The second generation of mobile communications is growing rapidly to the third generation due to various communication techniques and the increasing number of users. PCS, the communication method of the third generation, should be able to provide users with various services, independently of the current location. To PCS, the mobility management of users is essential. The mobility management method which has been used has a structural drawback: as the number of users increase, HLR becomes the bottleneck. Everyone is expected to have one terminal in the third generation mobile communications age. Therefore, an enhanced mobility management scheme to reduce the bottleneck of the HLR, should be used in the third generation mobile communications. In this paper, we propose a new mobility management method where the trace of terminals is left in the VLRs, so that a call can be connected by querying only to the VLRs rather than to the HLR when the terminal-terminated-call occurs. The proposed method distributes messages to VLRs and effectively reduce mobility management cost. To estimate overall mobility management cost, we simulated the new method of PCS network. The simulation model is based on the Jackson's network, and makes it possible to estimate mobility management cost of PCS networks. IS-41 and proposed scheme are compared based on the computer simulation. Considering the delay times both in HLR and VLR, and considering both location registration cost and call delivery cost, the proposed modeling method shows the improvement.