共查询到19条相似文献,搜索用时 218 毫秒
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WiNoC(Wireless Network-on-Chip)中的无线路由器面临着比传统片上路由器更加严峻的拥塞问题,平衡有线/无线链路负载是当前无线片上网络的研究热点之一.为此本文提出并设计了一种基于优先级的交叉开关仲裁方案PbSA(Priority based Switch allocator),其将优先级更高的无线数据包优先路由至无线路由器;结合PbSA提出了拥塞感知的路由算法CARA(Congestion-Aware Routing Algorithm),该算法有效平衡有线/无线链路负载且避免死锁,提高了数据包在网络中的路由效率.此外,本文还提出了新颖的虚通道划分方法,它不仅减少了实现PbSA的硬件复杂度,而且缓解了无线路由器发生拥塞时对整个网络的影响.实验表明,虽然本文的方案引入了较小的面积和功耗开销,但是具有良好的流量自适应特性,从而在低注入率或高注入率的情况下较好的提升了网络性能. 相似文献
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在无线片上网络中,无线通信拥塞和故障对整个片上网络的通信效率具有严重影响.为此本文提出了一种针对无线通信拥塞和故障的容错路由算法,首先设计了无线通信拥塞和故障感知模型,该模型能够感知无线节点通信对的拥塞和故障信息,并对其编码发送给子网中的路由器;然后子网中的路由器根据接收到的无线节点通信对状态信息,判断数据包是否使用无线传输.实验表明,本文方案相较于对比对象能够在较小的额外面积、功耗开销下,保证较低的网络延迟和较高的网络吞吐率,并对无线节点通信对的永久性故障具有良好的容错能力. 相似文献
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无线片上网络中的无线信道面临着严重的可靠性挑战,无线路由器的容错设计对整个片上网络的传输效率有着较大的影响.本文提出一种EF-ACK容错无线接口设计,将多条确认信息配置在一个数据包内,通过无线信道传递确认信息数据包;在无线接口处设立重传数据缓冲区,以更高效的方式确认数据以及控制错误数据包的重传;另外,提出了基于网络状态的编解码控制,在网络情况较差时用BCH编码的方式提高数据的鲁棒性.实验表明,本文方案使用了较小的额外面积和功耗开销,高效地完成了对于数据的无线确认反馈,且在错误率较高时,可以保证网络中较低的网络延迟和较高的饱和吞吐量,大大提高了网络的性能. 相似文献
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本论文在分析无线传感器网络不同于普通有线网络的特征后,提出了一种适用于无线传感器网络的TCP 拥塞控制机制DW-TCP,此机制将TCP拥塞窗口分为拥塞丢包窗口和误码丢包窗口,在链路误码率较高时通过降低发送速率提高数据发送的可靠性,节约无线节点的能源消耗和系统不必要的开销,该机制不但考虑到拥塞丢包对数据发送速率的影响,而且考虑到无线链路中的误码丢包对数据发送速率的影响. 相似文献
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针对专用片上网络(Network on Chip,NoC)全局通信事务管理和可靠性设计问题,提出片上网络监控器的概念,用于获取全局网络实时状态信息及执行路径分配算法,基于此提出一种动态路由机制DyRS-NM.该机制能检测和定位NoC中的拥塞和故障链路,并能区分瞬时和永久性链路故障,采用重传方式避免瞬时故障,通过重新路由计算绕开拥塞和永久性故障.设计实现了RTL级网络监控器和与之通信的容错路由器模块,并将MPEG4解码器应用映射至基于网络监控器的4×4Mesh结构NoC体系结构中,验证了系统性能以及面积功耗开销.相比静态XY路由和容错动态路由FADR,DyRS-NM机制在可接受的开销代价下获得了更优的性能. 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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文中提出一种基于拥塞程度分级的速率调节算法.首先,对缓冲区进行多尺度排队分析,计算出缓冲区的溢出概率.其次,根据溢出概率的值,把节点拥塞程度分成三级.最后,针对每一级拥塞采取相应的速率调节方案来缓解拥塞.实验结果表明,该算法可以有效缓解拥塞,提高无线传感器网络的数据包投递率. 相似文献
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无线传感器网络(WSN)中多对一通信产生的网络拥塞是一个亟待解决的问题。针时WSN节点生命期有限的情况,引入了节点相对信息熵的概念,提出基于节点相对信息熵的拥塞避免机制:节点首先计算其联合信息熵为上游节点分配数据窗;然后上游节点根据收到的数据窗的大小来决定向下游节点发送数据包的大小。仿真分析表明,该算法有效地避免了网络数据包的丢失,减少了网络传输延迟,且具有良好的能量有效性。 相似文献
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Wireless network-on-chip (WiNoC) is a new paradigm to mitigate the long-distance transmission latency for conventional wired network-on-chip. The wireless routers in WiNoC have to handle a large number of packets which could cause data congestion, thus reducing the network performance. In this paper, we propose a novel wireless routing algorithm, called CPCA, which exploits the cross path congestion information as hints to route the packets. Under CPCA, the whole network is partitioned into sub-networks. In each subnet, the congestion information of the wireless router is propagated along the cross path. As a result, the routers in the same dimension can get the congestion degree of wireless router within the subnet. Based on the congestion information, CPCA can compute the suitable path for packets routing, which can prominently avoid the congestion aggravation in the wireless router. Experimental results show that our proposed method can effectively improve performance in terms of packets transmission latency and network throughput. 相似文献
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TCP在无线自组织网络中受到信道竞争和队列拥塞的双重影响,因而不能准确地调节数据发送速率从而降低了传输性能。本文针对该问题提出一种基于对信道竞争和排队拥塞联合检测的TCP速率调制策略。实验结果显示,本策略在吞吐量和端到端时延上均明显提高了TCP的性能。 相似文献
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The conventional TCP tends to suffer from performance degradation due to packet corruptions in the wireless lossy channels, since any corruption event is regarded as an indication of network congestion. This paper proposes a TCP error and congestion control scheme using corruption‐aware adaptive increase and adaptive decrease algorithm to improve TCP performance over wireless networks. In the proposed scheme, the available network bandwidth is estimated based on the amount of the received integral data as well as the received corrupted data. The slow start threshold is updated only when a lost but not corrupted segment is detected by sender, since the corrupted packets still arrive at the TCP receiver. In the proposed scheme, the duplicated ACKs are processed differently by sender depending on whether there are any lost but not corrupted segments at present. Simulation results show that the proposed scheme could significantly improve TCP throughput over the heterogeneous wired and wireless networks with a high bit error rate, compared with the existing TCP and its variants. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Lan Wang Geyong Min Irfan Awan 《International Journal of Wireless Information Networks》2006,13(2):161-171
Traffic congestion arising from the shared nature of uplink channels in wireless networks can cause serious problems for the provision of QoS to various services. One approach to overcome these problems is to implement some effective congestion control mechanisms at the downlink buffer at the mobile network link layer or at gateways on the behalf of wireless network access points. Active queue management (AQM) is an effective mechanism to support end-to-end traffic congestion control in modern high-speed networks. Initially developed for Internet routers, AQM is now being also considered as an effective congestion control mechanism to enhance TCP performance over 3G links. This paper proposes an analytical performance model for AQM using various dropping functions. The selection of different dropping functions and threshold values required for this scheme plays a critical role on its effectiveness. The model uses a well-known Markov-modulated Poisson process (MMPP) to capture traffic burstiness and correlations. The validity of the model has been demonstrated through simulation experiments. Extensive analytical results have indicated that exponential dropping function is a good choice for AQM to support efficient congestion control. 相似文献
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针对有线网络中的拥塞控制机制ECN进行改进,引入网络负荷因子的概念来更准确、有效的更新发送方的窗口大小,并将它和无线网络中的WELN机制相结合,提出了ECLN机制来提高在混合网络下的网络性能,并用NS2仿真工具在物理层引入无线信道错误模型来模拟无线链路上的丢包现象.仿真结果表明,该算法能够有效降低丢包数,明显提高网络的吞吐量. 相似文献
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Sungwon Yi Martin Kappes Sachin Garg Xidong Deng George Kesidis Chita R. Das 《Wireless Communications and Mobile Computing》2008,8(4):421-434
Wireless access points (APs) act as bridges between wired and wireless networks. Since the actually available bandwidth in wireless networks is much smaller than the bandwidth in wired networks, there is a disparity in channel capacity which makes the access point a significant network congestion point in the downstream direction. A current architectural trend in wireless local area networks (WLAN) is to move functionality from APs to a centralized gateway in order to reduce cost and improve features. In this paper, we study the use of RED, a well known active queue management (AQM) scheme, and explicit congestion notification (ECN) to handle bandwidth disparity between the wired and the wireless interface of an access point. Then, we propose the Proxy‐RED scheme, as a solution for reducing the AQM overhead from the access point. Simulations‐based performance analysis indicates that the proposed Proxy‐RED scheme improves the overall performance of a network. In particular, the Proxy‐RED scheme significantly reduces packet loss rate and improves goodput for a small buffer, and minimizes delay for a large buffer size. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献