Research of VLR mobility database failure recovery and performance analysis for cdma2000 system

This paper presents a VLR database failure recovery scheme for cdma2000 system. We propose to backup the mobility database periodically. When failure occurs, VLR reloads the database from the backup file. However, if there is any new event (MS moving in or out) before recovery, the new information will not appear in the recovered VLR. The MS moving-in problem can be solved by autonomous registration, but the MS moving-out may result in obsolete information, we propose to periodically scan the database and remove the obsolete entries. The proposed scheme can also eliminate failure expansion and recover failures caused by radio troubles. The ratio of database backup period to scan period is analyzed.