Femtocell is a Fixed-Mobile convergence, this promising Fixed/Mobile convergence (FMC) has come-up with solution of higher data rates and improved system performance for future wireless networks such as the Worldwide Interoperability for Microwave Access (WiMAX) (IEEE 802.16e), the 3rd (3GPP) Generation Partnership Project's (HSPA) High Speed Packet Access, (LTE) Long Term Evolution standards, and 3GPP2's Evolution Data Optimized (EVDO) standard. In parallel, Wireless-Fidelity(Wi-Fi), UMTS and mesh networks also are being developed to provide drifting high-rate data services in a more distributed fashion. Femtocells are low power base stations designed for small-service-area (home or office) that will significantly impact the cellular landscape in the next several years higher SNR (Signal to noise ratio) has been recommended for user side. One of the affecting technical issues related to femtocells concerns the impact on system performance. The focus of this study is to enumerate best option for femtocells to provide efficient utilization and improved performance. femtocell convergence have been taken with WiMax, Wi-Fiand UMTS and parameters of analysis chosen as system throughput and delay of the performance of deferent air-interfaces in femtocells environment over same application used /accessed. Found simulated results using OPNET 14Modelar suggested in this study that WiMax is the best option for femtocells it provides improved performance and supports high system throughput and relatively less delay in comparative to other two air-interfaces.