基于边际效用函数的网络资源调度

为解决当前基于效用的网络资源调度中模型通用性不强、求解算法效果差、速度慢等问题,提出了基于边际效用函数的效用最优化资源调度方法.它根据边际效用函数的特点,将网络应用分为弹性和非弹性应用,并通过每个应用的边际效用函数求出其效用函数.将上述效用函数应用于网络资源调度问题中,给出了问题求解的高效算法.仿真实验表明,与目前最新的同类算法及经典优化求解工具Lingo9.0中的算法相比,本文算法求得的总效用值平均提高5%和4%,而所用时间仅为上述算法的0.2%和0.003%.     

Ad Hoc中基于效用最大的优先级流控机制

针对AdHoc中流竞争,提出了一种分布式节点的最优化速率控制机制。给出了基于流优先级的效用函数。以最大化网络整体效用为目标,通过运用对偶理论和梯度投影算法,给出了每一端到端流获得最优值的迭代机制,它能够保证高优先级流的QoS。仿真结果表明该机制可以使网络资源根据流优先级进行有效分配,并且具有很好的收敛性。     

基于效用最大化的IEEE 802.11 DCF性能分析及改进

针对802.11 DCF在系统负载较大时不能有效利用带宽资源的缺点,该文提出一种基于效用函数的DCF优化机制(U-DCF)。通过设置站点吞吐量的对数效用函数,将带宽资源的有效利用问题建模为系统效用最大化问题;应用最优化理论将此系统问题等效为可分布式求解的用户问题,即各站点只须独立选择最大化其净效用的竞争参数(CWmin),则系统整体效用也获得最大化。仿真结果表明:与标准DCF相比,U-DCF通过预估系统的当前平均分组长度和竞争站点数来调整竞争参数CWmin,能够显著提高系统的饱和吞吐量,减小分组发送时延和丢帧率。     

基于时延和速率效用函数的LTE无线资源调度算法研究

为了提高LTE实时业务调度的公平性,在M-LWDF资源调度算法的优先级判断机制中引入了平均传输速率和保证比特速率,将经济学中的效用思想和效用函数引入M-LWDF调度算法,提出了一种基于时延效用函数和速率效用函数的M-LWDF改进算法,更好地体现了调度算法的时延特性和速率特性。仿真结果表明基于时延和速率效用函数的M-LWDF调度算法具有更高的公平性,能够更好地满足对实时业务的调度要求。     

认知无线网络中兼顾效用与公平的联合带宽和功率分配算法

对不同类型的业务采用了统一的效用函数形式,并在此基础上构造了基于网络效用最大化模型的优化问题。采用拉格朗日对偶方法对问题进行了求解,提出了一种分布式的联合带宽和功率分配算法。仿真结果表明,本算法能够有效地为不同类型认知用户分配合理的带宽和功率资源,在最大化所有认知用户总效用的同时保证用户之间的效用公平性。     

一种基于博弈论的无线mesh网络信道分配算法

无线mesh网络中的信道分配会极大地影响网络的性能。为了解决无线mesh网络中的信道分配问题,提出了一种基于博弈论的信道分配(GBCA)算法。该算法将网络中每一个节点模型化为一个博弈者,每个博弈者的策略为信道的分配方案,并将整个网络的吞吐量作为效用函数的目标,效用函数的物理意义则是在给定流量需求矩阵下传输的成功率。博弈者通过相互博弈来优化收益函数,以最大化网络吞吐量。并针对GBCA算法的不足,提出了一种改进算法———GBCA-TP算法。通过NS2.34仿真分析得出,GBCA算法和GBCA-TP算法在收敛性、分组丢失率和吞吐量上都要优于当前的算法。     

基于广义纳什讨价还价解的资源分配方法

为不同业务提供不同的服务质量保证(QoS)是IEEE 802.16无线Mesh网络关键问题。针对IEEE 802.16无线Mesh网络分布式资源分配问题,文中提出了一种基于广义纳什讨价还价解的资源分配方法。此方法结合多射频多信道的协议干扰模型,利用广义纳什讨价还价解,联合信道分配和自适应调制编码技术(AMC),定义业务端到端流量的效用函数,根据业务不同的讨价还价能力来提供业务的QoS保证。通过拉格朗日对偶原理,各个用户在分布式的情况下对对偶问题进行求解获得各自的速率分配方案,使用户在分布式的情况下以合作方式竞争资源,既能保证高优先级流的QoS,并使网络整体性能达到帕累托最优。实验结果表明所提方法能兼顾网络性能和用户优先级。     

基于分段线性函数的广义效用max-min公平分配算法研究

提出了一种基于分段线性函数的广义效用max-min（UMM）公平分配算法，可支持资源分配的上下限以及各种严格单调增和连续的效用函数。该算法避免了迭代计算，复杂度低于UMM公平的注水法。简化后的算法的复杂度与现有的基于分段线性函数的狭义UMM公平分配算法相同。该算法可应用于计算机和通信领域中的各种资源分配问题中。     

一种用于IEEE 802.16无线城域网TDD模式中的带宽调度方案

该文提出了一种用于IEEE 802.16宽带无线接入系统TDD模式下的公平而有效的带宽分配调度体系。与该领域中传统的固定带宽分配方式相比,该文提出的调度体系结构综合考虑了上下行链路不同业务带宽需求并进行动态带宽分配。该文提出一种新的亏空公平优先级队列(DFPQ)算法来调度不同优先级的业务流,可以为系统提供更好的公平性。仿真结果显示该文提出的调度体系结构能够很好地满足所有类型业务的服务质量(QoS)需求,并提供较好的公平性。     

基于时延和速率效用函数的LTE无线资源调度算法研究

为了提高LTE实时业务调度的公平性,首先在M-LWDF资源调度算法的优先级判断机制中引入了平均传输速率和保证比特速率,然后将经济学中的效用思想和效用函数引入到M-LWDF调度算法中,提出了一种基于时延效用函数和速率效用函数的M-LWDF改进算法,以便更好地体现调度算法的时延特性和速率特性。     

QoS-aware Two-level Dynamic Uplink Bandwidth Allocation Algorithms in IEEE 802.16j Based Vehicular Networks

Wireless communications play an important role in improving transportation environment safety and providing Internet access for vehicles. This paper proposes a QoS-aware two-level uplink dynamic bandwidth allocation (DBA) algorithm for IEEE 802.16j-based vehicular networks. IEEE 802.16j is an extension of standard IEEE 802.16 to support relay mode operation where traffics from/to subscriber stations (SS) are relayed to/from a base station (BS) via a relay station (RS). In such a vehicular network, the IEEE 802.16j BSs are installed along a highway, RSs are installed in large vehicles such as coaches, and the 802.16j interface is equipped on SSs such as individual passengers’ mobile devices within a moving coach. In the proposed DBA algorithm, a utility function, which considers characteristics of different types of services, is designed. The objective of the proposed two-level DBA algorithm is to allocate bandwidth to different types of services from BS to RSs and then from a RS to SSs with given quality of service (QoS) requirements. It aims at maximizing the utility of the overall network and minimizing the average queuing delay of the overall network. The simulation results show the effectiveness and efficiency of the proposed DBA algorithm.     

基于传输速率自适应的动态带宽分配算法

提出一种基于传输速率自适应的动态带宽分配算法,为异构无线网络中的多业务提供服务质量保证。根据所提的传输速率优先级决策模型,在传输速率QoS需求和异构网络容量约束的条件下,通过动态调整不同网络中各个移动终端所支持业务的传输速率来得到最优带宽重分配矩阵,以最大化整个异构网络的效用函数;将自适应带宽重分配问题描述为一个优化问题,采用动态优化的迭代算法自适应调节用户传输速率来进一步最大化该效用函数。理论分析和数值仿真结果表明,所提算法在给定传输速率且满足QoS需求的基础上,能够最大化网络的效用函数并减小新呼叫的阻塞概率。     

一种适于卫星IP广播网中的带宽分配策略

提出了一种适用于卫星IP广播网络的带宽分配策略。与现有的带宽分配策略相比,该策略采用的保证带宽分配和动态带宽分配相结合的方法,可以最大限度地利用系统的剩余带宽,提高了系统的带宽利用率。这种带宽分配策略是通过令牌桶算法实现的,实现起来比较简单,并可以和基于业务类别的服务质量保证机制结合起来使用。通过OPNET建模仿真,结果表明这种算法不但能对链路的总带宽进行预分配,还能对链路的剩余带宽实时地进行动态分配,实现了基于用户的服务质量的保证。     

一种分级WFQ的宽带无线接入系统QoS架构

文章介绍了加权公平排队(WFQ)分组调度算法和IEEE 802 16的QoS架构.在此基础上,文章结合分级WFQ分组调度算法和IEEE 802 16协议中所提供的控制机制提出了一种适合于BWA系统的QoS架构.该架构充分利用IEEE 802.16提供的控制机制,结合分级WFQ公平队列调度算法,在主动授予业务(UGS)、实时轮询业务(rtS)、非实时轮询业务(nrtPS)和尽力传输业务(BE)之间公平分配带宽,并保证各种业务的QoS特性,完成了在IEEE 802 16协议中留给用户自己定义的调度策略.     

A Bidding Algorithm for Optimized Utility-Based Resource Allocation in Ad Hoc Networks

This article proposes a scheme for bandwidth allocation in wireless ad hoc networks. The quality of service (QoS) levels for each end-to-end flow are expressed using resource-utility functions, and our algorithms aim to maximize aggregated utility. The shared channel is modeled as bandwidth resources defined by maximal cliques of mutual interfering links. We propose an entirely novel resource allocation algorithm that employs auction mechanisms where flows are bidding for resources. The bids depend both on the flow's utility function and the intrinsically derived shadow prices. Then we combine it with a utility-aware on-demand shortest path routing algorithm where shadow prices are used as a natural distance metric. We also show that the problem can be formulated as a linear programming problem. Thus we can compare the performance of our scheme to the centralized optimal LP solution, registering results very close to the optimum. We isolate the performance of the price-based routing and show its advantages in hotspot scenarios, and also propose an asynchronous version that is more feasible for ad hoc environments. Experimental results of a comparison with the state-of-the-art approach based on Kelly's utility maximization framework show that our approach exhibits superior performance for networks with both increased mobility or increased allocation period.     

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。     

Queue-aware uplink bandwidth allocation and rate control for polling service in IEEE 802.16 broadband wireless networks

IEEE 802.16 standard defines the air interface specifications for broadband access in wireless metropolitan area networks. Although the medium access control signaling has been well-defined in the IEEE 802.16 specifications, resource management and scheduling, which are crucial components to guarantee quality of service performances, still remain as open issues. In this paper, we propose adaptive queue-aware uplink bandwidth allocation and rate control mechanisms in a subscriber station for polling service in IEEE 802.16 broadband wireless networks. While the bandwidth allocation mechanism adaptively allocates bandwidth for polling service in the presence of higher priority unsolicited grant service, the rate control mechanism dynamically limits the transmission rate for the connections under polling service. Both of these schemes exploit the queue status information to guarantee the desired quality of service (QoS) performance for polling service. We present a queuing analytical framework to analyze the proposed resource management model from which various performance measures for polling service in both steady and transient states can be obtained. We also analyze the performance of best-effort service in the presence of unsolicited grant service and polling service. The proposed analytical model would be useful for performance evaluation and engineering of radio resource management alternatives in a subscriber station so that the desired quality of service performances for polling service can be achieved. Analytical results are validated by simulations and typical numerical results are presented.     

Efficient Uplink Bandwidth Request with Delay Regulation for Real-Time Service in Mobile WiMAX Networks

The emerging broadband wireless access technology based on IEEE 802.16 is one of the most promising solutions to provide ubiquitous wireless access to the broadband service at low cost. This paper proposes an efficient uplink bandwidth request-allocation algorithm for real-time services in Mobile WiMAX networks based on IEEE 802.16e. In order to minimize bandwidth wastage without degrading quality of service (QoS), we introduce a notion of target delay and propose dual feedback architecture. The proposed algorithm calculates the amount of bandwidth request such that the delay is regulated around the desired level to minimize delay violation and delay jitter for real-time services. Also, it can increase utilization of wireless channel by making use of dual feedback, where the bandwidth request is adjusted based on the information about the backlogged amount of traffic in the queue and the rate mismatch between packet arrival and service rates. Due to the target delay and dual feedback, the proposed scheme can control delay and allocate bandwidth efficiently while satisfying QoS requirement. The stability of the proposed algorithm is analyzed from a control-theoretic viewpoint, and a simple design guideline is derived based on this analysis. By implementing the algorithm in OPNET simulator, its performance is evaluated in terms of queue regulation, optimal bandwidth allocation, delay controllability, and robustness to traffic characteristics.     

Bandwidth allocation and admission control scheme based on Nash bargaining solution for WiMAX systems

Development of fair and efficient bandwidth allocation and admission control schemes is one of the key issues in the design of IEEE 802.16 broadband wireless access systems in time division multiple access (TDMA) mode. In this article, the problem of bandwidth allocation and admission control is formulated as a Nash bargaining model. The nash bargaining solution (NBS) derived from the cooperative game is adopted to maximize the spectrum utilization. Analysis and simulation results show that there is a unique Pareto optimal bandwidth allocation solution by using NBS among various flows. Furthermore, maximum utility of the system can also be maintained by using the admission control policy with different number of connections and variable channel qualities. The total throughput of the proposed scheme is close to the maximal one, while significantly improving fairness compared to the existing solutions.