基于混频偏置合成的高速太赫兹无线通信系统

提出一种基于载波抑制混频与载波偏置功率合成的高速太赫兹无线通信方案。发射端利用载波抑制混频器和载波偏置功率合成在140 GHz载波上实现了开关键控(OOK)调制;接收端利用包络检波接收器进行检波接收。分别开展了不同混频本振功率及偏置功率下的检波响应实验、不同基带信号功率及偏置功率下的检波响应实验,以及不同输入功率下的检波响应实验。实验结果对OOK调制器设计,以及OOK类通信系统的优化均具有较好的指导意义。最后,利用优化的系统参数在70 cm距离上实现了140 GHz, 16 Gbps的无线通信,系统误码率(BER)优于10-5。     

面向6G的高速太赫兹无线通信系统与关键技术验证

太赫兹通信以其可提供更高速、更大容量和更安全的数据传输的独特优势,在未来6G中成为重要的关键技术之一。基于固态电子的太赫兹通信系统存在带宽受限、频谱响应不平坦等问题,需要先进的信号形式结合灵活高效的处理方法来提升系统性能。搭建了基于固态电子的G波段太赫兹无线通信系统,通过采用比特-功率加载的离散多音(Bit and Power Loading-Discrete Multitone, BPL-DM)调制技术,实现了对系统频谱资源的有效利用;通过对通信速率的灵活调整、自适应削波和基于三阶多项式的后均衡技术,解决了峰值功率约束带来的挑战,提升了整体传输性能,实现了在195 GHz中心频率下,单通道130 Gbit/s的通信线路速率。基于以上技术,为进一步提升系统容量,搭建了4×4的多输入多输出(Multiple-Input Multiple-Output, MIMO)太赫兹通信系统,总线路速率超过399 Gbit/s。     

无线通信应用太赫兹技术研究进展

在过去的几年里,由于不同频段电磁频谱的传播特性差异、对带宽需求以及技术利用能力提升,无线通信应用的电磁频谱不断提高。在通信领域,为满足无线数据传输需求的爆炸性增长,特别是5G通信的发展,毫米波中低频段应用已经成功实现工程化并开始商业化。而对于以光波为载体的更高频率电磁波的光通信,也已经发展了几十年。在常规无线电波(毫米波)与常规光学(远红外)之间,存在着一段长期未能有效利用的空闲频谱资源,目前被统称为太赫兹频段(0.1~10 THz)。太赫兹频段在高速无线通信领域具备明显优势,成为有潜力的6G通信核心技术。可以预见,对这项技术的使用将助力6G通信实现网络全覆盖、高度智能化及网络安全性全面提升的愿景。文章主要关注通信领域,重点介绍了太赫兹频段的特点、构建太赫兹系统功能的器件类型与工艺集成实现技术。最后,预测了太赫兹通信技术的一些应用场景,进而显示出该技术对通信领域和人们日常生活的促进作用。     

太赫兹二维成像技术研究进展

太赫兹成像技术在人体安检、无损探伤、质量监控、生物医学、半导体特性表征等许多领域展现出广泛的应用前景。本文综述了各类太赫兹二维成像技术,包括太赫兹扫描成像、太赫兹单像素成像、电光调制太赫兹成像、太赫兹相机直接成像等技术,综述各类成像技术的研究背景,分析了具体的成像方法和成像结果,总结了不同太赫兹成像技术的优缺点并对今后太赫兹成像技术的发展趋势做出展望。     

高速长距离太赫兹通信系统研究现状与难点综述

随着低频段频谱资源日益紧张,无线通信载波频率开始向太赫兹频段发展,近年来太赫兹通信系统成为研究热点之一。围绕高速率长距离太赫兹通信系统,对比全电子学和光电子学2类太赫兹通信系统架构,介绍2类不同架构通信系统的国内和国外研究现状,总结全电子学和光电子学通信系统的优缺点,分析太赫兹通信系统的技术难点问题,为高速长距离太赫兹通信技术的发展提供参考。     

6G新频谱：太赫兹无线通信之“思与行”

太赫兹无线通信技术是未来6G潜在关键技术之一,引起了国内外广泛的关注。本文首先介绍了国内外相关研究计划和研究动向,分析了太赫兹通信技术的特点和优势。其次阐述了太赫兹通信技术在未来6G中的可能应用场景以及面临的挑战。最后提出了行动建议。     

用于太赫兹高速直接调制技术研究进展

分析了近年来太赫兹直接调制技术的发展情况,技术特点以及应用前景。随着外调制技术的快速发展,调制速率有大幅度的提高,并且与目前主流的基于肖特基二极管等固态器件太赫兹发射链路易于集成等特点,已被认为是一种在太赫兹高速通信领域中具有应前景的太赫兹调制技术。     

InP基三端太赫兹固态电子器件和电路发展

随着微电子技术的飞速发展,半导体器件的截止频率已经进入到太赫兹频段,太赫兹电路的频率特性得到极大发展。以固态器件为基础的太赫兹电路的工作频率进入到THz频段。本文重点介绍InP基双极器件和场效应器件的发展以及在太赫兹电路和系统中的应用。     

太赫兹科学与技术

太赫兹电磁波段的开发和利用具有重大的科学意义和潜在的应用价值,太赫兹科学技术已经成为本世纪最为重要的科技问题之一,除了本身具有很多重大的科学问题之外,它还是一种非常有效的研究手段。介绍了太赫兹科学技术的发展历史及国内外相关的发展情况,列举了太赫兹波的独特性质,概述了太赫兹科学技术在基础研究领域和应用研究领域的新进展。     

Adaptive equalization for high speed optical MIMO wireless communications using white LED

Light emitting diode (LED) is one of the most important light sources in the 21st century and has broad prospects in the illumination.Currently,the white LED is used not only for illumination,but also ...     

MIMO systems for broadband wireless communications

The emergence of broadband wireless access (BWA) and mobility poses significant challenges to the future telecommunications landscape. Multiple input multiple output (MIMO) is a potential technology that can be used to improve system performances such as coverage, capacity and data rates for broadband wireless networks. Although this technology has proved to be beneficial for both current and future services by many research results, it is not clear how these benefits can be practically achieved with a MIMO system. Fundamental issues on capacity enhancement and performance limits need to be addressed before operators will be willing to deploy MIMO systems in their networks. This paper addresses some of the key issues that remain open regarding MIMO technology for BWA. The paper focuses on MIMO channel modelling and capacity analysis.     

Low power consumption high speed CMOS dual-modulus 15/16 prescaler for optical and wireless communications

Frequency synthesizer is an important part of optical and wireless communication system. Low power comsumption prescaler is one of the most critical unit of frequency synthesizer. For the frequency divider, it must be programmable for channel selection in multi-channel communication systems. A dual-modulus prescaler (DMP) is needed to provide variable division ratios. DMP is considered as a critical power dissipative block since it always operates at full speed. This paper introduces a high speed and low power complementary metal oxide semiconductor (CMOS) 15/16 DMP based on true single-phase-clock (TSPC) and transmission gates (TGs) cell. A conventional TSPC is optimized in terms of devices size, and it is resimulated. The TSPC is used in the synchronous and asynchronous counter. TGs are used in the control logic. The DMP circuit is implemented in 0.18 μm CMOS process. The simulation results are provided. The results show wide operating frequency range from 7.143 MHz to 4.76 GHz and it comsumes 3.625 mW under 1.8 V power supply voltage at 4.76 GHz.     

Spread spectrum techniques for indoor wireless IR communications

Multipath dispersion and fluorescent light interference are two major problems in indoor wireless infrared communications systems. Multipath dispersion introduces intersymbol interference at data rates above 10 Mb/s, while fluorescent light induces severe narrowband interference to baseband modulation schemes commonly used such as OOK and PPM. This article reviews the research into the application of direct sequence spread spectrum techniques to ameliorate these key channel impairments without having to resort to complex signal Processing techniques. The inherent properties of a spreading sequence are exploited in order to combat the ISI and narrowband interference. In addition, to reducing the impact of these impairments, the DSSS modulation schemes have strived to be bandwidth-efficient and simple to implement. Three main DSSS waveform techniques have been developed and investigated. These are sequence inverse keying, complementary sequence inverse keying, and M-ary biorthogonal keying (MBOK). The operations of the three systems are explained; their performances were evaluated through simulations and experiments for a number of system parameters, including spreading sequence type and length. By comparison with OOK, our results show that SIK, CSIK, and MBOK are effective against multipath dispersion and fluorescent light interference because the penalties incurred on the DSSS schemes are between 0-7 dB, while the penalty on OOK in the same environment is more than 17 dB. The DSSS solution for IR wireless transmission demonstrates that a transmission waveform can be designed to remove the key channel impairments in a wireless IR system.     

Adaptive multi-standard circuits and systems for wireless communications

Telecom trends such as smooth migration towards higher data rates and higher capacities for multimedia applications, and provision of various services (text, audio, video) from different standards with the same wireless device require integrated designs that work across multiple standards, can easily be reused and achieve maximum hardware share at minimum power consumption. This can be achieved by using adaptive circuits that are able to trade off power consumption for performance on the fly. Realization of the adaptivity function requires scaling of parameters such as current consumption to the demands of the signal-processing task. This paper describes adaptivity design concepts and application of design for adaptivity to multi-standard circuits and systems for wireless communications. An exploratory multi-standard RF front-end is discussed with phase-noise tuning, noise-figure tuning, and input-intercept point tuning requirements of 21 dB, 12 dB, and 7 dB, respectively.     

Grey systems theory applications to wireless communications

This paper discusses grey systems theory (GST) applications in wireless communications and highlights its potential to cognitive radio. GST consists of information theory concepts and practical algorithms developed to address situations where information is incomplete and affected by random uncertainties. Two GST concepts, grey relational analysis (GRA) and grey model (GM) prediction theory are discussed. GRA provides a method to quantify the similarity between a reference data series and set of data while GM is used for modeling time series data and enables prediction of future values with limited data points and unknown probability distributions. These two techniques are surveyed with respect to their applications to wireless communications. Their application to predictive Cognitive Radio and as a similarity measure for case based reasoning cognitive engines is highlighted. A GRA based Automatic Modulation Classification (AMC) algorithm is applied to digital communications signals with preliminary results shown in simulation.