Guaranteed Cost Active Fault-tolerant Control of Networked Control System with Packet Dropout and Transmission Delay

The problem of guaranteed cost active fault-tolerant controller （AFTC） design for networked control systems （NCSs） with both packet dropout and transmission delay is studied in this paper. Considering the packet dropout and transmission delay, a piecewise constant controller is adopted. With a guaranteed cost function, optimal controllers whose number is equal to the number of actuators are designed, and the design process is formulated as a convex optimal problem that can be solved by existing software. The control strategy is proposed as follows： when actuator failures appear, the fault detection and isolation unit sends out the information to the controller choosing strategy, and then the optimal stabilizing controller with the smallest guaranteed cost value is chosen. Two illustrative examples are given to demonstrate the effectiveness of the proposed approach. By comparing with the existing methods, it can be seen that our method has a better performance.

Efficient Broadcast Retransmission Based on Network Coding for InterPlaNetary Internet

In traditional wireless broadcast networks,a corrupted packet must be retransmitted even if it has been lost by only one receiver.Obviously,this is not bandwidth-efficient for the receivers that already hold the retransmitted packet.Therefore,it is important to develop a method to realise efficient broadcast transmission.Network coding is a promising technique in this scenario.However,none of the proposed schemes achieves both high transmission efficiency and low computational complexity simultaneously so far.To address this problem,a novel Efficient Opportunistic Network Coding Retransmission(EONCR)scheme is proposed in this paper.This scheme employs a new packet scheduling algorithm which uses a Packet Distribution Matrix(PDM)directly to select the coded packets.The analysis and simulation results indicate that transmission efficiency of EONCR is over 0.1,more than the schemes proposed previously in some simulation conditions,and the computational overhead is reduced substantially.Hence,it has great application prospects in wireless broadcast networks,especially energyand bandwidth-limited systems such as satellite broadcast systems and Planetary Networks(PNs).

Joint Optimization Strategy for Video Transmission over Distributed Cognitive Radio Networks

A novel joint optimization strategy for the secondary user( SU) was proposed to consider the short-term and long-term video transmissions over distributed cognitive radio networks( DCRNs).Since the long-term video transmission consisted of a series of shortterm transmissions, the optimization problem in the video transmission was a composite optimization process. Firstly,considering some factors like primary user's( PU's) collision limitations,non-synchronization between SU and PU,and SU's limited buffer size, the short-term optimization problem was formulated as a mixed integer non-linear program( MINLP) to minimize the block probability of video packets. Secondly,combining the minimum packet block probability obtained in shortterm optimization and SU's constraint on hardware complexity,the partially observable Markov decision process( POMDP) framework was proposed to learn PU's statistic information over DCRNs.Moreover,based on the proposed framework,joint optimization strategy was designed to obtain the minimum packet loss rate in long-term video transmission. Numerical simulation results were provided to demonstrate validity of our strategies.

Problem of Network Transmission Based on Linux Server and Its Solution

Using Linux server as a gateway between the local area network and the Internet may lead to slow pace in network transmission and even data loss. In this study,the above problem and its solution were discussed.

PTN和OTN传输设备的优劣势及发展趋势

在信息技术飞速发展和通信网络日新月异的今天,传输设备在现代通信系统中有着举足轻重的地位。分组传送网(Packet Transport Network,PTN)和光传输网络(Optical Transport Network,OTN)是目前两大主流的传输技术,可满足人们对高速、大容量、低延迟的业务需求。因此,文章综合分析PTN和OTN传输设备,探讨其优劣势及未来发展趋势,旨在给相关领域决策者与研究人员提供参考,推动通信网络不断创新与发展。

PTN-OTN光传送网络架构设计及发展趋势分析

在信息技术快速发展的背景下,通信网络也在不断进步,以满足日益增长的数据需求,提供更可靠、更高效的服务。在不断创新的过程中,PTN(Packet Transport Network)和OTN(Optical Transport Network)的混合组网方法以及光传送网络架构,逐渐成为当前通信网络设计和优化的焦点之一。文中探讨了PTN-OTN混合组网方法及光传送网络架构。

OAM Technology of Packet Transport Network

The Packet Transport Network(PTN) technology includes Transport Multi-Protocol Label Switching(T-MPLS) and Provider Backbone Transport(PBT).T-MPLS is the simplified and reformed Multi-Protocol Label Switching(MPLS).It drops MPLS’connectionless features and its transport-unrelated forwarding processing,but adds the network model of the transport layer,protection switching and Operation,Administration and Maintenance(OAM) functionality.PBT enforces both OAM and protection functions,adds Time Division Multiplexing(TDM) business simulation and clock functions,and strengthens multi-service support capability.But PBT has no functions of traditional Ethernet address learning,address broadcast and Spanning Tree Protocol(STP).Both T-MPLS and PBT can well satisfy the requirements of packet transport.Compared to PBT,T-MPLS has better OAM functions.

Effect of Transmission Range on Ad Hoc on Demand Distance Vector Routing Protocol

The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.

A consensus time synchronization protocol in wireless sensor network

Time synchronization is one of the base techniques in wireless sensor networks(WSNs).This paper proposes a novel time synchronization protocol which is a robust consensusbased algorithm in the existence of transmission delay and packet loss.It compensates for transmission delay and packet loss firstly,and then,estimates clock skew and clock offset in two steps.Simulation and experiment results show that the proposed protocol can keep synchronization error below 2μs in the grid network of 10 nodes or the random network of 90 nodes.Moreover,the synchronization accuracy in the proposed protocol can keep constant when the WSN works up to a month.

PTN技术在轨道交通领域的应用前景

分组传送网(Packet Transport Network,PTN)技术在轨道交通领域具有广泛的应用前景,可以提高轨道交通系统的安全性、信号控制效率和车辆调度准确性,同时为乘客提供更好的信息服务。随着互联网技术的不断发展,PTN技术在轨道交通领域的应用将会越来越重要,并为轨道交通行业带来更大的发展机遇。

基于演化博弈的车联网分发消息激励机制

由于车联网中节点资源有限,车联网中存在不愿意传递消息的自私车辆节点,严重影响网络性能。为了改善网络性能,提出了一种基于演化博弈的车联网消息合作分发的激励机制,利用节点始终追求最大收益的有限理性的特点,根据节点传递消息的数量以及节点在固定时间内的空闲程度设计收益函数,引导自私节点努力参与到车联网中消息的传递过程,同时引入路边单元作为监管者加速车辆节点的策略更新过程。仿真结果表明自私节点比例越多,网络性能越差,而该激励机制可以有效地改善存在自私节点的车联网的网络性能。

用于线路纵差保护的PTN时分复用业务时延分析

PTN承载的时分复用业务具有显著随机性,利用此类业务传输线路纵差保护数据需要全面分析业务时延和通道不对称性。在全面分析业务时延形成机理的基础上,建立了时延模型,该模型包含固定时延和随机时延两种分量。给出了数据分组随机时延的数值仿真方法,该方法可用来研究以太网帧长、带宽占用率和路径跳数等不同条件下的时延分布特征。定量分析了PTN承载时分复用业务对线路纵差保护通信需求的适应性。研究成果具有工程参考价值。

PTN技术在河南电力传输网中的应用分析

电力通信网是坚强智能电网的重要组成部分。针对河南电力地区传输网面临的问题,从业务需求、技术路线,实施方案等方面进行了分析,归纳了PTN技术的标准进程和技术优势,论证PTN技术在河南电力地区传输网中的应用可以解决数据业务激增的问题,充分考虑当前及远期投资效益,其综合效益高于对SDH设备进行全面升级改造。

一种PTN网络中IEEE 1588v2非对称时延的解决方案

针对IEEE 1588v2协议双纤双向传输的非对称时延问题,采用粗波分复用技术实现主从端的精确时间同步,解决了非对称时延问题。分析了色散、折射率和温度等因素对单纤双向传输时延的影响,给出了实现精确时间同步的试验方案,并在中国移动的PTN现网中进行了试验。结果表明,采用该方法不仅能够达到时间同步的精度要求,而且可以节省光纤。

PTN技术在本地传输网中的应用探讨

简要介绍了PTN核心技术与应用现状,较详细地论述了本地传输网采用PTN技术的必要性;结合某地区本地传输网PTN规划实际,提出了PTN技术的3种组网模式,以及PTN独立组网和PTN+OTN联合组网2种方案,并对其进行了详细分析。

超级城域传输网PTN建设方案的探讨

3G业务的发展导致了PTN技术越来越广泛的应用,在一些超级城域网中,PTN组网将面临一般场景下难以碰到的困难,本文从网络架构、保护方式等方面对如何解决超级城域网中PTN网络建设问题进行了分析。希望能对今后PTN网络的建设起到有益的参考。

山东电力PTN数据承载网规划及建设方案

依托山东电力集团PTN数据承载网建设项目,从PTN数据承载网建设的必要性、PTN组网技术原则、网络保护策略、网络同步等方面介绍了山东电力2011～2013年PTN网络规划及建设方案,并以日照地区为例给出了初期建设方案。PTN网络独立于传统的SDH网络,将成为电力通信系统面向IP业务的第二张传送网,为智能电网的发展提供可靠的通信保障。此次山东电力在全省大规模统一部署PTN网络在国内电力系统尚属首例。

中国移动本地传输网PTN+OTN组网策略探讨

分析了中国移动本地传输网承载业务的变化趋势,总结了中国移动本地传输网的组成架构及演进趋势,探讨了PTN+OTN组网策略,对比分析了独立组网、叠加组网、融合组网3种组网方式,并对各种组网方式的组网策略、方案特征、适用场景等进行了深入探讨。

PTN在移动传输网分组化进程中的应用

电信业务和网络正在逐步演进为面向分组的业务和网络,移动城域网正面临着全面的建设和改造,即由电路域向分组域演进。3G网络的全面敷设带来了海量增长的数据业务源,这是推动城域网全面改造的原动力。本文重点介绍了分组传送网(PTN)技术在移动传输网中的重要地位和基于PTN组网的回传方案在HSDPA数据传输中的应用,介绍了将PTN设备作为网络分组化进程中的核心设备的方案,即一种网络融合、业务融合及运营商融合的新模式。

PTN技术在本地传送网中组网探讨

文章首先介绍了PTN技术标准、设备及应用情况,基于基站回传应用场景,探讨了PTN在本地传送网内各层可能的组网结构,然后就大、中、小型本地网分别提出了PTN端到端的整体组网架构。