Congestion based pricing algorithms are considered efficient approaches to control congestion and to distinguish services provided for users in computer networks. Game theory lends itself as a prevailing tool to design such algorithms. In this work, we propose a game theoretic congestion based bandwidth provisioning algorithm to address the scarcity for bandwidth provisioning scheme in IEEE 802.16 standard. To the best of our knowledge, the proposed algorithm is the first one to simultaneously control congestion and fairness while providing differentiated QoS guarantees. Simulation results reveal that the proposed scheme realizes our objective of controlling congestion, and provides differentiated QoS guarantees and proportional fairness among the different network classes.