Wireless communication has become increasingly important in the nowadays society, and people have more dependence on mobile communication than before. In wireless channels, the channel state changes over time and frequency for users so that the orthogonal frequency division multiple access (OFDMA) technology is coming up and being used in current wireless broadband access standards, for example, 802.16e WiMAX. In the case of time and bandwidth are limited, how to allocate the limited resource in the best way has become an important issue. In this thesis, we provide an algorithm designed under the 802.16e standard, the ultimate goal is to try to satisfy all users’ Quality of Service (QoS) requirements, raising the efficiency of using time and bandwidth to achieve optimal utilization of resources.