The AP aggregation algorithm has been proposed to reduce the number of active APs in overlapped WLANs by aggregating them to solve the problem of performance degradation due to interferences, and increased operational cost. However, this algorithm does not consider the mobility of hosts, although they usually join or leave the network randomly. In this paper, we propose an extension of the AP aggregation algorithm to deal with the mobility by considering the probability of each host to stay active. We verify the effectiveness of this extension through simulations using the WIM- NET simulator.