Invited Speakers

Invited Talk #1: Bridging the Gap Between Specification and Reality: Cellular Modem Development and Global Field Testing

Chaehag Yi
Seoul National University, Seoul Korea

Abstract: As wireless communications evolve from 5G-Advanced toward 6G, the cellular modem remains one of the most sophisticated components in modern communication systems. Its primary challenge is to bridge the gap between 3GPP specifications and the unpredictable behavior of real-world wireless environments. This invited talk provides a comprehensive overview of the modem development lifecycle, from algorithm design and silicon implementation to global field testing and future 6G architectures. The presentation examines the pre-silicon and post-silicon development processes. It introduces the hardware/software co-design of baseband SoCs, together with real-time processor clusters that execute L2/L3 protocol stacks. It also discusses the use of link-level simulators and FPGA-based emulation platforms. The post-silicon phase focuses on silicon bring-up, functional verification, and the transition from laboratory debugging to initial over-the-air calibration. Although conformance testing and channel emulation using commercial test systems are essential for validating compliance with 3GPP standards, they cannot fully reproduce the stochastic behavior of operational mobile networks. Modern field testing which includes drive testing, walk testing, and carrier acceptance testing remains indispensable for commercial deployment. Representative field challenges are also introduced to illustrate why real-world validation remains irreplaceable. We discuss the future evolution of modem engineering for the 6G era. Emerging technologies such as AI-native air interfaces, sub-THz communications, and Non-Terrestrial Networks (NTN) will require a fundamental shift from conventional modem architectures toward AI-assisted adaptive systems. By contrasting deterministic laboratory validation with the complexities of real-world deployment, this presentation provides practical insights into the engineering principles required to design, verify, and optimize next-generation cellular modems.

Biography: Chaehag Yi received the B.S., M.S., and Ph.D. degrees in Electronics Engineering from Seoul National University, Korea, in 1989, 1991, and 1996, respectively. He began his career at ETRI, working on CDMA technology, and later co-founded EoNex, where he developed WCDMA and LTE solutions. During his tenure at Samsung Electronics’ System LSI Business, he served as a Vice President, leading the development of smartphone modem chipsets across WCDMA, LTE, and 5G technologies. He joined the Ministry of Science and ICT (MSIT), Korea, where he was in charge of national R&D planning and management in future communications and radio technologies. He is currently a Visiting Professor in the Department of Next-generation Semiconductor Convergence at Seoul National University, teaching semiconductor systems and AI hardware design. His research interests include wireless communications, cellular modem architectures, semiconductor systems and AI hardware design.