Mobile communications evolve approximately every decade, with 5G and 5G-Advanced currently in use and 6G anticipated by 2030. 5G and beyond networks require diverse spectrum allocations: low-band for coverage, mid-band for both coverage and capacity, and high-band for ultra-high data rates. To meet increasing capacity demands, small cells are deployed, significantly increasing base station (BS) proximity and network densification. This results in frequent handovers, which can lead to unnecessary handovers, ping-pong effects, and handover failures, causing signaling overhead, network congestion, and session disruptions for mobile users. This paper proposes an optimization approach for handover candidate lists (HCLs) to reduce frequent handovers, unnecessary handovers, ping-pong effects, and handover failures in 5G and beyond networks. The developed framework improves handover performance by over 50% for Absolute handover events while maintaining good throughput.

This letter introduces Time-to-Exit (TTE), a soft mobility robustness optimization (MRO) parameter for handovers in 5G and beyond networks. The deployment of small cells to meet higher capacity demands complicates mobility management, leading to frequent handovers, increased ping-pong effects, unnecessary handovers, and handover failures due to premature, delayed, or incorrect cell transitions. We propose an instantaneous TTE estimation model that uses location measurements, moving speed, Reference Signal Received Power (RSRP), and quality thresholds (Q_rxlevmin and REFSENS) to optimize handover initiation before the user exits the serving cell. This method aims to reduce handover rates, ping-pong handovers, unnecessary handovers, and handover failures.