Figures of Merit Analysis for Over-the-Air Testing of the Non-Terrestrial Network Direct-to-Smartphone Handsets

Authors

  • Siyang Sun China Telecommunication Technology Labs China Academy of Information and Communications Technology, Beijing 100191, China https://orcid.org/0000-0002-6733-1272
  • Meijun Qu National Key Laboratory of Scattering and Radiation Beijing 100854, China
  • Zheng Liu China Telecommunication Technology Labs China Academy of Information and Communications Technology, Beijing 100191, China

DOI:

https://doi.org/10.13052/2026.ACES.J.410210

Keywords:

Direct-to-Smartphone (DTS), Figures of Merit (FoMs), Non-Terrestrial Network (NTN), Over-the-Air (OTA) testing

Abstract

The Non-Terrestrial Network (NTN) is a critical component of the 6G integrated space-air-ground-sea network. The comprehensive Over-the-Air (OTA) performance evaluation of NTN terminals is essential for ensuring wireless connection reliability and quality of experience. However, major international standards bodies including 3rd Generation Partnership Project (3GPP) and Cellular Telecommunications and Internet Association (CTIA) remain in the preliminary stages of developing their OTA specifications for mobile terminals supporting NTN communications. Accordingly, the objective of this paper is to investigate key Figures of Merit (FoMs) for OTA testing of NTN handsets from the perspective of satellite coverage multiplicity, to better characterize, distinguish, and rank OTA performance of different NTN handsets for future testing methodology development. During the analysis, coverage models are created for Low Earth Orbit (LEO) and Geosynchronous Orbit (GEO) constellations separately, based on which the coverage multiplicity for Starlink Direct-to-Cell (DTC) and TianTong-1 constellations is evaluated and determined for different target regions quantitatively. By comparing the coverage multiplicity and usage scenarios with those of the Global Positioning System (GPS), whose OTA FoMs and testing methods have been clearly defined in specifications, the FoMs for OTA testing of NTN handsets are recommended, including integrated FoMs for LEO (e.g., Total Isotropic Sensitivity [TIS] and Upper Hemisphere Isotropic Sensitivity [UHIS] metrics for receiver performance, and Total Radiated Power [TRP] and new Upper Hemisphere Radiated Power [UHRP] metric [corresponding to the UHIS] for radiation performance evaluation) as well as directional FoMs (e.g., requiring the average or minimum of Effective Isotropic Radiated Power [EIRP] and Effective Isotropic Sensitivity [EIS] values within a specific zenith angular range to exceed the limit) for GEO constellations, respectively.

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Author Biographies

Siyang Sun, China Telecommunication Technology Labs China Academy of Information and Communications Technology, Beijing 100191, China

Siyang Sun received the Ph.D. degree from the School of Electronic Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing, China, in 2011. He is currently an Associate Professor with China Telecommunication Technology Labs (CTTL), China Academy of Information and Communications Technology (CAICT). Since 2018, he has been a senior algorithm researcher at CTTL, CAICT and has been deeply involved in the research, standardization, and globalization of 5G/5G-Advanced MIMO OTA. He currently serves as the Co-Chair of the CTIA MIMO OTA Working Group. His research interests include MIMO antennas, metamaterials, and OTA testing for 5G, 5G-Advanced, and 6G communications.

Meijun Qu, National Key Laboratory of Scattering and Radiation Beijing 100854, China

Meijun Qu received the Ph.D. degree from the School of Information and Communication Engineering, Beijing University of Posts and Telecommunications (BUPT), Beijing, China, in 2020. From 2020 to 2025, she was with the School of Information and Communication Engineering, Communication University of China. Since 2025, she has been with the National Key Laboratory of Scattering and Radiation, Beijing, as an Associate Professor. Her research interests include antenna, metamaterial, and electromagnetic compatibility.

Zheng Liu, China Telecommunication Technology Labs China Academy of Information and Communications Technology, Beijing 100191, China

Zheng Liu received the B.S. degree from the Communication University of China in 2006 and the M.S. degree from the School of Information and Communication Engineering, Beijing University of Posts and Telecommunications (BUPT) in 2010. He is currently a senior engineer with China Telecommunication Technology Labs (CTTL), China Academy of Information and Communications Technology (CAICT). During 2010 to 2015, he has led the TDD LTE/LTE-Advanced MIMO OTA research, standardization, and globalization of TDD LTE/LTE-Advanced MIMO OTA at CAICT. Since 2015, he has been leading the R&D of 5G and 6G MIMO OTA at CAICT. He currently serves as the Chair of the CCSA TC9 WG5. His research interests include 5G-A and 6G channel models and transmission new techniques, AI enabled channel prediction and digital twin, measurement and testing, etc.

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Published

2026-02-20

How to Cite

[1]
S. . Sun, M. . Qu, and Z. . Liu, “Figures of Merit Analysis for Over-the-Air Testing of the Non-Terrestrial Network Direct-to-Smartphone Handsets”, ACES Journal, vol. 41, no. 02, pp. 186–193, Feb. 2026.

Issue

2026: Vol 41 Iss 2

Section

Advances in Next-Generation Antenna Systems and Their Testing Methodologies

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