WiMAX (Worldwide Interpretability for Microwave Access) is one of the leader standards of broadband Wireless Access (BWA). This standard becomes a competitor of 4G or LTE (Long Terme Evolution) with the introduction of different class of service flow (UGS, rtPS, nrtPS, BE). Each service class has its own QoS requirements. Even if the standard specify the transmission policy of each service class, it recommends the implementation of an admission control (AC) without any specification. This task is let to the operator. In this paper, we propose an implementation of an AC algorithm mechanism for IEEE 802.16. The performance evaluation of these networks by analytical models is not easy due to the state space explosion, thus we use the Stochastic Automata Networks (SAN) formalism to model our proposed AC mechanism. With the SAN we calculate the rewards of the proposed AC and we show that the proposed solution is efficient.