Algorithms Transformation Techniques for Low-Power Wireless VLSI Systems Design

This paper presents an overview of algorithmtransformation techniques and discusses their role inthe development of hardware-efficient and low-power VLSIalgorithms and architectures for communication systems. Algorithm transformation techniquessuch as retiming, look-ahead and relaxed pipelining,parallel processing, folding, unfolding, and strengthreduction are described. These techniques are applied statically (i.e., during the system designphase) and hence are referred to as static algorithmtransformations (SATs). SAT techniques alter thestructural and functional properties of a givenalgorithm so as to be able to jointly optimizeperformance measures in the algorithmic (signal-to-noiseratio [SNR] and bit error rate [BER]) and VLSI (powerdissipation, area and throughput) domains. Next, a new class of algorithm transformations referred toas dynamic algorithm transformations (DAT) is presented.These transformations exploit the nonstationarity in theinput signal environment to determine and assign minimum computational requirements foran algorithm in real time. Both SAT and DAT techniquesare poised to play a critical role in the development oflow-power wireless VLSI systems given the trend toward increasing digital signal processing inthese systems.     

Theoretical Analysis of PAPR Companding Techniques for FBMC Systems

Wireless Personal Communications - The offset quadrature amplitude modulation (OQAM) with filter bank multicarrier (FBMC) has turn on considerable interest in last decades over orthogonal frequency...     

Design and Performance Analysis of a New Soft Handoff Scheme for CDMA Cellular Systems

In this paper, a new soft handoff scheme for CDMA cellular systems is proposed and investigated. It is pointed out that some handoff calls unnecessarily occupy multiple channels with little contribution to the performance of handoffs in IS95/CDMA2000-based handoff schemes or systems. To alleviate performance degradation due to channel resource shortage during soft handoff, a new concept of channel convertible set (CCS), which contains several types of handoff calls that unnecessarily occupy extra channels by considering the relative mobility of the calls in the handoff area is introduced. A new scheme that reallocates those extra channels in the CCS to new handoff calls when there is no available free channel in the system is proposed. Furthermore, according to the variation of the CCS, the proposed scheme dynamically adjusts the number of guard channels reserved exclusively for handoff. Then, the feasibility and implementation issues of the proposed scheme are discussed. To evaluate and compare performance indexes of different soft handoff schemes, continuous-time Markov chain models are constructed. Automated generation and solution of the underlying Markov chains are facilitated by stochastic reward net models, which are specified and solved by stochastic Petri net package. Numerical results show that this scheme can significantly decrease both the number of dropped handoff calls and the number of blocked calls without degrading the quality of communication service and the soft handoff process.     

Two New Techniques Integrated for Energy-Efficient TLB Design

The translation lookaside buffer (TLB) is an essential component used to speed up the virtual-to-physical address translation. Due to frequent lookup, however, the power consumption of the TLB is usually considerable. This paper presents an energy-efficient TLB design for the embedded processors. In our design, we first propose a real-time filter scheme to facilitate the block buffering to eliminate the redundant TLB accesses without comparator delay. By modifying the address registers to be sensitive to the contents variation, the proposed real-time filter can distinguish the redundant TLB access as soon as the virtual address is generated. The second technique is a banking-like design, which aims to reduce the energy consumption per TLB access in case of block buffer miss. To alleviate the performance penalty introduced by the conventional banking technique, we develop two adaptive variants of the banked TLB. Both variants can achieve the high energy efficiency as the banked TLB while maintaining the low miss ratio as the nonbanked TLB. The experimental results show that by filtering out all the redundant TLB accesses and then minimizing the energy consumption per access, without any performance penalty our design can effectively improve the Energy^* Delay product of the TLB, especially for the data TLB with poor locality     

数字系统的诊断技术分析

文章讨论了故障诊断技术的产生,发展和存在的一些问题,并对一些故障诊断方法进行了分析,评价;最后,对故障诊断和ＡＩ技术的结合进行了探讨。     

基于UML的嵌入式系统设计分析

文章阐述了嵌入式系统和标准建模语言UML的概念,提出了基于UML的嵌入式系统设计方法,介绍了使用UML对嵌入式系统——无线接入点(Access Point)做面向对象分析与设计的过程。     

Analysis of FSO Systems with SISO and MIMO Techniques

Wireless Personal Communications - The capacity of the radio link can be improved a lot by using modern wireless technologies like Multiple Input and Multiple Output (MIMO) technology. Successful...     

WDM-PON接入技术及其最新进展

本文首先从时分复用无源光网络（TDM—PON）的不足引入波分复用无源光网络（WDM—PON）,接着介绍了ONU波长固定和可调WDM—PON,随后阐述了ONU无色和无光源WDM—PON。鉴于目前WDM-PON难以推广使用的现状,上行用TDMA替代WDMA会使WDM—PON看起来更加现实,所以本文也介绍了混合使用WDM和TDM的HPON。最后对WDM—PON与功率分配PON（PS—PON）的技术进行了比较。     

光学和光电子系统用的微机械加工技术

回顾了微机械加工技术的最新进展, 介绍了自由空间微型光学试验平台和光预对准的概念以及微机械加工的光学器件实例。     

防空体系光电对抗技术应用分析

光电对抗技术在军事上的广泛应用,使战争的进程和结局产生极速变化。从宏观的角度分析了防空体系预警系统的组成,并对光电对抗技术在防空中的应用作了介绍。     

DSP系统电源管理技术

电源效率既取决于硬件设计与组件选择,又取决于基于软件的电源管理技术。文章讨论了嵌入式系统的电源管理技术,介绍了如何将其集成到DSP的RTOS 中,并以TI的DSP/BIOS操作系统为例,给出了电源管理软件技术的实施方法。     

高能效系统的功耗优化技术

本本将叙述了各种系统选择方案及其对系统功耗的影响,全面介绍了处理器电源管理功能,并讨论总系统功耗的一些重要促进因素。本文网络版地址：http：//www.eepw.com.cn/article/164395.htm     

Reliability Prediction Techniques for Complex Systems

As electronic systems continue to evolve into more and more complex structures, the search for better and more efficient reliability prediction techniques naturally takes on added momentum. Needed are not only systematic methods of mathematical model building that will simplify the procedures involved but also noncomplex ways of obtaining solutions to many practical problems. This paper illustrates the applicability of transition diagram in describing the state space of a complex system, repairable or nonrepairable, and shows the methodology of writing the set of first-order linear differential equations representing the system performance by inspection of the transition diagram. A discussion of some applicable properties of linear signal-flow graphs is included. Methods of solving problems by inspection techniques are clearly explained and specific examples are given to illustrate the concepts. The mean time Tm for a system to pass for the first time from its initial state to a failed state is usually a statistic of prime interest. Certain properties of Laplace transform are used to illustrate how Tm of a general complex system, repairable or nonrepairable, can be obtained by solving a set of simultaneous algebraic equations. Flow graph techniques of solution by inspection are shown to be a valuable tool in obtaining analytical solutions for Tm of many practical systems.     

Design and Analysis of Data Communication Systems

A network can promote collaboration between many different and widely dispersed groups of workers. Expanding network capabilities and information flow throughout a business organization can help to improve quality, responsiveness, reaction time and, ultimately, sales and profits.     

液相外延温控系统与真空系统的全新设计

对液相外延温控系统和真空系统进行了全新的设计,温控系统运用单相可控硅过零触发技术,解决了移相触发技术中使系统电压畸变,功率因数下降的问题.并配以日本神港程序控制器,使得温度精度达到±0.1 ℃,且重复性和稳定性也相应地得到提高.真空系统加入了冲洗气体保护装置,有效地解决了以往冷阱变暖使油蒸汽反流的问题.     

线性和非线性寄存器系统的并行化技术

并行化技术可降低电路工作速率、延时和功耗,广泛应用于通信处理中.对线性寄存器系统,通过对系统状态方程和输出方程的讨论提出一般性的(1,N)并行化方法,其对任意并行路数N均有统一计算方法;并对某些情况下的(M,N)并行提出一种新实现方法.对非线性寄存器系统,给出其定义,对其状态转移进行线性化,提出线性化矩阵法的并行方法;并对其特例——非线性移位寄存器的并行化提出推广延时因子法.     

矿用RFID标签天线的分析与设计

本文提出了一种用于矿井人员定位系统的结构紧凑的Hilbert分形倒F标签天线.通过HFSS软件仿真,分别给出了普通倒F天线和Hilbert分形倒F天线的回波损耗、方向图及天线增益.仿真结果表明,这2种天线性能相当,但Hilbert分形倒F天线具有更小的尺寸,更符合矿用RFID标签天线小尺寸、低功耗的要求.制作的Hilbert分形天线经测试,在2.425 GHz的中心频率下,回波损耗为-38.28 dB,带宽为190 MHz.     

Controlled Intersymbol Interference Design Techniques of Conventional Interconnect Systems for Data Rates Beyond 20 Gbps

This paper presents a new design technique of high-speed interconnects with controlled intersymbol interference (ISI) to create efficient signaling over a band-limited channel. Performance of high-speed electrical links is limited by conductor loss, dielectric dispersion, and reflections in the board, package, and connector. These nonidealities result in significant ISI. In current systems, the effect of ISI is either mitigated through complex equalization, signal conditioning, and coding techniques, or through costly impedance control and manufacturing processes. In the proposed approach, instead of eliminating ISI, we shape the response of the channel into a set of channel characteristics with controlled ISI using simple passive structures in the board and the package. The resulting controlled ISI is exploited at the transmitter and receiver to simplify the architecture of the system and to achieve high data rates. The techniques to design interconnects with controlled ISI are reasonably simple to implement in conventional interconnect technologies. Simulation examples are given to demonstrate the validity and advantages of the design technique using duobinary and analog multitone (AMT) signaling methods.