonal SIM architectures. Within this framework, we derive a closed-form power allocation rule and propose an effective variable separation algorithm for multi-layer phase-shift design. Simulation results show that the proposed BD-SIM achieve a better communication-sensing trade-off and require fewer layers to attain performance comparable to conventional SIM.

Problem

• Stacked Intelligent Metasurfaces
• Integrated Sensing and Communication
• Phase Control
• Multiuser Communication
• Sensing Performance

Innovation

• Beyond-Diagonal Stacked Intelligent Metasurfaces
• Reconfigurable Impedance Networks
• Unified Alternating Optimization Framework
• Closed-Form Power Allocation Rule
• Variable Separation Algorithm