IEEE 802.16 standard suite defines the air interface specifications for fixed and mobile broadband access in wireless metropolitan area networks. Although it has been well-defined, efficient bandwidth allocation still remains as open issue. In this paper we analyse and develop a mathematical model ta evaluate the uplink throughput of the contention-based and delay-tolerant applications in IEEE 802.16 network, the basic goal is to maximize the uplink data throughput with an optimal bandwidth allocation mechanism. Our analysis results can be used for providing probabilistic throughput guarantee and determining the optimal contention period in a IEEE 802.16 system.