Design and implementation of a vehicle interface protocol using an IEEE 1394 network

A wide variety of in-vehicle devices such as camera sensors, navigation systems, telematics and communication equipments have been incorporated into a vehicle to realize Intelligent Transport Systems (ITS) applications. Because an efficient standardized network is required, ITS Data Bus (IDB) has been discussed to carry high-speed multimedia data for audio, video and other real-time ITS applications. For connecting devices in a standardized manner, the IDB network has architecture with a gateway called vehicle interface which is located between automaker’s proprietary network and the standardized IDB network. IEEE 1394 (also known as iLink or FireWire), which can transport multimedia data for consumer electronics, is a good candidate for IDB network. In this paper, we analyze the issues for existing AV/C protocol (application layer protocol over IEEE 1394) to comprise the IDB network. In addition, we designed and implemented the vehicle interface protocol as a higher layer of IEEE 1394 to address the AV/C protocol issues for realizing the whole IDB network architecture.     

基于IEEE1451.2的网络化智能传感器的研究

文章在网络传感器接口标准IEEE1451.2的基础上,结合煤炭工业自动化的发展要求和CAN总线的技术特点,提出了一种基于CAN总线的网络化智能传感器的设计思想;针对网络传感器节点,提出了一种在线编程的设计方法,并详细介绍了网络传感器的硬件结构、数字通信接口以及TEDS设计思想和通信数据格式。     

基于VXI、PXI和LXI的网络化混合测试系统设计

文章介绍了混合测试系统整体结构,重点阐述了系统采用的硬件结构以及两种关键技术。此混合测试系统采用VXI总线、PXI总线和LXI总线共同组建,把三种单一总线系统的优点集于一体,既保护了测试资产中的已有投资而节省资金,又由于能继续使用熟悉的硬件、接口和软件,从而节省了时间。最后通过在项目中的应用得出了系统能缩短延时,并有效工作的结论。     

Capacity estimation algorithm for simultaneous support of multi-class traffic services in Mobile WiMAX

Mobile profile of WiMAX technology, based on IEEE 802.16e standard, is due to support multi-application services, while benefiting a wide range of implementation flexibilities. The current document presents a simple capacity estimation methodology for WiMAX systems. In this paper, the term capacity concerns with the maximum number of simultaneous multi-service users that each specific Mobile WiMAX access point can jointly support. A dynamic PHY+MAC overhead removal method is formulated to achieve an improved system goodput with respect to users distribution and multi-burst construction strategy. A service delivery model is presented that investigates the QoS requirements of the services to be supported, along with elaborating an application profile as a consistent input for capacitating and dimensioning studies. The minimum resource consumption calculation for the joint-application users is derived at each given time. An incremental algorithm compares the optimal available resources with minimum service demand for each number of users to arrive at maximum system capacity. Using the proposed algorithm, different simulation scenarios are studied based on the most used WiMAX implementation parameters in practice. The simulation results prove the significant roll of overhead calculation in performance evaluation studies. Furthermore, these results can be used for network planning and dimensioning purposes, as well as providing reference measures for scheduling performance analysis and detailed simulations.     

Heuristic algorithms for two-dimensional uplink burst construction in IEEE 802.16 networks

Many burst construction algorithms have been proposed for Orthogonal Frequency Division Multiple Access (OFDMA). However, none meets the burst structure characteristics required by the IEEE 802.16 standard. In this study, two heuristic algorithms, Best Corner Oriented (BCO) and Best Subchannel Oriented (BSO), are proposed to provide high throughput for uplink burst construction in IEEE 802.16 networks. The BCO maintains all available slots as a continuous area and attempts to construct each burst from one of the two ending slots of this area. The BSO, however, constructs each burst in its best quality subchannels to adopt a better modulation coding scheme (MCS). The simulation results under a heavy load indicate that BSO and BCO achieve 2 and 1.5 times, respectively, the throughput achieved by Raster, the conventional algorithm. However, the superior performance of BSO is achieved at the expense of increased time complexity.     

以太网供电技术及受电端电路设计

为解决具有以太网接口的小型功率设备供电不便的问题,在分别分析IEEE 802.3af标准中的以太网供电系统构成、以太网供电传输方式、以太网供电过程及其他电气特性的基础上,提出了一种通过以太网获取电源的解决方案,并给出了详细的电路设计原理图。该方案可同时支持以太网供电输入和其他辅助电源输入,并可以同时输出3.3 V和5 V这2种电压供系统使用。测试结果表明,该设计方案具有较低的成本和较高的效率,能够很好地解决小型功率设备供电不便的问题。     

基于IEEE 11073标准的脉搏信息远程监测系统实现

随着医疗科技的迅猛进步,病人可以在家中进行重点监护.医疗器械种类繁多,各自有不同的连接方式.为了改善此状沉ISO、IEEE及CEN等标准组织分别对医疗器械提出标准.本研究遵循医疗仪器间的互相通讯的标准ISO/IEEE11073-20601,致力于实现遵循统一标准的远程医疗监测系统.     

基于FPGA的整数开方运算

在使用FPGA作为控制芯片对发电机进行控制时,发电机的三相电压有效值计算涉及到开方运算。若要在FPGA上实现某个数的开方运算,QuartusII提供了开方模块altfp_sqrt,但是这个模块有严格的使用要求,要求用户输入的被开方数是IEEE754标准浮点数,altfp_sqrt模块的输出结果也是IEEE754标准浮点数。这种浮点数不便于用户使用和阅读。用VHDL语言提出了一种基于FPGA的整数转换为IEEE754标准浮点数的方法,同时也提出了基于FPGA的IEEE754标准浮点数转化为整数的方法,应用这两种方法再结合Quartus II提供的altfp_sqrt模块实现了对整数的开方运算。以Quartus II为软件工具,以Cyclone II系列的EP2C8Q208C8为硬件平台,在发电机控制应用中对方法的正确性给予了证明。     

宽带系统中低复杂度RAKE接收机的性能研究

基于IEEE 802.15.3a建议的超宽带密集多径信道模型，对采用最大比和等增益两种合并方式的RAKE接收机的高速超宽带通信系统的性能进行了研究.理论分析和计算机仿真结果表明，在密集多径环境下，采用复杂度相对较低的等增益合并SRAKE接收机，可以使通信系统达到良好的误码率性能，所以其更适合于超宽带通信系统.     

一种适用于终端移动的OFDM无线局域网的信道估计方法

本文提出了一种适用于具有移动终端的OFDM无线局域网的信道估计方法.该方法采用了卡尔曼滤波算法进行了信道估计,并利用导频进行信道跟踪.将基于训练序列的信道估计结果作为Kalman滤波器的初始值和观测值,用基于导频的信道估计结果来计算Kalman滤波器参数.并利用导频进一步跟踪信道在时间上的变化.Simulink仿真结果表明,该算法比基于导频的信道估计方法和基于训练序列的信道估计方法效果都要好.