The bl ind scheme for channel estimation with high accuracy

摘要：基于多载波 OFDM 系统 ,提出了一种新的时变步长修正软加权判决递归二 乘信道估计盲方法( TVCPMSDWRLS) 。该法通过对常规算法步长进行自适应的科 学设计以便跟踪信道特征变化 ,同时利用接收机判决信息函数修正权系数 ,解决了常 规 RLS盲方法收敛速度慢、 信道估计性能不高的缺点。仿真证明:对于不同的时延 扩展、 时间以及信噪比(SNR) ,该法均表现出比常规方法更优的性能。同时 ,该法亦 可用于估计通信、 雷达、 航天等领域的其他特征参数。英文摘要：A blind channel estimation scheme , named as time2variance convergence parameter and cor rect sof t decision weight RLS ( TVCPMSDWRL S) met hod , based on orthogonal f requency division multiple (OFDM) systems was proposed. The no2 vel scheme could t race adaptively t he channel characteristic t hrough special timevariance gain design. And t he decision information f unction in receiver was al so adapted to correct t he gain. Simulation showed t hat the novel scheme had bet ter per2 formances with high accuracy and fast converges t han t hat of t he RL S met hod , especially via different time delay spread , time and SNR. Furt hermore , the scheme can also suitable in the ot her areas such as communication , Radar , spaceflight to estimate the ot her characteristic parameter s.　 基金项目:广东省自然科学基金资助项目(D06300640) ;广东省中山市科技计划项目 (2006A155) ;电子科技大学中山学院青年科技基金资助项目(2005Y12 和 2006Y02以及 2006Y05) ;福建省自然科学基金资助 项目(A0410004) ;厦门大学院士基金资助项目(06302E23011) ;厦门大学新世纪优秀人才基金资助项目(00002X07204

An Optimal Scheme for Memory Management in Fault-tolerant Real-time System

探讨如何把抢占门限应用于具有优先级提升和内存受限的实时系统,并进一步研究了互不抢占组内,linux平台上基于增量检测点的内存备份/恢复的方法及原型系统的实现。原型系统采用了可扩展的链接方式作为检测点文件格式,使得数据更加紧凑有序;在内存的备份操作上,提出了“影子脏位”算法来识别两检测点之间有无被改变的部分。原型实验验证了所提出方法的有效性。After analyzing how to apply preemption-threshold-scheduling into real-time systems among which the recoveries of safety tasks may be executed at higher priority levels and the sizes of memories are limited,we research realization methods about memory backuprecovery on the Linux platform based on increment checkpoints for no-preemption task groups.At last,taking the microcomputer interlocking simulation system as an example,prototype experiment of memory backup/recovery has been done on the Linux platform in the lab.Our prototype experiment takes an extendable checkpoint file layout to make data in a file compact.And with regard of memory backup operation,by using a″showdown of dirty-bit″ algorithm to identify the difference between two checkpoints,it implements an increment checkpoint to improve system performance.This experiment has proved the validity of proposed methods.广东省自然科学基金(06029667

ACO-OFDM系统叠加训练序列时间同步方法

针对插入序列降低频带利用率的问题,提出了叠加序列的时间同步方法。通过将复数序列构造具有共轭对称结构,IF-FT（快速傅里叶逆变换）后得到实数具有镜像反函数特性的序列线性叠加在OFDM（正交频分复用）符号上,解决了传统插入序列独占发射功率的缺陷。仿真表明,与传统方法相比,该方法在低信噪比下具有更高的同步准确率,同时提高了系统频谱利用率

YAG∶Ce~(3+)在激光照明应用中的研究进展

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