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基于平均队列长度和滞留时间的RED算法 总被引:1,自引:0,他引:1
在无线通信网络环境下,提出了一种改进的基于平均队列长度和滞留时间的RED算法。这种算法根据平均队列长度和滞留时间计算数据包的丢弃概率,比传统的单纯基于平均队列长度的RED算法相比较,能更有效地实现无线网络中的拥塞控制。 相似文献
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传感器网络拥塞避免与控制的模糊AQM算法 总被引:2,自引:0,他引:2
传感器网络节点通信能力有限,当数据到达速率持续超过节点转发能力时网络会发生拥塞;传感器网络是任务型网络,对不同优先级的信息具有不同的服务质量要求.针对传感器网络信息传输的上述特性,提出了一种新的拥塞避免与控制算法FAQM(Fuzzy Active Queue Management).该算法在综合考虑数据包的随机指数标记概率和优先级权值的基础上,建立了模糊逻辑推理系统,并以数据包丢弃因子作为参量来实现数据流的智能调控.NS2仿真实验结果表明:FAQM算法能减少高优先级数据包的丢弃率和节点间链路的时延,稳定节点队列长度,在有效避免与控制拥塞网络的同时提升网络整体QoS(Quality of Service)性能. 相似文献
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SABlue:一种带加速因子的自适应AQM算法 总被引:1,自引:0,他引:1
该文在分析SBlue算法的基础上,提出了一种带加速因子的自适应AQM算法SABlue(Self-tune Accelerate Blue)。算法将瞬时队长作为早期拥塞检测参量,根据队列负载因子控制丢包步长,实现丢包概率幅度的自适应调整,最终将路由队列长度稳定在目标区域内。为了提高网络突变跨度较大情况时算法的响应速度,在队列警戒区域内引入了加速因子。实验表明,SABlue面对突变流和不同RTT的网络场景,队列收敛时间短,丢包率小,且具有较好的鲁棒性,算法综合性能优于其他AQM算法。 相似文献
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主动队列管理 (ActiveQueueManagement,AQM)技术作为Internet拥塞控制的一种有效方法 ,对于提高In ternet的服务质量具有十分重要的作用 .本文根据TCP拥塞控制算法基于数据包丢失的窗口变化机制 ,设计了一种基于模糊逻辑的主动队列管理算法 .该算法依据路由器中队列长度的变化情况 ,根据一定的模糊自校正原则来调整数据包的丢弃概率 ,从而使路由器中的队列长度稳定在参考值附近 .仿真结果表明该算法不但十分有效 ,而且对不同的网络状况具有很好的适应能力 . 相似文献
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一种基于模糊逻辑的主动队伍管理算法 总被引:2,自引:0,他引:2
主动队列管理(AciiveQueue Management,AQM)技术作为Internet拥塞控制的一种有效方法,对于提高Internet的服务质量具有十分重要的作用,本文根据TCP拥塞控制算法基于数据包丢失的窗口变化机制,设计了一种基于模糊逻辑的主动队伍管理算法,该算法依据路由器中队列长度的变化情况,根据一定的模糊自校正原则来调整数据包的丢弃概率,从而使路由器中的队列长度稳定在参考值附近,仿真结果表明该算法不但十分有效,而且对不同的网络状况具有很好的适应能力。 相似文献
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实时流业务的超期丢包率是衡量无线网络传输过程服务质量的常用参数,但是该参数并不能反映出具有不同重要度的数据包对视频质量的影响.该文将实时传输流的数据包重要度与超期丢包率结合,提出加权超期丢包率的概念,更加准确地描述丢包与视频质量的关系,在无线环境下提出基于数据包不同重要度的适用于实时约束流的主动队列管理算法,通过主动丢弃数据包以最小化服务过程中实时流的加权超期丢包率.仿真结果表明,相比于传统的队列管理算法和实时视频流滤波器算法,该超期数据包主动丢弃算法能够有效降低加权超期丢包率,提供更好的服务质量,提高大约0.5~1.5 dB的峰值信噪比(PSNR)增益. 相似文献
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一种参数自适应的主动队列管理算法-自适应BLUE 总被引:3,自引:0,他引:3
BLUE算法是一种典型的主动队列管理(Active Queue Management,AQM)算法,研究表明BLUE算法优于RED算法.BLUE算法使用丢包事件和链路空闲事件控制网络拥塞.但由于BLUE算法在参数设置方面存在不足,尤其是当TCP连接数突然剧烈变动时,容易导致队列溢出或空闲的频繁发生.该文引进参数自适应机制,提出了自适应BLUE算法,并借鉴了RED算法的早期拥塞检测机制.NS仿真实验表明该算法能有效保持队列长度的稳定,减少队列溢出或空闲现象的发生,在提高链路利用率的同时降低丢包率. 相似文献
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基于速率的主动队列管理算法的性能分析 总被引:1,自引:1,他引:1
主动队列管理是解决网络拥塞的主要措施。针对基于队列的主动队列管理算法的不足,提出了一种基于速率的新算法RAQM,该算法以数据到达速率与路由器最大服务速率的差值为指标计算丢包概率,能够快速地对网络流量的变化做出反应,该算法计算简单,而且只需要设置一个参数K。通过现代控制理论分析了RAQM/TCP系统的稳定性。仿真结果表明,RAQM能够维持较低的队列长度并保持队列的稳定,从而减小了分组端到端时延和时延抖动。最后讨论了参数K对算法性能的影响。 相似文献
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Bijan Jabbari 《International Journal of Communication Systems》1990,3(4):351-356
This paper proposes an admission strategy for connection-oriented services at the access node of a broadband integrated packet network based on asynchronous transfer mode. Based on an estimate of the probability of cell loss and in the absence of buffering, we determine the number of sources from different classes of bursty traffic which can be accepted. The parameters which are used to describe the traffic sources are average bit rate and peak bit rate. We will evaluate the cell loss estimate for homogeneous and heterogeneous cases. Furthermore, we will examine the variation of this estimate as the average to peak ratio changes. The estimate is an upper bound for the probability of cell loss. Based on this upper bound simple and robust allocation of resources to bursty sources can be developed. The proposed strategy can be implemented using simple computations or via a look-up table to determine admission or denial of an incoming call and therefore allocating the required capacity. The procedure results in efficient use of the bandwidth, ensuring the desired service quality for connection-oriented services and results in proactive control of network congestion. 相似文献
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《Signal Processing: Image Communication》2004,19(5):405-419
In a wireless network packet losses can be caused not only by network congestion but also by unreliable error-prone wireless links. Therefore, flow control schemes which use packet loss as a congestion measure cannot be directly applicable to a wireless network because there is no way to distinguish congestion losses from wireless losses. In this paper, we extend the so-called TCP-friendly flow control scheme, which was originally developed for the flow control of multimedia flows in a wired IP network environment, to a wireless environment. The main idea behind our scheme is that by using explicit congestion notification (ECN) marking in conjunction with random early detection (RED) queue management scheme intelligently, it is possible that not only the degree of network congestion is notified to multimedia sources explicitly in the form of ECN-marked packet probability but also wireless losses are hidden from multimedia sources. We calculate TCP-friendly rate based on ECN-marked packet probability instead of packet loss probability, thereby effectively eliminating the effect of wireless losses in flow control and thus preventing throughput degradation of multimedia flows travelling through wireless links. In addition, we refine the well-known TCP throughput model which establishes TCP-friendliness of multimedia flows in a way that the refined model provides more accurate throughput estimate of a TCP flow particularly when the number of TCP flows sharing a bottleneck link increases. Through extensive simulations, we show that the proposed scheme indeed improves the quality of the delivered video significantly while maintaining TCP-friendliness in a wireless environment for the case of wireless MPEG-4 video. 相似文献
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Effective buffering of optical packets is essential to the efficient working of optical packet switches. In this paper three
new schemes, which involve sorting and finding the least occupied buffer, are proposed. Their performance is compared with
the common round-robin scheme. The results show that all these new schemes are able to enhance the optical packet switch performance
significantly in terms of packet drop/loss probability. In addition, the results show that not all the newly arrived packets
need to be sorted in order to obtain the minimum packet drop probability. As computation/processing time is significant in
optical packet switching, partial sorting of the newly arrived packets with tolerable packet drop probability appears to be
a viable proposition. Conversely, a complete sort of newly arrived packets wastes packet processing time unnecessarily while
significantly increasing the packet drop probability. 相似文献
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In this paper, we study efficient power control schemes for delay sensitive communication over fading channels. Our objective is to find a power control law that optimizes the link layer performance, specifically, minimizes the packet drop probability, subject to a long‐term average power constraint. We assume the buffer at the transmitter is finite; hence packet drop happens when the buffer is full. The fading channel under our study has a continuous state, e.g., Rayleigh fading. Since the channel state space is continuous, dynamic programming is not applicable for power control. In this paper, we propose a sub‐optimal power control law based on a parametric approach. The proposed power control scheme tries to minimize the packet drop probability by considering the queue length, i.e., reducing the probability of those queue‐length states that will cause full buffer. Simulation results show that our proposed power control scheme reduces the packet drop probability by one or two orders of magnitude, compared to the time domain water filling (TDWF) and the truncated channel inversion (TCI) power control. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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In this paper, a scheme for estimating the proportion of the incoming traffic that is not responsive to congestion at a router is presented. The idea of the proposed scheme is that if the observed queue length and packet drop probability do not match the predictions from a model of responsive (TCP) traffic, then the error must come from nonresponsive traffic; it can then be used for estimating the proportion of nonresponsive traffic. The proposed scheme is based on the queue length history, packet drop history, and expected TCP and queue dynamics. The effectiveness of the proposed scheme over a wide range of traffic scenarios is corroborated using ns-2-based simulations. Potential applications of the proposed algorithms in traffic engineering and control are discussed. 相似文献
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为了提高系统性能并最大限度降低算法实现复杂度,本文提出了一种新的高清视频联网系统中丢包率的更优近似分析方法,重点研究包长度对丢包率的影响。首先使用马尔可夫链模型估算数据包的误码率,进而得出数据包网络时延的概率分布,最后计算出基于包长度的丢包率的理论表达式。仿真结果表明,通过减小发包大小可以有效降低丢包率,同时基于包长度的丢包率的理论分析方法可以有效地运用到高清视频联网系统的分析研究中。 相似文献
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In this paper, we propose an aware-based adaptive opportunistic retransmission control scheme for wireless multimedia Mesh
networks. The proposed scheme provides maximum retransmission count optimization based on environment-aware to improve packet
relay probability. The scheme discriminates the types of packet loss in wireless link by means of environment information
and selects the retransmission count by taking the IEEE 802.11 wireless channel characteristics into consideration. Furthermore,
the maximum retransmission count of MAC is adjusted adaptively. Extensive simulations demonstrate that the proposed scheme
significantly reduces packet collision probability and packet loss rate, and thus improves network throughput. 相似文献