On the End-to-End Delay Analysis of the IEEE 802.11 Distributed Coordination Function

2007 ◽  
Author(s):  
J.S. Vardakas ◽  
I. Papapanagiotou ◽  
M.D. Logothetis ◽  
S.A. Kotsopoulos
Keyword(s):  
Ieee 802.11 ◽  
Delay Analysis ◽  
Distributed Coordination ◽  
End To End Delay ◽  
Distributed Coordination Function ◽  
End To End ◽  
Coordination Function

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.

Evaluating The Performance for DCF Protocol and EDCA Protocol

2015 ◽  
Vol 72 (5) ◽  
Author(s):  
Ahmed Abu-Khadrah ◽  
Zahriladha Zakaria ◽  
Mohdazlishah Othman
Keyword(s):  
Real Time ◽  
Packet Loss ◽  
Area Network ◽  
Distributed Coordination ◽  
Data Types ◽  
End To End Delay ◽  
Main Challenge ◽  
Qos Parameters ◽  
End To End ◽  
Coordination Function

Nowadays supporting quality of service (QOS) for real time application is the main challenge of the wireless area network. 802.11standards use distributed Coordination Function (DCF) protocol and Enhanced Distributed Channel Access (EDCA) protocol in the MAC layer. DCF protocol has only one queue for different data types, it deals with data depending on the arriving time. There is no priority to serve real time applications faster. However EDCA protocol has four queues and each queue works with specific data type. Voice, video, best effort and background are the different queues in the EDCA protocol. Different parameters and priorities are defined for each queue. The voice queue reserves the highest priority and serves its data first. In this paper QOS parameters are measured for both DCF and EDCA protocol by using OPNET simulation. The QOS parameters must reach the requirements to support QOS. The results show how QOS parameters do not reach the requirements when using DCF protocol. The values of the end to end delay and the packet loss percentage are 0.514second, 19.04% respectively. But, when using EDCA protocol the end to end delay becomes 0.0624 second and the percentage of the packet loss decreases until reach 0.00617%. So the QOS parameters achieve requirements with EDCA protocol and support QOS.

Distributed Approach for QoS Guarantee to Wireless Multimedia

2007 ◽  
pp. 195-201
Author(s):  
K. Chetan ◽  
P. Venkataram ◽  
R. Sircar
Keyword(s):  
Ieee 802.11 ◽  
Wireless Multimedia ◽  
Distributed Coordination ◽  
Access Method ◽  
Qos Guarantee ◽  
Distributed Approach ◽  
Research Areas ◽  
Distributed Coordination Function ◽  
Active Research ◽  
Coordination Function

Providing support for QoS at the MAC layer in the IEEE 802.11 is one of the very active research areas. There are various methods that are being worked out to achieve QoS at MAC level. In this article we describe a proposed enhancement to the DCF (distributed coordination function) access method to provide QoS guarantee for wireless multimedia applications.

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