SMTC Configuration and Window Adjustment Strategies for Beam Hopping in NR‐NTN

ABSTRACT Beam hopping is an effective transmission strategy for nonterrestrial networks (NTNs), enabling satellites to allocate limited power and spectrum resources across different geographical regions over time. However, in NR‐based NTN systems, beam hopping complicates synchronization monitoring because synchronization signal block (SSB) arrivals observed at a user equipment (UE) may be distributed across multiple disjoint time intervals within a beam hopping period. Under such conditions, the existing Synchronization Signal Block Measurement Timing Configuration (SMTC) framework, which was not designed to explicitly account for beam hopping‐induced timing dispersion, may provide insufficient monitoring coverage. This paper investigates the limitations of the current SMTC mechanism in beam hopping NR‐NTN systems and develops an analytical framework for characterizing SSB monitoring requirements. The analysis shows that the required number of SMTC configurations is governed by the number of illumination groups observed by the UE, and that the current configuration constraint may result in both incomplete timing‐group coverage and residual window misalignment. To address these limitations, an enhanced SMTC monitoring framework is proposed, combining location‐based configuration selection with timing‐aware window adjustment. The proposed framework allows the network to maintain a larger candidate configuration pool while enabling the UE to activate only a capability‐limited subset relevant to its location. Simulation results show that the proposed scheme improves SSB monitoring success probability across clustered and scattered beam hopping scenarios while clarifying the trade‐off between monitoring performance and UE duty cycle. These results provide design insights for future NR‐NTN evolution and practical beam hopping deployment.