In this paper, we propose an accurate analytical model to analyze the performance of initial ranging requests in IEEE 802.16 networks. Two metrics, connection probability and average connection delay, are investigated to evaluate the network performance. Performance observation demonstrate that the connection probability is not heavily influenced by the contention window size and reconnection retry limitation but the average connection delay is sensitive to the above two parameters. Moreover, we find that improving the service capacity and buffer size of base station can optimize the connection probability and average connection delay.