智能超表面辅助低轨卫星通信技术综述

卫星通信能够提供超视距、大容量的通信服务,但在城市区域、峡谷森林等视线受遮蔽严重的区域,会出现视距衰落严重、多径效应显著等问题,影响通信质量。近年来出现的智能超表面(RIS)可以通过动态控制反射单元的电磁性质,构建可控电磁环境,为改善低轨(LEO)卫星通信质量提供新的思路。本文基于RIS基本原理与优势,对RIS用于LEO卫星通信中信道建模、信道估计、波束成形等关键技术进行探讨,最后分析了目前RIS在实际应用中面临的主要挑战,以期为LEO卫星场景下的RIS研究提供参考。     

智能超表面性能仿真与测试

作为6 G的潜在关键技术之一,智能超表面(Reconfigurable Intelligent Surface,RIS)通过改变电磁波的电磁特性,可以智能地重构无线传播环境.对RIS辅助通信系统在不同场景和系统参数配置条件下的性能进行了数值仿真、系统级仿真和外场测试.仿真和测试结果表明,RIS不但可以扩大用户覆盖范围,...     

面向新一代移动通信的智能天线技术

第三代移动通信系统,最重要的技术特征将是智能移动通信技术,即系统的各功能模块将由智能化处理单元来实现,作为智能化处理单元重要组成部分的智能天线,其在新一代移动通信系统中的开发和应用研究已成为当今移动通信界的热点。本文就其技术思想、研究成果及现有水平进行了讨论,并就其进一步的发展进行了简要论述。     

面向6G的信息超材料和智能超表面通信与感知技术

目前,信息超材料和智能超表面(Reconfigurable Intelligent Surface, RIS)已经在全球范围内受到了产业界与学术界的广泛关注,在5G和未来6G网络中具有重要机遇和应用前景。针对信息超材料和智能超表面在6G时代通信和感知的需求,分析与阐述了基于信息超材料和RIS的通信与感知理论、基本算法和系统设计,并对信息超材料和RIS的进一步发展进行了展望。     

智能超表面技术5G化演进探讨

随着移动通信网络发展演进,5G网络进入规模化商用的下半场5G-Advanced时代,6G业务需求和潜在技术也逐渐成为研究热点.在梳理5G/5G-Ad-vanced网络深度覆盖、扩容提速等网络需求和6G技术演进趋势的基础上,分析6G技术在5G/5G-Advanced网络阶段先试先用的必要性和可能性,提出6G技术5G化演进...     

智能超表面在波束及信息调控中的应用

现代移动通信中无线信道的随机性、不确定性和不可控性是影响通信质量的关键因素,往往会导致接收端信号质量降低,从而限制了信息传输的速率与范围。目前正兴起的6G技术研究中,智能超表面是被积极讨论的研究方向之一,其是由亚波长结构组成的超薄人工表面,具有现场可编程能力和时空信息调制能力,可精准、高效地操控电磁波,可被用于重塑无线传播环境。通过对智能超表面的概念、基于时空调制的波束调控方法、基于智能超表面的无线中继以及通信系统 4 个方面的综述和分析,展示了智能超表面在辅助移动通信中具有的应用潜力,为6G的发展提供了新的思路。     

面向6G的可重构智能表面部署与应用思考

可重构智能表面是6G的潜在关键技术之一,它通过对无线信号的可控反射,可以有效提升期望区域的覆盖性能.得益于其低成本、轻体量等特性,可重构智能表面在6G网络部署中具备很大的潜力.基于可重构智能表面的技术原理以及潜在应用场景,对其在6G中的部署及应用进行了分析,着重聚焦全透明、半透明、非透明智能表面的特性及其在应用部署中的...     

无线网络中智能超表面部署研究

智能超表面(Reconfigurable Intelligent Surface,RIS)作为面向未来的改变传播环境的技术,在无线通信系统中起着重要的作用,可通过改变无线信道环境,来改变信号的传播特性,从而能够按需提供无线网络的覆盖和容量.相比传统无线通信的被动适应无线信道,转化为未来无线通信的自适应可重构无线信道.在...     

智能超表面系统的通信感知一体化：现状、设计与展望

通信感知一体化（integrated sensing and communication,ISAC）是6G的主流趋势,将ISAC引入智能超表面（reconfigurable intelligent surface,RIS）系统,具有扩展系统覆盖范围、提升通信和感知性能、降低系统成本和功耗三大优势。在概述和分析RIS系统ISAC研究现状的基础上,提出了两种非正交ISAC方法,支持盲区用户在非正交时频资源上的通信和感知,最后探讨了RIS系统ISAC的技术挑战和未来发展。     

面向新一代移动通信的智能移动通信技术

第三代系统移动通信,其最重要的技术特征将是智能移动通信技术,即系统的各功能模块将由智能化处理单元来实现.本文在论述了智能移动通信技术在新一代移动通信系统中的地位和作用后,就智能天线、智能传输、智能接收、和智能化通信协议等方面的技术思想、研究成果和发展水平进行了综合评述.最后,讨论了智能移动通信技术将出现的进一步发展.     

Short packet communication in underlay cognitive network assisted by an intelligent reflecting surface

We propose short packet communication in an underlay cognitive radio network assisted by an intelligent reflecting surface (IRS) composed of multiple reconfigurable reflectors. This scheme, called the IRS protocol, operates in only one time slot (TS) using the IRS. The IRS adjusts its phases to give zero received cumulative phase at the secondary destination, thereby enhancing the end-to-end signal-to-noise ratio. The transmitting power of the secondary source is optimized to simultaneously satisfy the multi-interference constraints, hardware limitations, and performance improvement. Simulation and analysis results of the average block error rates (BLERs) show that the performance can be enhanced by installing more reconfigurable reflectors, increasing the blocklength, lowering the number of required primary receivers, or sending fewer information bits. Moreover, the proposed IRS protocol always outperforms underlay relaying protocols using two TSs for data transmission, and achieves the best average BLER at identical transmission distances between the secondary source and secondary destination. The theoretical analyses are confirmed by Monte Carlo simulations.     

可重构全息超表面辅助卫星通信关键技术

超密集低地球轨道卫星通信网络能弥补传统地面网络频谱资源稀缺、覆盖范围有限的不足,有潜力提供全球大规模接入的高速率服务。由于卫星的高速移动性,卫星通信对天线性能,如波束控制能力和天线增益等,也提出了更为严苛的要求。因此,对一种新型的超材料天线——可重构全息超表面（reconfigurable holographic surface,RHS）辅助卫星通信展开了研究。RHS采用全息原理对超材料单元进行电控,从而实现波束成形。基于 RHS 的硬件结构和全息工作原理,提出了一种 RHS 辅助多卫星通信方案,该方案同时考虑卫星跟踪和数据传输。同时,设计了全息波束成形优化算法以最大化和速率。仿真结果验证了所提方案的有效性并表明了相较于传统相控阵天线,RHS提供了一种成本效益更高的卫星通信支持方式。     

Channel estimation for reconfigurable intelligent surface-assisted mmWave using multidimensional Runge Kutta orthogonal matching pursuit algorithm in MIMO systems

In the context of Reconfigurable Intelligent Surface (RIS) assisted millimeter wave communications within the Multiple Input Multiple Output (MIMO) system, Channel Estimation (CE) poses a significant challenge due to signal sparsity and blockages between transmitters and receivers. Consequently, communication faces difficulties without a direct line-of-sight path, leading to increased pilot overhead. To address these obstacles, this research introduces a channel estimation approach for RIS-aided millimeter wave communication employing the Multidimensional Runge Kutta Orthogonal Matching Pursuit (MRKOMP) algorithm in MIMO systems. The proposed method aims to enhance network coverage and channel capacity for efficient data transmission. By utilizing the multiscale cumulative residual distribution entropy function, the method establishes an indirect path when the line-of-sight is obstructed. Furthermore, the multidimensional orthogonal matching pursuit methodology calculates sparsity levels and facilitates sparse recovery. Optimization of the weight parameter through the Runge Kutta optimizer effectively eliminates sparsity, resulting in improved spectral efficiency and RIS gain. Simulation results demonstrate a significant 99.9% enhancement in network capacity and spectral efficiency compared to existing methods.     

The key technologies of millimeter wave MIMO communication system in space information network

With the rapid development of space information network and the increasing expansion of mankind activity,the requirements of communication quality become higher between mobile satellites and earth stations.In order to meet the demands of high data rate,large capacity and broadband real-time communication,applying millimeter wave frequency band to mobile satellite communication system has attracted great attention.Beamforming,tracking and channel estimation were introduced in millimeter wave MIMO system to fully understand the challenges of space information network which will face in the future.     

Design of the intelligent network segment of future mobile communication systems

Future mobile communcation systems will have to provide sophisticated services at quality levels comparable with those provided by fixed systems. An additional requirement is that these systems should be deployed by minimally impacting the existing infrastructures. In this respect an important component of future mobile communication systems is their intelligent network segment, which contains the logic of the services provided and the relevant data required for providing these services. In the context of this paper we study the problem of designing this segment. Our reference system is UMTS, but the practices presented herein may be applied to other systems as well. We identify two major problems, the first at the Mobility and Services Control Point (MSCP) level and the second at the Mobility and Services Data Point (MSDP) level. Our aim in this paper is the following. First, the overall design process is decomposed into a sequence of well-defined problems. Second, the problems are formally stated and theoretically formulated. Third, owing to the computational complexity associated with the theoretical formulations, we take the first steps towards the design of approximate (heuristic) algorithms. Finally we provide results and draw subsequent conclusions. © 1998 John Wiley & Sons, Ltd.     

基于5G的无人机智能组网的应急通信技术开发及应用

在成立国家应急管理部后,国家越来越重视灾害事故后应急通信保障能力.为了使灾后地面通信设备被损害,从而无法对正常通信进行保证的问题得到解决,根据无人机机载基站快速创建天地一体化网络应急通信方案也备受重视.以此,本文就将5G技术作为基础,开发无人机智能组网的应急通信方案.