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为了满足用户需求,IEEE802.16支持多种QoS。在IEEE802.16-2004定义的mesh模式的调度机制下,针对实时业务和非实时业务对时延具有不同敏感性的特点,提出了一种区分服务的时隙调度算法。该算法优先处理实时业务,并通过拥塞情况,自适应地调整实时业务的预留带宽。最后对算法进行了仿真,结果表明该算法下业务的延迟、服务请求拒绝率、时隙利用率均有所改善。 相似文献
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针对设备到设备(D2D)通信资源分配中的时隙调度时延以及信道增益变化导致吞吐率下降的问题,提出了一种公平性时隙调度(FTDS)算法。首先,基于频谱复用模式建立系统模型,并归纳为一组合优化问题;然后,在模型的次优求解中,FTDS算法将调度周期划分为多个等长的时隙,根据优先级策略将D2D用户分配至不同时隙调度,从而适应D2D用户多于蜂窝用户的应用场景;同时,为了权衡服务质量(QoS)与系统吞吐率的关系,构造一满足性权值与传输速率相互制约,共同决定用户调度优先级。仿真实验中,FTDS算法相比TDS、RANDOM算法,吞吐率平均增幅分别达到11.09%和40.64%,且FTDS算法下D2D用户被调度频次累积分布更为集中;同时,相比TDS算法调度时延最大降低31.22%。仿真实验表明,FTDS算法拥有更优的吞吐率性能、更公平的调度机制、更小的调度时延。 相似文献
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针对云计算环境中虚拟机资源负载均衡问题,并为实现云计算下虚拟机资源负载均衡高效调度以满足用户的QoS需求,提出了一种基于多维QoS实现负载均衡的虚拟机资源调度方法。首先,在云计算环境下建立多维QoS网络环境的数学模型;然后,提出一种基于蚁群算法的优化算法,用于实现云计算环境中虚拟机资源高效调度;最后,在云仿真平台CloudSim上进行仿真实验。实验结果表明,相对于其他资源调度算法,所提算法能高效解决云计算下虚拟机资源调度问题,减少虚拟机资源负载均衡离差,具有更好的性能,能完全满足云计算下和多维QoS环境下虚拟机资源负载均衡的需求。 相似文献
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给出了IEEE 802.16 PMP支持QoS的带宽调度算法,此算法由BS scheduler和SS scheduler共同实现,带宽的分配单位是时隙,并在NS-2上实现了该算法。通过建立仿真环境,对各种数据流的端到端的延时进行比较,结果表明算法的有效性。 相似文献
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针对WiMAX Mesh网络集中式下资源的调度和分配,分析了现有调度算法的研究进展与优缺点,结合标准对Mesh模式的QoS定义,提出了一种WiMAX Mesh网络集中式下基于分组的QoS调度算法。通过区分数据流的优先级方式对不同业务数据流进行分组,并计算组内流节点的权值,保证同种业务流间高传输要求和低传输节点的公平性。仿真结果表明,与HRF和LRC算法相比,该算法对于分类业务的时延和网络吞吐量具有明显的优势,实现了区分业务的QoS保障。 相似文献
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将平滑轮询调度算法(SRR)应用于DVB-RCS卫星网络的时隙调度中,实现了回传信道卫星终端(RCST)用户获得的时隙位置在调度表中均匀分布。首先按权值降序对RCST用户排序,采用向量来表示权值的二进制编码。以这些权值向量作为行向量来表示权值矩阵,同时根据权值向量的维数来构造权值扩展序列。结合权值矩阵,通过遍历权值扩展序列来确定RCST用户的调度顺序。仿真结果表明与轮询(RR)调度算法相比,基于SRR的时隙调度算法缩小了业务包时延的变化范围,降低了包时延标准差。 相似文献
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无线Ad Hoc网络中QoS感知的跨层资源分配算法 总被引:2,自引:0,他引:2
在分析无线Ad Hoc网络资源分配模型的基础上,提出一种QoS感知的跨层资源分配算法CL-QARA (cross layer QoS aware resource allocation).其主要思想是,引入价格作为资源分配的度量指标,以QoS带宽需求为参数,将网络层的动态资源分配信息与MAC层CSMA/CA接入机制相结合,以改进MAC层的冲突退避算法.设计了改进的退避算法和呼叫接入控制算法,以实现MAC层与网络层的跨层技术.通过QoS感知的资源分配算法和跨层技术协同工作,为QoS服务提供了业务保障.仿真结果表明,CL-QARA算法具有良好的收敛性和稳定性.与其他算法相比,CL-QARA能够有效地提供QoS保证,提高了网络的效用和性能. 相似文献
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本文简单介绍了IEEE802.15.3协议,分析了协议的MAC层QoS机制。针对实时VBR(VariableBitRate)业务流,提出了一种改进协议机制的信道资源分配算法,并在性能上与平均资源分配算法进行了分析和比较,通过仿真验证了此分配算法能有效降低实时VBR码流的丢帧率,提高系统传输的QoS性能。 相似文献
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The game theoretic dynamic spectrum allocation (DSA) technique is an efficient approach to coordinate cognitive radios sharing the spectrum. However, existing game based DSA algorithms lack a platform to support the game process. On the other hand, existing medium access control (MAC) protocols for cognitive radio networks do not fully utilize the adaptability and intelligence of the cognitive radio (CR) to achieve efficient spectrum utilization, let alone fairness and QoS support. Therefore it is necessary to develop DSA-driven MAC protocols with the game theoretic DSA embedded into the MAC layer. In this paper, based on the analysis of challenges for the game theoretic DSA in realistic applications, we conclude that a unified game theoretic DSA-driven MAC framework should constitute of four integral components: (1) DSA algorithm, deriving the spectrum access strategy for data communication; (2) negotiation mechanism, coordinating players to follow the right game policy; (3) clustering algorithm, limiting the negotiation within one cluster for scalability; (4) collision avoidance mechanism, eliminating collisions among clusters. With our MAC framework, DSA-driven MAC protocols can be conveniently developed, as illustrated in the design process of a concrete QoSe-DSA-driven MAC protocol. The game theoretic DSA-driven MAC framework can fulfill merits of game theoretic DSA algorithms including high spectrum utilization, collision-free channel access for data communication, QoS and fairness support. Through simulations, the merits of the DSA-driven MAC framework are demonstrated. 相似文献
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基于测量的TCP拥塞控制的公平性研究 总被引:1,自引:0,他引:1
通过分析传统TCP算法的局限性,讨论TCP Vegas、TCPW两种基于源端实时带宽测量拥塞控制算法的原理以及带宽分配的公平性,结合主动队列管理技术,提出一种基于加权缓存区容量分配RED算法.理论分析和仿真实验表明该算法提高了带宽分配的公平性.保持了网络的高吞吐量,并实现服务QoS保证. 相似文献
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《Journal of Network and Computer Applications》2010,33(4):467-476
This paper investigates variable rate control strategies for real-time multimedia variable bit rate (VBR) services over IEEE 802.16 broadband wireless networks. A data rate control mechanism is derived for the case where the uplink channel provides real-time services and the traffic rate parameter remains constant. This paper shows that the common queuing scheduling algorithms have some bandwidth allocation fairness problems for the real-time polling service (rtPS) in the MAC layer. In other words, the use of a VBR for the rtPS by a WiMAX system results in additional access latency jitter and bandwidth allocation disorder in the transmitted multimedia streams during the regular time interval polling of subscribe stations (SSs) for the contention bandwidth request period. However, the proposed scheduling algorithm solves these SSs contending with bandwidth resource allocation problems based on an extended rtPS (ertPS) of quality-of-service (QoS) pre-programming for a ranging response non-contention polling period. The adopted bandwidth allocation of max–min fairness queue scheduling uses a time constraint condition to transmit real-time multimedia VBR streaming in an IEEE 802.16 broadband wireless environment. In addition, we use the ns-2 simulation tool to compare the capacity of multimedia VBR stream and show that the proposed ertPS scheduling algorithm outperforms other rtPS scheduling algorithms. 相似文献
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802.16是新一代宽带无线接入的标准。标准中明确定义了在MAC层实现QoS的机制,例如:MAC层的通信是基于连接的;将上层业务流根据QoS的要求进行分类等。但是标准对上行带宽的分配机制却未加以定义。我们就这个问题进行了研究,并提出了一种有效的上行带宽分配机制。 相似文献
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We consider a cross-layer scheme for the downlink multiuser Orthogonal Frequency Division Multiple Access (OFDMA) for mobile WiMAX (Worldwide Interoperability for Microwave Access) based on IEEE802.16e standard. We propose an intelligent Medium Access Control (MAC) that adapts with the physical layer (PHY) in response to the different QoS requirements of the diverse service flows in the system. This adaptation is represented by a joint packet scheduling and slot allocation scheme interaction in both MAC and PHY layers. Based on this interaction, a fair and efficient QoS guaranteed resource allocation for a mixture of real-time and non real-time service flows is achieved. We provide extensive simulation results showing the performance aspects of the proposed cross-layer scheme. 相似文献
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