Issues and challenges in dense WiFi networks

The IEEE 802.11 Working Group has initiated a new study group known as IEEE 802.11ax which is aiming to devise ways to improve spectrum efficiency, in particular to enhance the system throughput in highly dense scenarios, frequently referred to as Overlapped Basic Service Set (OBSS). In this paper we revisit some of the common problems faced in traditional WiFi networks and show how their effects could be amplified in dense deployments, especially in co-channel scenarios. We then highlight our findings through a simulation based study and draw inferences from these. Some of the key insights from this study are: link suppression and deadlock effects could potentially amplify in co-channel deployments thereby significantly degrading the throughput performance. Also, increasing the concentration of APs in a given area may not always lead to better performance and therefore AP placement needs to be carefully managed in OBSS scenarios. Where AP placement cannot be controlled due to unmanaged environments, findings indicate the need for intelligent load balancing and channel selection algorithms to minimize the impact of the aforementioned effects.