Mobile WiMAX is a rapidly growing broadband wireless access (BWA) technology that is very applicable for the emerging mobile multimedia applications due to its packet based approach. In order to improve the performance of mobility, the concept of ASN anchored mobility is proposed by WiMAX Forum to keep the routing path prior to the anchor point unchanged during handover. However, the key management issue is still a critical procedure that may affect the handoff latency. In this paper, we presented a simplified ASN anchored mobility scheme to overcome the above problem. From the analysis of control flow between MS and the network of the existing proposed scheme, it can be inferred that the anchor ASN could be slightly modified for better performance. A simplified scheme, which slightly modifies the current handover procedure and utilizes the encapsulation technique, is proposed to improve the handover performance. In addition to the simplified handover procedure, it is analyzed that the little overhead is introduced.