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Internet中支配延迟的特征行为研究 总被引:2,自引:0,他引:2
通过对CAIDA机构授权的原始海量样本数据处理得到单向链路延迟,在此基础上计算了路径上最大的链路延迟对端到端延迟的比例以及路径上链路个数分布,基于此定义了支配延迟.针对链路延迟对端到端延迟的影响进行分析,表明支配延迟之间的差异是导致端到端延迟呈现多峰分布的主要原因.支配延迟更多地出现在路径的中间部分和AS自治域内部,说明延迟瓶颈从网络的接入部分向传输部分转移,得出传输延迟在总延迟中的影响逐渐减小,路径中的支配延迟将主要由传播延迟决定的结论. 相似文献
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Computer networks supporting virtual circuits deliver packets at the destination in the same sequence as they are received at the source. But packets may arrive at the destination out of sequence if the source is connected to the destination by multiple links. Consequently, in addition to queueing delay and service time (transmission delay) the packets suffer a resequencing delay. The sum of the queueing delay, service time, and resequencing delay is called the total delay. Assuming a Poisson stream of packets, a two-stage hyperexponential service time distribution and m equal capacity links connecting the source to the destination, the distribution and expected value of resequencing delay are derived here. With numerical examples it is shown that the mean total delay decreases very rapidly with the number of links m . The mean queueing delay increases rapidly with the mean service time, and the mean resequencing delay increases slowly with the mean service time 相似文献
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Jin-Fu Chang Tzi-Hui Yang 《Communications, IEEE Transactions on》1994,42(11):2926-2928
This paper analyzes the end-to-end delay of a selective-repeat ARQ protocol which tries to adaptively use the channel idle time. The end-to-end delay consists of three parts: queueing delay at the transmitter, transmission delay over the channel, and resequencing delay at the receiver. Although this paper succeeds only in obtaining approximate end-to-end delay, the agreement with simulation is generally good 相似文献
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The intrinsic delay time of submicron InP-based HEMT's has been evaluated by coupling the delay time analysis with a 2D Ensemble Monte Carlo Simulation. The relationship between the delay time and the transit time is explained. It is shown that the delay time can be quite different from the transit time depending on the velocity modulation. The delay from each segment of the HEMT is calculated to study the distribution of the delay inside the device. The delay from the gate region was the major contributor while that from the drain region was also important. The bias dependence of the delay in each region of the device was calculated to explain the bias dependence of the total intrinsic delay time. The intrinsic delay time increase at low Vgs was due to the increase of τd and τs and the increase at high Vds was due to the increase of τd. As a means of validation, the simulated data have been compared with experimental intrinsic delay time data at various bias points. Good agreement was found over a wide Vgs and V ds range 相似文献
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苏林奋 《电信工程技术与标准化》2020,(7)
5G业务场景uRLLC要求端到端时延小于1ms,低时延是5G专线业务最大的特征。网络架构重构为CU-DU-AAU, CU放置位置会影响时延。通过软管道隔离来实现网络切片会造成带宽抢占,丢包重传会增大时延。通过网络结构调整可以降低线路传输时延,通过FlexE的1.5层快速转发可以降低设备转发时延,通过信道硬隔离隔离可以避免业务拥塞。综合以上技术方案可以有效实现5G专线业务低时延的特性。 相似文献
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通过对几种脉冲信号延迟电路的分析,提出了计数延迟与专用延迟线电路相结合的距离特性模拟方法,以适应大的雷达脉冲重复频率变化范围及产生各种宽度的延迟脉冲,满足多种雷达的仿真测试需求。 相似文献
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在宽带卫星通信链路中,由于器件通带特性不理想和行波管放大器的工艺受限等原因使卫星信道的群时延波动较大,导致误比特性能恶化。群时延的补偿算法需要复杂的数学运算,因此工程上一般采用线性均衡对信道群时延特性进行校正。针对群时延失真严重情况下线性均衡效果下降的问题,对比研究了线性均衡、非线性均衡对信道群时延校正的性能,仿真分析了采用恒模算法的线性均衡和采用voherra模型的非线性均衡在群时延失真信道下的性能,得出了两类均衡器在群时延失真信道下的误码率性能曲线,结果表明低阶调制下采用非线性均衡可以较好的消除宽带卫星信道群时延的影响。 相似文献
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基于网络拓扑的动态时延估算模型的研究 总被引:1,自引:0,他引:1
网络时延测量技术是了研究互联网的重要手段。针对网络时延估算问题,首先通过网络仿真分析了不同网络拓扑结构下时延序列与路径长度的关系,引入RTT相似度的概念来刻画这种关系。并以此作为网络时延估算的基础,设计了时延估算架构并提出了基于网络拓扑的时延估算模型。该模型利用线性回归的方法得到时延估算方程及估算精度。结合这些数据给出了动态时延估算方法,该方法可以根据不同的估算精度要求动态地选取测量节点进行时延估算,从而使时延估测系统更加灵活和高效。 相似文献
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利用泰勒级数近似的射线追踪算法,针对1 000 km范围内的超视距目标时差定位系统进行传播路径仿真建模,计算分析了不同波导环境下的差分时延误差和多径相对时延,评估了时差定位系统对大气波导超视距目标的时延差精度.计算结果表明,由于大气折射环境随距离的变化,无源定位系统的差分时延误差会随着通信距离的增大而增大.当系统通信距离达到近1 000 km时,较强的表面波导环境可使差分时延误差达到近30 ns,多径相对时延可达近20 ns;蒸发波导可使时延误差达近40 ns,多径相对时延同样可达近20 ns.通过对实际波导环境超视距链路时延效应的定量分析,为无源时差定位系统的工作性能和参数设计提供了环境保障和技术支撑. 相似文献
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Simple models for the delay, power, and area of a static random access memory (SRAM) are used to determine the optimal organizations for an SRAM and study the scaling of their speed and power with size and technology. The delay is found to increase by about one gate delay for every doubling of the RAM size up to 1 Mb, beyond which the interconnect delay becomes an increasingly significant fraction of the total delay. With technology scaling, the nonscaling of threshold mismatches in the sense amplifiers is found to significantly impact the total delay in generations of 0.1 μm and below 相似文献
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由于继电器触点开关“吸合”“释放”时要产生延时参数。此延时给自动控制带来麻烦。本文论述了继电器触点“开”“关”延迟理论。设计了一种简单可靠的延时测试电路。用此电路对市场上两种继电器抽检测试结果,均符合继电器技术条件要求。论文从理论上计算了它的延迟时间,并与测试结果进行了分析。本电路可应用于对继电器有延时要求的设计师和工厂检验人员制作检测装置或设备使用。 相似文献
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Yongzhi Liu Zhiping Lin 《IEEE transactions on circuits and systems. I, Regular papers》2008,55(6):1560-1570
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This paper presents measured error-rate performance of binary FSK with discriminator detection in simulated Rayleigh fading with time delay spread. Measured relations between error rate and carrier-to-noise ratio are shown for a range of time delay spreads. We have verified that the effect of time delay spread on error rate can be described by only one parameter, the ratio of the rms delay spread to the transmitted baud time. Intersymbol interference from time delay spread causes an irreducible error rate for FSK, even for infinite carrier-to-noise ratio. For 64 kbit/s binary FSK, the 2.6μs rms delay spread typical of the urban environment produces an irreducible error rate of 3 percent. The measured irreducible error rate for binary FSK with discriminator detection is proportional to the fourth power of the ratio of rms delay spread to baud time. This functional dependence is identical to that predicted analytically for FSK with incoherent matched-filter detection. 相似文献