Telecommunication agencies are facing the problem of spectrum scarcity with respect to the dramatic increase of demand of new spectrum to support 5G network services. The inefficient usage of the limited spectrum necessitates the coexistence of different radio access technologies in the same spectrum. Sharing the spectrum without negative impact is a prerequisite for telecommunication agencies before allowing new radio access technology to coexist with incumbent technology already using the spectrum. In this work, we develop general analytical models to evaluate the potentials of the Frame Based Equipment (FBE) MAC protocol that can be used by LTE-LAA networks to share the spectrum with Wi-Fi. We derive the expressions of the performance of both networks and we validate them by NS3 simulations. We show that FBE can be a good tradeoff that offers an acceptable LTE-LAA performance while reducing the negative impact on Wi-Fi if both network parameters are well tuned. In particular, increasing the Wi-Fi data rate, increases the performance of LTE-LAA and the overall performance.