Association and Deployment Considerations in Dense Wireless LANs

Wireless LANs based on the IEEE 802.11 standard are one of the most commonplace indoor wireless access solutions. As the ever growing demand for data consumption necessitates higher rates and volumes, it is fairly common to observe more and more WLANs being deployed in close proximity to each other. As distances between WLAN installations diminish, the access points (APs) and stations (STAs) in these WLANs create a complex interference environment, which is also compounded by the indoor propagation environment. In this paper, we investigate the impact of two important parameters related to the deployment and operation of densely deployed wireless LANs on the aggregate throughput obtained by all the nodes in these WLANs. The first such operational parameter we investigate is access point and user station association; namely, whether STAs associate with a random "strong" AP or the AP from which they obtain the strongest received power. The second operational parameter we consider is the way in which APs are placed in the indoor environment; namely, whether APs are deployed randomly or in a manner to reduce inter-AP interference. In order to account for the complex node interactions in the MAC layer, which is crucial for accurate performance estimation, we perform packet-level simulations using OPNET. Our results show that the type of node association used in densely deployed WLANs has a critical impact on the aggregate throughput. In comparison, the type of AP deployment used is not nearly as significant; varying from moderate to no impact at all.