An improved simulation model is presented in this paper for modeling resource allocation strategies in wireless communications based on new event scheduling mechanisms involving real time systems methodologies. Such mechanisms are more suitable than the currently utilized Calendar Queue algorithm for simulating concurrent events in cellular networks. The proposed simulation model is based on a novel real time event scheduling algorithm extending the known in Discrete Event Simulation methodology, Calendar Queue algorithm. The new algorithm is analyzed and its implementation issues involving multithreading technology are discussed. The application of the new scheme in modeling GSM cellular networks shows significant enhancements with regards to network modeling performance compared to rival simulation modeling techniques.