IEEE 802.16 standard or WiMax network is one of the new alternatives for broadband wireless access. Among its promising applications is the creation of a wireless backhaul support for WiFi traffic. In this context, it is mandatory to design a Call Admission Control in the WiMax Base Station for resource allocation for the integration of both network technologies. In this paper, we investigate this subject by proposing an optimal call admission control and resource allocation for WiMax and WiFi integration. The optimization problem is formulated as a Semi-Markov Decision Process. By presenting a comprehensive analysis, we discuss different design trade-offs alternatives.