A novel low‐power receiver topology for RF and microwave applications

A novel low‐power receiver topology for radio‐frequency and microwave applications is presented. The proposed solution exploits a simple connection between the low‐noise amplifier and the subsequent mixer, which is realized by means of a high‐value resistor and a current mirror, achieving low noise and high linearity performance with an extremely low power consumption. The criteria for its optimal design are derived in order to accomplish the main trade‐offs among noise figure (NF), linearity, and current consumption performance. As a case of study, the new topology has been designed in the case of I/Q direct conversion receiver for IEEE 802.15.4 standard (ZigBee) applications at 2.45 GHz. The receiver exhibits a NF of 8.7 dB, 50Ω input impedance, a voltage gain of 26 dB, an input‐referred third‐order intercept point of ?13 dBm, and a power consumption of 8.6 mW, which represent one of the best performance trade‐offs obtained in the literature. Copyright © 2008 John Wiley & Sons, Ltd.     

NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.     

一种基于低中频接收相位选择发射结构的工作在2.4GHz面向WPAN应用的超低功耗收发机

This paper presents a 2.4 GHz CMOS transceiver for the wireless personal area network （WPAN） inte- grated in 0.18/zm CMOS technology. This transceiver adopts a low-IF receiver, a MUX based transmitter and a fast-setting fractional-N frequency synthesizer. For achieving low cost and low power consumption, an inductor- less receiver front-end, an adaptive analog baseband, a low power MUX and a current-reused phase-locked loop （PLL） have been proposed in this work. Measured results show that the receiver achieves-8 dBrn of lIP3 and 31 dB of image rejection. The transmitter delivers 0 dBm output power at a data rate of 2 Mbps. The current consumption is 7.2 mA in the receiving mode and 6.9 mA in the transmitting mode, respectively.     

一种WPAN网络信标期融合改进方案

基于超宽带技术的ECMA标准采用分布式网络结构,是高速无线个域网理想的选择,本文针对该标准的信标期融合算法进行了研究,并利用无线个域网的信标时隙复用的特性,提出了一种改进的信标期融合方案,经过仿真验证,该方案可以大幅减少网络稳定所需时间,有效减少网络开销。     

Empirical analysis of the reliability of low‐rate wireless u‐healthcare monitoring applications

In this paper, we demonstrate an empirical analysis of the reliability of low‐rate wireless u‐healthcare monitoring applications. We have considered the performance analysis of the IEEE 802.15.4 low‐rate wireless technologies for u‐healthcare applications. For empirical measurement, we considered three scenarios in which the reliability features of the low‐rate wireless u‐healthcare monitoring applications have been measured: (i) distance between sensor nodes and base station; (ii) deployment of the number of sensor nodes in a network; and (iii) data transmission by different time intervals. The experimental results show that received data are used to calculate BER and analyze the performance according to the scenarios. The BER is affected when varying the distance between sensor node and base station, the number of nodes, and time interval. Copyright © 2011 John Wiley & Sons, Ltd.     

基于AES跳频算法的蓝牙WPAN网络数据传输性能

建立了无线个人区域网(WPAN)网络模型,分析了影响网络数据传输性能的因素。推导了WPAN数据吞吐率和蓝牙跳频序列汉明互相关性能以及蓝牙微微网数量三者之间的关系,采用AES算法生成跳频选择序列代替原有蓝牙算法,改善了WPAN网络数据传输,并进行了计算机仿真。使用SOC平台和CSR公司的Bluecore4蓝牙模块两套方案对仿真结果进行验证,证明了理论分析的正确性。在此结果的基础上得出,采用汉明互相关性能更优秀的AES跳频序列选择算法可以提高WPAN网络的数据传输性能。     

基于IEEE802.15.4协议的延时线问题探讨

IEEE802.15.4协议引入了延时线的概念,给协议带来了一定的影响.通过探讨工作在饱和状态、星形拓扑、信标使能的传感器网络下带时隙的马尔可夫链模型,推导出了该状态下的延时计算公式.仿真表明,延时线对延时的影响可以忽略,主要起节能作用.针对延时线的引入导致接入概率降低的问题,提出了让接入时隙的分布和节点数据长度相关的解决方案.     

一种基于计算机USB接口的可见光无线接入技术

本文介绍了用于室内无线接入的基于计算机USB接口的可见光无线通信系统的基本原理、相关技术和发展现状及应用领域。针对室内环境下无线光通信接入系统存在的问题提出了解决方法,并展望了未来计算机通信中这种无线接入技术的前景。     

基于蓝牙的无线个域网安全性研究

蓝牙技术是一种飞速发展的近距离无线通信技术,在无线个域网的构建过程中获得了越来越广泛的应用。本文以蓝牙设备构建无线个域网面临的网络安全问题为基石,分析了基于蓝牙技术的无线个域网安全模式,探讨了蓝牙密钥管理技术和加密算法。     

Portability in MAC protocol and transceiver software implementations for LR‐WPAN platforms

In a variety of emerging networked computing system domains over the years, there have been bursts of activity on new medium access control (MAC) protocols, as new communication transceiver technologies with greater data‐movement performance or lower power dissipation have been introduced. To enable implementations flexible to evolving standards and improving application‐domain insight, such MAC protocols are typically initially implemented in software, and interface between applications or system software, typically executing on an embedded processor or microcontroller, and the evolving radio transceiver hardware. Many challenges exist in implementing MAC protocols across evolving or competing transceiver hardware implementations and processor architectures. Some of these challenges are peculiar to the requirements of MAC protocols, and others are a result of the plethora of system and processor architectures in the embedded systems domain. This article studies the challenges facing software implementations of MAC protocols running on embedded microcontrollers, and interfacing with radio transceiver hardware. Experience with an implementation of the IEEE 802.15.4 MAC across three hardware platforms with different processor, system, and systems software architectures is presented, focusing on implementation approach and interfaces. Pitfalls are pointed out, and guidelines are provided for ensuring that new MAC implementations are easily portable across processor architectures and transceiver hardware. Copyright © 2010 John Wiley & Sons, Ltd.