基于竞争粒子群算法的大气激光通信数据跨层调度研究

不同层之间的大气激光通信数据资源分配不均衡，影响到数据跨层调度效率，提出基于竞争粒子群算法的大气激光通信数据跨层调度方法。采用自适应调制编码技术分析大气激光通信信道状态，对通信数据包实施纠错以及调制编码组合，以此搭建大气激光通信系统模型。以通信系统模型为基础建立跨层资源分配目标函数，将混沌初始化策略和自适应高斯变异算法加入到竞争粒子群算法中，利用竞争粒子群算法获取目标最优解，实现数据跨层调度。实验结果表明，所提方法的误报率最大值仅为2.5%,调度准确度始终在92%以上，调度时间最大值是11.35 ms。     

基于遗传算法的通信网络节点自适应调度方法

常规的网络节点调度方法主要以监测为主,节点传输的通信数据存在冗余问题,影响网络调度效果。因此,设计了基于遗传算法的通信网络节点自适应调度方法。选取通信网络节点簇头,确定通信网络初始化部署完成后的节点竞争半径。基于遗传算法构建通信网络节点自适应调度模型,剔除通信冗余节点,降低网络节点的调度能耗,从而实现网络节点的有效调度。采用仿真实验的方式,验证了该调度方法的调度效果更佳,能够应用于实际生活中。     

基于成簇传输的M2M网络资源分配策略

针对机器通信网络中节点规模增加将带来信令拥塞及调度复杂等问题,提出了适用于大规模机器通信网络的成簇传输策略,并基于联盟形成博弈,提出与成簇传输相适应的可以分布式实现的联合网络结构形成及资源分配策略,以同时兼顾机器网络中的通信性能及调度性能。通过Matlab工具对其性能进行仿真验证,结果表明相比于独立传输策略,该策略可实现节点时延性能及网络调度性能的灵活折中。     

基于自适应遗传算法的无线激光通信网络负载均衡成簇算法

由于无线激光通信网络吞吐量低、节点传输延时高和存在分组丢失率多等问题，提出基于自适应遗传算法的无线激光通信网络负载均衡成簇算法。利用AGCH算法对无线激光通信网络节点进行分组和成簇，从中取得簇头节点，构建资源调度模型，利用该模型对簇头节点中的资源进行分配调度，采用自适应遗传算法对建立的模型进行求解，以此提升无线激光通信网络负载均衡效果，实现无线激光通信网络负载均衡。实验结果表明，通过对该算法进行网络吞吐量测试、节点传输延时测试和分组丢失率测试，验证了该算法的有效性强、实用性高。     

基于网络编码的多信源组播通信系统

本文首先介绍网络编码理论的基本概念,回顾了近年来网络编码的研究动态。接着在使用NetFPGA开发平台的基础上,提出网络编码组播通信系统及其整体设计方案。由于本系统的主要功能是由硬件实现,所以和传统组播通信网络相比,具有时延小,没有了调度和排队时间,使得网络中链路负载更均衡,体现出了网络编码的优势。     

无线Mesh网络视频流媒体自适应编码与传输控制研究

讨论了无线Mesh网络（WMN）中视频流媒体自适应编码与传输控制的问题,包括视频流媒体可分级编码的必要性和实现原理,传输过程中的主动丢包策略,并讨论了对其进一步改进的方法。使读者对WMN中视频流媒体的自适应编码和传输控制有概括性的了解。     

非正交自适应多址中继系统复数域网络编码方案性能分析与优化功率分配

无线中继与网络编码是提高无线通信系统数据可靠性和吞吐率的重要技术手段。该文重点分析了单中继非正交自适应多址系统复数域网络编码问题,即在中继采用选择解码转发自适应策略下的系统可靠性能及其优化设计。首先,论文推导了非正交自适应多址系统复数域网络编码方案的误符号率性能上界、分集度和编码增益;然后,论文以系统编码增益为优化目标,讨论了最优功率分配问题。结果表明,在保证系统满分集的前提下,非正交多址中继系统采用选择解码转发自适应中继策略能以更低的系统实现复杂度获得优于中继采用链路自适应再生策略所能获得的系统性能。此外,优化源节点和中继节点的功率分配因子可以有效地增加系统编码增益、改进系统性能。     

IMT—Advanced协作中继的网络编码技术

网络编码技术的本质是在中间节点上对多条输入链路的数据信息进行线性或非线性处理转发。网络编码技术应用于IMT—Advanced系统中时,不仅可用于提高中继转发效率,还可用于设计干扰利用传输策略,以节约小区内的时频资源。文章针对多址接入中继信道模型,讨论了几种可提高中继转发效率的网络编码传输策略,研究了基于网络编码的干扰利用传输策略,分析了网络编码标准化过程中所面临的各种问题,指出引入网络编码技术对中继传输协议、控制帧格式以及用户调度和资源管理算法等的影响。     

基于TDMA短波通信网络的仿真

以采用TDMA接入方式的无线短波通信网络为仿真对象,通过对TDMA工作原理的分析,根据TDMA工作方式,抽象出TDMA无线网络的行为模式,应用离散事件系统仿真方法中事件调度法仿真策略和面向对象建模方法,对其建立了仿真模型,进行了仿真流程的设计,并且介绍了在VC＋＋下构建短波通信网络模型所需要的类定义。通过仿真数据的处理和分析,对影响网络性能的各个参数做出了相应的评价。     

大型Web网络数据中心资源高效挖掘技术研究

在大型Web网络数据中心构架中包含海量的多媒体信息资源,为了高效挖掘资源,提高资源的调度能力,提出一种基于模糊语义本体映射的大型Web网络数据中心资源高效挖掘技术。对大型Web网络数据中心的资源信息流进行信息流重建,采用泛化学习方法进行资源信息流的模糊聚类处理,结合语义本体映射方法实现互信息特征提取,以提取的特征为训练集,进行数据迭代,实现资源优化挖掘。仿真结果表明,采用该方法进行大型Web网络数据中心资源挖掘的准确性较好,资源调度的效率得到提高。     

Transmission scheduling in a multi‐channel wireless network with bidirectional relaying links

Using network coding in a wireless network can potentially improve the network throughput. On the other hand, it increases the complexity of resource allocations as the quality of one transmission is affected by the link conditions of the transmitter to multiple receivers. In this work, we study time slot scheduling and channel allocations jointly for a network with bidirectional relaying links, where the two end nodes of each link can exchange data through a relay node. Two scenarios are considered when the relay node forwards packets to the end nodes. In the first scenario, the relay node always forwards network‐coded packets to both end nodes simultaneously; in the second scenario, the relay node opportunistically uses network coding for two‐way relaying and traditional one‐way relaying. For each scenario, an optimization problem is first formulated for maximizing the total network throughput. The optimum scheduling is not causal because it requires future information of channel conditions. We then propose heuristic scheduling schemes. The slot‐based scheduling maximizes the total transmission rate of all the nodes at each time slot, and the node‐based scheduling schedules transmissions based on achievable transmission rates of individual nodes at different channels. The node‐based one has lower complexity than the slot‐based one. Our results indicate that although the node‐based scheduling achieves slightly lower throughput than the slot‐based one, both the proposed scheduling schemes are very effective in the sense that the difference between their throughput and the optimum scheduling is relatively small in different network settings. Copyright © 2015 John Wiley & Sons, Ltd.     

The approach of hybrid adaptive coupling synchronization among N Lorenz systems and its application in secure communication for multi-unmanned aerial vehicle formation

In this paper, it is proposed that a hybrid global adaptive coupling synchronization scheme among $N$ Lorenz chaotic dynamical nodes to realize the secure communication system between base station and multi-unmanned aerial vehicle (UAV) formation. The specific method is that the feedback drive–response synchronization is utilized for first two nodes of base station and the leader of multi-UAV formation, and the nodes of all UAVs are coupled by unidirectional adaptive coupling synchronization according to a directed link in ad hoc network of multi-UAV formation. It is demonstrated that the asymptotic stability of the proposed hybrid adaptive coupled synchronization by constructing the Lyapunov function. In this way, the encrypted information formed by plaintext information masked into the chaotic sequence generated by the chaotic dynamical node of base station; meanwhile, it is fed back into the base station node as the drive system. On the other hand, encrypted information is forwarded to the leader node as the response system for decryption. The feedback driver–response synchronization is used to realize secure communication between the base station and the leader of multi-UAV formation. Meanwhile, secure communication among its leader and followers is achieved through the unidirectional adaptive coupling synchronization in the network. This strategy ensures the multi-UAV formation decrypting encrypted information synchronously and effectively improves the security, consistency, and overall performance of their commands.     

非对称协作分集通信中网络编码的应用

该文提出了网络编码在非对称三点协作传输系统中的应用。通过协作分集技术和网络编码技术的联合运用,不但可得到无线通信传输系统的分集增益,也可得到系统的编码增益。该文设计的方案,充分考虑无线通信环境的差异性,利用非对称调制方式,在保证较差通信环境中取得通信可靠性的同时,在较优链路采取较高速率进行传输,利用较优链路传输更多的信息,实现系统资源的充分利用。在方案的具体实现中,通过在中继链路的中继节点加入已知信息实现网络编码,使得系统的译码性能得到增加。仿真结果表明,将网络编码技术应用于非对称协作分集通信中,相对比非协作传输方案可增加分集增益,降低系统的误比特率。跟传统对称传输系统相比,可充分利用系统资源,提升了系统传输容量。     

Optimized in-band control channel with channel selection scheduling and network coding in distributed cognitive radio networks

This article proposes an optimized in-band control channel scheme with channel selection scheduling algorithm and network coding based transmission paradigm in the distributed cognitive radio network (...     

Time and power scheduling in an ad hoc network with bidirectional relaying and network coding

Network coding (NC) is a technique that allows intermediate nodes to combine the received packets from multiple links and forwarded to subsequent nodes. Compared with pure relaying, using NC in a wireless network, one can potentially improve the network throughput, but it increases the complexity of resource allocations as the quality of one transmission is often affected by the transmission conditions of multiple links. In this paper, we consider an ad hoc network, where all the links have bidirectional communications, and a relay node forwards traffic between the source and the destination nodes using NC. All transmissions share the same frequency channel, and simultaneous transmissions cause interference to each other. We consider both digital NC and analog NC strategies, referred to as DNC and ANC, respectively, and schedule transmission time and power of the nodes in order to maximize the overall network throughput. For DNC, an optimum scheduling is formulated and solved by assuming that a central controller is available to collect all the link gain information and make the scheduling decisions. Distributed scheduling schemes are proposed for networks using DNC and ANC. Our results indicate that the proposed scheduling scheme for DNC achieves higher throughput than pure relaying, and the scheduling scheme for ANC can achieve higher throughput than both DNC and pure relaying under certain conditions. Copyright © 2013 John Wiley & Sons, Ltd.     

Network correlated data gathering with explicit communication: NP-completeness and algorithms

We consider the problem of correlated data gathering by a network with a sink node and a tree-based communication structure, where the goal is to minimize the total transmission cost of transporting the information collected by the nodes, to the sink node. For source coding of correlated data, we consider a joint entropy-based coding model with explicit communication where coding is simple and the transmission structure optimization is difficult. We first formulate the optimization problem definition in the general case and then we study further a network setting where the entropy conditioning at nodes does not depend on the amount of side information, but only on its availability. We prove that even in this simple case, the optimization problem is NP-hard. We propose some efficient, scalable, and distributed heuristic approximation algorithms for solving this problem and show by numerical simulations that the total transmission cost can be significantly improved over direct transmission or the shortest path tree. We also present an approximation algorithm that provides a tree transmission structure with total cost within a constant factor from the optimal.     

监测无线传感器网络休眠调度算法

休眠调度设计是无线传感器网络一种重要的通信节能方法。针对监测典型应用,为了实现长时间的监测应用要求,充分利用冗余部署提供的能量资源,提出了一种能量相关的分布式自适应休眠调度算法。算法利用极大独立集构建思想,结合节点层次级别、实时的能量消耗、连通度等信息动态选择连通支配节点集作为网络骨干,使得网络活跃节点数量最小化。仿真试验分析表明,算法能够有效地利用冗余节点提供的能量资源,扩展了网络的生命周期。     

不对称速率传输中网络编码与信道编码的联合设计

本文针对双向中继信道中不对称速率传输的情况进行了研究。在实际双向中继信道的通信传输中,由于信道质量,发射功率,业务需求等条件的不对称,双向信道的传输速率往往也是不对称的。本文提出了一种称为子集编码的方案,将调制、物理层网络编码、信道编码联合起来设计,使得较差信道的信道编码码字为较好信道的子集,这样中继节点可以利用信道编码的线性性质对接收到的叠加信号直接进行译码,从而使译码复杂度降低50%;同时,较好信道使用高阶调制,较差信道使用低阶调制,利用较好信道提高了系统的传输速率。仿真结果表明,与对称速率传输相比,本文提出的方案在提高系统有效性的同时,又保证了系统的可靠性。      

多媒体IP技术

在IP网络上进行多媒体通信要涉及网络结构、服务模型、信息编码压缩以及传输控制等技术问题。为了保证服务质量，可以在路由器上引入资源预留机制。另外为了实现将来的集成服务（IS）因特网，要对现有的路由器进行更多的改进，如配置信息包分类和调度模块、认可控制模块和策略控制代理模块等。     

基于身份认证的安全量子中继器网络编码方案

本文将量子一次一密通信方法引入到量子中继器网络中,提出了基于身份认证的安全量子中继器网络编码方案.针对编码过程中存在的主动攻击问题,用一次一密的方式实现任意相邻节点通信过程中的身份认证,优化编码算法,最终在源节点与目的节点间生成量子纠缠态作为信道,构成量子隐形传态网络.方案分析表明,这种方案可以实现高可靠性、高安全性的远程量子通信.