Performance evaluation of location information distributionstrategies for mobility tracking

摘要

A user location information distribution strategy is proposed formobile systems. Local anchors (LAs), replicated databases and forwardingpointers are applied in an integrated way that greatly reduces thelocation update rate and the call delivery cost incurred by locationtracking. In particular, the visitor location registers (VLRs)associated with a user's home and workplace are selected as the user'sLAs, which are connected by a forwarding pointer chain. When the userchanges their registration area (RA) within a local signal transferpoint (LSTP) region, the new location is reported to the home locationregister (HLR) and to the replicas. In the call delivery procedure, if acall orginates from one of the LAs or replicas, the HLR does not need tobe queried. An analytic model is developed and numerical examples aregiven to compare the performance of the proposed scheme, the standardscheme, the replication scheme and the local anchoring scheme. Theresults show that the proposed strategy outperforms the other threestrategies over a wide range of system parameters