A Collision Avoidance Mechanism for IEEE 802.11e EDCA Protocol to Improve Voice Transmissions in Wireless Local Area Networks

Author(s):  
Khalim Amjad Meerja ◽  
Abdallah Shami
10.5772/50911 ◽  
2012 ◽  
Vol 9 (1) ◽  
pp. 12 ◽  
Author(s):  
Eui-Jik Kim ◽  
Sungkwan Youm ◽  
Hyo Hyun Choi

This paper presents an analytical model for the performance evaluation of an IEEE 802.11e network in non-saturation environments. We first characterize the probability distribution of the MAC layer packet service time. Based on the probability distribution model of the MAC layer packet service time, we then study the queuing performance of the wireless local area networks (WLANs) at different traffic loads based on the IEEE 802.11e MAC protocol. The numerical results show that we can choose a feasible number and bandwidth of the node which determines the system performance that a user demands.


Connectivity ◽  
2020 ◽  
Vol 146 (5) ◽  
Author(s):  
A. V. Lemeshko ◽  
◽  
O. M. Tkachenko ◽  
А. О. Makarenko ◽  
O. M. Tkalenko ◽  
...  

The article analyzes the scope, technologies and principles of wireless local area networks, which allowed to mark the “bottlenecks” of these technologies, which need special attention when designing: the problem of hidden node; mutual interference between neighboring cells (intrasystem EMC); intersystem interference; providing QoS for responsible applications; expansion of wireless local area networks; the impact of network deployment features. The methods used to solve EMC problems in wireless local area networks are shown and their efficiency is analyzed: the mechanism of access to the transmission medium; IEEE 802.11e (QoS) standard; additional standards designed to reduce the impact of interference (802.11 h and k); coding and modulation. It is shown that the accounting of intrasystem and intersystem interference should be carried out in the early stages of design of wireless local area networks. It is shown that the existing mechanisms of access to the transmission medium are designed to organize the conflict-free operation of transceivers within a single access point and are vulnerable to interference created by transmission stations of neighboring access points. The dynamic sensitivity control algorithm is aimed at partially solving this problem, however, the main disadvantage of the DCC algorithm proposed for use in Wi-Fi 6 is that stations located near access points have a higher probability of access to the environment due to a higher signal level. Relative to electromagnetic interference, which leads to a shorter detection range of the carrier. That requires the development of advanced mechanisms to control the sensitivity of the service area of access points. Based on the analysis, a conclusion is made about the need to develop a methodology for designing wireless local area networks based on information systems, taking into account electromagnetic interference. Which will reduce the time of their design and increase the efficiency of their further operation.


2016 ◽  
Vol 9 (3) ◽  
pp. 204-211
Author(s):  
Ishwar Baidari ◽  
S. P. Sajjan ◽  
Ajeet Singh

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),


Author(s):  
Chaithra. H. U ◽  
Vani H.R

Now a days in Wireless Local Area Networks (WLANs) used in different fields because its well-suited simulator and higher flexibility. The concept of WLAN  with  advanced 5th Generation technologies, related to a Internet-of-Thing (IOT). In this project, representing the Network Simulator (NS-2) used linked-level simulators for Wireless Local Area Networks and still utilized IEEE 802.11g/n/ac with advanced IEEE 802.11ah/af technology. Realization of the whole Wireless Local Area Networking linked-level simulators inspired by the recognized Vienna Long Term Evolution- simulators. As a outcome, this is achieved to link together that simulator to detailed performances of Wireless Local Area Networking with Long Term Evolution, operated in the similar RF bands. From the advanced 5th Generation support cellular networking, such explore is main because different coexistences scenario can arise linking wireless communicating system to the ISM and UHF bands.


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