Polarization Behaviours at 2, 5 and 60 GHz for Indoor Mobile Communications

The behaviours of linear polarizations at 2.15, 5.3 and 61.7 GHz in corridors are studied in this paper. It shows that there is no significant difference between the received powers for vertical and horizontal polarizations. Depolarization is obvious at 2.15 GHz due to different antenna type is applied at the receiver, and it is more serious in non-line-of-sight (NLOS) cases.     

60GHz毫米波无线通信技术标准研究

随着多媒体设备的广泛应用,世界各国相继开放60 GHz频率附近大于5GHz频宽免许可频带,60 GHz毫米波无线通信系统的研究成为学术界和产业界研究的新热点之一.综述了60 GHz无线通信的优势和应用范围,介绍了国内外技术标准和产业发展动向和趋势.     

60 GHz宽带无线通信射频芯片研究进展

60GHz无线通信技术由于其超高速的数据传输能力,将成为第4代无线通信技术的代表,引发了学术界和工业界研究热潮。近几年,随着半导体技术的发展,基于不同工艺的60GHz宽带无线通信射频芯片已经不断有报道。文中跟踪了近些年国外60GHz无线技术研究情况,分别从应用、技术特点、标准状况和芯片研究进展等方面介绍了60GHz宽带无线通信系统及其发展趋势。     

Measurements at 2.4, 3.4, 5.2, 28 and 60 GHz for Device-to-Device Wireless Communications

Wireless Personal Communications - Wireless communication networks with increased demand for higher speed in data transfer have paved way for device-to-device (D2D) wireless communications. This...     

Wideband Propagation Measurements and Channel Implications for Indoor Broadband Wireless Local Area Networks at the 60 GHz Band

This paper addresses some wideband propagation characteristics for Indoor Broadband Wireless LANs at the 60 GHz band. Important system design characteristics from measured results obtained from two wideband 60 GHz LOS radio links are presented. Measurements had been undertaken using the swept frequency channel sounding method. Analysis from the complex frequency responses in a worst-case scenario have yielded to a lower coherence bandwidth value of 5 MHz. Minimum and maximum B_0.9coherence bandwidths obtained with a directional horn transmit and an omnidirectional receive antenna is 1.10 MHz and 105.33 MHz respectively. It has been observed that the coherence bandwidth fluctuates significantly with the location of the receiver with respect to the base station. These results can be used for modelling and design of future Indoor BWLANs.     

A Wireless Network for Wide-Band Indoor Communications

We propose and analyze a wide-band indoor communication system that uses radio as the transmission medium either on a stand-alone basis or to supplement a hard-wired network for those situations where complete portability is desired. One principal impairment to such a system is intersymbol interference caused by frequencyselective fading. A novel media-access scheme is proposed which permits the use of resource sharing, wherein a small pool of time slots is effectively shared among all users to provide added protection against channel impairments on an as-needed basis. Our results show that the use of resource sharing and diversity provide excellent protection against intersymbol interference caused by frequency-selective fading with negligible impact on throughput. Furthermore, resource sharing plus diversity can permit significantly higher data rates without large queueing delays. For example, a wireless network with a 10 Mbit/s data rate in a 10 MHz bandwidth using four antennas at the base station has a less than 10^-4outage probability at a 10^-4BER in buildings with less than 58 ns rms delay spread. A loading of 75 percent is permitted for a queueing delay of less than 20 packet transmission times all but 0.01 percent of the time.     

Polarization Modulation for Wireless Communications Based on Metasurfaces

As an alternative to conventional wireless communication techniques that use amplitude, frequency, and phase modulations, polarization modulation (PoM) provides an additional degree of freedom for the modulation of carrier waves and allows the realization of simple transceiver designs. PoM also enhances physical-layer security in wireless communication systems owing to its vector-attribute and direction-dependence features. In this study, a prototype of PoM wireless communications based on a digital coding metasurface that can dynamically control the polarization of electromagnetic waves in a certain frequency band is demonstrated. The binary digital signals can be encoded on the optical rotation states of the circularly polarized beams through the real-time control of the bias voltages applied on the metasurface and successfully decoded at the receiving end. Because the metasurface is separated from the emitting antenna, the design can simplify the setup for multichannel communications and provide more flexibility by setting the emitting antennas at different operating frequencies at any time.     

Short-Range Wireless Communications for Next-Generation Networks: UWB, 60 GHz Millimeter-Wave WPAN, And ZigBee

This article presents standardization, regulation, and development issues associated with short-range wireless technologies for next-generation personal area networks (PAN). Ultra-wideband (UWB) and 60 GHz millimeter-wave communication technologies promise unprecedented short-range broadband wireless communication and are the harbingers of multigigabit wireless networks. Despite the huge potential for PAN, standardization and global spectrum regulations challenge the success of UWB. On the other hand, ZigBeetrade is expected to be a crucial short-range technology for low throughput and ultra low-power consumption networks. The current status and direction of future development of UWB, emerging 60 GHz millimeter-wave PAN, and low data rate ZigBee are described. This article also addresses wireless MAC protocol issues of 60 GHz multigigabit PAN.     

Models for Wireless Data Communications in Indoor Train Environment

The provisioning of wireless data services in the railway environment will become increasingly important for train operators and train constructors in the upcoming years. In this paper, we present models to predict train-to-wayside wireless data communications characteristics in terms of throughput, jitter, and packet loss predictions for 2G/3G networks. To this end, an extensive measurement campaign is carried out along a Belgian Intercity railway track. Based on these measurements, we apply a multiple regression, window mean, and autoregressive model. We find that the window mean model is recommended for the prediction of throughput and jitter, while the multiple regression model is more favorable for the prediction of packet loss. The implementation of these predictions in train-to-wayside communication systems can enhance the provisioning of seamless network connection necessary for a wide variety of data services.     

Wireless Indoor Communications Using an Optical Highway

The wireless indoor communications system employing an optical backboneprovides an economic and flexible approach for local area networks in officebuildings. In this approach the wireless communication serves small picocellsthat are interconnected by optical highways. The performance of the system isenhanced by assigning specific subcarriers for the individual picocells whichenables the transmission of the radio channels without altering theirmodulation format. The reception is simplified by a direct optical-microwavemixing method providing simultaneous optical detection and frequency shifting.This method allows for simple and cost-effective radio nodes.     

高码率无线红外室内传输系统的通信性能

讨论仿真室内的红外漫射通信系统,并观测在提高系统传输码率情况下无线红外室内通信系统的性能。系统使用NRZ的OOK调制,在室内环境下,采用漫反射传输会导致多径效应,而多径传输又必然会带来码间干扰,因此采用均衡器来减弱码间干扰对系统性能的影响。仿真结果显示高码率无线红外室内通信的可行性。     

基于无线传送的室内通信系统

对于家庭网络内部的各种智能家电,远程访问系统主要通过双芯电缆来直接控制和访问.为了克服安装布线的繁琐,提出利用无线数传MODEM芯片FFR2000,构建了基于无线传送方式的家庭网络内部通信系统,以实现各种控制和访问,并给出了系统硬件设计和软件控制过程.     

Indoor channel measurements and characterization at 60 GHz for wireless local area network applications

This work presents propagation measurement results at 60 GHz in order to determine the characteristics of indoor radio channels between fixed terminals. Path loss measurements are reported for line-of-sight (LoS) and non-line-of-sight (NLoS) cases, fading statistics in a physically stationary environment are extracted and a detailed investigation of the people movement effect on the temporal fading envelope is performed. Models that presented to predict path loss provide excellent fitting with errors of 1.13 and 3.84 dB for LoS and NLoS topographies, respectively. The dynamic range of fading in a quiescent environment is 8.8 dB and increased to 35 dB when a person moves between the fixed terminals with the channel becoming extremely nonstationary. Temporal variations induced by the moving people depend on the speed, the number of individuals the body sizes and the environment. Slow fading is observed as well as a quasi-wide-sense stationary (QWSS) behavior of the fading, but up to 50 ms of time.     

Step-Wisely Refinement Based Beam Searching Scheme for 60 GHz Communications

In the emerging 60 GHz millimeter-wave communications, the beam-forming technique has been widely recommended to efficiently compensate the significant path-loss in such bands. Unfortunately, the complexity of beam searching procedure, which is used to find the optimal beam-pair from a prescribed codebook, may generally tend to be unaffordable with the increasing of antenna elements. By formulating the beam-searching as a numerical optimization problem and properly exploring the beam characteristics generated by different array element numbers, the article proposed a fast beam searching algorithm. Compared with the existing schemes in current standards, our algorithm can significantly reduce the preamble transmissions accompanying energy consumption during beam searching process. Numerical simulation results further validate the superiority of the presented algorithm.     

Radio-Optical System Design and Transmission Experiments for a Mobile Broadband Communications System at 60 GHz

The paper presents the system designconcept for a mobile broadband communications systemat 60 GHz. A dense WDM system is used for the opticalbackbone employing novel add/drop multiplexers. Forsimplicity, there is no signal processing andfrequency generation at the base station and a masteroscillator signal are used for millimetric carriergeneration. The master oscillator signal is modulatedonto the optical carriers by a novel concept ofsimultaneous external modulation, simplifying systemdesign significantly. Transmission experiments over acomplete downlink path using uncoded 2-FSK have beencarried out and a BER of 10^-9at 50 MBit/s hasbeen obtained. Furthermore, 512-carrier DQPSK-OFDMtransmission at 45.8 MBit/s using 35 MHz bandwidth at60 GHz has been demonstrated.     

A Model of 60 GHz Indoor Radio Channel

A novel model of millimeter-wave (MMW) indoor radio channel is presented in this paper. The model is related the random properties of the MMW radio channel to the underlying geometry of the environment. The geometric simplicity of the MMW channel is allowed examining fundamental deterministic properties of the wave propagation behavior in environments of predefined randomness. The dimensions and properties of environments are described by various probability distributions. Stochastic influence on the radio channel is studied for the down-link of a wireless local area network at 60 GHz. Other related factors, such as amplitudes of path lengths, angles of departure, and amplitudes, as well as spatial power densities, average power of the direct paths are investigated.     

6.0-6.4GHz室内MIMO无线信道测量与传播特性分析

工作在6GHz以上高频段的多输入多输出(Multi-Input-Multi-Output,MIMO)无线通信系统是下一代无线移动通信的有力竞争方案.目前,对制约无线系统性能的高频段空时无线信道特性研究仍较少见.针对这一现状,采用基于网络分析仪的信道测量平台对典型办公环境下6.0-6.4GHz MIMO无线信道特性进行测量和分析.为了明确高频段为系统设计带来的新问题,将测量得到的高频段MIMO信道特性参数与低频段对比.对比结果表明,6.2GHz频段与2.45GHz频段MIMO信道传播特性存在较大差异.在对6.0-6.4GHz室内覆盖MIMO无线通信系统进行设计和评估时,需要基于6.0-6.4GHz频段无线信道传播的新特性对系统的关键技术和方案进行调整.     

60GHz宽带双极化阵列天线研究

本文提出了一种基于低温共烧陶瓷（Low Temperature Co fired Ceramic,LTCC）工艺的60GHz频段宽带双极化4×4阵列天线。所提出的阵列天线采用双馈技术L型探针天线单元结构、“立交桥”式复杂馈电网络,以及加载等效腔体结构,具有体积紧凑、工作频带宽、增益较高、增益带宽平缓、端口隔离度高、交叉极化电平低等优良特点。此外,分析了加载等效腔体结构对双极化天线阵列性能的影响。所提出的60GHz宽带双极化阵列天线可实现天线与芯片的AiP系统封装集成,满足宽带无线通信系统或毫米波雷达系统高性能、高集成度、小型化的应用需要。     

高码率无线红外室内传输系统的噪声抑制

主要讨论室内的高码率红外漫射通信;系统在背景光噪声以及障碍物下的性能。系统使用NRZ的OOK调制,在室内环境下,对系统最大的影响来自由荧光引起的噪声,这种噪声存在直流到500kHz的范围里。克服这种噪声的有效方法是把前置放大器的输出通过一个高通滤波器。但这又会发生基线偏移(baseline wander),若使用线性编码或者使用在接收器上活性基线恢复可去除基线偏移。