Understanding MMIO-Based Device Register Access
How a Linux device driver maps register offsets through MMIO, the MMU, and the system interconnect for on-chip and PCIe devices.
Junseok Kim
Interests
- Cellular Protocols3GPP 5G NR/LTE Standards
- Embedded SystemsHW/SW Co-Design, Multi-Threaded Execution
- Modem PerformanceThroughput, Power, Latency, CPU Profiling
- Next-Gen WirelessAI-Native RAN, Open-RAN
Understanding the Linux Kernel Driver Structure
How Linux kernel drivers connect user-space software to hardware through system calls, MMIO, DMA, and interrupts.
NR Power Headroom Report (3/3): How a gNB Scheduler Uses PHR
How a gNB uses PHR to estimate RB feasibility, separate power limits from link quality, and choose RB × MCS candidates.
NR Power Headroom Report (2/3): What Does PHR Tell the gNB?
How NR calculates power headroom, distinguishes Type 1, Type 2, and Type 3 PH, and reports real or reference transmissions through a PHR MAC CE.
NR Power Headroom Report (1/3): Understanding Uplink Power Control
How a UE turns an uplink grant into PUSCH transmit power—and what changes when it reaches its power limit.
Sionna Setup Guide: WSL2, Ubuntu 24.04, and CUDA 13.0
A practical setup guide for running NVIDIA Sionna PHY / SYS / RT on Windows through WSL2. This guide includes notes from an actual installation, including RTX 50-series compatibility warnings and l...
Welcome
This is Junseok Kim’s personal website for publications, technical notes, and recent updates.