Weibull衰落信道下多跳通信系统的性能分析

分析了在独立不同分布Weibull衰落信道下配有非再生中继的多跳无线通信系统性能. 基于调和几何平均不等式,得到了更易于数学处理的端到端信噪比上界. 通过计算上界的矩母函数、概率密度函数和矩等闭式表达式,得到了多跳通信系统的平均端到端信噪比、信道容量和平均误比特率等重要性能界. 数值仿真结果表明该界是紧的.     

基于应用层流量优化的中继路径选择方案

基于网络层路由协议的缺省单一路径难以满足高带宽应用的端到端传输需求,多径传输是一种有效方式。在基于应用层中继的多径传输系统的基础上,提出基于应用层流量优化的中继路径选择方案：借助于应用层流量优化机制,提出中继路径选择过程中遵循的规则,提出基于运营商定义域的最优中继路径生成算法,为数据传输分配优质的中继路径,同时在运营商定义域之间以及中继服务转发器之间保持负载均衡。仿真结果表明,提出的方案在选择优质中继路径方面具有较优性能,同时能够灵活地均衡运营商定义域之间的负载。     

Relay selection with feedback beamforming information through designed sector sweep report frame for mmWave WPANs

This paper proposes a novel relay selection strategy based on the feedback beamforming （BF） information through designed sector sweep （SSW） report frame for millimeter-wave （mmWave） wireless personal networks （WPANs）. First, an SSW report frame compatible with IEEE 802.11ad standard is designed. Second, an approach collecting instantaneous channel state information （CSI） overheard during BF is devised. Third, with the aim of minimizing the outage probability and maximizing the overall network throughput capacity, the optimal relay selection issue for non-line-of-sight （NLoS） links is formulated as a bipartite graph, and Kuhn Munkres （KM） algorithm is provided to resolve it. Both theoretical analysis and simulation results show, with CSI considering NLoS conditions and selected relays according to the overall network throughput capacity maximization principle, the improvements achieved over opportunistic relay selection strategy in terms of overall network throughput capacity and outage probability with minimal modifications to IEEE 802.1lad.     

Decentralized transceiver optimization for multi-relay aided multiuser MIMO networks

In this paper, the decentralized transceivers and corresponding channel state information （CSI） signaling concepts are proposed for weighted sum rate （WSR） maximization, via linear downlink transceiver＂ optimization in multi-relay aided multiuser multiple-input multiple-output （MIMO） networks. Three decentral- ized algorithms are proposed with the local CSI requirements at the base station （BS） and the relay nodes. In the first proposed algorithm, the generalized channel inversion precoding is used at the BS to avoid the second hop channel sharing requirements among the relay nodes, and decentralized transceiver optimization of the relay nodes and users are developed to maximize the WSR. A minimum mean square error （MMSE）-based enhanced method is proposed as well. To further improve the performance, we provide a novel structure of the precoding matrix of the BS. The decentralized joint BS, relay and user transceiver optimization problem is formulated and solved. Also, the CSI signaling and decentralized processing in the time division duplex （TDD） system are analyzed. Simulation results show the effectiveness of the decentralized transceiver design compared to the existing algorithms.     

Low-complexity optimal spatial channel pairing for AF-based multi-pair two-way relay networks

This paper considers a multi-pair two-way relay system with multi-antenna users and proposes a low-complexity optimal spatial channel pairing （SCP） strategy at the relay station （RS） for such a system. The proposed SCP scheme, following the BD-like beamformer at RS, pairs the uplink spatial subchannels of each user pair with the corresponding downlink spatial subchannels by maximizing sum-rate （Max-SR）. Furthermore, a new mathematical inequality （arrangement inequalities of a product） is developed and applied to obtain sufficient and necessary conditions for achieving Max-SR-SCP. This also yields a simple low-complexity implementation of the proposed SCP in contrast to the NP-hard complexity of the original Max-SR-SCP problem. Simulation results illustrate that the proposed Max-SR-SCP achieves substantial sum-rate gains over other pairing schemes.     

电力系统继电保护整定计算软件探析

介绍电力系统继电保护整定计算软件的相关问题,着重探讨了对该软件的改进措施.     

红外光通信装置的设计与实现

介绍2013年大学生电子设计竞赛F题红外光通信装置的设计与实现。整个系统采用两个LM567（PLL）音频锁相环集成电路来完成红外光通信,性价比高,结构简单。     

基于eNSP的DHCP网络实验的设计与实施

随着网络技术的快速发展,网络规模越来越大,采用固定IP地址的分配方式给网络管理工作带来的问题日益凸显。通过eNSP仿真实验平台设计了两个不同的实验,分析了在同一网段中的DHCP的配置方法和不同网段DHCP中继代理的配置方法,仿真实验证明采用DHCP协议对网络设备实现动态IP地址的管理和分配,可以有效地提高网络管理员的工作效率,且灵活性好。     

基于改进蚁群算法的方向过电流保护整定优化

本文提出了基于蚁群优化算法的方向过电流保护整定配合的优化模型。首先说明了方向过电流保护的时间特性,然后建立了方向过电流整定优化模型。优化目标是所有主保护动作时间之和最小,考虑了主后备保护配合约束、保护动作时间约束、启动电流约束等。本文所提方向过电流保护为非线性优化问题,提出利用改进蚁群优化算法来求解该模型。最后本文利用IEEE8节点进行仿真分析,并与其他方法进行对比,说明本文所提算法在求解保护配合优化问题的优势。     

继电保护信息系统终端设备智能测试系统

为了达到快速、精准的继电保护信息系统终端设备测试效果,设计一种继电保护信息系统终端设备智能测试系统。利用无线方式将数据采集模块所采集的终端设备数据传输至数据处理模块;利用信号处理算法除掉原始数据中的干扰数据,使其符合监测预警模块的要求;实现终端设备运行状态量变化实时监测,并发出预警等级信息;智能测试模块将高于监测预警指标的终端设备数据形成录波数据,利用保护装置结合录波数据获取保护运作行为结果,通过评价运作行为结果完成终端设备智能测试。实验结果表明,所研究的系统能够实现继电保护信息系统终端设备的智能化测试,提升测试终端设备的工作效率与电力企业的经济效益。