scholarly journals Defining Quantiles for Estimating IP Packet Delay Variation in NGN Core Networks

2011 ◽  
Vol 1 (03) ◽  
Author(s):  
Dao Ngoc Lam ◽  
Le Nhat Thang ◽  
Le Huu Lap
Keyword(s):  
Network Performance ◽  
Estimation Method ◽  
Packet Delay ◽  
Distribution Functions ◽  
Estimation Accuracy ◽  
Core Network ◽  
Approximate Methods ◽  
Core Networks ◽  
Ip Packet ◽  
Delay Variation

Traffic delay is one of the important metrics used for evaluating network performance. Delay and delay variation characteristics of IP packets transferred over multi-section networks can be derived, estimated or composed from component distributions of IP package delay in each network section. Approximate methods are needed in the cases of unknown or complicated delay distribution functions, which are unavailable or unusable in practice. The ITU-T has proposed a method for estimating IP packet delay variation. One of noticeable factors affecting the estimation accuracy is the packet delay population quantile which has not been adequately considered. The objective of this paper is to examine the optimal range of quantiles used for estimating the IP packet delay variation in the NGN (Next Generation Network) core networks. The paper is composed from the following ideas. Firstly, several concepts and mathematical formulas related to delay metrics based on probability and statistics theory are defined. The approximate method of ITU-T for estimating the IP packet delay variation in a multi-section network is revised. Then, another method based on convolution for composing the empirical IPTD distribution functions is proposed for the same target as the first one. Secondly, a number of test cases are implemented to measure the IP packet delay on several sections of an NGN core network. Sample data are used for computing and estimating the IP packet delay variation for multi-section networks by two methods with certain hypotheses. Finally, these methods are compared and evaluated both theoretically and empirically in regards to the estimation accuracy versus quantiles of the IP packet transfer delay. The best range of quantiles is determined to ensure the accuracy of the estimation method applied for the NGN core network.

scholarly journals Checking the Accuracy of Siitperf

2021 ◽  
Vol 13 (2) ◽  
pp. 2-9
Author(s):  
Gábor Lencse
Keyword(s):  
Flow Control ◽  
Network Performance ◽  
Loss Rate ◽  
Packet Delay ◽  
Free Software ◽  
Linux Kernel ◽  
Measurement Results ◽  
Commercial Network ◽  
Delay Variation

Siitperf is the world’s first free software RFC 8219 compliant SIIT (Stateless IP/ICMP Translation, also called as Stateless NAT64) tester, which implements throughput, frame loss rate, latency and packet delay variation tests. In this paper, we show that the reliability of its results mainly depends on the accuracy of the timing of its frame sender algorithm. We also investigate the effect of Ethernet flow control on the measurement results. Siitperf is calibrated by the comparison of its results with that of a commercial network performance tester, when both of them are used for determining the throughput of the IPv4 routing of the Linux kernel.

Accuracy of the IP packet delay variation estimation

2009 ◽  
Author(s):  
Andrey Sokolov
Keyword(s):  
Packet Delay ◽  
Ip Packet ◽  
Delay Variation

scholarly journals IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)

2002 ◽  
Author(s):  
C. Demichelis ◽  
P. Chimento
Keyword(s):  
Performance Metrics ◽  
Packet Delay ◽  
Ip Packet ◽  
Delay Variation

scholarly journals A Mathematical Model of Shifted Gamma Distribution for Internet Traffic Packet Delay over a Next Generation Core Internetwork

2013 ◽  
Author(s):  
Dao Ngoc Lam ◽  
Le Huu Lap ◽  
Le Nhat Thang
Keyword(s):  
Mathematical Model ◽  
Gamma Distribution ◽  
Traffic Engineering ◽  
Packet Delay ◽  
Internet Traffic ◽  
Core Network ◽  
Next Generation ◽  
Broadband Internet ◽  
Delay Distribution ◽  
Ip Packet

Broadband  Internet  traffic  is transported over the  next generation  core internetworks, which are composed of several IP/MPLS/GE network sections and transport  multi-services. In practice, IP packet delay is normally  measured  in  each  separated  network  section but  not  over  a  whole  internetwork.  It  is  proved  in  the paper  that  packet  delay  distribution  of  Internet  traffic component  in  core  network  sections  can  be approximately  expressed  as  a  shifted  gamma distribution.  Moreover  a  new  explicit  mathematical model  based  on  shifted  gamma  distribution  has  also been proposed to compose delay distribution of Internet traffic  packet  transported  over  a  core  internetwork from  component  ones  in  each  network  section.  It  is resulted from this model that Internet packet delay over an  internetwork  inherits  distribution  properties  from that  over  component  networks.  Other  properties  and parameters  relationship  of  the  model  such  as  additive property of shape and location parameters, the relation between  distribution  lower  moments  and  parameters, the dependence  of distribution  on parameters variation are also exposed in the paper. The proposed model of IP packet  delay  distributions  has  a  certain  scientific significance  and  plays  an  important  role  in  practical performance analysis, network  planning, designing and traffic engineering for improving the quality of service

Investigating the Analysis of Power Saving Mode in IEEE 802.11 for Wi-Fi Communication

2018 ◽  
Vol 6 (3) ◽  
pp. 13-19
Author(s):  
Isam Aameer Ibrahim ◽  
Haider TH Salim ◽  
Hasan F. Khazaal
Keyword(s):  
Ieee 802.11 ◽  
Network Performance ◽  
Power Saving ◽  
Packet Delay ◽  
Access Point ◽  
Battery Life ◽  
Global Issues ◽  
Time Ratio ◽  
Power Saving Mode ◽  
Saving Mode

One of the major global issues today is energy consumption. Consequently, power management was introduced in various communication technologies. For IEEE 802.11wireless communication, there is a Power Saving Mode scheme (PSM) for increase the battery life of cell phone. In this PSM, there are two key parameters: beacon period interval (BI) and listen interval(LI). In most work these values are chosen arbitrary. Here, a scheme to determine the optimal BI and LI for accomplishing the most astounding conceivable vitality proficiency is introduced. This is implemented with the application of a numerical sample to the standard IEEE 802.11 PSM and Access Point-PSM (AP-PSM) schemes. To ensure the quality of network performance analysis on the normal and change of parcel delays is doing. The well-known queuing (M/G/I) model with bulk services are utilized. After the implementation of the proposed analysis, “maximum rest plan time ratio optimal Sleep Scheme (OSS)” which is when participate stations stay in the doze mode it can be determined. In this research shows that the optimal BI and LI produce optimal OSS time ratio scheme also achieved optimal average and variance of packet delay.

scholarly journals Low-complexity beam-domain channel estimation and power allocation in hybrid architecture massive MIMO systems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Xiao Chen ◽  
Zaichen Zhang ◽  
Liang Wu ◽  
Jian Dang
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Mimo Systems ◽  
Beam Steering ◽  
Estimation Method ◽  
Low Complexity ◽  
Estimation Accuracy ◽  
Hybrid Architecture

Abstract In this journal, we investigate the beam-domain channel estimation and power allocation in hybrid architecture massive multiple-input and multiple-output (MIMO) communication systems. First, we propose a low-complexity channel estimation method, which utilizes the beam steering vectors achieved from the direction-of-arrival (DOA) estimation and beam gains estimated by low-overhead pilots. Based on the estimated beam information, a purely analog precoding strategy is also designed. Then, the optimal power allocation among multiple beams is derived to maximize spectral efficiency. Finally, simulation results show that the proposed schemes can achieve high channel estimation accuracy and spectral efficiency.

scholarly journals UAV Based Estimation of Forest Leaf Area Index (LAI) through Oblique Photogrammetry

2021 ◽  
Vol 13 (4) ◽  
pp. 803
Author(s):  
Lingchen Lin ◽  
Kunyong Yu ◽  
Xiong Yao ◽  
Yangbo Deng ◽  
Zhenbang Hao ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Point Cloud ◽  
Forest Canopy ◽  
Estimation Method ◽  
Vertical Direction ◽  
Estimation Accuracy ◽  
3D Point Cloud ◽  
Area Index ◽  
Better Than

As a key canopy structure parameter, the estimation method of the Leaf Area Index (LAI) has always attracted attention. To explore a potential method to estimate forest LAI from 3D point cloud at low cost, we took photos from different angles of the drone and set five schemes (O (0°), T15 (15°), T30 (30°), OT15 (0° and 15°) and OT30 (0° and 30°)), which were used to reconstruct 3D point cloud of forest canopy based on photogrammetry. Subsequently, the LAI values and the leaf area distribution in the vertical direction derived from five schemes were calculated based on the voxelized model. Our results show that the serious lack of leaf area in the middle and lower layers determines that the LAI estimate of O is inaccurate. For oblique photogrammetry, schemes with 30° photos always provided better LAI estimates than schemes with 15° photos (T30 better than T15, OT30 better than OT15), mainly reflected in the lower part of the canopy, which is particularly obvious in low-LAI areas. The overall structure of the single-tilt angle scheme (T15, T30) was relatively complete, but the rough point cloud details could not reflect the actual situation of LAI well. Multi-angle schemes (OT15, OT30) provided excellent leaf area estimation (OT15: R2 = 0.8225, RMSE = 0.3334 m2/m2; OT30: R2 = 0.9119, RMSE = 0.1790 m2/m2). OT30 provided the best LAI estimation accuracy at a sub-voxel size of 0.09 m and the best checkpoint accuracy (OT30: RMSE [H] = 0.2917 m, RMSE [V] = 0.1797 m). The results highlight that coupling oblique photography and nadiral photography can be an effective solution to estimate forest LAI.

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