蓝牙中的自适应跳频技术

自适应跳频是蓝牙技术中采用的预防频率冲突的机制，他能有效地防止频率碰撞。从而保证系统正常的吞吐量。     

A low power high-performance area efficient RF front-end exploiting body effect for 2.4 GHz IEEE 802.15.4 applications

The rising internet-of-things applications in home automation, smart wearables, healthcare monitoring demand small, area efficient, high-performance and low power radio frequency (RF) blocks for effective short-range communication. This growing market demand is addressed in this paper by proposing a fully CMOS radio frequency front-end (RFE) exploiting bulk effect. Apart from the primary function of frequency translation, proper circuit performance concerning the linearity, conversion gain, and noise figure is required for low-cost densely integrated transceivers operating in the 2.4 GHz ISM band. The proposed RFE at 2.4 GHz is designed and implemented in UMC 180 nm CMOS process technology with two modes of operation. In high gain mode (Mode-I), the post-layout simulation with SpectreRF shows a peak gain of 30.06 dB, IIP2 at 64.52 dBm, IIP3 at −2.74 dBm and a DSB-NF of 7.68 dB while consuming only 9.24 mW from the 1.8 V supply. In the high linear mode (Mode-II), the RFE achieves a higher IIP3 of 10.78 dBm, IIP2 of 91.56 dBm, the conversion gain of 23.5 dB, DSB-NF of 9.46 dB while consuming a low power of 3.6 mW. The fully CMOS circuit occupies a core area of only 0.0021 mm². The proposed front-end exhibits a spurious free dynamic range (SFDR) of 81.18 dB ensuring the high dynamic operation of the wireless system.     

超宽带及其在无线个域网中的应用

近年来,超宽带(UWB)无线通信成为短距离、高速无线网络最热门的物理层技术之一。介绍了超宽带无线通信技术的概念及其信号传输过程中使用的关键技术,包括脉冲成形技术、调制技术以及接收技术,给出了超宽带无线传输系统的基本模型,最后分析了该技术在无线多媒体个域网中的应用。     

基于MB-OFDM UWB的短距离无线多媒体传输

超宽带（UWB）是实现高速无线个域网（WPAN）多媒体传输的关键技术。UWB以超短周期脉冲进行调制，并使用超宽的RF频谱带宽传递数据，可通过重叠的原则共享已占用的频谱资源；其具有频谱利用率高、抗多径衰落能力强、发送功率极小、系统安全性好等特点。UWB可为消费类电子设备提供高速无线连接解决方案，使视频连接和桌面应用等能在通用射频平台上运行。因此，研究UWB的标准化、产品化与市场化进程，剖析其主流技术。对于制订我国相关标准，促进UWB技术与系统产品在中国的发展和实施，具有积极的现实意义。为使UWB主流技术能被进一步了解，在跟踪研究UWB标准化的基础上，分析了作为国际上第1个商用UWB标准的多频带正交频分复用（MB—OFDM）方案的原理与技术特征，并阐述了基于该方案的无线多媒体超宽带（WiMedia UWB）平台与应用环境，产品整合进展及应用前景．     

室内802．11b WLAN与UWB—WPAN ＆ ZigBee-WPAN的干扰

目前，大量的无线设备应用在2．4GHz这一开放频段，很明显各种设备之间存在着潜在的干扰问题，在将来的办公或家庭环境中，如何避免或减少各种WPAN设备与WLAN的相互射频干扰的问题变得重要起来。本文将分析由UWB、ZigBee技术分别构成的两种新型WPAN设备和WLAN之间的影响，分别从WLAN设备链路的吞吐量和信噪比等角度分析了802．11bWLAN和两种短距离技术设备的干扰，并进行了WPAN设备的工程实验和模拟仿真。     

无线网络的QOS机制分析研究

无线网络越来越受到人们的关注,由此带来的多媒体业务流量的剧增,使无线网络的资源管理、服务质量（QoS）保障等问题日益突出.文章主要分析IEEE802.11e D3.0和IEEE802.15.3 D16两种协议标准的工作机制并对两者的性能作出了比较分析.     

超带宽技术在无线个域网中的应用

超宽带技术与现有的其它无线通信技术相比,有着数据传输速率高、功耗低、安全性好等特点,它是目前无线通信学术界研究的热点问题。本文首先对超宽带技术的特点作了详细的介绍,然后分析了UWB技术在高速WPAN中的应用情况,最后对应用前景做出了展望。     

蓝牙与802.11b的干扰与共存分析

无线局域网和蓝牙都工作在2.4GHz的ISM频段,它们如果在一起工作,在无干扰防范措施时数据碰撞明显,传输效率低下.为了提高传输效率,该文分析了碰撞的原因、理论模型与概率,结合无线局域网和蓝牙间的距离、吞吐量、丢包率影响的实际测试结果,从发射功率调整、距离控制和帧长控制方面提出了小范围、低密度应用环境下的无线局域网和蓝牙共存技术和方法.     

Non-coherent UWB Radio for Low-rate WPAN Applications: A Chaotic Approach

The requirements of low cost, low power and longer operation range for low-rate wireless personal area network (LR-WPAN) applications has driven the utilization of non linear communication approach. In this paper, a combined ultra-wideband (UWB) and chaotic communication technologies is proposed to meet these challenging demands. Among the candidates, the differential chaos shift keying (DCSK) modulation appears to be a very promising solution. The DCSK is a family of transmit reference (TR) system where a correlator based receiver is used to demodulate the received signal. However, this is not very well understood in the literature and therefore we will exemplify this issue in terms of noise performance. Furthermore, the feasibility study of the proposed DCSK is presented through the scalability and link budget analysis in two different operation modes. The system performance in both additive white Gaussian noise (AWGN) channel and standardized IEEE 802.15.4a UWB multipath channels are provided in order to further demonstrate the capability of the proposed system.     

一种改进IEEE802.15.3MAC协议机制的信道资源分配算法

本文简单介绍了IEEE802.15.3协议,分析了协议的MAC层QoS机制。针对实时VBR(VariableBitRate)业务流,提出了一种改进协议机制的信道资源分配算法,并在性能上与平均资源分配算法进行了分析和比较,通过仿真验证了此分配算法能有效降低实时VBR码流的丢帧率,提高系统传输的QoS性能。