Improving access latency in non-terrestrial NB-IoT systems
Vu, Hoang Minh (2026)
2026
Master's Programme in Computing Sciences and Electrical Engineering
Informaatioteknologian ja viestinnän tiedekunta - Faculty of Information Technology and Communication Sciences
Hyväksymispäivämäärä
2026-04-14
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202604143878
https://urn.fi/URN:NBN:fi:tuni-202604143878
Tiivistelmä
This thesis investigates the performance of Narrowband Internet of Things (NBIoT) in Geostationary Orbit (GEO) non-terrestrial networks (NTN), which extend connectivity to areas not served by terrestrial base stations. A novel and simple approach is introduced to improve the random access channel (RACH) procedure, specifically focusing on the first message of the preamble transmission from user equipment (UE) to the GEO satellite. A simulation framework and its accompanying algorithm are developed to illustrate the workflow of the RACH procedure under GEO-specific channel conditions, including long propagation delay and residual Doppler effects.
The evaluation examines preamble detection and collision probabilities across four scenarios: (1) comparing multiple preamble transmissions against the traditional single-preamble method, (2) assessing performance under varying network traffic message rates, (3) evaluating the impact of different satellite antenna gains, and (4) validating the approach further by increasing the number of transmitted preambles.
The comparative analysis demonstrates that the multiple preamble scheme yields approximately 25% improvement in preamble detection probability, while collision probability remains reasonably low under sparse network traffic. These findings validate the potential of the proposed approach for early‑phase NB-IoT deployments over satellite links, where moderate load conditions are expected.
The evaluation examines preamble detection and collision probabilities across four scenarios: (1) comparing multiple preamble transmissions against the traditional single-preamble method, (2) assessing performance under varying network traffic message rates, (3) evaluating the impact of different satellite antenna gains, and (4) validating the approach further by increasing the number of transmitted preambles.
The comparative analysis demonstrates that the multiple preamble scheme yields approximately 25% improvement in preamble detection probability, while collision probability remains reasonably low under sparse network traffic. These findings validate the potential of the proposed approach for early‑phase NB-IoT deployments over satellite links, where moderate load conditions are expected.