scholarly journals On the evaluation of the IEEE 802.11ac WLAN performance with QoS deployment

2021 ◽  
Vol 24 (3) ◽  
pp. 1618
Author(s):  
Ziyad Khalaf Farej ◽  
Omer Mohammed Ali
Keyword(s):  
System Performance ◽  
High Speed ◽  
Network Performance ◽  
Local Area ◽  
Data Rate ◽  
Medium Access ◽  
Node Number ◽  
High Speed Data ◽  
Ieee 802.11Ac ◽  
The Impact

The increase in the number of users on wireless local area networks (WLAN) and the development of large size applications have increased the demand for high-speed data rate and low latency. The IEEE 802.11ac was developed to provide very high throughput WLANs. Many enhancements are added to the medium access control (MAC) and physical (PHY) layers to increase data rate and improve network performance, these features enable the IEEE 802.11ac standard to provide quality of service (QoS) for multimedia applications. This paper concentrates on the impact of QoS on the system performance in term of delay and throughput. Four scenarios are proposed to investigate the network performance with different (from 1 up to 8) spatial stream (SS). The objective modular network testbed in C++ (OMNet++ modeler v5.5.1) is used to simulate and model these scenarios. For 8×8 SS, the results of simulation show the best throughput (maximum) and delay (minimum) values of (622, 484, 399.3, 382.96 Mbps) and (0.0211, 0.0589, 0.1037, 0.1202 sec) for 5, 15, 30 and 45 node number scenarios respectively. Although the number of nodes increases, the system performance decreases, however when QoS is deployed the performance is enhanced and its best improvement is obtained at the highest (45) node number scenario with values of 94.4% and 56.1% for throughput and delay respectively.

scholarly journals Performance Analysis of Wireless Local Area Network for a High-/Low-Priority Traffic Ratio at Different Numbers of Access Categories

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 693
Author(s):  
Kvitoslava Obelovska ◽  
Olga Panova ◽  
Vincent Karovič
Keyword(s):  
Network Performance ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Local Area ◽  
Area Network ◽  
Large Network ◽  
Medium Access ◽  
Massive Growth ◽  
Adaptive Adjustment ◽  
The Impact

The performance of Wireless Local Area Network (WLAN) is highly dependent on the processes that are implemented in the Medium Access Control (MAC) sublayer regulated by the IEEE 802.11 standard. In turn, various parameters affect the performance of the MAC sublayer, the most important of which is the number of stations in the network and the offered load. With the massive growth of multimedia traffic, research of the network performance depending on traffic types is relevant. In this paper, we present the impact of a high-/low-priority traffic ratio on WLAN performance with different numbers of access categories. The simulation results show different impact of high-/low-priority traffic ratio on the performance of the MAC sublayer of wireless LANs depending on different network-sizes and on network conditions. Performance of the large network with two access categories and with the prevalent high-priority traffic is significantly higher than in the case of using four categories on the MAC sublayer. This allows us to conclude that the performance improvement of the large network with the prevalent high-priority traffic can be achieved by an adaptive adjustment of the access categories number on the MAC sublayer.

Appraisal of OFDM for multi-carrier, high-speed data rate wireless communication networks

2019 ◽  
Author(s):  
Muhammad Bello Abdullahi
Keyword(s):  
Wireless Communication ◽  
Communication Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Research Work ◽  
Wireless Systems ◽  
Data Rate ◽  
High Quality Research ◽  
Global Issues ◽  
High Speed Data

Orthogonal Frequency Division Multiplexing (OFDM) is used to achieve multi-carrier signals and high- Speed data rate in free space. OFDM-based systems operate in the hostile multipath radio environment, which allows efficient sharing of limited resources. This research work was designed, developed and simulated an OFDM System using the basic blocks of Simulink in MATLAB/Simulink software, to support multi-carrier, high-speed data rates. This was achieved in backing of collection and review of high-quality research papers, which reported the latest research developments in OFDM communications networks, and its applications in future wireless systems. The research work significantly increases the speed of data rate signals, and many critical problems associated with the applications of OFDM technologies in future wireless systems are still looking for efficient solutions. This would overcome the global issues and challenges facing the limited bandwidth in wireless communication network.

SpaceWire

2018 ◽  
pp. 38-70
Author(s):  
Anargyros T. Baklezos ◽  
Christos N. Capsalis
Keyword(s):  
System Performance ◽  
High Speed ◽  
Data Communication ◽  
Space Missions ◽  
Development Cost ◽  
Communication Links ◽  
Recent Developments ◽  
High Speed Data ◽  
Electromagnetic Behavior ◽  
Point To Point

SpaceWire is a point-to-point bit shipping protocol for high-speed data communication links and networks providing equipment compatibility and seamless component reusability. It has found great application in many space missions reducing the development cost, offering architectural flexibility and improving reliability. This chapter delves into the standard describing the SpaceWire, focusing on the lower levels that play a key role in the electromagnetic behavior of the system and concern cable assemblies, shielding, bonding, and grounding. Findings regarding emissions affecting spacecraft components are presented as well as other EMC issues that have an impact on the system performance. Recent developments and upcoming updates to the standard are also presented and discussed.

scholarly journals Performance Analysis on Multiple Device Connections of Small Office Home Office Network

2021 ◽  
Vol 18 (4(Suppl.)) ◽  
pp. 1457
Author(s):  
Muhamad Nur Ashaari ◽  
Murizah Kassim ◽  
Ruhani Ab. Rahman ◽  
Abd Razak Mahmud
Keyword(s):  
Performance Analysis ◽  
Packet Loss ◽  
High Speed ◽  
Network Performance ◽  
Network Services ◽  
Quality Of Services ◽  
Home Office ◽  
Internet Connections ◽  
The Impact

Malaysia has been supported by one of the high-speed fiber internet connections called TM UniFi. TM UniFi is very familiar to be used as a medium to apply Small Office Home Office (SOHO) concept due to the COVID-19 pandemic. Most of the communication vendors offer varieties of network services to fulfill customers' needs and satisfaction during the pandemic. Quality of Services is queried by most users by the fact of increased on users from time to time. Therefore, it is crucial to know the network performance contrary to the number of devices connected to the TM UniFi network. The main objective of this research is to analyze TM UniFi performance with the impact of multiple device connections or users' services. The study was conducted to analyze the QoS on its traffic, packets transfer, RTT, latency, and throughput. Wireshark simulation program has been used as a network traffic capture where PCAP files have been analyzed by using PCAP Analyzer for Splunk. Traffic filtering has been enabled to capture selected traffic to measure network performance. The result shows that better network performance can be achieved if a smaller number of devices are connected at the same time.  The percentage of packet loss, RTT, latency is increased when more users connected at the same time. The throughput also shows a decrease for multi-device connections. Based on the analysis it can be concluded that TM UniFi still can provide good network services for the SOHO network environment and sufficient bandwidth despite the rapid user growth in Malaysia.

Effect of Fiber-Optics Nonlinearities in Long Haul and Ultra-High Speed DWDM Optical Transmission Networks at 10, 40 and 100 Gb/s Ultra-High Speed Data Rates

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Farman Ali ◽  
Yousaf Khan ◽  
Shahryar Shafique Qureshi ◽  
Shabir Ahmad ◽  
Muhammad Waqas
Keyword(s):  
Raman Scattering ◽  
Fiber Optics ◽  
Wavelength Division Multiplexing ◽  
High Speed ◽  
Stimulated Raman Scattering ◽  
Ultra High Speed ◽  
Data Rates ◽  
High Speed Data ◽  
The Impact ◽  
Stimulated Raman

AbstractThe impact of major nonlinearities in optical fiber such as SRR (Stimulated Raman Scattering) and Four Wave Maxing (FWM) in cascaded amplifier Dense Wavelength Division Multiplexing optical long reach and high speed data rate transmission scheme have been investigated at different data rates. Pulse walk off effect is considered for the purpose of calculating Stimulated Raman Scattering (SRS) nonlinear factor. Examination has been accomplished to assess signal to noise ratio thinking about the consolidated impact of SRS and FWM within the sight of amplified spontaneous emission noise to achieve minutest noise at altered data rates.

Directly modulated lasers in negative dispersion fiber links

2007 ◽  
Vol 15 (2) ◽  
Author(s):  
P. Krehlik
Keyword(s):  
High Speed ◽  
Negative Dispersion ◽  
High Speed Data ◽  
Directly Modulated Lasers ◽  
Signal Distortions ◽  
Induced Signal ◽  
Optimal Driving ◽  
The Impact ◽  
Dispersion Tolerance ◽  
Laser Chirp

AbstractIn the paper the impact of frequency chirp of directly modulated lasers is considered in context of high-speed data transmission over negative dispersion fiber. Chirp/dispersion induced signal distortions are described, and detailed investigations of their influence on 10 Gb/s transmission system performance are presented. The desired laser chirp characteristics and optimal driving conditions are determined. It is also demonstrated that directly modulated laser with low chirp offers similar or even better dispersion tolerance than unchirped (externally modulated) source. Experimental verification of described investigations is presented at the end.

scholarly journals The Impact of Dynamic RTS Threshold Adjustment for IEEE 802.11 MAC Protocol

2009 ◽  
Vol 5 (1) ◽  
pp. 5-20 ◽  
Author(s):  
Mostafa Mjidi ◽  
Debasish Chakraborty ◽  
Naoki Nakamura ◽  
Norio Shiratori
Keyword(s):  
Ieee 802.11 ◽  
Data Transmission ◽  
Mac Protocol ◽  
Threshold Value ◽  
Local Area ◽  
Wireless Channel ◽  
Main Element ◽  
Medium Access ◽  
Hidden Terminal ◽  
The Impact

In recent years, wireless technologies and application received great attention. The Medium Access Control (MAC) protocol is the main element that determines the efficiency in sharing the limited communication bandwidth of the wireless channel in wireless local area networks (WLANs). IEEE 802.11 introduced the optional RTS/CTS handshaking mechanism to address the hidden terminal problem as well as to reduces the chance of collision in case of higher node density and traffic. RTS Threshold (RT) determines when RTS/CTS mechanism should be used and proved to be an important parameter for performance characteristics in data transmission. We first investigate to find a meaningful threshold value according to the network situation and determine the impact of using or disengaging the RTS/CTS optional mechanism and dynamically adjust the RTS Threshold to maximize data transmission. The results show a significant improvement over existing CSMA/CA and RTS/CTS schemes. Our adaptive scheme performed even better when data rate increases. We verify our proposed scheme both analytically and with extensive network simulation using ns-2.

scholarly journals High-speed visible light communication systems based on Si-substrate LEDs with multiple superlattice interlayers

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fangchen Hu ◽  
Shouqing Chen ◽  
Yuyi Zhang ◽  
Guoqiang Li ◽  
Peng Zou ◽  
...  
Keyword(s):  
Visible Light ◽  
Radio Frequency ◽  
Communication Systems ◽  
High Speed ◽  
Visible Light Communication ◽  
Data Rate ◽  
Si Substrate ◽  
Theoretical Derivation ◽  
Wall Plug Efficiency ◽  
The Impact

AbstractHigh-speed visible light communication (VLC), as a cutting-edge supplementary solution in 6G to traditional radio-frequency communication, is expected to address the tension between continuously increased demand of capacity and currently limited supply of radio-frequency spectrum resource. The main driver behind the high-speed VLC is the presence of light emitting diode (LED) which not only offers energy-efficient lighting, but also provides a cost-efficient alternative to the VLC transmitter with superior modulation potential. Particularly, the InGaN/GaN LED grown on Si substrate is a promising VLC transmitter to simultaneously realize effective communication and illumination by virtue of beyond 10-Gbps communication capacity and Watt-level output optical power. In previous parameter optimization of Si-substrate LED, the superlattice interlayer (SL), especially its period number, is reported to be the key factor to improve the lighting performance by enhancing the wall-plug efficiency, but few efforts were made to investigate the influence of SLs on VLC performance. Therefore, to optimize the VLC performance of Si-substrate LEDs, we for the first time investigated the impact of the SL period number on VLC system through experiments and theoretical derivation. The results show that more SL period number is related to higher signal-to-noise ratio (SNR) via improving the wall-plug efficiency. In addition, by using Levin-Campello bit and power loading technology, we achieved a record-breaking data rate of 3.37 Gbps over 1.2-m free-space VLC link under given optimal SL period number, which, to the best of our knowledge, is the highest data rate for a Si-substrate LED-based VLC system.

scholarly journals A Reservation Protocol Analysis for Multi-Channel Wireless Networks

2017 ◽  
Vol 2 (4) ◽  
pp. 340
Author(s):  
Peristera A. Baziana ◽  
Ioannis E. Pountourakis
Keyword(s):  
Access Control ◽  
Network Performance ◽  
Mac Protocol ◽  
Local Area ◽  
Substantial Contribution ◽  
Data Traffic ◽  
Medium Access ◽  
Reservation Protocol ◽  
Single Radio ◽  
Multi Access

A synchronous multi-channel multi-access Medium Access Control (MAC) protocol for Wireless Local Area Networks (WLANs) is studied in this paper. The proposed protocol introduces an access control reservation scheme and requires a single radio per station. The receiver collisionsphenomenon characterizes the performance of the proposedmulti-channel system. A priority scheme is considered in order to primary serve the time-sensitive traffic such as voice, as compared to the delay tolerant data traffic. The innovation of this paper is the extensive and accurate study of the receiver collisions effect on the network performance in multi-traffic environment. An analytic discrete time Markovian model is developed for finite number of stations and channels. The performance measures of throughput, delay, and average rejection probability at destination are analytically estimated. Numerical results are presented for comparison for various numbers of channels and stations. The proposed MAC protocol provides a substantial contribution to the understanding of wireless multi-channel multi-traffic environments.

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