VOIP QoS Over UMTS Network Using IEEE 802.11e EDCA Algorithm

Abstract

Local wireless networks based on IEEE 802.11e Enhanced Distributed Channel Access (EDCA), which is considered an indispensable technique for Medium Access Control (MAC), have recently become one of the most widely used approaches for transferring data between nodes, allowing multimedia mobile services to become a reality by using an alternative network to actual cellular systems. The OPNET tool was used to investigate a UMTS network in this article. Simultaneously, Internet user behavior is changing, with VoIP and peer-to-peer (P2P) services joining the already-established Web browsing, file sharing, and e-mail. However, because it was not designed to support these heterogeneous traffic situations, UMTS have significant performance restrictions in this scenario, such as the problematic simultaneous coexistence of TCP and UDP flows. This dissertation examines ways for providing QoS guarantees at the flow level in UMTS, mitigating and resolving various impairments while maintaining the technology's core feature: a distributed random access MAC protocol. To address these issues, an admission and rate control mechanism based on the IEEE 802.11e EDCA standard is presented of the DCF/EDCA protocol is designed, being able to capture the non-linear and reciprocal impact between network and traffic flows. The model also takes into account the dynamics of the QoS traffic differentiation factors. The analysis focuses on the factors that contribute to the reduced maximum number of VoIP conversations that can be active at the same time, such as the existing downlink / uplink inequity and the multi-rate anomaly. Each instance has its own set of solutions. Finally, the admissions control is discussed, as well as a number of policies. Adaptive policies work by modifying the EDCA parameters in real time. The results show that using the proposed admission control increases overall UMTS performance significantly, indicating that it is a viable solution for future distributed random access multimedia wireless networks.