异构无线网络中基于马尔可夫决策过程的区分业务接纳控制的研究

对异构无线网络中区分业务类型的接纳控制机制进行研究.分析了语音和数据2种典型业务在CDMA蜂窝网络和WLAN中的容量区域.基于马尔可夫决策过程理论,提出异构无线网络中区分业务类型的接纳控制理论模型,规定了不同类型业务的接纳控制行为并推导了系统状态转移概率.而且,进一步从用户角度对不同类型业务QoS要求和网络状态之间关系进行分析,提出一种基于模糊逻辑的接纳效用评估机制,在保证各类业务接入和切换成功率的基础上,推导出接纳效用最大的最优接纳控制策略.仿真表明,基于模糊逻辑的接纳效用评估能够有效反映网络状态动态变化对接纳控制的影响,最优接纳控制策略在平均接纳效用方面明显优于不考虑业务区分和用户移动性2种接纳控制机制,并且能严格保证各类业务的接入和切换成功率.     

一种基于对策模型的ATM网络连接接纳控制策略

本文先简述了ATM网络进行连接接纳控制(Connection Admission Control:CAC)的主要方法,其中主要综述了基于动态带宽分配的CAC策略,而后从合作对策模型的角度讨论业务间共享链路资源的公平性问题,提出一种基于时延带宽积的业务收益函数形式,并通过遗传算法求解待优化的对策函数,以决定对呼叫请求的接入或拒绝。仿真结果表明此方法能够更好地保证不同带宽和服务质量要求的业务共享网络资源的公平性。     

TD-SCDMA系统中的一种接纳控制策略

研究了TD-SCDMA系统中的接纳控制策略,并提出了一种基于路径损耗辅助的接纳算法.该算法通过测忖量路径损耗,在不同时隙内对用户进行资源分配,可以有效平衡时隙间负载,消除远近效应,保持系统稳定.仿真结果表明,该算法能够有效改善系统性能.     

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。     

多业务蜂窝CDMA系统中的呼叫接纳控制策略

基于码分多址(CDMA)技术的第三代(3G)移动通信系统将支持多种业务传输,有效的呼叫接纳控制策略将使系统在满足各类业务不同QoS要求的同时,能够为更多的用户提供服务,该文首先分析了多业务蜂窝CDMA系统的剩余容量与QoS约束间的关系,接着提出了适用于任意多类业务环境、基于信号干扰比(SIR)测量的两种呼叫接纳控制策略,局部策略与全局策略,并通过大量计算机仿真研究了两种策略在业务均匀分布和非均匀分布环境下的性能,仿真结果表明,在两种业务分布情况下,全局策略的性能部优于局部策略。     

基于决策理论的CDMA网络中多类业务的准入控制策略

准入控制是码分多址(CDMA)蜂窝网络中服务质量保证的一个关键技术。该文提出了一个基于半马尔可夫决策过程理论的最优准入控制策略来支持有服务质量要求的多类业务的无线CDMA网络。用线性规划方法求解最优策略,从而在满足服务质量约束要求的同时最大化信道利用率。另外,还使用了加权公平阻塞约束来灵活地实现服务质量要求。数值结果表明此最优策略可以获得比基于阈值的准入控制方案更好的性能。     

多业务无线蜂窝移动通信系统的一种呼叫允许控制策略

第三代移动通信系统要求支持宽带多媒体业务,如话音、视频、数据等多种业务,不同业务有不同的QoS要求。本文提出的多业务无线蜂窝移动通信系统中一种基于QoS的呼收允许控制策略,对不同业务的切换呼叫给予不同的优先权。本文分析了两种呼叫允许控制（CAC）算法,一种是各种业务的切控呼叫无缓冲器,不进入排队系统;另一种是各种业务的切换呼叫设置有缓冲器,进入排除系统,并且话音、视频业务的切切呼叫比数据业务的切换呼叫有更高的优先权,系统的空闲信道应首先分配给话音、视频业务的切换呼叫,再分配给数据业务的切换呼叫。在分析两种CAC算法的呼叫阻塞概率、切换失败概率以及系统吞吐量的基础上,给出了计算机仿真结果。     

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。     

WLAN中基于效用的呼叫接纳控制策略

 为了在802.11的网络中提供服务质量(QoS)支持,IEEE 802.11 Task Group E提出了EDCF协议.然而EDCF只能提供业务区分服务,并不能提供服务质量(QoS)保证.为了能在重负载下提供QoS保证,在WLAN中加入呼叫接纳控制(CAC)机制是非常必要的.本文首先提出了一个新的3维Markov模型对非饱和状态下EDCF的吞吐量和平均接入时延进行了分析.并在此基础上,提出了一种基于效用函数的CAC策略,它可以使网络的总收益达到最大.最后通过大量仿真验证了所提出的CAC策略的有效性.     

APON系统中一种具有多优先级业务的动态带宽分配算法

基于ＡＴＭ的无源光网络（ＡＰＯＮ）上行信道的传输是采用时分多址接入（ＴＤＭＡ）方式来共享光纤的,根据光线路终端（ＯＬＴ）的指示,各光网络单元（ＯＮＵ）发出的信号占据不同的时隙。为了有效利用带宽,给出了一种具有多优先级业务的动态带宽分配算法—最少业务量损失算法,它通过分级允许控制为各优先级业务分配相应的带宽。当有一新的连接要求时,计算损失业务目标函数Ｑ来高速带宽分配。     

一种用于提供QoS保证的准入控制方法

本文推导了ON/OFF马尔可夫数据流的资源分配与延迟分布、丢失率的关系,在此基础上进行可准入性测试,并根据流的优先权大小给出一种优化的准入控制方法,可为各类流提供服务质量(QoS)保证.最后通过算例说明该方法的有效性.     

基于QoS的负载均衡策略接纳控制算法研究

介绍了一种新的接纳控制算法,能优先满足用户的服务质量,并减小网络的阻塞情况,使用户与网络的共同利益得到最优。仿真结果表明,该算法可保持各网络的负载均衡、减少掉话率,从而达到较好的用户满意度。     

Soft QoS in Call Admission Control for Wireless Personal Communications

In wireless multimedia communication systems, call admission control (CAC) is critical for simultaneously achieving a high resource utilization efficiency and maintaining quality-of-service (QoS) to mobile users. User mobility, heterogeneous nature of multimedia traffic, and limited radio spectrum pose significant challenges to CAC. QoS provisioning to both new calls and handoff calls comes with a cost of low resource utilization. This paper proposes a CAC policy for a wireless communication system supporting integrated voice and dataservices. In particular, soft QoS (or relaxed target QoS) is incorporated in the CAC policy to make compromises among different objectives.Numerical results are presented to demonstrate that (a) in dealing with the dilemma between QoS satisfaction and high resource utilization, how the resource utilization efficiency can be increased by introducing soft QoS; and (b) in accommodating different types of traffic, how the QoS of low priority traffic can be improved by specifying soft QoS to high priority traffic.     

Adaptive Call Admission Control for QoS/Revenue Optimization in CDMA Cellular Networks

In this paper, we show how online management of both quality of service (QoS) and provider revenue can be performed in CDMA cellular networks by adaptive control of system parameters to changing traffic conditions. The key contribution is the introduction of a novel call admission control and bandwidth degradation scheme for real-time traffic as well as the development of a Markov model for the admission controller. This Markov model incorporates important features of 3G cellular networks, such as CDMA intra- and inter-cell interference, different call priorities and soft handover. From the results of the Markov model the threshold for maximal call degradation is periodically adjusted according to the currently measured traffic in the radio access network. As a consequence, QoS and revenue measures can be optimized with respect to a predefined goal. To illustrate the effectiveness of the proposed QoS/revenue management approach, we present quantitative results for the Markov model and a comprehensive simulation study considering a half-day window of a daily usage pattern.     

MAC Layer Admission Control and Priority Re-allocation for Handling QoS Guarantees in Non-cooperative Wireless LANs

Providing QoS guarantee with appropriate service differentiation in IEEE 802.11 wireless LANs is quite desirable. However, users may be selfish and thus rigorously try to maximize their performance by demanding high services even though the network has already saturated. On the other hand, user misbehaviors such as misuse of priority and over-rate transmission pose further harm to performance of existing flows. These application layer non-cooperation makes successful resource allocation very challenging with existing contention based CSMA/CA channel access. In this paper, we propose a MAC layer coordinated QoS framework of admission control and priority re-allocation for quality of services of real-time applications in wireless LANs. Our focus is on priority based MAC schedulers where each user can set its flow priority in order to receive appropriate level of services. With channel condition information such as available bandwidth and mean delay exchanged among neighboring stations, users can enforce admission control based on the perceived channel status and may re-allocate their priorities to accommodate existing flows as desired. User misbehaviors are identified by estimating the flow transmitting rate and matching priority setting, or even punished by assigning appropriate low priorities. Extensive simulations results show that the proposed framework can effectively coordinate wireless users on keeping reserved transmission rate, using appropriate MAC priority, and allocating sufficient resource. Ming Li received his B.S. and M.S. in Engineering from Shanghai Jiao Tong University, China, in 1995 and 1998, respectively. He is currently a Ph.D. candidate in department of Computer Science, University of Texas at Dallas, where he received M.S. degree in Computer Science in Dec. 2001. His research interest includes QoS schemes for mobile ad-hoc networks and multimedia over wireless networks. B. Prabhakaran is with the faculty of Computer Science Department, University of Texas at Dallas. He has been working in the area of multimedia systems: animation & multimedia databases, authoring & presentation, resource management, and scalable web-based multimedia presentation servers. Dr. Prabhakaran received the prestigious National Science Foundation (NSF) CAREER Award in 2003 for his proposal on Animation Databases. He has published several research papers in various refereed conferences and journals in this area. He has served as guest-editor (special issue on Multimedia Authoring and Presentation) for ACM Multimedia Systems journal. He is also serving on the editorial board of Multimedia Tools and Applications journal, Kluwer Academic Publishers. He has also served as program committee member on several multimedia conferences and workshops. B. Prabhakaran has served as a visiting research faculty with the Department of Computer Science, University of Maryland, College Park. He also served as a faculty in the Department of Computer Science, National University of Singapore as well as in the Indian Institute of Technology, Madras, India.     

ATM网络中综合连接接纳控制与路由选择的模糊决策策略

本文提出了一种新的模糊决策策略,用于综合考虑连续接纳控制和路由选择,以求在ＡＴＭ网络中增加整个网络的吞吐量和降低信元丢失率与呼损率。文章中详细阐述了该模糊决策系统的原理,并给出了一种自适应调节系统参数的方法。仿真结果说明利用神经网络能够成功地实现此模糊系统。     

基于半马尔科夫决策过程的虚拟传感网络资源分配策略

针对传统无线传感网络(WSN)中资源部署与特定任务的耦合关系密切,造成较低的资源利用率,进而给资源提供者带来较低的收益问题,根据虚拟传感网络请求(VSNR)的动态变化情况,该文提出虚拟传感网络(VSN)中基于半马尔科夫决策过程(SMDP)的资源分配策略。定义VSN的状态集、行为集、状态转移概率,考虑传感网能量受限以及完成VSNR的时间,给出奖赏函数的表达式,并使用免模型强化学习算法求解特定状态下的行为,从而最大化网络资源提供者的长期收益。数值结果表明,该文的资源分配策略能有效提高传感网资源提供者的收益。     

A Novel Effective Bandwidth Based Call Admission Control for Multimedia CDMA Systems

A novel Call Admission Control(CAC)scheme is proposed for multimedia CDMA systems.The effectivebandwidth of real time calls is reserved in the CAC with the consideration of active factors.The admission of non-real timecalls is controlled by the system according to the residual effective bandwidth left from real time calls.Simulation resultshave shown that the novel CAC has greatly enlarged the admission region for real time calls and make the transmission de-lay of non-real time calls under an acceptable level.     

基于静态流感知的接纳控制研究

维持链路正常负载是业务流性能指标保证的关键,接纳控制是链路负载有效控制方式。相对链路容量有固定业务区分速率界值的静态流感知接纳控制,应用与流拥塞状态相关的判决概率实现业务接入区分。同时,利用优先公平调度机制的隐性测量功能测量链路优先队列队长和链路公平速率值,共同对下游链路流承载状态进行评价,并作为接纳控制进行判决的依据。仿真显示,相对基于测量的接纳控制算法具有更好的链路状态自适应性和较高的链路资源效率。     

Vector Quantization Based QoS Classification for Admission Control in CDMA Systems

Optimal power control is of great importance for CDMA systems and it can be controlled to provide the desired quality of service (QoS) to mobile hosts in a cellular radio system. The power levels of all the mobile hosts are determined and constantly tuned in order to achieve the required SINR (signal to interference and noise ratio) which changes dynamically. The SINR of all the K mobiles in a cell can be expressed in the form of a k-dimensional vector. It helps determine the operating point of the system and hence it is constantly monitored and updated due to the variability in the wireless channel conditions and user mobility. We view this continuously changing vector as the motion of a point in a higher dimensional Euclidean space, called the QoS space. We apply vector quantization technique to shrink the infinite-point space to a finite-point space by partitioning the former into N regions such that the points within a region reflect almost similar system performance and are identified by what we call a QoS index. We show how the system operating point can be mapped to one of the QoS indices. The location of the point or the region of operability in the QoS space conveys the system status in terms of the current load and the QoS being delivered. The dynamism in the system's input conditions due to wireless link characteristics and user mobility acts like an opposing force against which the system has to operate. The system reacts to all such changes preventing it from going into a region with an undesirable QoS index. We show how the apriori knowledge of the operating region helps in decision making pertaining to call admission and resource allocation in CDMA systems. Mainak Chatterjee received his Ph.D. from the department of Computer Science and Engineering at the University of Texas at Arlington in 2002. Prior to that, he completed his B.Sc. with Physics (Hons) from the University of Calcutta in 1994 and M.E. in Electrical Communication Engineering from the Indian Institute of Science, Bangalore. He is currently an Assistant Professor in the department of Electrical and Computer Engineering at the University of Central Florida. His research interests include resource management and quality-of-service provisioning in wireless and cellular networks, sensor networks, CDMA data networking, media access control protocols, Internet traffic, and applied game theory. Sajal K. Das is a Professor of Computer Science and Engineering and also the Founding Director of the Center for Research in Wireless Mobility and Networking (CReWMaN) at the University of Texas at Arlington (UTA). His current research interests include resource and mobility management in wireless networks, mobile and pervasive computing, wireless multimedia and QoS provisioning, sensor networks, mobile Internet protocols, distributed processing and grid computing. He has published over 250 research papers, directed numerous funded projects, and holds 5 US patents in wireless mobile networks. He received the Best Paper Awards in ACM MobiCom'99, ICOIN-2001, ACM MSWIM-2000, and ACM/IEEE PADS'97. Dr. Das is also a recipeint of UTA's Outstanding Faculty Research Award in Computer Science in 2001 and 2003, and UTA's College of Engineering Excellence in Research Award in 2003. He serves on the Editorial Boards of IEEE Transactions on Mobile Computing, ACM/Kluwer Wireless Networks, Parallel Processing Letters, Journal of Parallel Algorithms and Applications. He served as General Chair of IEEE PerCom-2004, CIT-2003 and IEEE MASCOTS-2002; General Vice Chair of IEEE PerCom-2003, ACM MobiCom-2000 and HiPC 2000-01; General Chair of ACM WoWMoM 2000-02; Program Chair of IWDC-2002, WoWMoM 1998-99; TPC Vice Chair of ICPADS-2002; and as TPC member of numerous IEEE and ACM conferences. He is the Vice Chair of IEEE TCPP and TCCC. Prior to 1999, Dr. Das was a professor of computer science at Univeristy of North Texas where he twice (1991 and 1997) received the Student Association's Honor Professor Award for best teaching and scholarly research. He received B.Tech. degree in 1983 from Calcutta University, M.S. degree in 1984 from Indian Institute of Science, Bangalore, and PhD degree in 1988 from the University of Central Florida, Orlando, all in Computer Science.