Scheduling strategy for networked control system based on variable sampling period and deadband feedback

A scheduling strategy of variable sampling period combined with deadband feedback for networked control system is proposed. Variable sampling period algorithm can allocate a reasonable sampling period to each controlled loop according to the network utilization and packet transmission time. Deadband feedback algorithm can alleviate network congestion by appropriately adjusting the packets in the network when the networked control system cannot be scheduled. According to the actual overload and utilization of the network, the designed scheduling strategy dynamically adjusts the sampling period and priority, and improves the performance of the system combined with deadband feedback. Based on the TrueTime platform, the proposed scheduling strategy is verified on a three controlled loops networked control system with interference nodes and limited network resources. The simulation results demonstrate that the designed scheduling strategy can overcome the uncertainty of the upper bound of network resources, improve output control performance, reduce integral absolute error value of the controlled loop, and shorten the packet transmission time. The overall control performance of the system is improved. The designed scheduling strategy is effective.     

Network coded multicast for multi-hop D2D communication systems

ABSTRACT

In this paper, we consider the wireless communication systems where multi-hop Device-to-Device (D2D) networks can coexist with the conventional cellular networks by sharing the downlink resource of cellular users (CUs). A multicast data flow is distributed over the multi-hop D2D networks where network coding (NC) can be employed at the intermediate nodes. To maximize the utility of the multicast flow, we formulate a joint optimization problem for the systems while guaranteeing the quality-of-service (QoS) for regular CUs. We propose a subgradient algorithm to solve the optimization problem by decomposing it into three sub-problems: multicast rate control, NC subgraph selection, and downlink resource reusing. In particular, we develop a greedy algorithm to deal with the downlink resource reusing sub-problem for it is NP hard. Numerical and simulation results prove the superior performance of the proposed techniques compared with the conventional routing scheme.     

太赫兹频段星地通信信道建模与仿真

太赫兹频段作为至今尚未被完全开发的超高通信频段,具有超大带宽等优点,将其应用于第五代（the 5th Generation,5G）、后五代（Beyond 5G,B5G）移动通信系统,除实现更高速率传输外,还可实现地面移动网络与卫星网络频谱资源的共享,有利于推动新一代空天地一体化通信网络建设.文章提出了一种适用于星地通信系统的太赫兹信道建模与仿真方法,分析了自由空间损耗、分子吸收损耗、云雾衰减、雨衰减及多普勒频移等太赫兹信道的影响因素,构建了星地太赫兹通信信道建模流程,并给出了分步骤信道参数的生成方法.通过数值仿真,对不同天气状况下传输距离和频率对传输信号的影响进行了分析,并基于所生成的信道响应对误码率进行评估,从而验证了所提出模型和方法的可用性.所提建模方法能够提供不同传输条件下的动态太赫兹信道响应数据,从而为今后太赫兹频段无线通信系统的设计与开发提供评估与测试依据.     

Stabilizing network control for pneumatic systems with time-delays

This paper concerns with control design for networked pneumatic systems with uncertain communication delays. In the practical networked control systems (NCSs), there are usually unavoidable plant and communication delays. It has been known that time delays may not only deteriorate the system performance, but also destabilize the controlled plant. To alleviate the influence resulting from time delays while maintaining performance, a mixed fuzzy-PID/neural network compensating scheme is applied to the pneumatic system with communication delays. Real-world experiments verify effectiveness and superiority of our proposed approach.     

基于TrueTime的无线网络控制系统仿真研究

无线网络控制系统（WiNCS,Wireless Networked Control Systems）是基于无线网络的分布式控制系统,融合了计算机、通信、网络与控制技术,具有无需布线、组网和维护方便、易于扩展以及良好的可移动性等优点。为了研究影响WiNCS控制性能的因素,利用WiNCS惯用的仿真工具Truetime,建立仿真系统,对网络时延、干扰、采样周期、传输速率、功率控制、节点间距离等因素进行了仿真研究,给出了仿真结果及相应的结论,对进一步研究无线网络控制系统有一定的帮助。     

A Technique for Adaptive Voice Flow Control in Integrated Packet Networks

Integrated packet-switched networks have potential for providing improved performance by dynamically sharing transmission bandwidths between various users and user types, but new flow control methods are needed to deal with packetized voice traffic. This paper describes a packet voice flow control concept based on embedded speech coding. Results are presented from a computer simulation study of the technique in the context of a multilink wideband packet speech network. Several control methodologies are described, leading to an end-to end feedback approach that achieves stable operation and efficient utilization of network resources by adaptively matching transmitted voice bit rates to prevailing network conditions. Issues in the design of embedded speech coding algorithms are reviewed and a candidate structure based on channel vocoding principles is presented, along with the subjective results of some preliminary listening tests     

通讯资源受限网络系统的非均匀采样切换控制

针对含有通道资源受限和量化器的网络控制系统难于控制的问题,提出了基于切换原理的输出反馈控制器设计和动态调度方法.考虑到介质访问约束的影响,利用开关调度矩阵将通信受限的网络化控制系统,转化为含有多个子系统的非均匀采样的切换系统.利用Lyapunov稳定性理论推导出系统鲁棒镇定的充分条件,设计了可以满足任意切换稳定的最优鲁棒控制器和最优动态调度器.最后,通过仿真实例验证了所提出方法的有效性.     

Topology discovery services for monitoring the global grid

The dynamic joint optimization of both computational and network resources has the potential of guaranteeing optimal performance Io geographically distributed grid applications. A grid network information and monitoring service (NIMS) has been recently proposed to complement computational resource status information with network resource status information. NIMS information includes, but is not limited to, information already available in the network control plane (e.g., network topology, link capacity occupation, communication delay). This study first reviews some measurement methodologies and network sensors suitable for implementing NIMS components, and then describes some tools currently utilized for monitoring grid network infrastructures. Finally, two implementations of a NIMS component, called the topology discovery service (TDS), are proposed and evaluated. The TDS provides grid users (e.g., applications) or the programming environment middleware with up-to-date information on the grid network infrastructure topology and status. Both proposed implementations can be utilized in any global grid network based on commercial routers without requiring modifications of router management and control protocols.     

基于CAN的大客飞机航电系统局域网通信设计

提出一种基于CAN总线的大客飞机航电系统局域网通信仿真系统设计方法,探讨了CAN总线在航电总线中应用的优点及可能性。仿真系统硬件通过CAN总线通信卡及工控机实现,软件通过模块化设计方法实现。通信仿真系统实现了各子系统相关数据的传送、处理,以及相关信息的实时显示。应用表明,局域网通信系统工作正常、性能良好,能实现测试设备之间高速率的数据传输与转换,具有良好的实用价值。     

Deep learning-driven distributed communication systems for cluster online educational platform considering human–computer interaction

The wireless network environment has become increasingly complex, diverse, and dynamic. In recent years, the introduction of new concepts such as green networks and smart networks has diversified the optimization objectives of the spectrum resource management. Under this background, this paper proposes the novel deep learning-driven distributed communication systems for cluster online educational platform considering human–computer interaction. Before the modeling, the literature review and the state-of-the-art methodologies are introduced. For the framework design, first, the novel distributed communication system is designed considering the integration of the Q-learning under the deep neural network structure. Then, the cluster computing model is integrated for the system to enhance the robustness. Later, the human–computer interaction together with the movement tracking models is proposed to finalize the interactive online platform. The simulation results show that the proposed algorithm can extract the information accurately, and transmission efficiency is guaranteed. Compared with the latest platforms, the proposed outperforms from the aspects of accuracy and efficiency.     

语音信号数字传输系统GUI设计与仿真

首先将所设计的通信系统拆分成语音输入、抽样、量化、编解码以及调制解调等模块;然后通过Matlab编程进行模块设计功能实现;最后通过GUI编程实现各个通信系统模块的调用和链接,从而最终实现语音信号数字化传输系统通信系统的仿真。通过基于GUI界面设计和仿真结果表明,仿真模型能够反映话音信号数字带通系统的动态工作情况,具有较强的演示性、可视性和实用性;同时对于利用软件无线电技术构建无线通信具有十分重要的参考意义。     

Low-energy wireless communication network design

Energy-efficient wireless communication network design is an important and challenging problem. Its difficulty lies in the fact that the overall performance depends, in a coupled way, on the following subsystems: antenna, power amplifier, modulation, error control coding, and network protocols. In addition, given an energy constraint, improved operation of one of the aforementioned subsystems may not yield better overall performance. Thus, to optimize performance one must account for the coupling among the above subsystems and simultaneously optimize their operation under an energy constraint. In this article we present a generic integrated design methodology that is suitable for many kinds of mobile systems and achieves global optimization under an energy constraint. By pointing out some important connections among different layers in the design procedure, we explain why our integrated design methodology is better than traditional design methodologies. We present numerical results of the application of our design methodology to a situational awareness scenario in a mobile wireless network with different mobility models. These results illustrate the improvement in performance that our integrated design methodology achieves over traditional design methodologies, and the tradeoff between energy consumption and performance.     

机器类通信流量建模与过载控制

机器类通信(或MTC通信)定义为通过蜂窝网络进行数据传输的机器通信,作为未来泛在网络的重要组成部分,具有广阔的应用前景和市场潜力。为评估MTC接入时的网络性能,以3GPP参考流量模型和G/M/1队列模型的通解为基础,为MTC通信建立Beta/M/1队列模型;通过推导形状参数为任意正整数的Beta分布的概率生成函数的解析解,给出Beta/M/1模型性能评估的求解过程;利用数值分析,给出Beta/M/1模型的主要特征。为解决MTC接入时系统面临的过载问题,提出了3个解决办法,分别是:1)不同属性终端间聚类;2)改变MTC终端到达时间间隔分布;3)分段均匀随机退避算法。所提Beta/M/1模型及分段均匀随机退避算法可作为物联网/MTC通信/海量终端入网性能分析及过载控制的参考模型。     

Networked Control for Singular Systems Over Unreliable Channel with Limited Capacity

This paper addresses networked control problem for discrete-time linear singular systems over unreliable channel. It is assumed that the controller can only receive the transmitted sequence of finite coded signals via unreliable channels, which may be lost due to the limited communication capacity and transmission errors. By introducing compensation terms at every update instant and auxiliary systems in each sampling interval, both state- and output-based coder–decoder–controller procedures are proposed. Then, a uniform sufficient feedback stabilization condition involving the size of coding alphabet, the sampling period and data packet dropout rate is obtained. Finally, an example is given to illustrate the design procedures and effectiveness of the proposed results.     

FC-AE-ASM网络数据发送控制算法研究

该文研究FC-AE-ASM(Fibre Channel-Avionics Environment- Anonymous Subscriber Messaging,光纤通道-航空电子环境-匿名订户消息)网络的数据发送控制问题。从FC-AE-ASM网络的基本原理出发,提出了基于时间片轮转的数据发送控制算法,推导出在该算法下数据集合严格实时的充分必要条件,以链路占用率为性能衡量指标,证明在最差条件下,采用该算法后FC-AE-ASM网络的实时性可以得到保证。最后采用OPNET进行了仿真,通过结果分析,说明了理论分析的正确性。     

无线mesh网的跨层设计及其应用

根据无线mesh网跨层设计的基本原理,分析了跨层设计系统中各模块的功能和各种需要考虑的因素。提出一种综合了无线mesh网高效的状态信息交换方法和先进路由算法的跨层设计实现方案,可根据网络当前链路状态、拥塞情况和能量等因素,合理选择传输路径。同时还给出了该方法在电网高压输电监控系统中的应用实例。仿真和实验表明所提方案在实际应用时在强壮性、吞吐量和时延等方面都有良好的性能。     

基于CAN总线的A320模拟器硬件仿真方案研究

针对飞机模拟器硬件仿真时系统模块多、通信频繁、结构复杂而导致模块间布线繁杂,以及由此产生的干扰等问题,提出一种基于CAN总线的驾驶舱仿真方案。该方案中上位机负责逻辑运算,下位机负责操作信息采集,通过CAN总线将上、下位机组成一个网络,实现驾驶舱功能仿真。阐述系统的总体结构,设计了整个驾驶舱的数据传输协议,结合实际应用,给出了节点中数据收发模块的硬件设计结构和数据传输软件实现方法。实际测试结果表明,该设计布线简洁,数据传输稳定可靠,达到预期目标。     

软总线技术在航空武器视景仿真系统中的应用研究

为满足实时仿真系统中信息共享的要求,提出了数据软总线的设计实现方法.该方法较好地解决了系统中多个模块间的数据传输.文中应用于航空武器视景仿真系统中的实例,表明数据软总线的应用满足了该仿真系统评估武器性能,培训武器操作人员的要求,对同类仿真系统的设计具有一定的参考价值.     

Deadband Scheduling in Sensor Node and Controller Node for Wireless Networked Control Systems

A deadband scheduling method is proposed for wireless networked control system (WNCS), in which multiple loops share the same wireless network. The bandwidth of wireless network is very limited. The signal transmission among nodes vies for network resources, which will lead to the increase of network congestion and delays in WNCS. Deadbands are set up in both sensor and controller nodes so as to achieve network scheduling. In the sensor node, whether the sensor node sends data packet to wireless network or not depends on a deadband scheduling strategy. The deadband form is according to the difference between current sampling signal and the previous transmission signal, as well as the difference of two consecutive sampling signals. In the controller node, we use the deviations and their variation rate to build another deadband. Simulation results indicate that the proposed deadband scheduling method significantly achieves dynamic performance in WNCS, while effectively reducing network delays and network data packet traffic.     

一种改进的CNN端到端自编码器通信系统

针对现有端到端神经网络通信系统的泛化能力改进及自编码器优化等问题,提出了一种基于卷积神经网络(Convolutional Neural Network,CNN)的端到端通信系统改进方案。该方案在自编码器结构中引入一维卷积层(Conv1D),通过对参数的重新设计,优化了网络性能。发送端采用多层Conv1D对输入序列进行特征提取,通过训练获得发送信号的最佳调制和编码方案;接收端同样采用多层Conv1D,来恢复受到噪声污染的符号。仿真实验表明,在不同输入比特长度及编码速率条件下,所提系统表现出了良好的泛化能力。并且,在加性高斯白噪声信道和瑞利衰落信道下,训练模型的误码性能与传统的调制方式性能相吻合,验证了系统方案的可行性和有效性。此外,对于数字传输常见的突发信道,所提方案具有良好的适应性,可获得1 dB左右误码性能的改善。