A Simulation Study on IEEE 802.11k Wireless Networks and Hidden Node Detection

Abstract

The hidden node phenomenon is a well known problem in wireless networks. This problem has impacts both on performance and stability in the network. By the introduction of 802.11k these problems can be minimized with the awareness of hidden nodes. This thesis presents the upcoming 802.11k standard in details. It discusses the different parts of the k-amendment and how to perform a diversity of measurements to improve the overall quality of the network. Furthermore the thesis simulates the hidden node problem in different scenarios and investigates their respective results. The unfairness problems in a hidden node environment are studied by simulation using ns2, and a fairness index is used to illustrate the results of these simulations. The detection and identification of hidden nodes are studied, both in theoretical aspects and simulation scenarios. Two main cases concerning this detection are shown: passive scan and active scan. Both cases use promiscuous mode, however the active scan introduces extra traffic into the network to detect all potential hidden nodes.