基于RF的智能家居无线通信网络架构设计

随着智能家居的发展,智能管控需求大幅提升,有线网关已经无法满足功能需求。针对此问题,基于433 MHz频段的无线RF通信网络模块,设计一种适用于家庭网络的关联、管理系统。用搭载RF无线模块的智能终端通过内置Wi Fi模块发射控制信息或状态查询指令,通过服务器验证RF通信协议中的数据帧;采用PIC16F726单片机及SPI串行接口构成触发模块,以验证和筛选各类指令;采用高集成度、频率自调的Si4421型号单晶射频芯片来降低大型网络下服务器的负载,服务器再将处理、整合后的信息发送给指定设备终端,从而实现高效、全面的无线智能家居。     

基于软件无线电架构的智能天线幅相校准

针对天线阵对多通道幅度和相位一致性的要求,在基于软件无线电(Software Defined Radio,SDR)架构的智能天线基础上提出了射频通道幅相测算和板级幅相测算相结合方案,具备幅相慢变特性的射频通道采用离线参数法,而板上多通道采用在线测算法,并采用星座旋转算法实现了相位校准.最后通过现场可编程门阵列(Fiel...     

Experimental studies of direction of arrivals using a smart antenna testbed in wireless communication systems

This paper presents some preliminary results from experimental studies on space‐division‐multiple‐access (SDMA) for wireless communications. A smart antenna system utilizing direction‐of‐arrival (DOA)‐based beamforming techniques can enhance signal quality by reducing co‐channel interference from mobiles located at angles spatially distinct from the base station. Adopting both smart uplink and downlink beamforming, a communication system with an antenna array can increase the cell coverage of a base station and significantly boost capacity compared with conventional antenna systems. However, successful implementation of DOA‐based beamforming techniques depends on the DOA characteristics. This paper presented the feasibility of direction finding and DOA variation with respect to frequency. Furthermore, the angle spread was studied for selected environments. The results demonstrate the feasibility of applying proposed smart antenna system utilizing DOA‐based beamforming algorithm for increasing channel capacity and improving system performance in frequency‐division‐duplex (FDD) wireless communication systems. Copyright © 2003 John Wiley & Sons, Ltd.     

智能天线技术在地空通信中的应用分析

总结了现有地空通信存在干扰的模式、途径和干扰抑制方法,重点分析了地空通信采用智能天线技术的优势和干扰抑制效能,同时也探讨了采用智能天线带来系统抗截获、电磁兼容等性能的改善,提出了地空通信应用智能天线涉及的关键技术。相关研究对工程应用有一定的参考价值。     

Propagation-prediction and site-planning software for wireless communication systems

Propagation-prediction and site-planning software for wireless communication networks has been developed. The software has a user-friendly graphical user interface (GUI), and provides calculations for large-scale and small-scale propagation parameters, including path loss (or received power) and delay profiles. Angles of arrival/departure, which are useful for the design of wireless systems employing multiple antennas, are also provided in the simulation. Some of the main features of the software include the use of a computationally efficient ray-tracing approach for simulating propagation in wireless environments, and the fact that users can upload AutoCAD .dxf files for indoor or outdoor environments. Both a single-building floor plan or an entire city layout can be simulated, and the user is provided with the ability to assign wall geometries and electrical parameters. User-defined realistic antenna radiation patterns for both the transmitting and receiving antennas are incorporated in the simulation. Broadband as well as polarization-dependent simulations are also included in the software.     

Design of a wideband multi-standard antenna switch for wireless communication devices

A wideband Low Power Single Pole 6-Throw (SP6T) antenna switch has been designed for GSM/DCS/802.11b mobile standards using a newly improved architecture and fabricated using a pseudomorphic depletion mode 0.18 μm HEMT GaAs process. The switch exhibits less than 1 dB insertion loss and isolation performances from up to 53 dB at 0.8 GHz down to 42 dB at 2.5 GHz. The circuit DC power consumption is less than 500 μW in full power transmission condition and makes it suitable for use in mobile terminals like mobile phones or PDAs. The paper presents simulation results validated by experimental measurements on an IC prototype.     

Distributed wireless communication system: a new architecture for future public wireless access

The distributed wireless communication system (DWCS) is a new architecture for a wireless access system with distributed antennas, distributed processors, and distributed control. With distributed antennas, the system capacity can be expanded through dense frequency reuse, and the transmission power can be greatly decreased. With distributed processors control, the system works like a software or network radio, so different standards can coexist, and the system capacity can be increased by coprocessing of signals to and from multiple antennas.     

An ultralow-power UHF transceiver integrated in a standard digitalCMOS process: architecture and receiver

A broad range of high-volume consumer applications require low-power battery-operated wireless microsystems and sensors. These systems should conciliate a sufficient battery lifetime with reduced dimensions, low cost, and versatility. Their design highlights the tradeoff between performance, lifetime, cost, and power consumption. Also, special circuit and design techniques are needed to comply with the reduced supply voltage (down to 1 V, for single battery cell operation). These considerations are illustrated by the design of a prototype receiver chip realized in a standard 0.5-μm digital CMOS process with 0.6-V threshold voltage. The chip is dedicated to a distributed sensors network and is based on a direct-conversion architecture. The circuit operates at 1-V power supply in the 434-MHz European ISM band and consumes only 1 mW in receive mode. It achieves a -95 dBm sensitivity for a data rate of 24 kb/s     

VLSI architecture of a K-best detector for MIMO--OFDM wireless communication systems

roughput MIMO-OFDM systems.     

软件通信结构的目标及其构成

近三年来,个人移动通信技术发展异常迅猛。在基础设施方面,第三代宽带CDMA通信系统更是各个厂家必争之地。新技术的不断出现和新的要求的提出使得通信系统更新换代越来越快。如果不能使新旧系统之间具有很好的连续性和继承性,对运营商和用户都是很大的损失和浪费。为了解决这一问题,软件通信结构（SCA）应运而生。SCA建立了独立于设备的结构框架,其目标是确保软件和硬件的可移植性和可配置性,并确保根据SCA开发的产品之间的互通。首先提出SCA的是联合战术无线电系统（JTRS）。之后,软件定义无线电（SDR）论坛也接受SCA规…     

Evolution and standardization of the smart antenna system for software defined radio

Transitioning proprietary or legacy software defined radio networks to open architectures, while often complicated, is increasingly critical to improve the interoperability and compatibility among SDR networks and the subsystems within those networks as well. With this in mind, two consortia, the SDR Forum and the Object Management Group, have teamed to define an open Smart Antenna specification. This specification defines a model (including an API) that simplifies the integration of an SA subsystem into a traditional SDR network. The specification is called the "Platform Independent Model (PIM) and Platform Specific Model (PSM) for the Smart Antenna" or "SA API specification." This article introduces the SA API, which provides a standard model and standard service of the SA system operating in SDR networks.     

激光通信与成像卡塞格林形式收发光学天线结构初解

在激光通信和成像系统中,卡塞格林形式的光学天线不论作为激光信号收发装置还是光学成像装置,像差的存在必然会降低其信号强度和成像质量等性能。通过分析三级像差理论和光学天线微扰理论,依据天线增益因子与遮挡比之间的关系,提出一种方便快捷求解卡塞格林式光学天线结构的方法。此方法在考虑光学天线效率的同时,也可以满足光学系统设计的体积尺寸、像差的要求,在仅知道光学系统焦距、主次镜间距和遮挡比的情况下,可以快捷求出光学天线结构参数。不但给出了四类卡塞格林式光学天线的光学结构参数计算公式,并且结合实际使用对不同的适用场合进行说明及优缺点对比。通过四种典型光学天线的实例计算结果和最优结果比对,表明此方法是一种方便快捷精准求解卡塞格林式的光学天线结构的方法,在工程上具实际指导意义。     

用于无线局域网的轴向模螺旋天线设计

根据无线局域网通信天线的要求,设计了三种工作在5GHz频段性能良好的轴向模螺旋天线,其中一种为普通螺旋天线,第二种为加绕寄生螺旋天线,第三种为锥形加绕寄生螺旋天线。通过电磁仿真软件HFSS计算及对结果分析表明,加绕寄生螺旋将改善天线的轴向辐射特性,而锥形结构将扩展天线带宽。     

天线振动对数字无线通信系统影响机制研究

振动会造成天线相对位置变化,产生干扰信号,导致通信质量下降.基于振动天线辐射理论模型,定量分析了四进制相移键控(quadrature phase shift keying,QPSK)系统天线振动对通信性能的影响,推导了QPSK系统天线在振动条件下系统误符率(symbol error rate,SER)公式,并通过计算机...     

Design and implementation of a wireless sensor network architecture using smart mobile devices

Wireless sensor networks improve the quality of human daily life like ubiquitous city and healthcare services as well as the fundamental monitoring such as environment pollution, tunnel monitoring, earthquake diagnostic, and so on. To increase usability and feasibility of collected sensor data, a wireless sensor network should be required to apply a variety of mobile devices to give the information at anytime and anywhere to users. Thus, we present multi-sensor centric smart sensor network architecture using general mobile devices in order to provide more efficient and valuable sensor network application and services. The proposed system architecture is based on IEEE 802.15.4-2006 standard with smart mobile devices. We also show some scenarios with on-demand request and real time event driven data to show the feasibility of the proposed architecture using five kinds of sensors such as magnetic, photodiode, microphone, motion and vibration. Based on the experiment results, we show that the proposed system has the potential as smart mobile device-based wireless sensor network architecture.     

未来无线通信中智能天线技术的发展趋势

在未来无线通信中使用智能天线技术可以减少信号间干扰，降低基站发射功率，提高频谱效率，降低建立新无线网络的成本，优化业务质量，在多技术网络中实现透明操作，本文介绍了智能天线收发机结构的最新进展及其优点，探讨了在未来系统中采用智能天线的发展趋势以及所面临的问题。     

一种新的量子无线通信的层次结构和信道编码

量子无线通信具有信息量大、传输瞬时性和安全性良好等优点。文章在研究量子自由空间传播特性的基础上,总结了量子无线收发信机纠缠态的分发机制,并提出了适用于无线广域网的量子无线层次网络结构。针对如何进行信道编码,使其性能接近系统容限,以及如何将量子信道编码转换为经典编码的问题,提出采用三量子比特的信道编码,并给出一种非规则的编解码方法,用EXIT图分析了其性能,结果表明该体系结构适合未来的量子无线通信应用。     

Graphene based tunable and wideband terahertz antenna for wireless network communication

A wide band terahertz dipole-antenna using graphene with tunable resonant frequency is proposed. Presence of graphene in the antenna is shown to electrically tune resonant frequency and to push the antenna to resonate with multibands in terahertz regime. The proposed terahertz antenna shows maximum of five tuning frequencies and better performance parameters such as return loss of ?? 39.7 dB, maximum directivity of 9.3 dB, five resonant tuning frequencies (multi resonances) at chemical voltage of 0.5 eV, maximum fractional bandwidth of 15.6%, maximum radiation efficiency of 21.5% and large bandwidth of 2.32 THz. Large bandwidth of the antenna can be very useful for highest possible data transfer among wireless devices. The proposed graphene based terahertz antenna has the dimensions of few micrometers so miniaturization i.e. size is reduced to 0.007 mm² which is suitable for size limited future applications such as Wireless Networks on Chip, software defined meta material and Wireless Nano Sensor Networks (WNSNs). Size of the proposed terahertz antenna is less than that reported in the literature. One reconfigurable and miniaturized antenna may replace a number of single function radiators, thereby also cost and size of a WNSNs can be abridged while performance is improved.

     

Broadband multimode antenna and its array for wireless communication base stations

A wideband dual‐polarized antenna coupling cross resonator is proposed for LTE700/GSM850/GSM900 base stations. An additional resonance is introduced to obtain strong coupling between the dipole and resonator. Moreover, the input impedance of the proposed antenna is steadily close to 50 Ω, which results in better impedance matching. Therefore, a wide bandwidth can be achieved with multiresonance. A prototype is fabricated to verify the proposed design. The measured results show that the antenna has a fractional bandwidth of 35.7% from 690 MHz to 990 MHz for |S₁₁| < ?15 dB. Stable radiation patterns as well as gain are also obtained over the entire operating band. Moreover, a five‐element antenna array with an electrical downtilt of 0° to 14° is developed for modern base station applications. Measurement shows that a wide impedance bandwidth of 34.7% (690 MHz to 980 MHz), stable HPBW (3‐dB beamwidth) of 65 ± 5°, and high gain of 13.8 ± 0.6 dBi are achieved with electrical downtilts of 0°, 7°, and 14°.     

一种软件定义无线网络负载均衡架构及算法

软件定义网络( SDN)为实现异构无线网络中的负载均衡提供了新的思路。设计了一种软件定义的无线网络负载均衡架构,并提出对应算法。首先,根据接收信号强度构建候选网络列表;其次,根据各候选网络的可用负载比率标准差进行负载差异分级;再次,将服务质量匹配度函数和负载均衡指数线性组合成联合优化函数,并根据负载差异分级对联合优化的权重进行动态调整,合理设置门限进行接纳控制。与传统算法相比,所提算法一方面可使各类业务阻塞率明显降低大约20%,另一方面使不同网络的归一化负载更加接近。该算法在进行网络负载均衡的同时,能够有效降低业务阻塞率,从而有效提升异构无线网络的整体性能。