Abstract-The paper utilized the idea of bandwidth quantization and proposed a dynamic and adaptive bandwidth reallocation for admission control in mobile WiMAX networks. Based upon four QoS mechanisms (excluding the best effort), adaptively degrade and recover bandwidth to an existing user may improve the system performance but with tradeoff of complexity. Hand over and new calls were taken into account. The paper did analytical evaluations with multidimensional Markov chain; bandwidth utilization and blocking/dropping probability were the performance indices for comparison. The results presented that the utilization was increased and those probabilities were reduced simultaneously.Index Terms-QoS, adaptive admission control, bandwidth quantization and reallocation, hand over