The people studied the various replication techniques to replicate HLR in PCS network. Replication is the key strategy for improving reliability, fault tolerance and availability in Distributed System. Personal Communication Service (PCS) network is the integration of cellular Network and conventional wired network. To support user mobility, the locations of the Mobile Stations (MSs) should be constantly tracked using a database. The widespread deployment of PCS will lead to a tremendous increase in the number of updates and queries to the location database. The centralized, stand-alone Home Location Register (HLR) in GSM can be a potential bottleneck.