基于博弈论的移动WiMAX接纳控制

移动WiMAX是一种重要的宽带无线接入技术,它具有数据传输率高、覆盖范围广、支持多种数据业务等优点。为了保证不同业务的QoS,该文提出一种基于博弈论的接纳控制算法。该算法首先给不同的业务赋予不同的优先级,然后建立一个非合作二人博弈模型,通过求解纳什均衡决定是否接纳连接请求,以及带宽的预留方案。仿真结果表明,该算法能够提高带宽的利用率,降低新发起连接的阻塞概率和切换连接的丢弃概率,并且能给不同业务提供区分服务。     

3G动态预留呼叫接纳控制算法研究

第三代移动通信技术支持不同服务质量(QoS)的多媒体业务,而呼叫接纳控制(CAC)技术是移动通信中的关键技术之一.本文提出一种动态预留呼叫接纳控制算法,该算法根据小区中各业务的话务量预测各业务所需信道教,从而为切换业务和新业务预留一定的信道.通过比较动态预留算法与新呼叫受限算法和中断优先级算法的性能,得出动态预留算法在降低语音和数据业务的呼叫阻塞率、中断率方面有明显的改善,是一种比较理想的呼叫接纳控制算法.     

基于优先级的IEEE802.16系统接纳控制算法研究

鉴于IEEE802.16标准中未对接纳控制机制提出定义,为了提高系统带宽利用率,在分析现有无线网络接纳控制技术的基础上,结合IEEE802.16的具体机制提出了一种基于业务优先级的接纳控制算法。相比于先到先服务的接纳机制,该算法严格区分业务优先级,为不同优先级业务预留带宽,以保证实时业务的服务质量(QoS)要求。利用NS2网络模拟软件对算法进行了仿真和性能评估。结果表明,本接纳控制算法可以较好地保障高优先级业务的实时性,同时在重负载情况下系统带宽利用率有了明显提高。     

适应自相似业务流量模型的CAC算法研究

分析了呼叫接纳控制算法研究的现状，提出一种适应自相似业务流量模型的呼叫接纳控制算法，在接纳判决过程中引入概率接纳机制。理论分析和仿真结果验证了算法的可行性和在自相似业务流量模型下相对于传统呼叫接纳控制算法的优越性。     

IEEE 802.11中基于传输时间的接纳控制算法研究

在IEEE 802.11无线局域网中引入基于传输时间的实时业务接纳控制算法,当新申请的业务 加入系统后使系统总的传输时间超过预算时,拒绝该业务加入。对已接纳的业务流按照令牌桶算法分配传输时间,并采用轮询机制保证实时业务的服务质量。通过拒绝接纳过多的实时业务流,为非实时业务留出部分资源,避免了实时业务耗尽系统资源使非实时业务得不到服务的情况。     

基于蚁群算法的OFDMA系统接纳控制

由于接纳控制算法的优劣关系到网络资源能否被有效利用。文中提出了一种新的OFDMA系统的接纳控制算法。结合蚁群算法对用户需要的的总传输功率进行计算,并通过该功率对用户进行接纳控制。仿真结果表明,文中所提算法可使系统的总传输功率减小,增加用户的可接入数量,达到资源有效利用的目的。     

自相似业务下视频服务器的接纳控制

VOD 系统中,有限的磁盘 I/O 带宽或缓存空间往往成为系统的瓶颈。针对这一问题,提出了自相似业务下视频服务器的接纳控制算法。该算法运用等效带宽理论,通过在线测量系统所剩资源和周期容限的幅度变化来实时调节调度周期的大小,使得系统所剩资源达到动态的“等量”平衡。仿真结果表明,该算法不但简化了接纳过程,节约了系统资源,提高了算法的可实现性,而且系统的接纳率比 Lee,Yeom 所提算法的接纳率提高了 15%,并且还可根据系统的 QoS 参数灵活调整接纳率。     

SPANRACS中Rq接口实现资源预留的研究

下一代网络TISPAN主要研究固网与移动网络融合,它提出的资源接纳控制子系统实现了接入控制、资源预留等功能。Rq接口是RACS中连接SPDF,A—RAC两个功能实体重要的接口。本文对RACS的整体架构、实体功能进行了描述;对Rq接口的功能、信息模型、具体的消息进行了研究;以IPTV具体业务为例,描述了Rq接口实现资源预留过程的具体消息流程。     

LTE-Advanced中继系统基于资源共享的呼叫接纳控制方法

针对LTE-Advanced中继系统提出了一种基于资源共享的呼叫接纳控制方法。如果目标站点内新用户和切换用户共享资源已经被使用完,切换用户可以使用目标站点为切换用户预留的资源接入系统,而新用户则可以通过目标站点所在小区内的站点间资源共享接入系统。仿真结果表明,与LTE-Advanced系统固定带宽预留方案和LTE-Advanced中继系统固定带宽预留方案相比较,提出的算法能有效降低小区内新用户阻塞率和切换用户的掉话率,并且能够提高系统的资源利用率。     

区分服务网络中确保业务端到端时延的接纳控制算法研究

该文提出了一种对区分服务网络中时延敏感业务进行接纳控制的SACiD(Service Admission Control in DiffServ)算法,它不仅保证用户业务的端到端时延不超过确定的上界,而且能比较充分利用网络资源。仿真结果表明,SACiD算法可以保证时延敏感业务的服务质量,而且其业务接纳率和带宽利用率接近综合服务网络中接纳控制算法的性能,但它的存储器需求却远小于它们。此外,SACiD算法运算简单,具有与区分服务一致的可扩展性,可以为区分服务网络的资源管理提供支持。     

Comparative study of two CPU router time management algorithms in cellular IP networks

Providing good quality of service (QoS) in cellular IP networks is an important requirement for performance improvement of the cellular IP network. Resource reservation is one of the methods used in achieving this goal and is proven to be effective. The main resources to be reserved in a cellular IP network are bandwidth, buffer and central processing unit (CPU) cycles. Router CPU cycle is the time taken by the router to process the packet of the flow before forwarding it to the next router (hop). This paper proposes a model for CPU cycle optimization of routers for real‐time flows in a cellular IP network. The model applies both genetic algorithm (GA) and particle swarm optimization (PSO) as soft computing tools to optimize the CPU cycles and reduces the flow processing time at each router in the route taken by a flow. Simulation experiments illustrate a comparative study of the model.     

Dynamic RSVP protocol

RSVP is a resource reservation setup protocol that can be used by a host to request specific QoS for multicast multimedia flows on the Internet. Multiprotocol label switching (MPLS) architecture also needs RSVP. The fact that the resolutions of the display system used in different receiver nodes might have different, multi-resolution characteristics is supported in the MPEG-4 standard, and the EZW compression algorithm can cease decoding at any point in the bitstream. However, RSVP does not provide a more flexible mechanism. In this article we propose an extension of RSVP to provide the needed mechanism, coined dynamic RSVP (DRSVP), to dynamically adjust reserved resources on nodes without much effort. It provides different video resolutions to different receiver nodes with different needed reserved resources. Therefore, it does not waste precious Internet resources to transmit unnecessary multimedia packets.     

Enabling novel premium service classes in DiffServ over MPLS‐enabled network

Network resources dimensioning and traffic engineering influence the quality in provisioned services required by the Expedited Forwarding (EF) traffic in production networks established through DiffServ over MPLS‐enabled network. By modeling EF traffic flows and the excess of network resources reserved for it, we derive the range of delay values which are required to support these flows at DiffServ nodes. This enables us to develop an end‐to‐end (e2e) delay budget‐partitioning mechanism and traffic‐engineering techniques within a framework for supporting new premium QoS levels, which are differentiated based on e2e delay, jitter and loss. This framework enables ingress routers to control EF traffic flow admission and select appropriate routing paths, with the goal of EF traffic balancing, avoiding traffic congestion and getting the most use out of the available network resources through traffic engineering. As a result, this framework should enable Internet service providers to provide three performance levels of EF service class to their customers provided that their network is DiffServ MPLS TE aware. Copyright © 2008 John Wiley & Sons, Ltd.     

Design and analysis of an algorithm for fair service in error‐prone wireless channels

In order to support diverse communication‐intensive real‐time and non‐real‐time data flows over a scarce, varying and shared wireless channel with location‐dependent and bursty errors, we define a service model that has the following characteristics: short‐term fairness among flows which perceive a clean channel, long‐term fairness for flows with bounded channel error, worst‐case delay bounds for packets, short‐term throughput bounds for flows with clean channels and long‐term throughput bounds for all flows with bounded channel error, expanded schedulable region, and support for both delay sensitive and error sensitive data flows. We present the wireless fair service algorithm, and show through both analysis and simulation that it achieves the requirements of the service model in typical wireless network environments. The key aspects of the algorithm are the following: (a) an enhanced fair queueing based service scheme that supports decoupling of delay and bandwidth, (b) graceful service compensation for lagging flows and graceful service degradation for leading flows, (c) support for real‐time delay sensitive flows as well as non‐real‐time error sensitive flows, and (d) an implementation within the framework of the simple and robust CSMA/CA wireless medium access protocol. This revised version was published online in July 2006 with corrections to the Cover Date.     

Adaptive resource allocation framework for user satisfaction maximization in multi-service wireless networks

In order to capture and maintain a representative share of the wireless communication market, effective ways to manage the scarce physical resources of cellular networks are fundamental for cellular network operators. In this context, this paper proposes an adaptive Radio Resource Allocation algorithm that targets the user satisfaction maximization in cellular networks with multiple services. The proposed algorithm is mathematically derived from a utility-based cross-layer optimization framework and employs user weights as well as an innovative service weight that is adapted to meet the satisfaction target of the most prioritized service. Furthermore, the proposed algorithm is scalable to several services classes and can be employed in the current and future generations of wireless systems that guarantee orthogonality among the allocable resources. The performance evaluation is conducted in realistic scenarios of the downlink of an Orthogonal Frequency Division Multiple Access based cellular network serving video and Constant Bit Rate flows, where we assume imperfect Channel State Information at the transmitter. Significant gains in the joint system capacity were obtained, demonstrating that the adaptability and service prioritization allow the accomplishment of simultaneously maximizing the user satisfaction for distinct services.     

一种面向最经济服务流的可视化动态贝叶斯网络模型

将面向最经济服务的流演算机制引入到动态贝叶斯网络结构的学习中,提出一种面向最经济服务流的可视化动态贝叶斯网络分解协调模型(SFO-DBNs)及具体实现算法;该算法把Ford-Fulkerson流分解算法推广到多源、多汇的情况下,并加入了时间片t因素对服务流稳定性约束,可以把一个描述复杂大系统流演算的贝叶斯网络动态协调分...     

Residual resources aware distributed admission control mechanism in mobile multi-hop network

Without considering current residual resources of the medium, nodes in mobile ad hoc networks (MANETs) admit the data flow arbitrarily, and the quality of service (QoS) of the data flows deteriorates. To release the contending on the resources induced by the overloaded flows, the admission control mechanism can effectively keep the balance between injected data flows and network capacity, and it is viewed as the most important technology in MANET. A novel distributed residual resources aware admission control mechanism is proposed in this paper, where the residual resources and the service rate are studied thoroughly. Considering the medium utilization, frame retransmission and backoff procedure, the passive method is applied to predict the residual resources, and the binomial distribution is utilized to model the medium status; moreover, based on the cooperation between the source node and intermediate nodes, the path meeting the resource demand is probed across the network, and the flows are rejected while the residual resources cannot meet its demand. Results show that the network load can be constrained by our proposed admission control mechanism, and the QoS of the data flows can be guaranteed effectively.     

Analysis of Multi-Server Scheduling Paradigm for Service Guarantees during Network Mobility

Multi-server scheduling of traffic flows over heterogeneous wireless channels affix fresh concerns of inter-packet delay variations and associated problems of out-of-sequence reception, buffer management complexity, packet drops and re-ordering overhead. In this paper, we have presented an exclusive multi-server scheduling algorithm that is specifically tuned for mobile routers equipped with multiple wireless interfaces and has attained multiple care-of-address registrations with its home agent (HA). The proposed adaptive, Self-clocked, Multi-server (ASM) scheduling algorithm is based on predetermined transmission deadlines for each arrived packet at the mobile router. The mobile flows receive desired service levels in accordance with their negotiated service rates and are only constraint by the cumulative capacity of all active links. The major challenge lies in the handling of asymmetric channels to stitch into a unified virtual channel of higher capacity with reliable service guarantees during mobility. The sorted list of transmission schedules is used to assign physical channels in increasing order of their availability. This approach specifically encapsulates the physical layer disconnections during the handovers and ensures continuous service to ongoing flows. The proposed scheduling scheme is supplemented by an analytical model and simulations to verify its efficacy. The simulation results demonstrate higher degree of reliability and scalability of service provisioning to flows during mobility.     

一种支持硬件加速的虚拟网络功能部署模型

为解决以软件实现的虚拟网络功能(VNF)性能受限问题,软件定义网络和网络功能虚拟化(SDN/NFV)等新型网络架构引入了硬件加速资源。硬件加速资源的部署,使得VNF能够为日益增长的数据流量提供服务保障。该文针对已有研究未考虑具有高性能数据处理需求的服务链VNF部署问题,提出一种支持硬件加速的VNF部署模型。该模型基于硬件加速资源的承载特性,在保证未加速VNF到商用服务器的优化部署下,优先实现交换机中加速资源的复用,并根据网络业务的性能需求,灵活调整加速资源与VNF的映射约束。仿真实验表明,与其他典型部署方法相比,在引入相同硬件加速资源的情况下,该模型可以承载更多的业务流量,满足服务链高性能数据处理需求,有效提高了部署在网络中加速硬件的资源利用率。     

Flow‐oriented detection of low‐rate denial of service attacks

In this paper, an approach of detecting low‐rate denial of service attack is proposed on the basis of principal component analysis algorithm. The proposed approach analyzes low‐rate denial of service attack flows and handles complicated network flows by using principal component analysis algorithm to establish the network traffic matrix model, which is established on the basis of a large number of data acquisitions. Simulation results show that the proposed approach can predigest the high dimension vector, which is composed of networks flows, guarantee the detection precision, and reduce the computation consuming. Copyright © 2014 John Wiley & Sons, Ltd.