面向5G的无线宽带多载波传输技术初探

在2016年乌镇举办的第三届世界互联网大会上,美国高通公司首次提出了5G的概念,是4G之后的延伸与发展,目前正处于开发和研究当中,是未来移动通讯发展的新趋势。目前,我国关于5G的无线宽带多载波传输技术主要有滤波器组多载波(FBMC)、广义频分复用(GFDM)和正交频分复用(OFDM)。文章主要以5G无线宽带多载波传输技术为中心,详细介绍了目前主流的几种5G无线宽带多载波传输技术,并对这几种传输技术进行对比和分析,对我国关于5G无线宽带多载波传输技术取得进展和突破奠定基础。下面将针对5G的无线宽带多载波传输技术展开详细讨论。     

MIMO无线传输技术综述

MIMO无线传输技术是通信领域的一项重要技术突破,它能在不增加带宽与功率的情况下成倍地提高无线通信系统的容量和频谱效率,堪称新一代无线通信系统中的关键技术之一,近年来引起了人们的广泛关注与研究兴趣。回顾无线移动通信的发展历程,概述天线分集技术与智能天线技术,剖析MIMO无线传输技术的原理与国内外研究现状:传统单天线系统向多天线系统演进、智能天线向多天线系统演进、MIMO无线传输技术的原理、MIMO系统中的分集与复用、MIMO无线信道建模、MIMO系统中的多天线设计等,为深入认识与进一步研究MIMO无线传输技术奠定基础。     

第三代移动通信系统无线传输技术分析

介绍第三代移动通信系统无线传输技术的研究情况,对当前两种主要的无线传输技术候选方案进行比较和分析,最后对无线传输技术的发展进行预测。     

基于宽带码分多址的无线接入技术

宽带CDMA是第三代移动通信系统(IMT-2000)的核心技术。主要介绍了无线接入并从无线传输技术要求出发,分析了宽带码分多址(W—CDMA)的若干优势,着重分析了基于第三代移动通信系统(IMT—2000)的宽带CDMA无线接入的关键技术。     

得寸就要进尺 随心打造全新的大画面娱乐方式 BenQ（明基）W1500

近年来,无线传输技术开始走向家用投影领域,也成为未来家庭影院投影机的主要发展方向之一。无线传输技术最大的优势在于能突破使用环境的限制,无需采用复杂的布线系统就能轻松实现影音信号的传输,大大简化了家庭影院系统的组建。明基作为全球最大的投影机生产厂商之一,近日特别针对无线影音传输推出了首款支持WHDI 5GHz无线影音传输技术的家庭影院投影机W1500,凭借着优秀而稳定的传输性能,全面支持3D高清无线影音传输,具有标志性的意义。     

WCDMA系统的发展与无线传输技术

本文首先介绍了WCDMA系统标准的发展过程，对WCDMA无线传输技术以及核心网的演进进行了比较全面的描述；然后系统了WCDMA系统的无线传输技术，对其中若干关键技术进行了重点阐述；最后介绍了WCDMA系统的R5版本中基本原则于IP的无线接入网络，以及高速下行数据分组接入技术。     

信道自适应主动块丢弃数字图像传输技术

数字图像的高效传输对于无线多媒体通信和网络图像交换等应用具有十分重要的意义。信道自适应主动块丢弃数字图像传输技术，在图像发送端以块为单位对图像进行划分，按照一定的规则主动丢弃部分图像块数据，以此减少所需要传输的比特流量，满足信道带宽要求，而在图像接收端通过全新的图像重建技术对丢弃的图像块数据进行恢复，从而完整地再现原图像。大量实验证明，该图像传输技术优于目前普遍采用的量化步长调节式数字图像传输技术，用它传输的图像质量得到明显提高。     

IMT-2000移动通信系统无线传输技术的选择原则和评价方法

本文描述了IMT-2000移动通信系统的无线传输测试环境,提出了选择无线传输技术的基本原则,给出了对无线传输技术进行评价的方法。     

现代移动通信中的微波磁性器件

移动通信的业务主要是:(1)便携式双向无线电话的无线通话;(2)单向通信的无线寻呼系统;(3)如车队,火车调度之类的调度系统;(4)移动电话;(5)无线电数据包交换。而这些业务的工作频段的超高频(UHF)、L波度、C波段和Ku波段等,工艺都在微波频率范围。由于微波磁性器件的非互易等特殊功能,为使高速多路无线通信得以实现,微波磁性器件是不可能缺少的一种基础元件。 微波磁性器件在移动通信系统的基台和手机中都是不可缺少的基础件和关键件,对其基本要求则是高性能(低插入损耗、高隔离、宽频带高温度稳定性),小型轻量、低成本,尤其是用于手机中的     

第三代移动通信系统的演进趋势

本文根据世界各国向ITU提交的无线传输技术(RTT)方案 ,讨论了向第三代移动通信系统演进的趋势。     

5G小数据传输增强技术

移动互联网和物联网应用产生大量的间歇性小数据,5G系统需要高效支持这类数据的传输.基于5G R15/R16的技术基础分析5G小数据传输增强技术的设计目标;根据5G R17最新标准进展,分析RRC非激活状态下终端小数据传输增强技术,包括小数据传输基本过程和资源配置与选择、小数据传输的发起、后续数据传输等技术方案;并对小数...     

An integrated CDMA code assignment model for voice and data traffic in wireless communications

Wireless personal communication requires a provision of integrated services of multimedia traffic, such as voice and data, over the radio link. The multiple access protocols of code-division multiple-access (CDMA) techniques have been widely investigated in the recent literature. This paper presents an innovative multiple access protocol for CDMA-based wireless communication systems by fully utilizing the characteristics of voice and data traffic. In other words, a voice terminal can reserve a spreading code to transmit packets in multiple talk spurts, while a data terminal can transmit packets by either using the unassigned codes or borrowing the codes from the voice terminals during their silent periods. We build mathematical models for voice and data subsystems, respectively. Two performance parameters, the average dropping probability for voice packets and the average transmission delay for data packets, are derived based on the equilibrium point analysis. The effects of the two performance parameters on the system performance are discussed by varying the code reservation intervals of the voice terminals.     

Delay analysis of selective-repeat ARQ with applications to link adaptation in wireless packet data systems

Radio link control (RLC) protocols are typically employed for reliable in-sequence delivery of service data units (SDUs) in wireless packet data systems. The RLC layer segments packets obtained from the upper layer (referred to as SDUs) into smaller RLC transmission units (or blocks) and uses selective-repeat automatic repeat request (SR-ARQ) for error recovery of RLC blocks. In earlier work, SR-ARQ performance is typically characterized in terms of the long-term throughput or in-sequence delivery delay of RLC blocks. The SDU delivery delay which is a more meaningful measure of RLC performance (in terms of the service provided to a higher layer, e.g., transmission control protocol) has not been quantified. In this paper, we analyze the SDU delivery delay of SR-ARQ as a function of the SDU size and the channel coding scheme employed. Closed-form delay expressions as well as approximations are provided. The analysis is verified through enhanced general packet radio service RLC simulations. Based on the analysis, we propose that link adaptation be backlog dependent in order to reduce the SDU delivery delay at the RLC layer.     

光子太赫兹通信技术

随着无线数据传输速率需求的爆炸式增长,太赫兹频段(0.1~10 THz)以其丰富的频谱资源备受关注。太赫兹光子学的通信技术因具有超宽带、调制效率高、谐波干扰小等技术优势,被公认可以极大地促进数据传输速率向Tbit/s发展。本文以光子太赫兹通信3个方面关键技术的综述分析为基础,包括光子太赫兹通信的收发器件、基带信号处理技术、系统架构与实验验证等,探讨光子太赫兹通信技术的发展趋势,并从宏观与微观尺度展望光子太赫兹通信的潜在应用场景。     

行星表面有人探索高速无线网络体系架构及关键技术

针对行星表面有人探索任务对高速无线通信的需求，提出了一种基于异构组网思想的网络体系架构，并对关键技术进行了分析和设计。该架构采用“三网两体制”的设计思路，将整个网络分为高速传输网、多媒体接入网、覆盖扩展网三个组成部分，三层网络分别完成高速骨干传输、多节点多业务接入、覆盖范围灵活改变的功能。根据三个网络不同的节点处理能力和传输需要，设计了高速传输体制、灵活接入体制两种传输体制，及基于无线多跳的覆盖扩展技术、多子网通信切换技术、多体制融合技术等关键技术。该网络架构具有裁剪灵活、协议开销小、支持业务类型多等特点。     

Exploiting Multiuser MIMO in the IEEE 802.11 Wireless LAN Systems

By adopting multiple-input-multiple-output (MIMO) antenna technologies, IEEE 802.11 wireless LANs are evolving into high speed systems. While only one user can transmit at a time in the conventional IEEE 802.11 systems, we investigate the possibility of multiuser transmission by using MIMO antennas, which is now known as multiuser MIMO. The multiuser MIMO technique enables multiple users to receive packets over the downlink simultaneously, but it should be carefully used in the IEEE 802.11 systems for interoperation with non-MIMO legacy terminals. Through analysis and simulation evaluation, we demonstrate that multiuser transmission with a scheduling algorithm and single-user transmission with enhanced spatial multiplexing achieve enhanced performance by exploiting multiuser diversity in the space and time domains. Especially, when the number of stations is large, multiuser transmission shows better performance than enhanced single-user transmission.     

Wireless Mesh Network and IEEE 802 Standards

Although the wireless broadband access system is developing rapidly, its development is limited due to some disadvantages , such as small capacity of bandwidth and small coverage . The Wireless Mesh Network (WMN) is one of the important technologies for "last mile "broadband wireless access . The WMN can integrate with multiple wireless systems , such as Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN), and Wireless Metropolitan Area Network (WMAN), to improve the performance of the wireless network and enlarge the coverage range . With the wide applications of the WMN, the IEEE 802 standard group is devoted to promoting the development of the WMN technology and establishing the related technical standards . At present, WMN standards have appeared in IEEE 802.11s , 802.15, 802.16, and 802.20.     

Design and implementation of adaptive WLAN mesh networks for video surveillance

This paper presents a novel design and practical experiments of adaptive wireless mesh networks based on 802.11 based Wireless Local Area Networks for supporting public video surveillance. A network of video cameras and sensors can be equipped with wireless communication modules to form wireless surveillance at only a small expense of cost and labor. However, large and redundant multimedia data transmitted through the wireless medium pose challenging problems such as decrease in Quality of Service (QoS) and system reliability. To support seamless transmission of surveillance data through wireless means, we propose a wireless surveillance network design based on the protocols and functions of IEEE 802.11 mesh standard. One of the key functions of our adaptive mesh network is the “Multi-Gateway Routing with Congestion Avoidance”, which provides enhanced QoS support via adaptive congestion control. Network congestion is predicted in a distributed manner and amounts of data traffic transmitted to the congested path are redirected to multiple gateways. Redirection of traffic flows are made in such a way to provide quicker transmission for more time critical packets. Experimental studies via practical testbed implementation and simulation via NS-3 are conducted to prove the superiority of our proposed scheme.     

A High-Throughput MAC Protocol for Wireless Ad Hoc Networks

One way to improve the throughput of a wireless ad hoc network at the media access (MAC) layer is to allow as much as possible concurrent transmissions among neighboring nodes. In this paper, we present a novel high-throughput MAC protocol, called Concurrent Transmission MAC(CTMAC), which supports concurrent transmission while allowing the network to have a simple design with a single channel, single transceiver, and single transmission power architecture. CTMAC inserts additional control gap between the transmission of control packets (RTS/CTS) and data packets (DATA/ACK), which allows a series of RTS/CTS exchanges to take place between the nodes in the vicinity of the transmitting or receiving node to schedule possible multiple, concurrent data transmissions. To safeguard the concurrent data transmission, collision avoidance information is included in the control packets and used by the neighboring nodes to determine whether they should begin their transmissions. Also, to isolate the possible interference between DATA packets and ACK packets, a new ACK sequence mechanism is proposed. Simulation results show that a significant gain in throughput can be obtained by the CTMAC protocol compared with the existing work including the IEEE 802.11 MAC protocol.     

面向未来无线通信系统的小蜂窝网络综述

为了满足人们日益增长的数据流量需求,未来无线通信系统将向更小的小区部署迁移。小蜂窝网络是下一代无线通信系统的关键技术,也是适应未来更加复杂通信环境的有效途径。首先介绍了小蜂窝网络的基本概念,论述了其主要的技术特点和独特的应用优势,分析了其在未来无线通信系统中与其他各种技术可能的融合场景并讨论了对应的特点和存在的难题;然后概述了小蜂窝网络技术发展过程中所面临的主要挑战,分析了目前主要的研究成果和解决方案;最后,结合下一代无线通信的关键技术,如大规模多输入多输出通信、毫米波通信、D2D(Device-to-Device)通信和认知无线电技术等,总结了小蜂窝网络的应用现状并分析了其市场和发展前景。