Paving the Way for Economically Accepted and Technically Pronounced Smart Radio Environment

Recently,Reconfigurable Intelligent Surfaces(RISs)have been introduced to provide the necessary flexibility for the design of the Smart Radio Environment(SRE),which can be optimally shaped to facilitate efficient signal transmissions.In line with the concept of smart cities,SRE needs to be carefully designed with respect to the city infrastructure and utilization of resources.In this paper,we provide our vision on RIS integration into future Smart Cities by highlighting the potential technical,environmental,and economic motivations of RIS deployment in harmony with various ecosystems at a city level such as buildings facades.To this end,we are pointing out some scenarios for mitigating the conflict between RIS realization and the existing building facade’s ecosystems such as advertising display and solar cells on building walls.Also,in this fashion,the proposed vision supports a win-win relationship between all stakeholders of different ecosystems.This study presents guidelines for not only enabling seamless economically accepted RIS widespread utilization but,also more technically sounding SRE by supporting enhanced RIS features and more advanced applications that cannot be attained by traditional passive RIS.Moreover,based on the current research directions,we offer promising insights for cost-effective mass pro-duction through motivating two scenarios of“all on silicon”and“all as metasurface”fabrication technology.With this study,we aim to encourage the metasurface researchers,that for a broad deployment of the technical solution,economic,environmental,and other commercial requirements should be planned together,early on in the design phase.

面向智慧农业的无芯片射频跨域感知研究进展

随着传统农业逐渐向智慧农业转型,室温条件下具有低成本、长寿命、低功耗、小型化的检测手段对于农业环境及动植物本体指标检测至关重要,尤其对于无法进行电路有线连接的农业场景。随着器件传感和无线通信的整合,无芯片射频识别(chipless radio frequency identification,CRFID)因为具有轻量、价格合理、普适性等优势被广泛应用,CRFID标签具有理论上的“无限”寿命,代替了集成电路,成为标识传感信息融合的重要媒介,适用于农业环境、动植物生长监测、物流运输、食品品质检测等。该研究首先介绍了CRFID系统构成,以及其基本原理,指出天线是CRFID实现跨域感知的关键要素之一,随着农业场景中气体、环境温湿度、pH值等变化,天线负载敏感材料的电导率、磁导率、介电常数变化,引起CRFID标签的反向散射信号变化;其次,基于时频域标签,介绍了CRFID用于湿度、温度、气体(二氧化碳、氨气、乙烯)、pH和食品(猪肉、牛肉、鱼肉、果蔬、牛奶)检测的国内外最新研究进展,对比了相关传感器的关键性能指标;最后,针对CRFID技术的成功案例,指出了该类型传感器面临的主要研究挑战、未来研究方向和潜在解决方案,指出了未来智慧农业检测场景的低功耗、小型化、抗干扰发展趋势。CRFID技术的成功应用将有利于提升农业场景传感检测的智慧化程度,有助于人类及动植物生产活动健康评估。

Simultaneously transmitting and reflecting(STAR)RISs for 6G:fundamentals,recent advances,and future directions

Simultaneously transmitting and reflecting reconfigurable intelligent surfaces(STAR-RISs)have been attracting significant attention in both academia and industry for their advantages of achieving 360°coverage and enhanced degrees-of-freedom.This article first identifies the fundamentals of STAR-RIS,by discussing the hardware models,channel models,and signal models.Then,three representative categorizing approaches for STAR-RISs are introduced from the phase-shift,directional,and energy consumption perspectives.Furthermore,the beamforming design of STAR-RISs is investigated for both independent and coupled phase-shift cases.As a recent advance,a general optimization framework,which has high compatibility and provable optimality regardless of the application scenarios,is proposed.As a further advance,several promising applications are discussed to demonstrate the potential benefits of applying STAR-RISs in sixth-generation wireless communication.Lastly,a few future directions and research opportunities are highlighted.