P-order metric UWB receiver structures with superior performance

The generalized Gaussian probability density function is shown to better approximate the probability density function of the multiple access interference in ultra-wide bandwidth systems than the Gaussian approximation and the Laplacian density approximation. Two ultra-wide bandwidth receiver structures based on this new approximation using a p-order metric receiver decision statistic are investigated for the detection of time-hopping ultra-wide bandwidth wireless signals in multiple access interference channels. The first receiver outperforms both the conventional matched filter ultra-wide bandwidth receiver and the soft-limiting ultra-wide bandwidth receiver when only multiple access interference is present in UWB channels. The second new receiver with adaptive limiting threshold outperforms the conventional matched filter ultra-wide bandwidth receiver, the soft-limiting ultra-wide bandwidth receiver, and the adaptive threshold soft limiting ultra-wide bandwidth receiver in all multiple access interference-plus-noise environments. In multipath channels, a new Rake receiver based on the p-order metric receiver is proposed for signal detection. Mathematical analysis and numerical results show that this new Rake receiver can achieve larger signal-to-interference-plus-noise ratio than the standard matched filter Rake receiver when multipath components are resolvable in UWB channels.     

A Comparative Analysis of Optimum and Suboptimum Rake Receivers in Impulsive UWB Environment

In this paper, the performance of rake receivers in the presence of fading and impulsive noise is addressed. The optimum maximum likelihood (ML) rake receiver for impulsive fading channel is derived, and a suboptimum rake receiver with a reduced complexity is obtained for practical purposes. Numerical results show that the suboptimum rake receiver exhibits almost the same performance as the optimum rake receiver. It is also observed that, as the number of fingers of a rake receiver increases, the performance of the rake receiver designed for impulsive environment improves, while the rake receiver optimized for Gaussian environment experiences performance degradation in an impulsive environment     

Soft-Limiting Receiver Structures for Time-Hopping UWB in Multiple-Access Interference

A novel receiver structure based on soft-limiting is proposed for detecting a time-hopping ultrawide-bandwidth (UWB) signal in the presence of multiple-access interference (MAI). The proposed structure contains a nonlinear limiter for suppressing the MAI. Simulation results show that the proposed receiver achieves better bit-error-rate performance than the conventional matched receiver when operating in MAI. When operating in an MAI-plus-Gaussian-noise environment, the receiver structure outperforms the conventional matched-filter receiver for moderate to large values of signal-to-noise ratio (SNR). A receiver structure with adaptive limiting threshold is further proposed to ensure that the performance of the soft-limiting receiver always meets or surpasses the performance of the conventional UWB receiver for all values of SNR. Application of the soft-limiting structure in the fingers of a rake receiver is shown to enhance the signal-to-noise-plus-interference ratio.     

接收机非线性测试分析

介绍了接收机非线性产生的原因及其对接收机造成的影响。讨论了目前几种接收机非线性表示方法在复杂电磁环境下进行接收机干扰分析时存在的局限性。提出了利用接收机非线性项系数直接进行接收机非线性性能表示,并给出了进行接收机非线性项系数测试和计算的方法。利用该方法对一台接收机进行了具体的测试和计算,根据计算结果进行接收机受干扰仿真分析,与实测能够较好地吻合。     

Performance of Jointly Optimized Prefilter-Equalizer Receivers

A linear receiver for digital communication over unknown dispersive and noisy channels obtained by jointly optimizing the prefilter and equalizer has been described by the authors in a recent paper [4]. An extension to incorporating a decision-feedback equalizer is made. Performance of the new receiver is evaluated by means of computer simulation. Comparison of the performance of the new receiver, the matched filter-equalizer receiver, and the fixed low-pass filter-equalizer receiver is made both with respect to convergence rate and error rate. It is conjectured that the new receiver exhibits performance superior to both the matched filter-equalizer receiver and the fixed low-pass filter-equalizer receiver.     

基于AlGaN/GaN HEMT太赫兹探测器的340 GHz无线通信接收前端

利用天线耦合AlGaN/GaN HEMT太赫兹探测器的自混频和外差混频效应,分别设计并测试了340 GHz频段直接检波式和外差混频式接收机前端。通过接收机信噪比的测量和接收功率的定标,得到了两种接收机的等效噪声功率。直接检波模式下探测器的响应度约为20 mA/W,直接检波模式和外差混频模式下接收机的等效噪声功率分别约为?64.6 dBm/Hz1/2和?114.79 dBm/Hz。在相同的载波功率和接收信号带宽条件下,当本振太赫兹波功率大于?7 dBm时,外差混频接收的信噪比优于直接检波的信噪比。当本振功率大于0 dBm时,外差混频接收机表现出优良的解调特性,其信噪比高出直接检波接收机的信噪比10 dB以上。     

Generalized performance analysis of a delay diversity receiver in asynchronous CDMA channels

In this letter, the performance for the delay diversity receiver is analyzed in asynchronous code division multiple access (CDMA) channels. The outage probability and the bit error probability of the delay diversity receiver are accurately derived and compared with those of the conventional diversity receiver. From the analytical and numerical results, it is confirmed that the delay diversity receiver achieves a remarkable diversity gain with reasonable cost and complexity in asynchronous CDMA channels. Specifically, for roughly the same hardware complexity, the delay diversity receiver achieves nearly twice the diversity order of the conventional receiver.     

Per-survivor processing sequence detection for DS/CDMA systems withpilot and traffic channels

A per-survivor processing (PSP) sequence detection receiver is proposed for DS/CDMA systems with pilot and traffic channels. The proposed receiver jointly estimates channel parameters and data symbols from pilot and traffic channels, and is derived by modifying the receiver of Choi (see IEEE Proc. Commun., vol.146, no.5, p.1-7, 1999). As a result, the new receiver can outperform the receiver of Choi in exchange for additional computation. Computer simulation results demonstrate the advantage of the proposed receiver over existing ones     

Performance analysis of optimum receivers for differentially encoded M-PSK in low SNR

A recent paper has proved that the classical receiver for coherent detection of differentially encoded M-PSK in AWGN is optimum for the MAP sequence detection criterion. In this letter, we show that asymptotically, as SNR tends to zero, the MAP symbol detection criterion receiver is equivalent to the classical differentially coherent receiver, for M greater than two. An asymptotic relative efficiency figure of merit is defined in order to compare the performances of the classical coherent receiver and the classical differentially coherent receiver.     

Signal processing for the multistate myoelectric channel

In the multistate myoelectric channel, a single myoelectric signal source is used to control a multifunction powered prosthesis. The selection of a prosthesis function requires a receiver to process the myoelectric signal, contaminated with noise, and to decide on the basis of the received signals which function is desired. Thus the channnel cleady presents a problem of choice of receiver and of decision strategy. Previous sotutions to this problem have been basically empirical. In this paper we seek the optimum receiver where optimum is in the minimum probability of error sense. First a model is developed for the bipolar myoelectric signal to provide information about the relevant signal parameters and statistics. Using this information the Bayes minimum probability of error receiver is derived for an orbitrary signal parameter set. The optimum signal parameter set is then found for the Bayes receiver, and the receiver performance calculated. The receiver performance is measured and compared with the calculated performance. A significant performance improvement is seen in the optimum receiver over a more conventional receiver.     

同步CDMA系统的一种次最优的2维Rake接收机

本文研究自适应阵列与用户接收相结合的检测技术,给出了同步ＣＤＭＡ的一种次最优２维Ｒａｋｅ接收机。通过计算机仿真,与传统的２维Ｐａｋｅ接收机作了比较,说明这种接收机克服了传统接收机具有的空间相应效应和远近效应。文中最后分析了联合自适应阵列的多用户接收在蜂窝环境的容量,指出两种技术的结合能弥补各自的缺陷,从而大大提高系统的容量。     

采用LTCC技术的X波段接收前端MCM设计

多芯片组件(MCM)是目前实现机载雷达接收前端小型化的最有效途径。文中对X波段全频段多功能接收前端的组成、采用LTCC技术的MCM设计实现及实物测试数据进行了叙述和分析,给出了采用LTCC技术的X波段多功能接收前端MCM设计的一种解决方案。该MCM接收前端的测试指标满足雷达通用接收前端要求,为雷达小型化多功能接收前端的设计提供了参考依据。     

A Low Noise 100 GHz Sideband-Separating Receiver

We have built a 100 GHz sideband-separating receiver. The receiver, a breadboard for the band 3 cartridges for ALMA, achieves a SSB noise temperature of 6hf/k with a 4–8 GHz IF. We show that it is possible to meet the ALMA specifications. The design of the receiver is reviewed and the relationships between the receiver noise temperature and properties of the components used in the receiver are discussed.     

基于判决自相关超宽带接收机研究

首先介绍了基于判决自相关(简称DDA)超宽带接收机的接收原理和结构,理论分析了接收误码率特点;比较了基于判决自相关接收机与Rake接收机和基本TR接收机的基本参数要求,并在标准信道模型下仿真对比了它们的接收性能;考察了窗口宽度因子N对基于判决自相关接收机接收性能和结构的影响;通过提高判决自相关系统脉冲功率可在相同能量效率条件下获得与平均TR系统相近的接收性能,且具有更高传输率的优点。     

激光告警装置的布设及其评价方法研究

为了提高激光告警装置在激光对抗中的作战效能,研究了激光告警装置的布设及布设效能的评价方法。首先根据激光告警装置的工作原理、设备性能和战术使用原则,将激光告警装置的布设要素分解为警戒区域、警戒空间、基准方位、布设数量和水平状态等5个子项,分析每一子项的布设要求,建立对应的布设效果评分模型;然后采用层次分析法确定各要素的权重,进而得到告警装置布设效果的总体评价模型;最后给出了布设及布设效能评价方法的应用实例。提出的布设效能评价方法能够用于激光告警装置防护效能的自动评估,已应用于激光对抗系统的虚拟训练系统中。     

TH-UWB通信系统数字接收机的芯片设计

设计了一种结构简单的UWB通信系统单用户数字接收机芯片。分析了跳时脉位调制(TH-PPM)超宽带信号的产生原理,在传统TH-UWB相关接收模型的基础上,采用一种结构简单且易于数字相关处理的接收机。该结构能有效降低接收机的复杂度。采用Cadence的Spectre仿真工具,对设计的电路和版图进行了仿真。后仿真结果表明,系统可正确地恢复信息码。设计的数字接收机采用SMIC 0.18μm标准CMOS工艺,工作电压为1.8 V。     

先进米波雷达DBF 模拟接收机设计

现代雷达系统对接收机提出了更高的要求,数字化接收机能满足这些要求并已经成为现代雷达、通信等接收系统的一种主流实现方式。文中研究了数字接收机,重点讨论了模拟接收机与数字模块的匹配、增益的计算和分配。根据设计要求,给出了一种模拟接收机详细设计方案,进行了各部分分析计算和详细设计,按照设计方案进行了工程样机研制,调试完成后给出了测试结果。测试结果表明:模拟接收机指标完全满足设计要求,并应用到了样机系统中,且工作稳定可靠。     

Neural network-based receiver for wireless communications

A novel approach, based on neural networks, for the design of a receiver for TDMA wireless communications is described. The receiver utilises three functional blocks: time-frequency analysis, feature extraction, and pattern classification. Computer simulation results are presented comparing the performance of the new receiver against a conventional MSK receiver for a Rayleigh fading multipath channel. The results show that the new receiver is capable of achieving a performance comparable to that of the MSK receiver without the regular transmission of a training sequence     

CMOS RF receiver system design: a systematic approach

A unified system-level design methodology for highly integrated CMOS radio frequency receiver design is introduced. This complete system-level design methodology is targeted to minimize the total power consumption of the receiver. System-level design techniques which can be used to derive the overall receiver radio specifications and study noise and linearity performance of receivers are presented. Then, a few circuit examples of building blocks in receiver signal chain are analyzed to show a linear relationship between power and dynamic range of the blocks. The result is then used to derive the optimal system specification distribution among receiver signal chain building blocks yielding the minimum total receiver power consumption for a given system performance. The theory and an actual CMOS Bluetooth receiver design are compared showing very good agreement.