Multiple constraints QoS multicast routing optimization algorithm in MANET based on GA

Usually multiple quality of service （QoS） guarantees are required in most multicast applications. This paper presents a multiple con-straints algorithm for multicast traffic engineering in mobile ad hoc networks （MANET）. The proposed algorithm is a new version of multiple constraints QoS multicast routing optimization algorithm in MANET based on genetic algorithm （MQMGA）. The proposed MQMGA can optimize the maximum link utilization, the cost of the multicast tree, the selection of the long-life path, the average delay and the maximum end-to-end delay. Experimental result shows that the approach is efficient, has promising performance in multicast traffic engineering and for evaluating the route stabilitv in dvnamic mobile networks.     

Multiple constraints QoS multicast routing optimization algorithm in MANET based on GA

Usually multiple quality of service (QoS) guarantees are required in most multicast applications. This paper presents a multiple constraints algorithm for multicast traffic engineering in mobile ad hoc networks (MANET). The proposed algorithm is a new version of multiple constraints QoS multicast routing optimization algorithm in MANET based on genetic algorithm (MQMGA). The proposed MQMGA can optimize the maximum link utilization, the cost of the multicast tree, the selection of the long-life path, the average delay and the maximum end-to-end delay. Experimental result shows that the approach is efficient, has promising performance in multicast traffic engineering and for evaluating the route stability in dynamic mobile networks.     

QoS Support Polling Scheme for Multimedia Traffic in Wireless LAN MAC Protocol

Quality of service （QoS） support is a key attribute for multimedia traffic including video, voice, and data in wireless local area networks （LANs） but is limited in 802.11-based wireless LANs. A polling-based scheme called the point coordination function （PCF） was developed for 802.11 LANs to support the transmission of multimedia traffic. However, the PCF is not able to meet the desired practical traffic differentiation requirements for real-time data. This paper describes a QoS support polling scheme based on the IEEE 802.11 medium access control （MAC） protocol. The scheme uses a two-level polling mechanism with the QoS classes differentiated by two different access policies. Stations with higher priority traffic such as key or real-time data form the first level and can access the common channel through an exhaustive access policy. Other stations with lower priority traffic form the second level and can access the channel through a gated access policy. A system model based on imbedded Markov chain theory and a generation function were setup to explicitly analyze the mean information packet waiting time of the two-level polling scheme. Theoretical and simulation results show that the new scheme efficiently differentiates services to guarantee better QoS and system stability.     

低复杂度的MIMO-OFDM系统自适应调制方案

以最小化发射总功率为目标,提出了一种低复杂度的MIMO-OFDM无线通信系统的自适应调制方案.在发射端,基于已知信道状态信息,应用奇异值分解将空分复用信道转化为并行的子信道,并将表征信道增益的信道矩阵特征值用于子信道自适应调制优化设计中.针对MQAM调制,采用变步长的贪婪算法得到优化的子信道比特加载及功率分配方案.仿真结果表明,所提出的简化算法与一种近似最优的自适应调制算法性能接近,但复杂度降低了30%以上.     

Two-Level Cross-Talked Admission Control Mechanism for QoS Guarantee in 802.11e EDCA

This paper describes a two-level cross-talked admission control mechanism that guarantees quality of service （QoS） requirements for multimedia applications over wireless local area networks （WLANs）. An enhanced distributed channel access analytical model is used to compute the maximum number of admitted users according to the QoS requirements and the packet arrival characters. Then, some channel resources are reserved for handoff calls based on the maximum number of admitted users and the call-level traffic model. The channel utilization ratio is also measured to reflect the current system traffic load. The maximum number of admitted users and the channel utilization ratio are used for admission control for applications with QoS requirements in the call level and for rate control of best effort applications in the packet level using the p-nonacknowledgement scheme. Thus, the QoS requirements are statistically guaranteed while the system is efficiently utilized. Simulations validate the effectiveness of this mechanism to guarantee the QoS and bandwidth utilization.     

无线多媒体传感器网络的关键技术研究进展

本文从网络传输层面综述了无线多媒体传感器网络的总体架构、节点的硬件组成和网络协议栈架构,并对影响其实用化的最关键技术低延时和低能耗网络设计技术做了介绍。在此基础上给出了关键网络传输技术在未来实现突破的方向,即低延时的实时MAC技术,低延时、低能耗的路由关键技术,多媒体信息安全技术,面向多核和众核的多媒体终端设备的研制和多模态软件构件技术的研究以及高压缩比的多媒体信息流压缩编码技术等等。     

一种移动分组无线网flooding组播改进协议

论述了移动无线网及现有几个组播协议的特点 ,分析了在特定军事领域的可行性和必要性 .重点讨论了对于洪泛协议的一个改进方案 ,该方案可以加强flooding组播协议的网络负载的均衡 ,并且对改进方案与其他方案进行了比较研究 .这些结论对于移动无线网组播协议的研究和应用有重要的意义     

双信道无线传感器网络移动代理路由算法

针对移动代理在信道竞争过程中的相互碰撞及相互抑制问题,提出了一种移动代理联合优化路由算法(MACORA).首先利用双层图模型将双信道无线传感器网络中的信道变换问题转化成双层图中的路由问题,进而可将寻路业务和数据传输业务分别放在双层图的控制层和数据层中同步传输,然后将双层图的控制层和数据层融合成一个双层网络,并在这个双层网络中为每个业务实时选路,最后充分利用不同网络层间的空闲信道资源来减少移动代理在信道竞争过程中的相互碰撞及相互抑制概率,达到降低网络堵塞率及数据包传递失误率2个目标.仿真结果表明,与动态传感器网络移动代理路由算法及无线传感器网络移动代理路由算法相比,MACORA算法能将数据包的传递成功率提高15%,并能有效降低网络的平均通信延迟.     

WDM光网络中多播业务量疏导方法分析

在光层多播树路由中疏导低速业务实现阻塞率降低和吞吐量提高是光网络比较复杂的联合优化问题。分析了WDM（wave-length division multiplex）网络中多播业务量疏导问题的研究方法和成果,分析比较了静态多播业务和动态多播业务的疏导方法,并讨论了各种多播业务疏导方法性能、特点及存在的问题,最后总结了关于动态多播疏导的未来研究思路。     

稀疏码多址接入系统中基于分层编码的多播资源分配算法

稀疏码多址接入(sparse code multiple access,SCMA)技术被认为是一种能有效提高频谱效率的技术。将稀疏码多址接入技术应用于无线多播通信中可以扩展多播系统的容量。对多播系统的容量进行了推导,采用分层编码技术应用在SCMA系统的多播传输中,使得系统容量不再受限于多播系统中最差用户的信道质量,采用资源分配算法来最大化多播系统容量。为了减少最优化问题的计算复杂度,又提出了快速次优化算法(fast suboptimal algorithm, FSA),该算法分为码本分配和功率分配2个阶段。仿真结果显示,提出的快速次优化算法在SCMA系统中的多播系统功效要优于正交频分多址接入(orthogonal frequency division multiple access, OFDMA)系统中的多播系统功效。并且,在SCMA系统和OFDMA系统中,提出算法的系统功效都要远优于传统多播(conventional multicast, CM)策略的系统功效。     

Convergence of Broadband and Broadcast/Multicast in Maritime Information Networks

Recently, the fifth-generation(5 G) of wireless networks mainly focuses on the terrestrial applications.However, the well-developed emerging technologies in 5 G are hardly applied to the maritime communications,resulting from the lack of communication infrastructure deployed on the vast ocean, as well as different characteristics of wireless propagation environment over the sea and maritime user distribution. To satisfy the expected plethora of broadband communications and multimedia applications on the ocean, a brand-new maritime information network with a comprehensive coverage capacity in terms of all-hour, all-weather, and all-sea-area has been expected as a revolutionary paradigm to extend the terrestrial capacity of enhanced broadband, massive access, ultra-reliable,and low-latency to the vast ocean. Further considering the limited available resource of maritime communication infrastructure, the convergence of broadband and broadcast/multicast can be regarded as a possible yet practical solution for realizing an efficient and flexible resource configuration with high quality of services. Moreover, according to such multi-functionality and all-coverage maritime information network, the monitoring and sensing of vast ocean area relying on massive Ocean of Things and advanced radar techniques can be also supported. Concerning these issues above, this study proposes a Software Defined Networking(SDN) based Maritime Giant Cellular Network(MagicNet) architecture for broadband and multimedia services. Based on this network, the convergence techniques of broadband and broadcast/multicast, and their supporting for maritime monitoring and marine sensing are also introduced and surveyed.     

两跳固定中继蜂窝网络的子载波信道分配策略

针对频率复用因子为1的两跳固定中继节点的蜂窝网络中,移动业务分布的时变性和非均匀性,提出了基于同向分配逆向共享的子载波信道资源环状分配策略。该策略无需基站之间的协作也能有效地保证相邻小区节点之间的最小同频干扰距离。通过理论分析和仿真,在用户业务非均匀分布下,与传统两跳蜂窝系统的子载波信道分配策略相比,提出的分配策略系统平均频谱效率有明显改善,尤其在业务分布主要集中在小区边缘时,其平均频谱效率增益可以达到3倍。     

无线Ad Hoc网络在分层协议约束下的容量分析

为研究路由和MAC(Media Access Control)协议对无线Ad Hoc网络容量的影响,进而为设计高性能协议提供理论依据,从分层协议角度讨论了无线分布式多跳网络的容量。在不考虑物理层技术时,对网络层和MAC层协议进行分类,分析和对比了各类协议对网络空间重用度、单跳时间贡献度和网络容量的影响。理论和仿真结果表明,当网络节点密度不变时,由于时空二维相逆性,网络空间重用度和单跳时间贡献度呈现反向关系;而网络容量趋于一致,与节点数目呈平方根正比关系;采用无握手的MAC机制时,网络容量比采用握手MAC时提高15%左右。     

电力光纤通信网络的多环组网优化

依据电力系统通信业务的特点,提出了多环组网优化的整数线性规划算法,用于SDH组网优化设计.研究了在一个电力光纤网络中如何组成多个SDH环,以疏导所有低速业务流,并最小化组网成本.依据提出的算法开发了相应的软件,并以某中国东部一城市的电力光纤网络为例给出了具体的优化设计方案.     

下一代互联网中的智能QoS组播路由算法

将遗传算法、模拟退火算法、禁忌搜索算法这3种智能优化算法引入基于QoS的优化组播树计算中·首先建立了支持QoS组播的高速网络模型,在此基础上给出了组播算法问题的数学模型·分析了在组播算法问题中应用这3种智能算法所面临的关键问题及解决方案,然后给出了3种算法在费用寻优和运行时间性能方面的对比·仿真表明,这3种算法都有较高的性能,能够满足下一代互联网支持QoS组播的需求·     

用遗传算法优化WCDMA网络QoS

3G蜂窝移动通信系统旨在提供多种业务,比如语音业务、数据业务以及基于分组交换网的多媒体业务。为了提供这些业务的服务质量保证,提出了一种优化WCDMA(W ideband Code-D ivision Mu ltip le Access)网络QoS(Quality of Service)的遗传算法(GA:Genetic A lgorithm)。使用该算法,研究了如何实时对WCDMA网络参数进行最优配置,以最大限度地提高使用不同输入通信流量混叠业务用户的满意度。仿真实验结果表明,该算法可以根据混叠输入通信流量动态有效地配置网络参数,以使服务的性能达到最优化:使用GA后,网络的频谱利用率达到18%;GA的收敛速度相当好,例如在假定所有的通信量混和的情况下,经过20~30次的反复后,就可以达到最优的配置参数。     

WMSNs中粒子群优化的多径流量分配路由算法

针对无线多媒体传感器网络(WMSNs)节点能耗问题,提出了一种基于粒子群优化的多路径自适应流量分配路由MATDR-PSO算法。通过建立能效优化模型,将最小能耗和能耗均衡2个特性转化为多目标优化问题;利用粒子群优化算法动态分配多路径上各条链路流量来实现网络的能效优化。仿真实验表明:MATDR-PSO算法能够在降低全网节点消耗总能量的同时保证能耗的均衡特性,显著提高了网络的生命周期。     

Traffic Engineering for Proactive Failure Recovery of IP Networks

As a promising approach to improve network reliability,proactive failure recovery (PFR) re-routes failure affected traffic to backup paths without waiting for the completion of IP routing convergence.However,the failure affected traffic may cause congestion if it is not carefully allocated over the backup paths according to their available capacity.A post failure traffic engineering (PostTE) scheme is proposed to balance the load in the PFR scheme.Loop-free backup paths are prepared in advance to cover all ...     

基于低密度奇偶校验编码的自适应调制方案

为克服无线信道时变衰落特性对传输性能的影响 ,提出了基于低密度奇偶校验 (L DPC)编码的自适应调制传输方案。该方案将所有子信道传输的信息采用同一个 L DPC码进行编码 ,每个子信道根据各自当前的噪声水平动态选取调制方式 ,而各个子信道的瞬时噪声根据 L DPC译码前后信息序列的符号改变情况进行估计。仿真结果表明 :在 Nakaga-mi时变衰落信道下 ,该系统方案可以很好地适应信道的时变衰落特性 ,在满足系统输出误比特率的条件下 ,可以很低的系统复杂度实现信息的最佳传输 ,并获得距离理论极限3d B的良好传输性能     

基于跨层设计的传感器网络寿命最大化算法

面向监测应用的无线传感器网络,当链路存在干扰时,节点在传输数据时会对位于其干扰范围内的节点造成信号干扰,从而使得这些节点不能正确收到其它节点传输的数据.针对这种场景下的网络寿命最大化问题,分析了网络流量和节点能耗,提出了一种将功率控制和数据聚合路由相结合的非凸优化模型.通过对数转换方法将非凸优化问题转化为凸优化问题,利用优化理论和方法将凸优化问题分解为聚合数据率分配子问题和功率控制子问题,最后给出了联合优化问题的分布式解法.仿真实验表明,使用该方法可以有效减少数据通信量,均衡各个节点的能量消耗,有效延长网络寿命.