Research

Research Interest

Integrated Wireless Communications

• AI/ML Algorithms for Physical Layer

• Massive MIMO Systems

• Interference Management Techniques for Smart Small-Cell Networks

• Ultra-Reliable and Low-Latency Communications in Wireless Networks

• Full-Duplex Radios

• New Radio Waveform

• New Radio Multiple Access

• Hybrid Beamforming in mm-Wave Systems

• 3D Ray-Tracing-based Performance Evaluation

• Channel Models

AI/ML Algorithms for Physical Layer

Samsung's Delegate in charge of 3GPP RAN1 Rel-18 AI/ML Standardization from 2021

Published in IEEE Wireless Communications 2020

Published in IEEE Access 2020

Presented at IEEE Globecom 2020

3D Ray-Tracing based Wireless Communication SW Platforms

Produced two digital maps for 3D ray-tracing tool (WiSE): Veritas C in Yonsei University/GangNam Station

Exhibited at World It Show (WIS): Creative ICT Forum Convergence Korea 2017/Smart ICT PyeongChang Olympic 2018

SWPOSTER_final.pdf

Performance Analysis of Massive MIMO Systems

Published in IEEE Transactions on Wireless Communications 2015 (One of the top 5% IEEE TWC papers cited in 2017)

Presented at IEEE ICC 2014/IEEE Globecom 2016

As a core technology of 5G, to maximize spectral efficiency and to conserve energy, researchers have proposed massive MIMO systems. They considered simple linear precoders and filters, including the zero-forcing (ZF) and maximum ratio transmission/combining (MRT/MRC) techniques, to mitigate the interference that arise from large-scale MIMO transmission. Compressive sensing techniques could be applied to reduce channel estimation overhead. Next generation communication systems will need integrated technologies of massive MIMO and full duplex to boost data rate efficiently.

Power Normalization (ZF)

User Cross Point

Compressed Channel Feedback

Uplink Performance with Full Duplex

New Waveform for New Radio

Published in IEEE Wireless Communications 2018

Presented at EuCNC 2017

Waveform Multiplexing

In recent years, researchers have both clarified 5G communication requirements and discussed its potential applications, including servicing the Internet of Things (IoT), gigabit wireless connectivity, and the Tactile Internet, as well as the various requirements of massive machine-type communication (mMTC), enhanced mobile broadband (eMBB), and ultra-reliable low-latency communication (URLLC). 3GPP has discussed numerology multiplexing, which operates on a single frequency band to support the integrated devices or the central controllers of applications with different requirements. It has not yet been determined which waveform will be used for numerology multiplexing systems and how such systems can be designed. To establish these systems, researchers must evaluate them using new radio waveform candidates.

Channel Models for 5G

Reproduced Conventional Channel Models (e.g., 3GPP Channel Model in TR 38.901)

Published in IEEE Wireless Communications Letters 2018

Published in IEEE Wireless Communications 2020

Dual-Polarized MIMO Channel Model

A good solution for installing a compact antenna array could involve a collocated dual-polarization antenna system. One dual-polarization antenna could then play, equivalently, the roles of two dipole/patch-type antennas as long as there is high cross-polarization discrimination (XPD). It remains an open question as to how much XPD is needed to sustain MIMO performance at reasonable cost and level of complexity.

Millimeter Wave Channel Model

5G new applications and services will be launched in the millimeter-wave (mm-Wave) range due to a shortage of bandwidth in the sub-6 GHz bands, which legacy radio communication systems have made tremendous use of because of the excellent radio propagation property. Mm-Wave channel models have been thoroughly investigated through extensive measurements and simulations and accurate models are vital for the design of mm-Wave communication systems.

Millimeter Wave Technologies

Hybrid Beamforming Systems
Lens Embedded MIMO Systems

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