Modeling of Enhanced Distributed Channel Access with Station Grouping: A Throughput Analysis

Abstract

Machine to Machine (M2M) communication networks are expected to connect a large number of power-constrained devices in long range applications with different quality of service (QoS) requirements. Medium access control with QoS support such as the enhanced distributed channel access (EDCA) defined by IEEE 802.11e provides traffic differentiation and corresponding priority classes, which guarantees QoS according to the needs of applications. In this paper, we employ a station grouping mechanism for enhancing the scalability of EDCA to handle the massive number of access attempts expected in large M2M networks. Furthermore, we develop a discrete time Markov chain (DTMC) model to analyze the performance of EDCA with station grouping. Using the developed DTMC model, we calculate throughput for each access category as well as for different combinations of grouping and EDCA parameters. The numerical results show that the model can precisely reveal the behavior of EDCA mechanism. Moreover, it is demonstrated that employing the proposed grouping mechanism for EDCA increases the normalized throughput significantly for all classes of priority.