移动云计算中基于协作式博弈模型的资源分配方案

提出一种基于协作式博弈的资源分配方案。首先, 在服务提供商创建长期可用预留资源公用库完毕后, 通过一种访问控制机制为用户提供移动应用服务, 提出一种优化算法实现访问控制的最优决策; 其次, 提出一种协作式博弈模型进行利益分配, 在服务提供商建立合作后, 通过使用资源公用库而获得的运营收入, 在服务提供商之间进行分配博弈。仿真实验结果表明, 该方法是有效的, 能够帮助服务提供商就容量提升制定最优策略, 以实现利益最大化。     

异构无线网络中基于非合作博弈论的资源分配和接入控制

对异构无线网络中无线资源分配和呼叫接入控制进行研究.基于非合作博弈理论,提出了不同无线资源的带宽和连接数量分配的理论模型.结合网络连接的效用函数,对非合作博弈的无线资源分配中的纳什均衡点的存在性和唯一性进行论证.而且,进一步对业务量与阻塞率之间的关系进行分析,提出了能够保证通信可靠性的接入控制算法.仿真结果表明,基于非合作博弈论的无线资源分配机制能够有效地解决带宽和连接数量的分配问题,并能在整体上保证分配的合理性和公平性.接入控制算法根据需要能够动态地调整在某一区域分配的连接数量,从而保证通信的可靠性.     

移动通信系统中一种合作博弈CAC 策略

由于无线频谱是极为有限的资源,呼叫接纳控制(call admission control,简称CAC)成为移动通信系统中无线资源管理的一个重要部分.针对流媒体对接入资源的过度占用问题,提出了一种基于合作博弈理论的CAC策略,博弈方是处于服务状态的业务和申请接入的新业务,基站是保证协议强制执行的外在力量,基站选择效用和最大的策略组作为博弈过程的最终结果.仿真结果表明,所提策略有效缓解了流媒体业务对资源的捕获效应,保证了用户接入的公平性,对于实际系统性能的改善具有重要的意义.     

Implementation of call admission control scheme in next generation mobile communication networks using particle swarm optimization and fuzzy logic systems

In the present and next generation wireless networks, cellular system remains the major method of telecommunication infrastructure. Since the characteristic of the resource constraint, call admission control is required to address the limited resource problem in wireless network. The call dropping probability and call blocking probability are the major performance metrics for quality of service (QoS) in wireless network. Many call admission control mechanisms have been proposed in the literature to decrease connection dropping probability for handoffs and new call blocking probability in cellular communications. In this paper, we proposed an adaptive call admission control and bandwidth reservation scheme using fuzzy logic control concept to reduce the forced termination probability of multimedia handoffs. Meanwhile, we adopt particle swarm optimization (PSO) technique to adjust the parameters of the membership functions in the proposed fuzzy logic systems. The simulation results show that the proposed scheme can achieve satisfactory performance when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization.     

高铁旅客认知频谱共享算法研究

针对高铁环境中包含多个主用户的主服务和多个次用户的频谱分配问题,提出一种认知博弈频谱共享算法。引入次用户优先级和用户传输业务等级,满足不同优先级用户的不同业务频谱使用需求,并根据主基站和次用户的距离变化更新主服务向次用户提出的价格函数,获得静态博弈下的纳什均衡解,同时分析不完全信息和完全信息的动态博弈,确定不完全信息动态博弈的稳定区间。分别对静态博弈和动态博弈进行仿真,结果表明,在该算法下,当次用户优先级相同时,不同业务等级租借不同的带宽,业务等级越高,租借的带宽也越多,随着距离的变化,较高的业务等级频谱变化较为迅速,而在同一业务等级下,用户优先级越高,则会租借到更多的频谱。     

An adaptive neural network admission controller for dynamicbandwidth allocation

In an access node to a hybrid-switching network (e.g., a base station handling the downlink in a cellular wireless network), the output link bandwidth is dynamically shared between isochronous (guaranteed bandwidth) and asynchronous traffic types. The bandwidth allocation is effected by an admission controller, whose goal is to minimize the refusal rate of connection requests as well as the loss probability of packets queued in a finite buffer. Optimal admission control strategies are approximated by means of backpropagation feedforward neural networks, acting on the embedded Markov chain of the connection dynamics. The case of unknown, slowly varying, input rates is explicitly considered. Numerical results are presented, comparing the approximation with the optimal solution obtained by dynamic programming.     

Adaptive performance management for universal mobile telecommunications system networks

In this paper, we introduce a framework for the adaptive control of universal mobile telecommunications system (UMTS) networks in order to improve bandwidth utilization of the radio channels. The key contribution of the paper constitutes the introduction of a performance management information base for dynamically adjusting the packet scheduler and admission controller. Thus, the adaptive control framework closes the loop between network operation and network control. Furthermore, the adaptive control framework can effectively deal with the different time scales of packet scheduling and admission control. Moreover, we present a traffic model for non-real-time UMTS traffic based on measured trace data. The analysis and scaling process of the measured trace data with respect to different UMTS bandwidth classes constitutes the basic concept of this traffic characterization. Using this traffic model and simulation on the IP level, the gain of employing the adaptive control framework is illustrated by performance curves for various quality of service measures.     

Optimization for adaptive bandwidth reservation in wireless multimedia networks

In future wireless multimedia networks, user mobility management for seamless connection regarding realtime multimedia applications is one of the most important problems. In this paper we propose an opportunity-cost concept-based approach for adaptive bandwidth reservation with admission control for handover calls utilizing network traffic information. Excessive reservation guarantees low blocking probability of handover calls at the cost of high blocking probability of new calls. According to our survey, however, it may degrade bandwidth utilization while no prioritization for handover admissions degrades quality of service (QoS) for ongoing calls. We consider both QoS assurance and bandwidth utilization in order to optimize the amount of bandwidth to reserve for handover admissions. We believe that our scheme could be utilized as a guideline for cost-effective radio resource allocation in mobile multimedia networks.     

基于拥塞的接纳控制算法*

提出一种基于带宽分配的多业务接纳控制算法,依据系统无线拥塞程度的不同相应地采用不同的机制来进行呼叫接入的判决,当系统发生严重拥塞时,拒绝接入所有的呼叫;而在系统发生中等程度的拥塞时,如果新呼叫所隶属的业务类型的数据流在系统中的传输性能已经恶化,拒绝接入此类呼叫;对于未发生拥塞和轻微程度的拥塞这两种情况,根据系统当前的容量限制和预定的带宽分配比例来决定是否接入新的呼叫。用MATLAB仿真确定拥塞程度门限,对算法仿真结果比较显示该算法性能上较优。     

Fuzzy-based adaptive bandwidth control for loss guarantees

This paper presents the use of adaptive bandwidth control (ABC) for a quantitative packet loss rate guarantee to aggregate traffic in packet switched networks. ABC starts with some initial amount of bandwidth allocated to a queue and adjusts it over time based on online measurements of system states to ensure that the allocated bandwidth is just enough to attain the specified loss requirement. Consequently, no a priori detailed traffic information is required, making ABC more suitable for efficient aggregate quality of service (QoS) provisioning. We propose an ABC algorithm called augmented Fuzzy (A-Fuzzy) control, whereby fuzzy logic control is used to keep an average queue length at an appropriate target value, and the measured packet loss rate is used to augment the standard control to achieve better performance. An extensive simulation study based on both theoretical traffic models and real traffic traces under a wide range of system configurations demonstrates that the A-Fuzzy control itself is highly robust, yields high bandwidth utilization, and is indeed a viable alternative and improvement to static bandwidth allocation (SBA) and existing adaptive bandwidth allocation schemes. Additionally, we develop a simple and efficient measurement-based admission control procedure which limits the amount of input traffic in order to maintain the performance of the A-Fuzzy control at an acceptable level.     

Service Adaptability in Multimedia Wireless Networks

Next-generation wireless communication systems aim at supporting wireless multimedia services with different quality-of-service (QoS) and bandwidth requirements. Therefore, effective management of the limited radio resources is important to enhance the network performance. In this paper, we propose a QoS adaptive multimedia service framework for controlling the traffic in multimedia wireless networks (MWN) that enhances the current methods used in cellular environments. The proposed framework is designed to take advantage of the adaptive bandwidth allocation (ABA) algorithm with new calls in order to enhance the system utilization and blocking probability of new calls. The performance of our framework is compared to existing framework in the literature. Simulation results show that our QoS adaptive multimedia service framework outperforms the existing framework in terms of new call blocking probability, handoff call dropping probability, and bandwidth utilization.      

一种基于连接的增强拥塞控制机制

文中针对越来越多的网络应用不采用端拥塞控制机制而导致非公平占用网络带宽问题,介绍了在路由器内部实现基于连接调度的增强拥塞控制方法。路由器使用公平排队调度算法代替传统的先来服务调度算法,可隔离和保护基于漏桶控制的连接。但采用基于窗口反馈拥塞控制机制ＴＣＰ连接会对数据包丢失敏感,路由器使用公平排队调度算法还需要结合相应的缓冲管理方法,才能保证ＴＣＰ连接获取公平的吞吐量。文中还讨论了基于连接的排队数据包     

基于跨层的自适应预留带宽和多重QoS保证的EDCA流接纳控制

提出了基于跨层的自适应带宽预留和多重QoS保证的802.11eEDCA分布式流接纳控制。首先自适应分配各站点OFDM子载波比特以最大化信道容量,并将比特率跨层传送到MAC层。基于此,提出了基于分布式测量的动态带宽预留机制,使预留带宽自适应各用户信道特点和业务特征;提出了半模式化的中心控制的剩余因子估计方法,从而克服了直接测量的不准确性和分布式估计的局部性,并降低了计算复杂度;提出了基于协议模型的带宽和碰撞率双重接纳标准,使多重QoS参数同时得到保证。通过这些措施得到自上至下的自适应接纳控制。仿真表明,提出的接纳控制机制能较大地提高资源利用率,更好地保证业务质量。     

弹性光数据中心网络中收益最大化的带宽分配算法

弹性光数据中心网络中的带宽分配需要兼顾云服务提供商收益和用户连接请求性能,对此提出收益最大化的带宽分配算法,其以子载波为基本单位将光纤带宽有效地分配给多个用户连接请求。首先,基于收益模型和虚拟子载波的概念建立带宽分配问题的整数线性规划模型;接着提出一种基于动态规划的带宽分配算法以及一种启发式的带宽分配算法,前者致力于获得最大的分配收益,后者则力求获得更好的时间效率;最后,通过仿真实验对所设计的带宽算法的性能进行验证。实验结果表明,相较于已有的弹性光数据中心网络中的带宽分配算法,设计的两种算法均能在带宽分配中获得更高的系统收益。     

Performance evaluation for DRED discrete-time queueing network analytical model

Due to the rapid development in computer networks, congestion becomes a critical issue. Congestion usually occurs when the connection demands on network resources, i.e. buffer spaces, exceed the available ones. We propose in this paper a new discrete-time queueing network analytical model based on dynamic random early drop (DRED) algorithm to control the congestion in early stages. We apply our analytical model on two-queue nodes queueing network. Furthermore, we compare between the proposed analytical model and three known active queue management (AQM) algorithms, including DRED, random early detection (RED) and adaptive RED, in order to figure out which of them offers better quality of service (QoS). We also experimentally compare the queue nodes of the proposed analytical model and the three AQM methods in terms of different performance measures, including, average queue length, average queueing delay, throughput, packet loss probability, etc., aiming to determine the queue node that offers better performance.     

基于深度强化学习的边缘网络内容协作缓存与传输方案研究

为了应对第五代无线通信网络中数据吞吐量急剧增加的问题,移动边缘缓存成为了一种有效的解决方案。它通过在边缘设备上存储网络内容,减轻回程链路和核心网络的负担,缩短服务时延。到目前为止,大多数边缘缓存研究主要在协作内容缓存的优化方面,忽略了内容传输的效率。研究超密集网络的内容协作边缘缓存与无线带宽资源的分配问题,通过余弦相似度和高斯相似度求解基站之间总的相似度,将网络中的小基站根据总相似度进行分组,把缓存和无线带宽分配问题建模成一个长期混合整数的非线性规划问题（LT-MINLP）,进而将协作边缘缓存与带宽分配问题转变为一个带约束的马尔可夫决策过程,并利用深度确定性策略梯度DDPG模型,提出了一种基于深度强化学习的内容协作边缘缓存与带宽分配算法CBDDPG。提出的基站分组方案增加了基站之间文件共享的机会,提出的CBDDPG算法的缓存方案利用DDPG双网络机制能更好地捕捉用户的请求规律,优化缓存部署。将CBDDPG算法与三种基线算法（RBDDPG、LCCS和CB-TS）进行了对比实验,实验结果表明所提方案能够有效地提高内容缓存命中率,降低内容传递的时延,提升用户体验。     

Buffer allocation in general single-server queueing networks

The optimal buffer allocation in queueing network systems is a difficult stochastic, non-linear, integer mathematical programming problem. Moreover, the objective function, the constraints or both are usually not available in closed form, making the problem even harder. A good approximation for the performance measures is thus essential for a successful buffer allocation algorithm. A recently published two-moment approximation formula to obtain the optimal buffer allocation in general service time single queues is examined in detail, based on which a new algorithm is proposed for the buffer allocation in single-server general service time queueing networks. Computational results and simulation results are shown to evaluate the efficacy of the approach in generating optimal buffer allocation patterns.     

无线多媒体通信网适应带宽配置在线优化算法

基于强化学习的方法,提出一种无线多媒体通信网适应带宽配置在线优化算法,在满足多类业务不同QoS(quality of service)要求的同时,提高网络资源的利用率.建立事件驱动的随机切换分析模型,将无线多媒体通信网中的适应带宽配置问题转化为带约束的连续时间Markov决策问题.利用此模型的动态结构特性,结合在线学习估计梯度与随机逼近改进策略,提出适应带宽配置在线优化算法.该算法不依赖于系统参数,如呼叫到达率、呼叫持续时间等,自适应性强,计算量小,能够收敛到全局最优,适用于复杂应用环境中无线多媒体通信网适应带宽配置的在线优化.仿真实验结果验证了算法的有效性.     

基于分布式PEP的卫星网络TCP性能增强协议

提出了一个基于分布式性能增强代理的卫星网络专有通信协议：XP协议,用于解决卫星网络环境中因长时延、高误码率和非对称信道带宽等因素所导致的TCP传输性能低下问题．协议的设计考虑到了与地面链路上TCP连接的接口关系和多连接共享同一卫星信道时的带宽分配问题．主要贡献包括两路半握手连接建立机制,速率控制和基于测量的动态带宽分配算法,以及基于发送方主动请求的延迟确认技术等．仿真和真实环境实验表明,分布式性能增强代理和XP协议的使用可显著提高网络中下行卫星链路的吞吐量,多数情况下带宽资源利用率可提高至85％以上,且在多连接共享带宽的情况下能够保持较好的公平性．     

一种动态带宽分配策略及其性能分析

针对当前网络中不同业务的服务质量需求,综合考虑业务优先级及业务负载,提出一种动态带宽分配策略——E-DBA。建立具有多重工作休假机制的Geom/G/1排队模型,使用嵌入式马尔可夫链导出排队模型的稳态指标。给出E-DBA的平均响应时间和信道利用率等系统性能指标表达式,并通过实验分析了第II类业务的保障带宽对系统性能的影响。