60 GHz无线收发实验平台的探究

详细介绍了一种60 GHz无线收发实验平台设计方案,由改进后的NI USRP(收发模块)、NetFPGA(数据处理模块)和PC(主控模块)组成,NI USRP与NetFPGA通过吉比特网口连接,NetFPGA依靠PCI与PC连接,实验平台工作在Linux系统上,并辅以LabVIEW做编程和测试分析,能实现1 Gbit/s以上的理论传输速率.该实验平台方案的收发模块和数据处理模块均可编程,Linux通过PCI对数据流进行捕获、分类、限速等操作,整个平台具有较好的开放性和拓展性,为进一步研究60 GHz通信中的信道建模、时隙分析、多址接入算法等问题提供了便利.     

Research on human blockage effect for indoor 26 GHz mm-wave communications

Based on 26 GHz indoor channel measurements, the blockage attenuation of human bodies was investigated. 2-ray and 4-ray human blockage models were proposed by calculation of the Vogler's multiple knife-edge diffraction field. Results show that 4-ray model fits quite well with measurement data. Human block attenuations are slightly bigger with 1 GHz than with 500 MHz bandwidth. In the blockage measurement of one person moving along the connec-tion line between the transmitter (TX) and receiver (RX), the smallest attenuation is found when the person is located at the middle of the connection line, and the biggest attenuation is observed when the person is nearest from the RX position. In the blockage measurements by multiple human bodies, the attenuation is bigger in the cases which the persons cross the TX-RX connection line with their front faces directed to the horn aperture at the RX than the cases with their lat-eral faces directed to the RX horn aperture. The blockage attenuation is larger with the increase of person numbers, about 5～8 dB more attenuation per person. The results can be used for design of mm-wave 26 GHz indoor communi-cations systems.     

60 GHz超高速无线网络接入机制研究

首先介绍了工作在60 GHz频段、支持1 Gbit/s以上数据速率的IEEE 802.15.3c标准和IEEE 802.11ad标准草案规定的无线接入机制的基本原理,然后对它们的特点和性能进行了详细的对比分析。研究结果显示:2种无线接入机制都采用了TDMA+CSMA/CA的混合机制,但各有所长;IEEE 802.11ad接入机制兼容性更好,能达到更高的数据速率,然而原理更复杂;IEEE 802.15.3c接入机制实现相对简单,同样也能达到Gbit/s级别的数据速率。最后,对全文进行总结并指出了未来的研究方向。     

Linux2.6内核下同步串行通信驱动的开发与应用

随着ARM/DSP双核处理器在地球物理勘探仪器中的推广应用,双核间的通信成为实现这种双核处理器系统的关键技术。针对Linux2.6版本内核,详细介绍了基于AT91TM9200的SSC同步串行通信设备驱动的模块化、分层次的设计架构,并在驱动中使用DMA传输模式、分段缓存技术和修改PDA控制器优先级。在此基础上给出了AT91RM9200/DSP56309双核的接口电路设计。试验表明,在AT91RM9200 /DSP56309双核中利用同步串行同步通信的设计,能够使系统高效、稳定、快速地进行数据传输,从而使双核处理器能够很好地协同工作。     

1.8 GHz TDD-LTE行业专网的运行环境影响分析

根据我国现行的频谱规划,在行业专网中可用于无线宽带专网建设的唯一授权可以使用的连续频段为1 785～1 805 MHz。由于多数行业专网承载业务和安全生产直接相关,有必要对该频段运行的无线运行环境进行分析。根据3GPP规划,该频段与Band3 FDD-LTE使用频段相邻,需要分析Band3频段对1.8 GHz TDD-LTE专网是否形成干扰。基于目前国家已经颁布的相关频率政策和型号核准要求对基站间干扰情况进行分析,并对相关型号核准文件提出建议。     

Polymer/carbon based composites as electromagnetic interference (EMI) shielding materials

The extensive development of electronic systems and telecommunications has lead to major concerns regarding electromagnetic pollution. Motivated by environmental questions and by a wide variety of applications, the quest for materials with high efficiency to mitigate electromagnetic interferences (EMI) pollution has become a mainstream field of research. This paper reviews the state-of-the-art research in the design and characterization of polymer/carbon based composites as EMI shielding materials. After a brief introduction, in Section 1, the electromagnetic theory will be briefly discussed in Section 2 setting the foundations of the strategies to be employed to design efficient EMI shielding materials. These materials will be classified in the next section by the type of carbon fillers, involving carbon black, carbon fiber, carbon nanotubes and graphene. The importance of the dispersion method into the polymer matrix (melt-blending, solution processing, etc.) on the final material properties will be discussed. The combination of carbon fillers with other constituents such as metallic nanoparticles or conductive polymers will be the topic of Section 4. The final section will address advanced complex architectures that are currently studied to improve the performances of EMI materials and, in some cases, to impart additional properties such as thermal management and mechanical resistance. In all these studies, we will discuss the efficiency of the composites/devices to absorb and/or reflect the EMI radiation.     

60GHz微带波导转换结构设计及其在通信集成前端中的应用

60 GHz无线通信技术具有非常宽的带宽,可以应用于超高速无线数据传输,已经成为第四代无线通信的重要组成部分,学术界和工业界对此投入了持续的关注。对60 GHz频段微带波导转换结构进行了设计,结果显示在57 GHz～64 GHz通信频率范围内,插入损耗小于1 dB,回波损耗小于-15 dB,达到了实用化要求。并利用MMIC芯片完成了60 GHz毫米波通信系统T/R模块的集成设计,对QPSK通信体制下的调制和解调信号进行了分析,验证了系统的可行性。     

一种适用于2.4GHz无线语音的IFA天线设计

设计了一种用于2.4GHz无线语音的IFA( Inverted -F Antenna)天线,该天线能够满足2.4GHz频段无线语音传输对天线尺寸、价格和性能的要求.使用有限元法进行数值仿真和设计,该天线可达到较好的效果.该天线的仿真和实测结果表明,在2.46 GHz的中心工作频率下,回波损耗为19.9 dB,带宽约为5...     

近水面2.4GHz信号传播损耗模型的校正研究

无线传感器网络的性能很大程度上受限于无线信道的特性。随着物联网事业飞速发展,近水面环境下2.4 GHz信号传播路径损耗模型的研究已成为无线传感器网络研究的重要课题之一。在近水面的环境下,针对基于IEEE802.15.4标准的2.4 GHz信号传播特性进行了实测研究,并利用最小二乘法对双射线模型进行拟合分析得到经验公式。研究结果表明:校正后的经验公式更符合实际环境中的信号传播路径损耗特点,这也为未来大规模铺设近水面无线传感器网络提供理论指导作用。     

60GHz无线通信系统在PPM调制下的信道容量分析

本文主要研究60GHz无线通信系统在高斯信道下的香农信道容量及在脉冲位置调制(MPPM)下的信道容量。理论分析与推导得到香农信道容量与传输距离的关系函数,由MPPM调制原理及高斯信道的数学模型推导系统在MPPM调制下信道容量与信噪比、信道容量与通信距离间的函数关系,利用Matlab仿真,得到不同条件下的关系曲线。研究结果表明,60GHz无线通信系统在高斯信道下的信道容量是通信距离和信噪比的函数,该系统更适合于短距离无线通信。高进制的PPM调制能够显著的提高系统数据传输速率,当数据率相同时,高进制调制的PPM能够提供的可靠通信距离更远。