共查询到20条相似文献,搜索用时 136 毫秒
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文章模拟了两个建筑楼中移动无线节点之间的数据传送情况,探讨TCP拥塞窗口控制机制在移动无线网络中的应用效果。针对具体的应用,提出了移动无线网络中TCP拥塞窗口控制机制的仿真思路,并用NS3模拟器进行了具体的仿真实现。 相似文献
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一种无线网络中基于ARQ的拥塞控制方法 总被引:1,自引:0,他引:1
提出了一种适用于无线网络的基于多拒绝自动请求重传(ARQ)算法的拥塞控制方法。谊方法结合随机早探洲(RED)算法,通过ARQ发送窗口和分割队列长度以及重传率进行拥塞控制。仿真表明,这种方法能预测链路拥塞,反馈链路拥塞程度,提高链路吞吐率。 相似文献
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传统TCP(传输控制协议)拥塞控制协议本是为有线网络设计,它假设包丢失完全是由网络拥塞引起。在无线网络环境下除了拥塞丢包外,还存在较高的比特误码率、路由故障等因素引起的丢包现象。当出现非拥塞丢包时,传统TCP将错误地触发拥塞控制,从而引起TCP性能低下。文章在分析传统TCP在无线网络中存在问题的基础上,对目前无线TCP发展和技术进行归纳和比较,进一步给出无线传输协议的研究和发展方向。 相似文献
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一种无线传感器网络拥塞控制机制 总被引:3,自引:1,他引:2
无线传感器网络的拥塞会增加网络延迟、降低网络吞吐量、尤其不利于传感器网络的节能。该文提出了一种能量有效的无线传感器网络拥塞控制机制,主要包括逐跳拥塞反馈和速率调节两部分。节点周期性地计算其上游节点发送速率和本地缓冲队列可用空间,并根据一定策略来推测在当前周期内发生拥塞的可能性;拥塞节点的上游节点收到拥塞反馈后根据自身缓冲队列的使用情况来降低速率,此拥塞节点同时向其下游节点申请提高发送速率;基站根据应用要求以闭环方式调节源速率。仿真实验表明,该文的拥塞控制机制不仅能有效地缓解网络拥塞,还保持了网络吞吐量的稳定并具有良好的能源有效性。 相似文献
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PEI Tingrui LEI Fangqing LI Zhetao ZHU Gengming PENG Xin Youngjune CHOI Hiroo SEKIYA 《电子学报:英文版》2017,26(3)
In wireless sensor networks, congestion leads to buffer overflowing, and increases delay. The tradi-tional solutions use rate adjustment to mitigate congestion, thus increasing the delay. A Delay-aware congestion con-trol protocol (DACC) was presented to mitigate congestion and decrease delay. In order to improve the accuracy of the existing congestion detection model which is based on the buffer occupancy of a single node, DACC presents a new model considering both the real-time buffer occupancy and the average transmission time of packets. DACC uses the untapped bits in the IEEE 802.11 Distributed coordination function (DCF) frames header to carry congestion infor-mation. During the congestion alleviation period, DACC presents a channel occupancy mechanism which is based on the real-time buffer occupancy for the purpose of decreas-ing delay and preventing packet loss. Simulation results indicate that in terms of delay, packet delivery ratio, col-lision and buffer load, DACC has comparative advantages than those of 802.11 DCF, Priority-based congestion con-trol protocol (PCCP) and Decoupling congestion control and fairness (DCCF). 相似文献
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文章用泛函微分方程建立了TCP拥塞控制协议的动态模型,通过该模型分析了当前Internet上使用的TCP拥塞控制算法,导出了稳定性条件,结果表明该算法在一定网络环境下是不稳定的. 相似文献
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In monitoring Wireless Sensor Networks(WSNs),the traffic usually has bursty characteristics when an event occurs.Transient congestion would increase delay and packet loss rate severely,which greatly reduces network performance.To solve this problem,we propose a Burstiness-aware Congestion Control Protocol(BCCP) for wireless sensor networks.In BCCP,the backoff delay is adopted as a congestion indication.Normally,sensor nodes work on contention-based MAC protocol(such as CSMA/CA).However,when congestion occur... 相似文献
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Maciej Jan Zawodniok Sarangapani Jagannathan 《International Journal of Wireless Information Networks》2007,14(4):251-263
In this paper, two novel energy-efficient rate adaptation schemes are presented. The proposed protocols use the Distributed
Power Control (DPC) algorithm to predict the channel state and determine the necessary transmission power which optimizes
the energy consumption. The first proposed rate adaptation scheme heuristically alters the modulation rate to balance the
energy-efficiency and the required throughput which is estimated with queue fill ratio. Moreover, the back-off scheme is incorporated
to mitigate congestion and reduce packet losses due to buffer overflows thus minimizing energy consumption. Consequently,
the nodes will conserve energy when the traffic is low, offer higher throughput when needed and save energy during congestion
by limiting transmission rates. The second rate adaptation scheme employs dynamic programming (DP) principle to analytically
select modulation rate and a burst size to be used during transmission. The proposed quadratic cost-function minimizes the
energy consumption while alleviating network congestions and buffer overflows. The proposed DP solution renders a Riccati
equation ultimately providing an optimal rate selection. The simulation results indicate that an increase in throughput by
96% and energy-efficiency by 131% is observed when compared to other available protocols, for example Receiver Based AutoRate
(RBAR).
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Sarangapani JagannathanEmail: |
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Collaborative in-network processing operations in Wireless multimedia sensor networks (WMSNs) often require effective synchronization control. Extensive researches in the traditional networks mainly focus on the synchronization control with the buffer management in the receiver. However, for WMSNs, the chaotic transport channel and low bandwidth introduce serious jitter. Jitter degrades the timing relationship among packets in a single media stream and between packets from different media streams and, hence, creates multimedia synchronization problems. Moreover, too much jitter will also degrade the performance of the streaming buffer. By only employing the buffer management scheme in the receiver, we can hardly satisfy the synchronization requirement of the in-network processing. In this study, we propose an active jitter detection mechanism for the synchronization control in WMSNs. This mechanism will improve the quality of service in multimedia networking by discarding the jitter-corrupted packets immediately and balancing the delay and jitter actively. We implement the proposed scheme in the practical WMSNs platform. The experiment results show that our scheme can reduce the average packet jitter effectively and improve the synchronization controlling performance significantly. 相似文献
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