The rate and energy efficiency of wireless channels can be improved by deploying software-controlled metasurfaces to reflect signals from the source to the destination, especially when the direct path is weak. While previous works mainly optimized the reflections, this letter compares the new technology with classic decode-and-forward (DF) relaying. The main observation is that very high rates and/or large metasurfaces are needed to outperform DF relaying, both in terms of minimizing the total transmit power and maximizing the energy efficiency, which also includes the dissipation in the transceiver hardware.

翻译：通过部署软件控制的超表面将信号从源端反射至目的端，能够提升无线信道的速率与能量效率，尤其在直射路径较弱时效果显著。尽管已有研究主要聚焦于反射优化，本文旨在将这一新技术与经典解码转发（DF）中继方案进行对比。核心发现表明：无论是在最小化总发射功率方面，还是在最大化能量效率（包含收发器硬件功耗）方面，均需要极高的传输速率和/或大规模超表面才能超越DF中继的性能。