We live in a communication technology continuing to evolve, we generate and process information at a rate never before recorded in the history of mankind. Currently computing platforms are run on Gigahertz multi-core processors churning out Gigabits streams of data that need to be transmitted as quickly as possible. This has led to an ever increasing need to develop wireless access technologies that support high throughput regardless of the transmission environment. In order to develop WiMAX (IEEE 802.16d) PHY layer performance the Adaptive Antenna System has been considered. An Adaptive Antenna System has been deployed at the receiver module to reduce the fading effects caused by proposed channel model. Adaptive Antenna Systems (AAS) uses various beam forming techniques to focus the wireless beam between the base station and the subscriber station. In this work, the transmitter (SS) and receiver (BS) are fixed and AAS installed at the receiver is used to direct the main beam towards the desired LOS signal and nulls to the multipath signals. FFT beam former based on Least Mean Square (LMS) algorithm is used. It has been proved through MATLAB simulations that the performance of the system significantly improved by AAS, where is beam forming implemented in the direction of the desired user. The performance of the system more increased by increasing the number of antennas at receiver.