Inter-system cell reselection parameter auto-tuning in a joint-RRM scenario

This paper presents an auto-tuning scheme, based on a fuzzy logic controller (FLC), for a standardized inter-system cell reselection (IS-CR) algorithm in a multi-radio access technology network. FLC modifies IS-CR parameters to reduce the number of call redirections between technologies during the admission control stage based on network performance indicators. Experience shows that call establishment delay is thus greatly reduced. To validate the proposed scheme, a dynamic system-level simulator comprising GSM and UMTS radio access technologies has been developed. This simulator includes a joint radio resource management (JRRM) entity, whose parameters are tuned by the FLC. FLC tuning capabilities are checked out in an extreme, albeit realistic, scenario, where most traffic is unevenly distributed in space and technologies. Results show that call redirections in the admission control stage can be significantly reduced, while keeping connection quality almost unaltered at the expense of increasing changes between technologies during the cell reselection process.