SIMULATION MODELING FOR THE ANALYSIS OF COMPETITION MECHANISMS AND SURVEY SUPPORT IN QOS MANAGEMENT

Abstract

With the rapid development of IEEE 802.11 wireless local area networks and the increasing volume of multimedia traffic, the problem of providing the required Quality of Service (QoS) has become particularly relevant. Modern WLANs operate under conditions of high user density and heterogeneous traffic, which significantly complicates medium access control at the MAC layer. Therefore, the study of medium access mechanisms and their impact on network performance indicators is of great importance. The aim of this research is to analyze and compare the efficiency of contention-based access mechanisms (DCF) and polling-based controlled access mechanisms (PCF) in IEEE 802.11 wireless networks in terms of QoS support. To achieve this goal, the following tasks are addressed: analysis of existing medium access mechanisms, development of WLAN simulation scenarios in the OPNET environment, investigation of the impact of different traffic types and station density on delay, throughput, and retransmission attempts, and evaluation of the effectiveness of combining contention and polling mechanisms. The simulation results demonstrate that the DCF mechanism is more efficient for non-multimedia traffic and low station density, providing lower overhead and higher throughput. At the same time, the PCF mechanism ensures better delay performance and significantly reduces the number of retransmissions for multimedia traffic and in high-density network scenarios. It is shown that an increase in the number of stations leads to a substantial degradation of QoS when only contention-based access is used. In conclusion, the study confirms that a combination of contention-based and polling-based access mechanisms can significantly improve QoS support in IEEE 802.11 WLANs. The obtained results can be applied in the design and optimization of wireless networks intended to support multimedia and real-time services.