Estimating call intercepting probability of integrated WLANs in a UMTS cell

Capacity of a UMTS cell increases drastically due to integration of WLAN(s) with it. The UMTS load shared by WLAN is dependent on users´ density and WLAN hotspot coverage. Users with ongoing UMTS sessions visit WLAN hotspots and corresponding sessions are handed over to WLAN. Traffic estimation in both WLAN and UMTS is mandatory to estimate the cell performance. The call intercepting probability of underlying WLAN hotspots helps estimate the net traffic in UMTS and WLAN in interworking scenario. In most of the articles, for analytical simplicity, the density of users in UMTS-only coverage is assumed to be fixed even when WLAN coverage increases. We observed that call density in UMTS-only coverage decreases with increasing WLAN coverage. This decreasing call density in UMTS-only coverage additionally contributes in increasing call intercepting probability. We develop an extended model to estimate call intercepting probability taking dynamic change in call density in UMTS-only coverage under increasing WLANs. Numerical results show that call intercepting probability increases by 9% over existing model.