Performance Evaluation of IEEE 802.11n WLAN in Dense Deployment Scenarios

The default medium access mechanism for Wi-Fi, Distributed Coordination Function (DCF), is a simple contention based protocol aimed at providing a fair distribution of resources among Wi-Fi nodes. However, DCF suffers from significant performance degradation in the presence of dense deployments. Hence, improving the performance of the Wi-Fi MAC layer is essential for efficient spectrum sharing among overlapping Basic Subscriber Set (OBSS) for next generation wireless networks. In this context, in this paper, we compare DCF with an existing Wi-Fi mechanisms, Power-Save Multi-Poll (PSMP) and Hybrid Coordination Function (HCF) Controlled Channel Access (HCCA), and show that, although standard scheduled access techniques enhance WiFi throughput, they also suffer a decrease on performance in dense deployments. As a starting point, we propose that scheduled access including contention-free channel access mechanisms should be considered in addition to DCF for dense deployments.