WLAN Performance Research Articles

Predictive Wireless Received Signal Strength Using Friis Transmission Technique

A good WLAN performance is crucial in determining the quality of experience (QoE) among the campus community. Proper WLAN planning and design should be done beforehand to ensure good WLAN performance. Various studies have discussed different methods of conducting WLAN planning to predict WLAN's best performance, including using artificial intelligence and mathematical approaches. One of the processes involved in performing WLAN planning is measuring performance parameters. Signal strength is one of the vital parameters to be measured in determining the excellent performance of WLAN in a particular area. When deploying a WLAN design in two different environments, the signal strength outcomes can differ due to various factors, including obstacles and path loss propagation issues within the deployment area. Higher Learning Institutions (HLIs) present a unique challenge as their building designs vary to accommodate student needs. As a result, the selection of materials used will also be different, affecting the WLAN performance. A detailed study should investigate the effect of path loss propagation and the type of obstacle that affects WLAN performance in HLI. Thus, this study focuses on predicting received signal strength using Friis Transmission and studying the effect of path loss propagation on WLAN performance. The simulated model significantly affects signal strength when the signal passes through different types of building material (non-LOS) and line-of-sight (NLOS), where concrete walls substantially affect the received signal strength between transmitters. The proposed model can assist network planners in designing robust WLAN infrastructure by improving signal strength, particularly in the HLI WLAN environment.Â

Key technologies of smart antenna in WLAN based on adaptive array

In order to improve the communication quality and transmission rate of WLAN, the key technologies of smart antenna in WLAN based on adaptive array are proposed. The adaptive array is used to suppress the WLAN interference signal, and the feedback from the output is used to adjust the weight loaded on the signal, and the optimal weight corresponding to the linear constraint minimum variance is obtained to achieve beamforming optimization. On this basis, the optimal antenna selection algorithm and the sub-optimal antenna selection algorithm are designed, and the sub-channel matrix with the maximum capacity can be obtained by repeated iterative calculation, so as to realize the smart antenna selection and further optimize the performance of WLAN. Experimental results show that the smart antenna signal has 100% coverage in WLAN compared with conventional methods. When the transmission rate is greater than 35 mb/s, the delay of the study method is not jitter compared to the contrast method. When the transmission rate is greater than 35 mb/s, the packet loss rate of the proposed method remains stable, while the packet loss rate of the two comparison methods begins to increase. When the transmission rate is greater than 12 mb/s, the throughput of the proposed method is more stable than the other methods. In conclusion, this method has the characteristics of large signal coverage, low delay, low packet loss rate and high throughput, and can be widely used in practice. The contribution of this study is that the weight of the antenna array can be dynamically adjusted through the adaptive algorithm, thus optimizing the quality of the received signal and improving the receiving sensitivity.

Multi-channel Bonding Effects of the IEEE 802.11ac on the WLAN Performance

Multi-channel Bonding Effects of the IEEE 802.11ac on the WLAN Performance

Machine Learning based Frame Size Optimization in WLAN Downlink MU-MIMO Channel with the Least Cost of Delay

The key enhancement in the medium access control (MAC) layer is frame aggregation introduced by the IEEE 802.11n/ac standard to accommodate the growing traffic demand in the WLAN by allowing multiple packets aggregated per transmission. Frame aggregation efficiently reduces control overhead in the MAC layer, such as the MAC header and thus it helps to enhance transmission efficiency and throughput performance of WLAN. However, heterogeneous traffic demand among streams in the WLAN downlink MU-MIMO channel creates a challenge to efficiently utilize the benefits of frame aggregation. Transmission efficiency is also compromised during frame size setting determination because when a frame size is larger, the impact of the overhead frame can be lower, but they are also more vulnerable to transmission errors. Thus, this trade-off between maximizing frame size and minimizing overhead frames should be addressed by employing an adaptive frame aggregation technique to derive the optimal frame size that would maximize the throughput in WLAN downlink MU-MIMO channel. Moreover, when frame aggregation approach is employed, more frames must wait before transmission in a buffer which causes a delay in the performance of WLAN. Thus, analysing the trade-off between maximizing throughput and minimizing delay is a critical issue that should also be addressed to enhance the performance of WLAN. However, the majority of the existing adaptive aggregation algorithms in the WLAN downlink MU-MIMO channel are focused to maximize the throughput or minimize the delay. The main contribution of this paper is to propose a machine learning-based frame size optimization algorithm by extending our earlier approach in considering the cost of delay to maximize the system throughput of WLAN. The effectiveness of the proposed scheme is evaluated over the FIFO Baseline Approach and earlier conventional approaches under the effects of various traffic patterns, channel conditions, and the number of STAs.

Power Amplifier and Low Noise Amplifier for WLAN Applications

WLAN applications operating at a frequency of 2.45 GHz are a frequently used communication method in transmission tools. The connection functions to send and receive data between access points and smart devices are also fulfilled by WLAN technology. Communication quality in data transfer gains importance for this technology at every stage. Front-end module structures are used to increase such quality affects directly the efficiency. Circuits including power amplifier (PA), low noise amplifier (LNA), antenna and filter are the most significant components compose front-end structures. In this study, PA and LNA using PW570 gain block & BFP760 RF transistor circuit respectively are proposed. By means of the usage of the proposed circuits, there will be considerable improvements in data communication speed and area of coverage, which are among the WLAN performance factors.

Performance of WLAN in Downlink MU-MIMO Channel with the Least Cost in Terms of Increased Delay

To improve the performance of IEEE 802.11 wireless local area (WLAN) networks, different frame-aggregation algorithms are proposed by IEEE 802.11n/ac standards to improve the throughput performance of WLANs. However, this improvement will also have a related cost in terms of increasing delay. The traffic load generated by mixed types of applications in current modern networks demands different network performance requirements in terms of maintaining some form of an optimal trade-off between maximizing throughput and minimizing delay. However, the majority of existing researchers have only attempted to optimize either one (to maximize throughput or minimize the delay). Both the performance of throughput and delay can be affected by several factors such as a heterogeneous traffic pattern, target aggregate frame size, channel condition, competing stations, etc. However, under the effect of uncertain conditions of heterogeneous traffic patterns and channel conditions in a network, determining the optimal target aggregate frame size is a significant approach that can be controlled to manage both throughput and delay. The main contribution of this study was to propose an adaptive aggregation algorithm that allows an adaptive optimal trade-off between maximizing system throughput and minimizing system delay in the WLAN downlink MU-MIMO channel. The proposed approach adopted different aggregation policies to adaptively select the optimal aggregation policy that allowed for achieving maximum system throughput by minimizing delay. Both queue delay and transmission delay, which have a significant impact when frame-aggregation algorithms are adopted, were considered. Different test case scenarios were considered such as channel error, traffic pattern, and number of competing stations. Through system-level simulation, the performance of the proposed approach was validated over the FIFO aggregation algorithm and earlier adaptive aggregation approaches, which only focused on achieving maximum throughput at the expense of delay. The performance of the proposed approach was evaluated under the effects of heterogenous traffic patterns for VoIP and video traffic applications, channel conditions, and number of STAs for WLAN downlink MU-MIMO channels.

Utilization of a Wireless Network Performing CSMA/CA with Random Backoff Algorithm

Optimizing WLAN performance in IEEE 802.11 network with extremely different working environments is a difficult task. We must use a network that can provide the most benefits to its end-users to improve network strength and data transmission. To increase performance in this congested situation, we construct an adaptive backoff algorithm for the IEEE 802.11 DCF that enhances in congested network conditions, system throughput is improved, the collision probability is reduced, and good fairness is maintained. This paper deals with the utilization of networks for different backoff strategies for different network conditions. The results obtained were comparatively much better than the existing methods.

Multi-Link Operation in IEEE 802.11be WLANs

The multi-link operation (MLO) is a new feature proposed to be part of the IEEE 802.11be Extremely High Throughput (EHT) amendment. Such feature represents a paradigm shift towards multi-link communications, as nodes will be allowed to transmit and receive data over multiple radio interfaces concurrently. To make it possible, the 802.11be Task Group has proposed different modifications in regards to nodes' architecture, transmission operation, and management functionalities. This article reviews such changes and tackles the question of how traffic should be distributed over multiple links, as it is still unresolved. To that end, we evaluate different load balancing strategies over the active links. Results show that in high load, dense and complex scenarios, implementing congestion aware load balancing policies to significantly enhance next-generation WLAN performance using MLO is a must.

Modeling and Analysis of Co-Channel Interference for IEEE 802.11 Wireless Local Area Network

With emerging network technologies, internet is used to provide backbone support for communication with each other. In this highly dynamic wireless environment Co-channel interference (CCI) create a constraint in terms of congestion. To maintain quality of service (QoS) in IEEE 802.11, WLAN performance analysis of CCI is necessary. In this paper, we present an analytical model for performance evaluations of the CCI effect in multi access point (AP) WLAN. The AP regions are overlapped to produce CCI effect which forces the network for retransmission of lost data results in congestion in the network. Various performance measures of the proposed scheme such as response time, queue length, probability of loss etc with respect to CCI factor is determined. Computational aspects of the proposed model in terms of graphs are presented.

MCS level이 전이중 통신 무선랜 시스템 성능에 미치는 영향 분석

MCS level이 전이중 통신 무선랜 시스템 성능에 미치는 영향 분석

FDoF: Enhancing Channel Utilization for 802.11ac

Multi-user multiple input multiple output (MU-MIMO) enables a multi-antenna access point to serve multiple users simultaneously, and has been adopted as the IEEE 802.11ac standard. While several PHY-MAC designs have recently been proposed to improve the throughput performance of a MU-MIMO WLAN, they, however, usually assume that all the concurrent streams are of roughly equal length. In reality, users usually have frames with heterogeneous lengths even after aggregation, leading to different lengths of a transmission time. Hence, the concurrent transmission opportunities might not always be fully utilized when some streams finish earlier than the others in a transmission opportunity. To resolve this inefficiency, this paper presents full degree-of-freedom (FDoF), a PHY-MAC design that exploits a novel power allocation scheme to reduce the idle channel time and further leverages frame padding to better utilize the spatial multiplexing gain. Unlike traditional MIMO power allocation, which aims at maximizing the theoretical sum-rate, FDoF’s power allocation explicitly considers heterogeneous frame lengths and minimizes the channel time required to finish concurrent frames, as a result improving the effective throughput. FDoF’s padding protocol then identifies proper users to reuse the remaining idle channel time, while preventing this padding from harming all the ongoing streams. Our evaluation via large-scale trace-driven simulations demonstrates that FDoF’s improves the throughput by up to $2.83\times $ , or by $1.36\times $ on average, as compared to the conventional 802.11ac. By combining FDoF’s power allocation with frame padding, the average throughput gain can be further increased to $1.75\times $ .

On the performance of WLAN and Bluetooth for in-car infotainment systems

The connected car is ushering in a new era of automotive design. Driven by increasing customer demand for connectivity and advances in electronics, connected cars are now equipped with advanced infotainment systems with a variety of applications. Seamless integration of consumer electronic (CE) devices into car infotainment systems is crucial for mimicking home and office user experience. Because wireless communication is more user-friendly than wired communication, it has become the preferred method for connecting CE devices to car infotainment systems. WLAN1and Bluetooth2are the most promising technologies for this purpose. Both systems operate in the spectrum-scarce 2.4 GHz unlicensed industrial, scientific and medical (ISM) radio band. The coexistence between WLAN and Bluetooth has garnered a significant amount of attention from both academic and industry researchers. However, the unique features of vehicle mobility and the high density of devices in a limited roadway area necessitate further investigation in the automotive domain.This paper focuses on the coexistence between WLAN and Bluetooth systems among vehicle infotainment applications, and on WLAN co-channel interference. Performance is evaluated using experimental measurements in real-world scenarios. The mobility effect is studied in detail. Results show that an onboard WLAN network is strongly affected by the surrounding networks. Coexistence duration decreases exponentially with relative speed between automobile networks. WLAN effect on Bluetooth is extremely high when WLAN's non-overlapped channels 1, 6, and 11 are simultaneously occupied. WLAN interference leads to a significant number of clippings in Bluetooth audio signals, especially in high WLAN traffic load situations. An exponential decease in the number of clipping events as a function of speed is observed.

TRAFFIC DESIGN MODEL FOR OPTIMUM PERFORMANCE ENHANCEMENTS OF IEEE 802.11B QOS PARAMETERS

Purpose: The objective of this research is to design a traffic model for optimum performance analysis and enhancements of IEEE 802.11b QOS parameters. It investigated the effect of traffic distribution on the quality of service parameter on WLAN, in other to establish enhanced WLAN Performance. In order to evaluate the mean packet delay and network throughput performance, this research has presented a traffic loading for MAC DCF which supports WLAN’s QOS Parameters.Methodology: Based on this model, a computer simulation model over a MATLAB Simulink was developed.Results: In this research, results show that the IEEE 802.11b does not perform well in terms of high throughput, and low mean delay at high traffic load conditions. Furthermore, it was also shown that the mean packet delay of arrived packets decreases as the number of workstations decreases, but at saturation, it was shown that throughput decreases, mean packet delay increases. Therefore, to achieve a better enhanced network performance, it was observed that IEEE 802.11b WLAN QOS parameters can be improved to a maximum throughput.

Performance Analysis of the IEEE 802.11n Block-ACK Mechanism in an Error-Prone Channel

A Block-ACK mechanism is adopted to improve the performance of WLAN in IEEE 802.11n, through Block-ACK mechanism stations can transmit more MPDUs at one-time and receiver only responds to a single Block-ACK frame, thus the mechanism effectively improves the efficiency of the MAC layer. In this paper, we analyze the saturation throughput of Block-ACK mechanism by considering the freezing of backoff counter, anomalous slots and non-ideal channel, the accuracy of our model is verified by the NS-2 simulation results.

Protection of smart substation based on WLAN complies with IEC 61850 using traveling wave analysis

Fast protection of distribution substation based on traveling wave is becoming a reality today. The transient traveling wave is mostly used in protection to determine the faulted line and the fault location. The advantages of signal of traveling wave includes immunity to system oscillation, transition resistance, CT saturation, and neutral point operation modes. In this article, a detailed study for analyzing the performance of using WLAN for real time protection based on the transient traveling wave. The high sampling frequency needed for traveling wave causes blockage in communication in the process bus. Now a packing of multi samples with suitable compression techniques in Merging Unit (MU), or using feature extraction with Hilbert–Huang transform with WLAN compliance with IEC 61850 has been tested. Further, this article presents the modeling and simulation of a WLAN communication network for an automation system using the precepts of IEC 61850, which is currently becoming a trend in Substation Automation System (SAS) specification. This article also investigates the impact of impulsive and interface noise on WLAN performance. Finally, the article advocates the wide application of traveling waves in the digital substations based on the IEC 61850 protocol.

Surrogate modeling based cognitive decision engine for optimization of WLAN performance

Due to the rapid growth of wireless networks and the dearth of the electromagnetic spectrum, more interference is imposed to the wireless terminals which constrains their performance. In order to mitigate such performance degradation, this paper proposes a novel experimentally verified surrogate model based cognitive decision engine which aims at performance optimization of IEEE 802.11 links. The surrogate model takes the current state and configuration of the network as input and makes a prediction of the QoS parameter that would assist the decision engine to steer the network towards the optimal configuration. The decision engine was applied in two realistic interference scenarios where in both cases, utilization of the cognitive decision engine significantly outperformed the case where the decision engine was not deployed.

Performance Evaluation and Comparison of IEEE 802.11 and IEEE 802.15.4 ZigBee MAC Protocols Based on Different Mobility Models

Wireless systems continue to rapidly gain popularity. This fact is extremely true for data networks in the local and personal areas. Media Access Control (MAC) layer protocols have a critical role in making a typical Mobile ad hoc network and Personal ad hoc network more reliable and efficient. Choice of MAC layer protocol and other factors including number of nodes, mobility, traffic rate and playground size dictates the performance of a particular WLAN and WPAN. The aim of this paper is to analysis the performance of mobility models in IEEE802.11 MAC and IEEE 802.15.4 ZigBee MAC using NS2.34.These mobility models are RPGM, RWM, Freeway mobility and city section mobility model. Then extraction of the simulation results based on the performance metrics to calculate a Packet Delivery Ratio, data loss, end-to-end delay and Throughput.

The Impact of Distance on WLAN and LAN Network Performance

The Impact of Distance on WLAN and LAN Network Performance

PERFORMANSI WLAN KANTOR PUSAT PEMERINTAH KABUPATEN BADUNFG

WLAN has been implemented widely, including in public area and government office. Badung Regency office has got benefit from the technology in applying its e- government services. However the WLAN performance in term of its QoS has not been evaluated after its installation. Then its delay, packet loss, throughput, and jitter were measured using Ekahau Heatmapper, Axence Nettols, Wi-Fi Analyzer, and Ubiquiti Unifi. The WLAN coverage area was calculated and analyzed. Generally, the performance is good. However there are areas in all 12 buildings in the offices that are needed more access points.

Performansi WLAN Kantor Pusat Pemerintahan Kabupaten Badung

WLAN has been implemented widely, including in public area and government office. Badung Regency office has got benefit from the technology in applying its e- government services. However the WLAN performance in term of its QoS has not been evaluated after its installation. Then its delay, packet loss, throughput, and jitter were measured using Ekahau Heatmapper, Axence Nettols, Wi-Fi Analyzer, and Ubiquiti Unifi. The WLAN coverage area was calculated and analyzed. Generally, the performance is good. However there are areas in all 12 buildings in the offices that are needed more access points.