期刊名称：Journal of Theoretical and Applied Information Technology
印刷版ISSN：1992-8645
电子版ISSN：1817-3195
出版年度：2014
卷号：64
期号：1
出版社：Journal of Theoretical and Applied
摘要：The simplicity of expanding and maintenance wireless network helped to use it widely in the public locations such as parks, airports and bus stations. Distributed Coordination Function (DCF) and Enhanced Distributed Channel Access (EDCA) protocols are used with WLANs. DCF protocol sends its data without any priority between different data types, and does not give any advantage of real time application such as voice over internet protocol (VOIP) or video conference. However EDCA protocol divides data to different class�s voice, video, best effort and background. Each class has its own priority and parameters. The default values of EDCA protocol give voice traffic the highest priority. Quality of Service (QOS) parameters such as end to end delay, packet loss and jitter values determine if the protocol support QOS or otherwise. This paper evaluates the performance of DCF protocol and EDCA protocol by using OPNET simulation and shows the differences between them, depending on QOS parameter values. The result of simulation shows the limitation of EDCA protocol when increasing the number of VOIP users. Therefore the EDCA protocol tolerates specific number of real time applications with acceptable values of QOS parameters.
