arXiv subjects

Hyun-Su Cha

Publications and source records attributed to Hyun-Su Cha.

3 recordsLinked to original sources

arXiv2024

5G NR Positioning Enhancements in 3GPP Release-18

New radio (NR) positioning in the Third Generation Partnership Project (3GPP) Release 18 (Rel-18) enables 5G-advanced networks to achieve ultra-high accuracy positioning without dependence on global navigation satellite systems (GNSS) with key enablers such as the carrier phase positioning technique, standardized for the first time in a cellular communications standard and setting a new baseline for future generations. In addition, Rel-18 NR supports positioning functionalities for reduced capability (RedCap) user equipment and bandwidth aggregation for positioning measurements. Moreover, the low power solutions are designed for low power high accuracy positioning use cases. Lastly, sidelink-based positioning is introduced in Rel-18. This article constitutes a comprehensive treatment of the Rel-18 NR positioning enhancements crucial for the development of next-generation networks.

cs.IT↗

arXiv2022

Toward cm-Level Accuracy: Carrier Phase Positioning for IIoT in 5G-Advanced NR Networks

High-precision positioning accuracy is among the key features of the future fifth-generation (5G-advanced) cellular networks to enable a wide variety of commercial, critical, and consumer use cases. 5G new radio (NR) systems have relied on (1) cellular temporal/angular-based positioning methods to provide the indoor environments with a moderate positioning accuracy that is well below the positioning requirements of these future use cases and (2) highly precise satellite carrier phase/code-based positioning methods for the outdoor deployments that are limited by the availability of the satellite coverage. This paper defines the relevant standard mechanisms and algorithms to use the carrier phase cellular-based measurements as a potential solution to achieve a high-precision positioning estimation accuracy in 5G-advanced NR networks. The presented positioning technique is evaluated using high-fidelity system-level simulations for indoor factory (InF) deployment scenarios. The numerical results demonstrate that the presented technique can significantly improve the positioning accuracy compared with the state-of-the-art NR positioning methods. Our findings in this paper also show that the carrier phase method not only provides an indoor complement to the outdoor satellite positioning but also provides an outdoor alternative to the high-precision satellite methods.

eess.SP↗

arXiv2016

A Desired PAR-Achieving Precoder Design for Multi-User MIMO OFDM based on Concentration of Measure

For multi-user multiple-input and multiple-output (MIMO) wireless communications in orthogonal frequency di- vision multiplexing systems, we propose a MIMO precoding scheme providing a desired peak-to-average power ratio (PAR) at the minimum cost that is defined as received SNR degradation. By taking advantage of the concentration of measure, we formulate a convex problem with constraint on the desired PAR. Consequently, the proposed scheme almost exactly achieves the desired PAR on average, and asymptotically attains the desired PAR at the 0.001 point of its complementary cumulative distribution function, as the number of subcarriers increases.

cs.IT↗