GAME based dynamic resource scheduling in QoS aware radio access networks

Radio resource management and QoS are finally inseparable in wideband CDMA networks. In this paper, we propose a novel wireless resource scheduler, called GAME-C, that integrates our genetic algorithm for mobiles equilibrium (GAME) with the standard CDMA transmitter closed loop power control (CLPC). GAME assigns optimally both transmitting power and bit rate to every mobile station. Optimal allocation is in the sense that every user gets only enough resources necessary for meeting or exceeding its QoS requirements while minimizing interference to other users. Having done that, we gain further benefits as well. In addition to QoS provisioning, lower transmitting power extends a mobile station battery life. Moreover, the base station coverage efficiency is improved by decreasing the probability of blocking new connections or dropping current ones. In short, GAME-C expands the number of QoS-satisfied mobile stations in a cell. Various simulations show improvements achieved over the established (CLPC) basic scheme.     

认知无线电网络动态QoS保证机制研究

针对认知无线电网络提出了一种基于中间件的分布式动态QoS保证机制DQAM,当网络对应用承诺的QoS保证发生变化,或者应用对网络的QoS要求发生变化时,通过网络和应用之间的反馈和协商,在分析当前网络状态和应用需求的基础上,根据特定的策略对网络和应用进行动态干预,在保证一定QoS的前提下,使应用最大程度的适应网络,网络最大限度的支持应用,以提高认知无线电网络对应用的支持能力和应用对网络的适应能力。对DQAM的原理、系统组成以及运行方式等,进行了讨论;从体系结构、工作过程、信息收集与策略生成和节点（任务）重构等4个方面,给出了DQAM的基本框架,并通过一个典型场景就DQAM的应用问题进行了探讨。     

Performance analysis of a threshold based distributed channel allocation algorithm for cellular networks

Rapid advances of the handheld devices and the emergence of the demanding wireless applications require the cellular networks to support the demanding user needs more effectively. The cellular networks are expected to provide these services under a limited bandwidth. Efficient management of the wireless channels by effective channel allocation algorithms is crucial for the performance of any cellular system. To provide a better channel usage performance, dynamic channel allocation schemes have been proposed. Among these schemes, distributed dynamic channel allocation approaches showed good performance results. The two important issues that must be carefully addressed in such algorithms are the efficient co-channel interference avoidance and messaging overhead reduction. In this paper, we focus on our new distributed channel allocation algorithm and evaluate its performance through extensive simulation studies. The performance evaluation results obtained under different traffic load and user mobility conditions, show that the proposed algorithm outperforms other algorithms recently proposed in the literature.     

An efficient metric-based (EM-B) location management scheme for wireless cellular networks

In the current era, the wireless cellular network is gaining much attention in the network mobility for qualitative service. Towards enhancing the QoS and narrowing the dilemma of network management (location management) an efficient metric-based location management technique is introduced in this paper to capture the current location of mobile subscribers. The attributes of this technique are based on metrics calculation and location management message routing path determination. First, the current mobile switching center will calculate the shortest metric-based path between current and master (previous) location of mobile terminals (user), thereafter it performs the location management procedure through the optimal suggested path by the mobile switching center. This proposed technique will reduce the signaling cost, registration delay, call setup delay, network overheads and total location management cost. The proposed analytical model checks the scalability and effectiveness of proposed system over certain attributes and a comparison is made with the existing available techniques.     

An efficient approach for distributed dynamic channel allocation with queues for real-time and non-real-time traffic in cellular networks

We are witnessing these days a rapid growth of mobile users. Therefore, frequency spectrum must be efficiently utilized, as available frequency spectrum is limited. This paper proposes a channel allocation scheme with efficient bandwidth reservation, which initially reserves some channels for handoff calls, and later reserves the channels dynamically, based on the user mobility. The direction of user mobility may not be straight always, but the user may also go left, right or backwards. Thus, QoS can be improved, if the channel reservation is made based upon the user mobility and the location of the user. We devise here a new algorithm that deals with multiple traffic systems by modifying the existing DDCA algorithm [Krishna, P.V., Iyengar, N.Ch.S.N., 2008. Optimal channel allocation algorithm with efficient channel reservation for cellular networks. International Journal of Communication Networks and Distributed Systems 1 (1), 33-51]. This algorithm reserves more channels for hot cells, less number of channels for cold cells and an average number of channels for the medium cells. Furthermore, we maintain queues for all types of calls. We model the system by a three-dimensional Markov Chain and compute the QoS parameters in terms of the blocking probability of originating calls and the dropping probability of handoff calls. The results indicate that the proposed channel allocation scheme exhibits better performance by considering the above mentioned user mobility, type of cells, and maintaining of the queues for various traffic sources. In addition, it can be observed that our approach reduces the dropping probability by using reservation factor.     

Efficient resource allocation scheme for multi-service based on interference mitigation in LTE-Advanced networks

The exponential growth of various services demands the increased capacity of the next-generation broadband wireless access networks, which is toward the deployment of femtocell in macrocell network based on orthogonal frequency division multiple access. However, serious time-varying interference obstructs this macro/femto overlaid network to realize its true potential. In this article, we present a macro services guaranteed resource allocation scheme, which can mitigate various dominant interferences and provide multiple services in macro/femto overlaid Third-Generation Partnership Project Long Term Evolution-Advanced networks. We model our multiple services resource allocation scheme into a multiobjective optimization problem, which is a non-deterministic polynomial-time （NP）-hard problem. Then, we give a low-complexity algorithm consisting of two layers based on chordal graph. Simulation results verify that the proposed scheme can achieve better efficiency than the previous works and raise the satisfaction ratio of Guaranteed Bit Rate （GBR） services while improving the average performance of non-GBR services.     

基于环-树型拓扑的无线传感网密钥管理方案

设计了一种基于无线传感网的拓扑模型--环-树型网络拓扑模型.基于该模型,结合节点命名机制,提出了一种新的密钥管理方案.该方案在拓扑结构上改变传统的三层分簇拓扑为四层分簇拓扑,在路由安全问题上采用二次核实机制.经仿真工具OMNET++实验,较传统的三层分簇拓扑模型,该方案的网络拓扑模型延长了第一个节点的死亡时间,且整个网络具有更长的生命周期和更好的安全保证.     

基于group based模型的无线传感器网络密钥管理方案*

由于无线传感器网络受电源、计算能力、内存容量等方面的限制,传统的基于公钥和可信任的密钥管理方式不再适用。为了进一步提高无线传感器网络的安全连通性,在分析DU Wenliang等人的groupbased节点投放模型的基础上,提出了一种改进的密钥管理方案：多密钥空间与多路径增强相结合的随机密钥预分配方案。结果分析表明,该方案需要较少的内存存储空间,不仅提高了系统的连通性,还降低了节点的被捕获概率。     

移动Ad Hoc网络中基于能量控制的QoS路由协议

实现QoS路由是保证在移动Ad Hoc网络中进行高效的多媒体业务传输的关键,然而现有的QoS路由协议很少考虑节能的问题,对此提出了一种基于能量控制的QoS路由协议。该协议采用跨层设计思想在MAC层和网络层同时提供能量控制,综合考虑了移动节点的发射功率和剩余能量状况。仿真结果表明该协议具有显著的节能效果,将为多媒体业务的持续传输提供一种有效途径。     

基于group-based模型的无线传感器网络密钥管理方案

由于无线传感器网络受电源、计算能力、内存容量等方面的限制,传统的基于公钥和可信任的密钥管理方式不再适用.为了进一步提高无线传感器网络的安全连通性,在分析DU Wen-liang等人的group-based节点投放模型的基础上,提出了一种改进的密钥管理方案:多密钥空间与多路径增强相结合的随机密钥预分配方案.结果分析表明,该方案需要较少的内存存储空间,不仅提高了系统的连通性,还降低了节点的被捕获概率.     

基于灰色模型的无线传感器网络动态功耗管理研究

传感器节点能量受限是制约无线传感器网络使用寿命的关键因素,为了节约传感器网络的能量,提出了灰色模型的动态功耗管理(DPM)方法.该方法利用传感器节点上的历史数据应用灰色模型预测未来值,预测过程中可以动态调整预测参数,实现自适应预测,和小波自回归预测算法相比,提高了预测的准确性.基本思想是根据Sink节点上的数据来决定整...     

基于CPK的高效移动Ad Hoc网络密钥管理方案

移动Ad Hoc网络具有的动态网络拓扑、无线链路的弱安全性、节点的有限物理保护和无中心基础结构等特性,使得它面临严重的安全问题。因此鲁棒的密钥管理服务是移动Ad Hoc网络的安全基础。提出了一个基于椭圆曲线组合公钥方案和门限密码系统的移动Ad Hoc网络密钥管理方案。本方案的主要创新点是提出了三层密钥管理模型,并基于此模型,提出了节点密钥生成、密钥份额分发、节点密钥更新、密钥份额更新和密钥撤销的具体实现。三层密钥管理模型实现较高的安全性和较低的密钥管理开销。与基于证书的和基于身份的密钥管理方案相比,本方案在安全性和效率方面更加适用于移动Ad Hoc网络。     

基于多项式和混沌序列的无线传感器网络密钥管理方案*

针对现有密钥管理方案占据存储空间大和安全性差的缺点,提出了一种基于多项式和混沌序列的混合密钥管理方案。该方案使用多项式建立节点间的共享密钥减少网络的存储开销,利用混沌序列对初值的敏感性特点解决多项式安全门限的问题,从而防止密钥的泄露。结果表明,本方案具有很高的安全性能,不仅节约了网络的通信资源,而且降低了节点的存储开销。     

马尔科夫逻辑网在信息安全风险管理中的应用

针对现有的企业安全风险管理中,风险处理方案的制定和管理措施的选择缺乏量化手段、手动风险分析方式耗时过长等问题,提出了一种基于马尔科夫逻辑网的信息安全风险管理方法。首先利用马尔科夫逻辑网对被评估系统组件及服务间依赖关系进行描述,进而利用马尔科夫逻辑网的边际推理模型来预估不同安全管理措施情况下的系统可用性值,从而为管理措施的选择提供了量化依据。案例研究表明,该方法能够为企业信息系统安全风险管理措施的选择提供可靠的量化依据,且方法实施简单易行。     

基于权重动态离散模型的WSNs定位算法

针对测距误差和距离权重对定位误差的影响,提出一种离散距离权重动态修正的定位算法。算法首先分区域获取动态路径损耗指数,建立接收信号强度测距简化数学模型,抑制接收信号强度测距误差。然后将静态距离权重因子离散化,为离散距离权重匹配动态权重系数,并在划定的动态取值范围内寻找最优权重系数,权重系数与接收信号强度正相关。基于MATLAB平台仿真结果表明,与其他算法相比,该算法能够较好地抑制接收信号强度测距的误差影响,显著降低平均定位误差,提高定位精度。     

基于小波-神经网络的数字电路I_(DDT)故障诊断

利用小波变换与神经网络相结合的方法,采用“能量-故障”特征提取方法和BP算法,提出了一种基于小波分析和神经网络的数字电路瞬态电流I_DDT故障诊断方法。该方法首先采样电源到地的瞬态电流I_DDT,然后通过小波分析提取电路的故障特征向量,最后输入到神经网络进行故障诊断。经过计算机软件对故障进行仿真,结果表明使用小波-神经网络的数字电路I_DDT方法行之有效。     

动态社会接触网络上的H1N1控制仿真研究*

给出了一个动态社会接触网络生成算法,基于该算法可得到同时具有无标度和小世界特性的网络模型;在讨论H1N1病程发展模型及传播参数的基础上,运用该模型对疫情在隔离、随机免疫、目标免疫和熟识者免疫四种控制措施下的发展趋势开展了仿真研究。仿真结果表明,目标免疫在上述四种控制措施中效能最高。模型算法与仿真结果对于传染病的社会传播控制有一定的理论和实践意义。