A novel vertical handoff algorithm based on fuzzy logic in aid of grey prediction theory in wireless heterogeneous networks

To coordinate the various access technologies in the 4G communication system, intelligent vertical handoff algorithms are required. This paper mainly deals with a novel vertical handoff decision algorithm based on fuzzy logic with the aid of grey theory and dynamic weights adaptation. The grey prediction theory (GPT) takes 4 sampled received signal strengths as input parameters, and calculates the predicted received signal strength in order to reduce the call dropping probability. The fuzzy logic theory based quantitative decision algorithm takes 3 quality of service (QoS) metric, received signal strength (RSS), available bandwidth (BW), and monetary cost (MC) of candidate networks as input parameters. The weight of each QoS metrics is adjusted along with the networks changing to trace the network condition. The final optimized vertical handoff decision is made by comparing the quantitative decision values of the candidate networks. Simulation results demonstrate that the proposed algorithm provides high performance in heterogeneous as well as homogeneous network environments.     

Dynamic wavelength and bandwidth allocation using adaptive linear prediction in WDM/TDM ethernet passive optical networks

Hybrid wavelength-division-multiplexing (WDM)/time-division-multiplexing (TDM) ethernet passive optical networks (EPONs) can achieve low per-subscriber cost and scalability to increase the number of subscribers. This paper discusses dynamic wavelength and bandwidth allocation (DWBA) algorithm in hybrid WDM/TDM EPONs. Based on the correlation structure of the variable bit rate (VBR) video traffic, we propose a quality-of-service (QoS) supported DWBA using adaptive linear traffic prediction. Wavelength and timeslot are allocated dynamically by optical line terminal (OLT) to all optical network units (ONUs) based on the bandwidth requests and the guaranteed service level agreements (SLA) of all ONUs. Mean square error of the predicted average arriv-ing rate of compound video traffic during waiting period is minimized through Wiener-Hopf equation. Simulation results show that the DWBA-adaptive-linear-prediction (DWBA-ALP) algorithm can significantly improve the QoS performances in terms of low delay and high bandwidth utilization.     

A Multiobjective Optimization Algorithm for QoS-Aware Path Selection in DiffServ and MPLS Networks

Introduction The enlargement of the Internet user commu-nity has generated the need for IP-based applica-tions requiring guaranteed quality of service (QoS)characteristics. For providing per-flow serviceguarantees without a per-flow state in the corerouters, the integration of DiffServ and multi-pro-tocol label switching (MPLS)[1]architecture hasbeen proposed. The MPLS architecture provides adistributed way for resource reservation and QoSpath setup through the use of a Label Distribut…     

QoS awared power and admission controls based on non-cooperative game theory in wireless networks

In order to better accommodate heterogeneous quality of service (QoS) in wireless networks, an algorithm called QeS-aware power and admission controls (QAPAC) is proposed. The system is modeled as u non- cooperative game where the users adjust their transmit powers to maximize the utility, thus restraining the interferences. By using adaptive utility functions and tunable pricing parameters according to QoS levels, this algorithm can well meet different QoS reqniremcnts and improve system capacity compared with those that ignore the QoS differ- ences.     

无线传感器网络环境下的QoS机制研究

在分析了无线传感器网络的QoS需求以及提供QoS需要考虑的问题的基础上，设计了一种基于移动Agent的QoS机制，通过移动Agent的迁移实现网络状态信息的采集与动态QoS指标的调整，在保证网络应用完成的同时延长了网络生命周期。     

典型Ad hoc网络协议传输多媒体数据的性能分析

针对多媒体数据的特点论述了在Ad hoc网络环境中各性能参数的要求,利用NS2仿真软件模拟了在Ad hoc网络环境中利用AODV,DSR及DSDV路由协议进行多媒体数据传输,并将网络吞吐量、延时抖动等4种多媒体数据敏感参数进行了比较.实验表明,由于多媒体数据类型的不同,AODV,DSR及DSDV协议的性能也各有差异,通过比较发现,DSDV的表路由机制不能满足Adhoc网络的多媒体业务要求,DSR可用于QoS要求不高的视频传输,AODV可用于传输视频及音频,但对延时要求较高的数据则不能满足.     

FUZZY REQUIREMENT BASED STRATEGY OF QoS SERVICE FOR BROADBAND TELECOMMUNICATION NETWORKS

IntroductionThere are many strategies for Qo S service inbroadband telecommunication networks[1] . Withthe fast evolution of chip and software techniques,the telecommunication networks are running withmore and more throughputcapabilities and self- ad-ministration capabilities.On the other hand,theapplication of methodologies based on concepts ofartificial intelligence in the telecommunication fieldis being more and more frequently used[2 ] .Thispaper gives a new strategy to evaluate the Qo S…     

Network lifetime global optimization for multi-source and single-sink topology in wireless sensor networks

The multi-source and single-sink (MSSS) topology in wireless sensor networks (WSNs) is defined as a network topology, where all of nodes can gather, receive and transmit data to the sink. In energy-constrained WSNs with such a topology, the joint optimal design in the physical, medium access control (MAC) and network layers is considered for network lifetime maximization (NLM). The problem of integrating multi-layer information to compute NLM, which involves routing flow, link schedule and transmission power, is formulated as a non-linear optimization problem. Specially under time division multiple access (TDMA) scheme, this problem can be transformed into a convex optimization problem. To solve it analytically we make use of the property that local optimization is global optimization in convex problem. This allows us to exploit the Karush-Kuhn-Tucker (KKT) optimality conditions to solve it and obtain analytical solution expression, i.e., the globally optimal network lifetime (NL). NL is derived as a function of number of nodes, their initial energy and data rate arrived at them.Based on the analysis of analytical approach, it takes the influence of data rates, link access and routing method over NLM into account. Moreover, the globally optimal transmission schemes are achieved by solution set during analytical approach and applied to algorithms in TDMA-based WSNs aiming at NLM on OMNeT<++> to compare with other suboptimal schemes.     

自组网中基于能量约束的QoS多播路由优化算法

在分析基于能量优化多播路由算法的基础上,提出了一种QoS多播路由的网络模型,并在网络模型的基础上,结合能量模型、极值元素组合和改进的遗传算法提出了一种基于能量的QoS多播路由优化算法EQMROA.仿真结果表明此算法是可行和有效的.它为移动Ad Hoc 网络QoS多播路由技术提供了一种新的有效途径.     

无线多媒体传感器网络的QoS路由算法

作为一种全新的信息获取和处理技术,无线多媒体传感器网络较之传统传感器网络更多地关注于音频、视频、图像等大数据量、大信息量媒体的采集与处理,在军事、民用及商业领域中具有广阔的应用前景.文中针对具有Mesh结构的无线多媒体传感器网络,给出了其带宽、时延和时延抖动等多约束的QoS路由问题模型的描述.基于基本遗传算法提出了一种多约束的QoS路由算法,给出了算法的具体实现流程,并对算法的收敛性和路由成功率等进行了实验仿真.     

AdHoc网络QoS多径路由协议的研究

QoS路由是提供QoS保证的一种重要手段,但大多数QoS路由是建立在单径的基础上,并没有充分利用Ad Hoc网络资源.文中提出了一种多径QoS路由协议QMPDSR.该协议主要考虑带宽和时延的约束来选择多条QoS路由.当QoS业务到达时,利用一条或多条路径同时传输QoS业务.实验表明,QMPDSR协议提高了分组投递率,降低了时延,路由开销的增加也不明显.     

构建全省网管通信网络平台

为适应电信管理网络向集中管理、集中维护方向发展的趋势,建立数据通信网为现有各分散的网管系统(如电话交换网管、传输网管、支撑网管等)提供一个统一的数据通信网络平台。各网管系统的信息都可以在此数据通信网上进行传递,使数据通信网成为一个真正的综合数据通信网。其网络结构是采用以省为中心,辐射地、市的广域网络,形成双星形网络结构。     

无线传感网络中QoS约束多播路由算法

分析了无线传感网络中具有时延、带宽和剩余能量等多QoS约束的多播路由问题.描述了一种适应于研究QoS多播路由的网络模型.提出了一种具有多QoS约束的能量有效的多播路由算法(EMRA),该算法成功地解决了无线传感网络中多播节点动态变化时的QoS路由选择问题.仿真实验证明了EMRA的有效性和优越性.     

无线Mesh网络的跨层设计理论与关键技术

由于无线M esh网络(WMN)在拓扑、传输和业务上的特性,传统的用于有线网络的分层协议设计方法已不能保证其服务质量(QoS).探索基于物理层、MAC层、路由等协议层的WMN跨层设计方法的目标是在无线资源利用率和多媒体业务的QoS需求两方面达到较好的折衷.WMN各个协议层在设计过程中的有关协议和算法要求附加统一的跨层管理器,监测各层的分组传输性能或需求,动态控制或调节相关算法.通过实现较高协议层的多媒体业务QoS需求与较低协议层的网络状态信息在各协议层之间的共享,可以达到对协议层控制算法的优化.在合理地选择跨层设计目标的基础上,多个协议层需要联合设计与优化.从物理层、MAC层、路由协议层和TCP层等层面介绍了WMN跨层设计的一般原则和方法.归纳了目前WMN跨层设计中亟待深入研究的一些理论和关键技术,包括自适应速率与节能机制、基于QoS需求的跨层MAC协议设计和路由协议设计等.     

一种基于视频虚拟检测线的交通流参数检测方法

实时交通流参数检测在智能交通系统中起着重要的作用。参数检测有多种方式,其中基于图像处理的视频车辆检测方式近年来发展很快,由于它具有检测区域大、系统设置灵活等突出的优点,已成为智能交通系统领域的一个研究热点。车辆的检测基于车道,在每个车道设置两条虚拟检测线来检测交通流参数,虚拟检测线的作用类似于电磁感应线圈。系统通过对视频虚拟检测线的预处理将二维的数字图像转化成一维的检测信号,减小了运算量,降低了运算负荷。提出的基于视频虚拟检测线特征的交通流参数检测系统已经在PC机上用VC 6.0实现,并对不同典型天气条件下的交通流视频进行了实验,实验结果表明该系统具有较高的车流量统计精度。     

Pre-emptive channel borrowing and traffic overflowing channel allocation scheme for multimedia overlay networks

This paper proposes a channel allocation scheme for multimedia wireless networks, in which a twolayer macro-cell or micro-cell architecture is considered. Macro-cells are used to access high-mobility services; while micro-cells, which are overlaid by the macro-cells, are used to cater low-mobility services. To analyze the scheme, a multidimensional Markov traffic model is firstly developed, in which traffic characteristic of two special periods of time is considered. And then, a pre-emptive channel-borrowing scheme combined with trafficoverflowing strategy for multimedia (voice, video or data) networks is proposed, in which handoff requests can not only borrow channels from adjacent homogenous cells, but also be overflowed to heterogeneous cells. Priority strategies are also dedicated to high-mobility services for they can pre-empt channels being used by low-mobility services in macro-cells. To meet the high quality of service (QoS) requirements of video services and increase the channel utilization ratio, video services can be transformed between real-time services and non-real-time services as necessary. Simulation results show that our schemes can decrease the blocking probabilities and improve the channel utilization.     

交通信号控制参数的仿真优化方法研究

为优化区域交通网络中各信号控制器的配时方案,利用递推最小二乘算法(RLS)和同时扰动随机近似(SPSA)算法,由检测器流量估计DynaCHINA动态网络交通仿真与分析系统的动态OD矩阵,输入并标定各路段的速度-密度模型参数和饱和流量,获得网络状态的准确估计,包括各路段的速度、密度、流量、队列长度等;在此基础上,利用SPSA算法优化各信号控制器配时参数,包括各信号控制器的周期、相位差和绿信比,使得网络中车辆的平均旅行延误、队列长度、或交叉口通过量等指标最优. 针对实际路网的测试表明,本文的参数标定方法可以获得准确的检测器流量估计,结果明显优于Ashok K的动态OD矩阵与检测器流量估计方法;与现有的基于Synchro信号配时优化软件获得的结果相比较,该方法可较大幅度缩短车辆在路网中的平均旅行延误,并可推广应用于更复杂的区域路网的信号控制参数优化等场合.     

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介绍了路况视频监控系统的现状和视频转码概况,提出了一种基于H.264的异构视频转码服务器设计方案,阐述了异构视频转码的机理,给出了转码服务器的构成,包括任务调度、转码等模块具体实现,就视频数据进程间通信和网络传输中的数据处理等关键技术进行了分析。采用级联象素域转码结构,使用多线程调度管理、共享内存、环形缓冲等技术实现了该转码系统,并已成功应用于江苏省高速公路的数字视频监控系统中。     

Watermark in the digital video broadcasting handheld transmission signal

Transmitter identification (TxID) technique is used to diagnose the operation status of radio trans-mitters in DTV distributed transmission network. A new TxID method for digital video broadcasting-handheld (DVB-H) system is proposed. Watermark is embedded in the DVB-H signal to form the composite signal. Ac-cording to watermarking theory we demonstrate the required signal level for watermarking signal to achieve given bit error Probability under different circumstance. By selecting the reference pattern to generate watermarking signal, peak-to-average power ratio (PAPR) of the transmitted signal can be improved. Simulation results show that even in wireless situation the receiver can distinguish the watermarking signal with low embedding strength, and distortion to the host signal can also be ignored.     

基于传播模型的非机动车违规过街行为研究

为研究信号交叉口非机动车违规过街行为，选取西安市的7个信号交叉口，通过视频拍摄获取资料，应用复杂网络来分析非机动车网络的结构特征和演化规律.建立了交叉口非机动车网络，基于SI模型的基本思想，提出了非机动车违规过街行为的传播模型.并通过python程序进行模拟分析，在不同的网络结构和不同的传播率下，获取了非机动车违规过街的行为趋势.结果表明：随着等待时间的增加，一旦有骑行者闯红灯，更多的骑行者将加入到违规过街的行列；在内向度和外向度方面，电动自行车均高于普通自行车；非机动车违规行为随着传播率及非机动车流量的增加而增加.