scholarly journals Improving WLAN Quality of Services (Qos) Using Opnet

2016 ◽  
Vol 9 (3) ◽  
pp. 204-211
Author(s):  
Ishwar Baidari ◽  
S. P. Sajjan ◽  
Ajeet Singh
Keyword(s):  
Ieee 802.11 ◽  
Local Area Networks ◽  
Local Area ◽  
Wireless Local Area Networks ◽  
Ieee 802.11E ◽  
Distributed Coordination ◽  
Medium Access ◽  
Access Delay ◽  
Coordination Function

Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. With the increasing demand and penetration of wireless services, users of wireless networks now expect Quality of Service (QoS) and performance comparable to what is available from fixed networks. Providing QoS requirements like good throughput and minimum access delay are challenging tasks with regard to 802.11 WLAN protocols and Medium Access Control (MAC) functions. This research is done to study, the presently implemented schemes (the Point Coordination Function (PCF) of IEEE 802.11, the Enhanced Distributed Coordination Function (EDCF) of the proposed IEEE 802.11e extension to IEEE 802.11), solves these issues and what can be done to improve them further. The metrics used were Throughput, Data Drop, Retransmission and Medium Access Delay, to analyze the performance of various MAC protocols in providing QoS to users of WLAN. Two scenarios, with same Physical and MAC parameters, one implementing the DCF and other EDCF, were created in the network simulation tool (OPNET MODELER) to obtain the results. The results showed that the performance of EDCF was better in providing QoS for real-time interactive services (like video conferencing) as compared to DCF, because of its ability to differentiate and prioritize various services. Index Terms - Wireless local area networks (WLANs),

scholarly journals Latency and Jitter Analysis for IEEE 802.11e Wireless LANs

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Sungkwan Youm ◽  
Eui-Jik Kim
Keyword(s):  
Local Area ◽  
Ieee 802.11E ◽  
Distributed Coordination ◽  
Mac Layer ◽  
Medium Access ◽  
Distributed Coordination Function ◽  
Packet Latency ◽  
Coordination Function ◽  
The Voice

This paper presents a numerical analysis of latency and jitter for IEEE 802.11e wireless local area networks (WLANs) in a saturation condition, by using a Markov model. We use this model to explicate how the enhanced distributed coordination function (EDCF) differentiates classes of service and to characterize the probability distribution of the medium access control (MAC) layer packet latency and jitter, on which the quality of the voice over Internet protocol (VoIP) calls is dependent. From the proposed analytic model, we can estimate the available number of nodes determining the system performance, in order to satisfy user demands on the latency and jitter.

scholarly journals Παροχή ποιότητας υπηρεσιών σε ασύρματα τοπικά δίκτυα πολυμέσων τεχνολογίας ΙΕΕΕ 802.11e

2011 ◽  
Author(s):  
Αναστάσιος Πολίτης
Keyword(s):  
Ieee 802.11 ◽  
Local Area ◽  
Multimedia Applications ◽  
Ieee 802.11E ◽  
Medium Access ◽  
Large Numbers ◽  
Integrated Architecture ◽  
Wireless Infrastructure ◽  
Networking Technology

The fast growth of Wireless Local Area Networks (WLANs) during the last decade, has led to their wide acceptance by the vast majority of electronic equipment users as the dominant wireless networking technology. The indisputable functionality standard of WLANs is the IEEE 802.11. At the same time, multimedia applications technology has received a similar success. It was, therefore, an expected result that the users of both technologies required that multimedia applications were adequately supported by the wireless infrastructure. Towards this direction, the IEEE has published a series of amendments to the initial WLAN standard. The widely accepted amendment for supporting multimedia in WLANs is the IEEE 802.11e. This specification defined the functionality of a new Medium Access Control (MAC), capable of providing Quality of Service (QoS) to applications with high demands from the network.However, the IEEE 802.11 has received negative reviews regarding its capability of multimedia support in highly congested wireless networks. These conditions are quite common, especially in infrastructure networks with large numbers of users (e.g., public hotspots, university networks etc.). As a response to this challenge, the international scientific community, has designed and proposed various enhancements mechanisms to improve the IEEE 802.11e functionality in high load situations.This thesis contributes to this international effort of QoS provisioning in multimedia WLANs, by developing and assessing a novel mechanism which combines, adapts and enforces the characteristics and the design techniques that have been proposed in the international bibliography, into an integrated architecture. The efficiency of the mechanism is evaluated and compared to other implementations, and the related experimental results are proven to be very promising.

A Cross-Layer Approach for Prioritized Frame Transmissions of MPEG-4 Over the IEEE 802.11 and IEEE 802.11e Wireless Local Area Networks

2011 ◽  
Vol 5 (4) ◽  
pp. 474-485 ◽  
Author(s):  
Yang Xiao ◽  
Yan Zhang ◽  
Mike Nolen ◽  
Julia Hongmei Deng ◽  
Jingyuan Zhang
Keyword(s):  
Ieee 802.11 ◽  
Local Area Networks ◽  
Local Area ◽  
Wireless Local Area Networks ◽  
Ieee 802.11E ◽  
Cross Layer

scholarly journals QoS-Based Two-Level user Scheduling Scheme for MU-MIMO Wireless LANs

2019 ◽  
Vol 9 (1S3) ◽  
pp. 32-39
Keyword(s):  
Local Area Networks ◽  
Local Area ◽  
Wireless Local Area Networks ◽  
User Scheduling ◽  
Medium Access ◽  
Frequency Selective Fading ◽  
High Data ◽  
Rate Transmission ◽  
Data Rate Transmission

The advances in physical layer technology has led to the performance upgradation of wireless local area networks (WLANs). More recently, multi-input multi-output (MIMO) is considered to be a key technology to enable high data rate transmission in WLANs. However, the actual benefit of this approach can be utilized, if there is an appropriate mechanism to select and schedule the users. Also, providing Quality of Service (QoS) support to user demands has become a major task in WLANs. In this paper, a two-level user scheduling approach for WLANs is discussed and its performance is evaluated using high-transmission rates with the assumption of frequency selective fading. For the purpose of comparison, some well-known medium access control (MAC) scheduling schemes are considered. It is shown that, the proposed scheme enhances throughput and achieves fairness among the users. Further, this scheme can be used to reduce contention during the acquisition of channel feedback.

scholarly journals Performance Analysis of Synchronous Multi-Radio Multi-Link MAC Protocols in IEEE 802.11be Extremely High Throughput WLANs

2020 ◽  
Vol 11 (1) ◽  
pp. 317
Author(s):  
Taewon Song ◽  
Taeyoon Kim
Keyword(s):  
Ieee 802.11 ◽  
Markov Chain Model ◽  
Careful Consideration ◽  
Mac Protocols ◽  
Media Access Control ◽  
Chain Model ◽  
Distributed Coordination ◽  
Media Access ◽  
Medium Access ◽  
Coordination Function

The representative media access control (MAC) mechanism of IEEE 802.11 is a distributed coordination function (DCF), which operates based on carrier-sense multiple access with collision avoidance (CSMA/CA) with binary exponential backoff. The next amendment of IEEE 802.11 being developed for future Wi-Fi by the task group-be is called IEEE 802.11be, where the multi-link operation is mainly discussed when it comes to MAC layer operation. The multi-link operation discussed in IEEE 802.11be allows multi-link devices to establish multiple links and operate them simultaneously. Since the medium access on a link may affect the other links, and the conventional MAC mechanism has just taken account of a single link, the DCF should be used after careful consideration for multi-link operation. In this paper, we summarize the DCFs being reviewed to support the multi-radio multi-link operation in IEEE 802.11be and analyze their performance using the Markov chain model. Throughout the extensive performance evaluation, we summarize each MAC protocol’s pros and cons and discuss essential findings of the candidate MAC protocols.

IEEE 802.11 Wireless Local Area Networks

2006 ◽  
pp. 77-117
Author(s):  
Stefan Mangold ◽  
Lars Berlemann ◽  
Matthias Siebert ◽  
Bernhard H. Walke
Keyword(s):  
Ieee 802.11 ◽  
Local Area Networks ◽  
Local Area ◽  
Wireless Local Area Networks

Improving WLAN Performance by Modifying an IEEE 802.11 Protocol

2013 ◽  
pp. 15-32
Author(s):  
Nurul I. Sarkar
Keyword(s):  
Ieee 802.11 ◽  
Ad Hoc ◽  
Packet Delay ◽  
Distributed Coordination ◽  
Bandwidth Utilization ◽  
Medium Access ◽  
802.11 Dcf ◽  
802.11 Networks ◽  
Distributed Coordination Function ◽  
Coordination Function

One of the limitations of the IEEE 802.11 distributed coordination function (DCF) protocol is its low bandwidth utilization under medium-to-high traffic loads resulting in low throughput and high packet delay. To overcome performance problems, traditional IEEE 802.11 DCF (“DCF”) protocol is modified to the buffer unit multiple access (BUMA) protocol. The BUMA protocol achieves a better system performance by introducing a temporary buffer unit at the medium access control (MAC) layer to accumulate multiple packets and combine them into a single packet (with a header and a trailer) before transmission. This paper provides an in-depth performance evaluation (by simulation) of BUMA for multiuser ad hoc and infrastructure networks. Results obtained show that the BUMA is more efficient than that of DCF. The BUMA protocol is simple and its algorithm (software) can be upgraded to 802.11 networks requiring no hardware changes. The BUMA protocol is described and simulation results are presented to verify the performance.

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