Traffic analysis on carrier accessing for WLAN indoor positioning system

Currently, the WLAN indoor positioning system attracts a lot of interests, not only because of the cheap implementation but also because of the high positioning accuracy comparing with other indoor positioning systems. The WLAN indoor positioning system contains two phases, which are offline phase and online phase. In the online phase, the WLAN equipment user (UE) has to access to the WLAN for the latest radio map and positioning software. Due to during the network allocation vector (NAV) duration, the WLAN channel is only reserved for one WLAN UE, others UEs' carrier accessing will be blocked. In addition, the blocked UE will make a retrial accessing, which will definitely introduce more traffic blocking to the WLAN. So In this paper, based on the analysis of the WLAN indoor positioning system architecture, a proper queuing model by using of the Extended Erlang B formula is proposed, which takes the retrial calling percentage into consideration in the proposed model. The simulation results show that the proposed method is more accurate and performs well to predict the blocking probability.