Location-Aware NAS Timer Optimization in NTN-TN Integrated Networks

2026-07-23

AI Summary

This work addresses the limitations of fixed or globally configured 5G Non-Access Stratum (NAS) timers in non-terrestrial network–terrestrial network (NTN-TN) integrated environments, which fail to account for user equipment (UE)-specific propagation delays, Access and Mobility Management Function (AMF) reachability, and path reliability variations, leading to excessive registration latency, high energy consumption, and frequent futile registration attempts. To overcome these challenges, we propose a location-aware, UE-specific dynamic NAS timer optimization scheme tailored for low Earth orbit satellite-based NTN-TN networks, enabling per-UE timer configuration for the first time. The approach models end-to-end delay using service link geometry, ground station distance, and inter-satellite hop count, and dynamically adjusts timer parameters based on predicted AMF queue exposure and real-time path reliability. Simulations demonstrate that the proposed method significantly reduces registration delay, UE energy consumption, and invalid registration attempts compared to conventional schemes, with particularly notable gains in minimizing unnecessary waiting periods.

Abstract

Efficient Non-Access Stratum (NAS) timer configuration is critical for reliable and energy-efficient Fifth Generation (5G) registration in Non-Terrestrial Network (NTN)-Terrestrial Network (TN) integrated systems, where Low Earth Orbit (LEO) satellite access introduces large registration bursts, heterogeneous propagation paths, and multi-hop satellite routing. Existing 3GPP NAS timers use fixed values, while prior closed-form timer models compute a global timer under network-level assumptions; both fail to capture user equipment (UE)-level differences in propagation delay, Access and Mobility Management Function (AMF) arrival position, and path reliability. In this paper, we propose a location-aware, UE-specific NAS timer optimization method for LEO NTN-TN integrated networks. The proposed method models the path-delay component using service-link geometry, ground-station distance, and Inter-Satellite Link (ISL) hop count, and adapts the endpoint-delay component according to each UE's expected AMF queue exposure and path reliability. Simulation results show that our method reduces registration latency, UE energy consumption, and avoidable registration attempts compared with fixed and global timer configurations, especially when timer over-provisioning causes unnecessary waiting.

Problem

• NAS timer optimization
• NTN-TN integrated networks
• LEO satellite
• propagation delay
• user equipment

Innovation

• location-aware
• UE-specific NAS timer
• LEO NTN-TN integration
• propagation delay modeling
• path reliability adaptation