Taking into account the security problems of 802.16 and according to the 802.16's specification, in this research work we have taken a novel approach to these issues by proposing and designing a 802.16-based intrusion detection system. Further on it has been investigated what is the performance of the offered system like. The performance and behavior of the proposed system has been tested and challenged using the NS2 network simulator so that the performance is analyzed by running a DoS attack via executing 50 FTP requests. Eventually the system's performance and operation can be observed in case of 802.16 downlink and uplink with IDS presence and without it.