基于IEEE802．16的WiMax组网技术

无线宽带城域网正在成为无线接入领域新的热点,基于此重点阐述了WiMax的组网方案,根据尽量对目前正使用网络兼容和补充的原则,提出了WiMax组网分3个阶段进行的策略,并且给出了每阶段的详细组网方案。     

A pseudo differential Gm-C complex filter with frequency tuning for IEEE802.15.4 applications

This paper presents a CMOS G_m-C complex filter for a low-IF receiver of the IEEE802.15.4 standard.A pseudo differential OTA with reconfigurable common mode feedback and common mode feed-forward is proposed as well as the frequency tuning method based on a relaxation oscillator.A detailed analysis of non-ideality of the OTA and the frequency tuning method is elaborated.The analysis and measurement results have shown that the center frequency of the complex filter could be tuned accurately.The chip was fabricated in a standard 0.35μm CMOS process,with a single 3.3 V power supply.The filter consumes 2.1 mA current,has a measured in-band group delay ripple of less than 0.16μs and an IRR larger than 28 dB at 2 MHz apart,which could meet the requirements of the IEEE802.15.4 standard.     

基于TMS320DM642的硬件实现IEEE1588时钟同步

采用美国国家半导体公司推出的专用集成有IEEE1588精准时钟协议硬件支持功能的以太网收发芯片DP83640,通过在物理层标记PTP时钟同步报文发送和到达的时刻,与TI公司的内置以太网媒体接入控制器(MAC)功能的TMS320DM642芯片连接实现高精度的时钟同步功能。     

MST-based topology control with NLOS location error compensation for location-aware networks

The topology control algorithms can improve the network capacity and network lifetime in location-aware networks. The topology control algorithms require accurate locations of mobile nodes or distances between each of the mobile nodes. The IEEE 802.15.4a-based location-aware networks can provide precise ranging distance between two mobile nodes. The mobile nodes can obtain their accurate locations by using accurate ranging distances. However, in the IEEE 802.15.4a networks, the ranging distance has a large measurement error in non-line-of-sight (NLOS) conditions. In this paper, we propose MST-based topology control with NLOS location error compensation algorithm to improve location accuracy and prevent mobile nodes from connecting to unstable links in NLOS condition. Performance evaluation shows the proposed algorithm constructs a topology map which has low location errors with considering the instability of NLOS links in NLOS condition.     

EEFA:高能效的IEEE 802.11N帧聚合调度算法(英文)

Packet size is restricted due to the error-prone wireless channel which drops the network energy utilization.Furthermore,the frequent packet retransmissions also lead to energy waste.In order to improve the energy efficiency of wireless networks and save the energy of wireless devices,EEFA(Energy Efficiency Frame Aggregation),a frame aggregation based energy-efficient scheduling algorithm for IEEE 802.1 In wireless network,is proposed.EEFA changes the size of aggregated frame dynamically according to the frame error rate,so as to ensure the data transmission and retransmissions completed during the TXOP and reduce energy consumption of channel contention.NS2simulation results show that EEFA algorithm achieves better performance than the original frame-aggregation algorithm.     

WiMAX的技术亮点和市场策略

文章从WiMAX成为3G新标准说起,着重介绍了WiMAX的技术优势及其市场策略,简单阐述了作者对WiMAX进入3G标准家族的感受和启迪。     

基于虚拟仪器技术的高频地波雷达系统的实现

本文在比较了几种常用的虚拟仪器软硬件平台后,并根据高频地波雷达的应用特点和环境,提出了一种基于VXI仪器的硬件平台和基于基C Builder的软件编程环境.接着对该VXI机箱内的各模块功能进行简述.本文从软硬件的角度说明应用虚拟仪器技术到高频地波雷达中具有基于传统仪器技术所无法比拟的优势.     

基于JTAG技术的Flash加载

主要介绍了目前世界上主要流行的一种Flash加载技术——利用JTAG技术加载Flash。文章分为3个部分。首先描述了JTAG加载Flash的原理。然后对JTAG加载Flash的优点做了说明。最后对实验性能做了详细分析。     

无线局域网相关技术标准和组网技术

由于无线局域网的技术日趋成熟及应用的普及，可满足移动数据和多媒体连网的需要，其在广电领域渗透应用不是不可能的，因此有必要前瞻性地跟踪该技术。本文论述了无线局域网的相关技术标准及组网技术。     

宽带无线接人——LMDS的应用和发展

本文对LMDS典型系统作了概述并着重讨论了当前LMDS的几种不同应用场景和相应组网方案 ,以及未来LMDS采用的毫米波加自由空间光无线这一新技术将基于光纤的带宽和业务扩展到终端用户的组网方案。最后介绍了新的固定宽带无线接入协议IEEE 80 2 .16- 2 0 0 1的主要特点