Abstract
In this paper, we study the rekeying issue in IEEE 802.16e WiMAX networks. The existing rekeying scheme—the Multicast and Broadcast Rekeying Algorithm (MBRA) unicasts new keys to each subscriber station (SS). This scheme does not scale well since it incurs large communication overheads when the number of SSs increase. In our work, first we propose a general tree-based rekeying scheme, which is more efficient than the MBRA. We also formulate an optimization problem to determine the optimal tree structure for given number of SSs. Furthermore, we present a novel and efficient rekeying scheme for WiMAX networks. Our new rekeying scheme utilizes efficient security schemes and the WiMAX network application feature. Both analysis and performance evaluation show that our rekeying scheme can significantly reduce the communication overheads.