基于3G的应急通信控制系统的设计与实现

研究了一种使用3G模块适用于家居应急保险防灾的无线通信系统,设计了该系统的总体方案,其中包括硬件系统和软件系统。硬件系统的核心采用华为MU509通信模块,软件主要实现语音通话、短信收发和远程控制等功能。使用Qt编程实现了整个软件系统,通过向3G模块发送AT指令进行通信控制,结合51单片机对该系统的部分外部设备进行远程控制。     

3G工业适配器节点的设计

从工业控制网络的无线化需求出发,针对3G网络应用到工业无线控制领域的方案,重点介绍了一种3G工业适配器节点的软、硬件设计。该适配器节点采用MU103完成传统网络和工业无线网络到3G网络的接入,采用MSP430F5438芯片完成数据采集、AT命令与自主协议的转换以及AT命令的执行任务,采用RS485接口完成适配器节点与仪表或工业无线网关的通信任务。实验室WIA网络以及Profibus网络检测结果表明,该适配器节点工作稳定、可靠,且具有较好的兼容性。     

Graph‐based resource allocation algorithms for multiuser downlink MIMO‐OFDMA networks

Multiuser multiple‐input multiple‐output orthogonal frequency division multiple access (MIMO‐OFDMA) is considered as the practical method to attain the capacity promised by multiple antennas in the downlink direction. However, the joint calculation of precoding/beamforming and resource allocation required by the optimal algorithms is computationally prohibitive. This paper proposes computationally efficient resource allocation algorithms that can be invoked after the precoding and beamforming operations. To support stringent and diverse quality of service requirements, previous works have shown that the resource allocation algorithm must be able to guarantee a specific data rate to each user. The constraint matrix defined by the resource allocation problem with these data rate constraints provides a special structure that lends to efficient solution of the problem. On the basis of the standard graph theory and the Lagrangian relaxation, we develop an optimal resource allocation algorithm that exploits this structure to reduce the required execution time. Moreover, a lower‐complexity suboptimal algorithm is introduced. Extensive simulations are conducted to evaluate the computational and system‐level performance. It is shown that the proposed resource allocation algorithms attain the optimal solution at a much lower computational overhead compared with general‐purpose optimization algorithms used by previous MIMO‐OFDMA resource allocation approaches. Copyright © 2012 John Wiley & Sons, Ltd.     

小样本目标识别问题下的BN参数学习

目标识别问题中存在大量不确定信息, 利用BN可以对不确定信息及其相互关系进行学习与推理。但是, 目标识别问题的样本量较小, 在参数学习过程中, 常因观测数据不足产生误差, 需要引入单调性信息等专家经验, 针对这一问题, 提出最小元算法。首先, 利用最小元表达单调性信息, 将其转化为参数学习可以直接利用的先验信息; 然后, 基于保序回归思想, 对参数学习结果进行优化, 消除误差, 得到相对准确的网络参数。以空中目标识别为仿真背景, 与最小子集算法比较, 验证了该算法在准确度与复杂度等方面的优势。     

Constellation constrained multiuser multiple‐input multiple‐output for high capacity and error performance over correlated fading channels

Channels' correlation has direct impact to degrade the capacity and reliability of multiple‐input multiple‐output (MIMO) systems considerably. In this paper, new signal constellation designs are investigated to mitigate fading correlation and maximize the capacity and error performance of multiuser MIMO (MU‐MIMO) over correlated channels, which is a major research challenge. Two methods are studied in a novel constellation constrained MU‐MIMO approach, namely, unequal power allocation and rotated constellation. Based on principles of maximizing the minimum Euclidean distance (d_min) of composite received signals, users' data can be recovered using maximum likelihood joint detection irrespective of correlation values. Compared with the identical constellation scenario in conventional MU‐MIMO, it is shown that constellation rearrangement of transmitted signals has direct impact to resolve the detection ambiguity when the channel difference is not sufficient, particularly in moderate to high correlations. Extensive analysis and simulation results demonstrate the superiority of proposed technique to capture most of the promised gains of multiantenna systems and application for future wireless communications. Copyright © 2014 John Wiley & Sons, Ltd.     

速率比例公平下多用户OFDM系统的自适应资源分配

在多用户正交频分复用(MU-OFDM)系统中,考虑各个用户之间具有比例数据传输速率限制条件下的一种公平的自适应资源分配方案的最优算法计算量巨大,为此,提出了一种将子信道分配和功率分配相分离的次优算法.首先,在假设相同功率分配的情况下进行子信道的分配,然后在保持一定比例公平条件下使总容量最大时进行最优功率分配.对该算法的仿真表明,在用户数为2、子信道数为10的系统中,所提算法的容量性能接近最优算法,而计算量由指数增长变为线性增长.所提资源分配算法的总容量比以前的算法在用户间的分配更公平也更灵活.     

The design of the MUSS operating system

This paper describes the design of a general purpose operating system called MUSS. One of the major objectives of the MUSS system is that it should be adaptable. The paper discusses the features of its design which lead to adaptability, in particular the method of structuring the system and the techniques and tools used in documenting it.     

光纤电子式电流互感器的优化设计

新型光纤数字化电子式电流互感器(ECT)是在普通ECT的基础上改进其存在的一些不足,使之精度更高,功耗更低,功能更完善,适用于数字化变电站的要求.文章首先介绍了新型光纤数字化ECT的总体设计,然后分别介绍了组成新型数字化ECT的高压侧数据采集器和低压侧合并单元(MU),最后介绍了新型数字化ECT的供能方案.     

电子互感器合并单元硬件构架研究与设计

在比较IEC60044—7/8标准和IEC61850—9—1标准中合并单元的基础上,基于IEC61850—9—1标准,利用DSP&FPGA构建了合并单元的硬件整体构架,硬件设计采用类似保护装置的分插件的设计思想.该方案保证了传输数据的准确性和实时性.     

User scheduling based on angles with block diagonalization in MU‐MIMO broadcast

This paper investigates user selection scheme in the multiuser multiple‐input multiple‐output (MU‐MIMO) broadcast (BC) scene with block diagonalization precoding. Block diagonalization is a suboptimal but practical linear precoding method, which can eliminate the multiuser interference by turning the MU‐MIMO BC channel into parallel MIMO channels. With this precoding method, we propose the best user from the user subset to maximize the total throughput in the MU‐MIMO BC system. The angles between subspaces used in this paper are induced from n ‐inner product, an extension from norm space to the n ‐dimensional space, which characterizes the orthogonality between subspaces. One of the algorithms achieves good performance by comparing the capacity greedily, the other one attains high capacity by reducing the cardinality of the user subset to improve the orthogonality between the user channels, which could be seen as a complexity reduction algorithm with respect to the former one. Indeed, they are all based on the angles between subspaces. Analysis shows that both of the proposed algorithms have lower complexity and better performance than the classical algorithms. The numerical results also confirm our analysis.