Power allocation for MIMO-OFDM systems with multi-user decoupling and scheduling

1 .INTRODUCTIONRecentinformation-theoretic results haveshownthat multi-ple-input multiple-output ( MI MO) channels have a greatpotential to i mprove spectral efficiency in rich scatteringwireless channels[1 ,2].Si multaneously,orthogonal frequen-cy division multiplexing (OFDM) has gained anincreasinginterest as a promisingalternativeforfuture highrate wide-band wireless systems because of its lowcomplexity signalprocessingto counteract frequency selectivity. The combi-nationof MI MOsy…     

战术分组无线网分群与群管理

在分组无线电网中，网络规模的增大和节点数目的增多会引起网络性能的下降，在这种情况下要对节点进行分群。文中对分组无线电的分群算法进行了分析，并提出了一种适用于战术分组无线电的分群算法和群管理的方法。     

基于电场感应的水下无线电力传输

为了验证水下电能传输的可行性和研究影响传输效率的因素,采用电场耦合原理进行了简单的无线充电电路设计,对电场耦合式无线电能传输的系统结构和基本工作原理进行介绍,分析了其相比于磁场耦合方式的特点,以及由此带来的相应优势,通过多物理场仿真模拟极板间电场分布,设计了一种LC双边的CPT系统,采用单片机组成脉宽调制控制电路并用功率放大电路模块组成发射端和接收端。结果表明了运用电场耦合原理进行无线充电的可行性,在研究中发现极板间的传输距离是影响水下无线充电效率的一个因素,而且两个电极之间的杂散电容也会影响极板间的功率,所以由于极板间隙的存在极板间的功率损耗较大。所提出的LC双边CPT系统,不仅实现了水下无线电能传输,还保证了在一定距离和频率下传输效率的稳定。     

A New Signal Processing Technique of π/4-DQPSK Modem Based on Software Radio

1 .INTRODUCTIONπ/4 DQPSKmodemhasbeenchosenasthemodemschemeinmanymobilecommunicationsystems[1 ] .Inπ/4 DQPSKmodem ,theinformationbitsaremappedintophasetransitionsratherthanabsolutephasevalues.Thisencodingofinformationinthetransitionsovercomesthephaseambiguityproblemsresultingfromtheestimationofcarrierphaseinnon differentialPSKsystems.Soπ/4 DQPSKallowsforsimplebasebanddifferentialdemodulation .Further,inπ/4 DQPSK ,themaximumphaseshiftisrestrict edto± 1 35°(ascomparedto± 1 80…     

A relay selection scheme based on geometric optimum in cooperative cognitive systems over mixed channels

This paper proposes a relay selection scheme based on geometric optimum principle to maximize the cognitive link＇ s connectivity with limited interference to primary user in cooperative cognitive systems. A dual-hop cognitive relay system is considered, in which the channel impulse response follows independent non-identical distribution （i. n. d. ） each hop, such as Rician, Rayleigh and Nakagami-m distribution. Then, closed-form expressions in terms of outage probability and average bit error rate （ABER） are obtained using amplify-and-forward （AF） relaying protocol over such mixed fading channels. Furthermore, the best range of the relay is derived. Extensive simulation re- suits are conducted to verify the theoretical analysis, which is useful to the network optimal design.     

磁分离酶联免疫测试分析仪的研制

给出了磁分离酶联免疫测试分析仪测试中成色物的吸光度与人体被测抗原的浓度之间的函数关系，通过试剂测试反应产物酚酞的吸光度与光的波长之间的函数关系，给出了磁分离酶联免疫测试分析仪的测试原理，讨论了根据非线性拟合所得到的参数，由测量得到的实际标本吸光度反算实际标本浓度的方法，给出了磁分离酶联免疫测试分析仪硬件电路的工作原理，提出硬件电路和软件系统的设计方案并且研制了样机。     

Reconstruction algorithm of computerized ionospheric tomography

Applying the technique of computer tomography to ionosphere detection, Computerized Ionospheric Tomography (CIT) can produce the large scale distribution of electron density in a two dimentional longitudinal section of ionosphere. According to the actual detecting condition of sparse receiver and limited projecting angle, polynomial interpolation method and projecting angle expansion method are proposed. A new energy function is formulated according to the constraint of least neighbourhood error. Simulated annealing is incorporated in the iteration of ART to get the global minimum of energy function. Sun Xiaon; born in May 1968, Ph. D. Current research interest is in computer graphics & Image processing Supported by the National Natural Science Foundation of China     

蜂窝环境下功率空时分布仿真的改进算法

为更好地对蜂窝环境下的功率空时分布进行仿真,引入“有效散射体”和“反射概率”两个有明确物理意义的概念,在单反射椭圆模型(GBSBEM)的基础上提出一种改进的仿真算法.该算法能更准确灵活地描述蜂窝环境下信号的功率空时特性.仿真结果与实测数据对比表明,在功率时延谱预测方面,改进算法与GBSBEM有同样的精度,而在功率方位谱预测方面,前者的均方相对误差要小于后者.     

宏小区高天线环境下波达角度和时间的预测

为提高对空时到达分布预测的准确度,介绍了一种适用于小区高天线环境下波达角度和时间预测、的改进的圆散射模型。分别给出了波达角度和时间分布概率密度函数的表达式。仿真结果与实测数据的比较表明,较传统的基于散射体的单反宏小区模型而言,改进的圆模型能更合理地对传播建模,且在波达角度和时间的预测方面具有更高的准确度。