● Advanced · 3GPP TS 38.321 v19.1.0

5G NR MAC Masterclass

The Medium Access Control layer — from the 3GPP specification to real network troubleshooting. Cinematic, scene-by-scene, 100% spec-accurate.
21Modules
882Animated scenes
~3.7hRuntime
v19.1.0Release 19
▶ Start Module 1 — Introduction to MAC

Where MAC lives

MAC sits in the middle of the NR L2 stack — taking SDUs from RLC, mapping logical channels onto transport channels, multiplexing them into transport blocks, and handing them to the physical layer. Everything above it is per-radio-bearer; everything MAC produces is per-transport-channel.

SDAPQoS flow → DRB
PDCPCiphering · ROHC
RLCSegmentation · ARQ
MACMux · HARQ · sched
PHYCoding · modulation

Curriculum

Twenty-one modules, each a ~45-scene cinematic lesson built straight from the spec. Module 1 is live; the rest unlock as they are produced.