In this study, we consider performance analysis of distance-based registration (DBR). DBR causes a mobile station (MS) to register its location when the distance between the current base station (BS) and the BS in which it last registered exceeds a distance threshold D. In general, DBR has some advantages over the other registration schemes but has a tendency to causes an MS to register more frequently than zone-based registration (ZBR) that is adopted in most of mobile communication systems. The DBR with implicit registration (DBIR) was proposed to improve the performance of DBR. In this study, we point out some problems of the previous analytical model based on continuous time Markov chain and analyze exact performance of the DBIR. We show that the DBIR always outperforms the DBR by using our exact analytical model.