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5G NR · Radio Access Network

The 5G RAN, finally explained the way an engineer needs it.

Most "5G RAN" courses stop at a block diagram and a list of acronyms. This one keeps going — into why the gNodeB was split into CU, DU and RU, what actually rides each interface, and what every protocol layer does to your packet, byte by byte.

Four animated, narrated chapters · a 57-diagram theory book · a 100-question exam. Built straight from the 3GPP 38-series, not from a vendor slide deck.

What makes this one different

I got tired of "5G RAN" material that draws three boxes — CU, DU, RU — slaps interface names on the arrows, and moves on. That tells you the what and none of the why. Why split there and not somewhere else? Why is the fronthaul so brutal that it dictates the whole transport design? What does PDCP actually do to a packet, and why did reordering move out of RLC in NR?

So this course is built backwards from the problems. We start with why the radio is hard — shared, finite, fading, mobile — and let every feature in the stack fall out of one of those. Then we take the gNodeB apart, wire it to the service-based core, and walk the protocol stack down to the bit field. Every claim is tied to the spec that backs it, so you can cite it in a design review the next morning.

It's the course I wish I'd had when I was staring at a NG-AP trace at 2am trying to remember which node terminates N2.

The curriculum

Chapter 1 and the theory book are free — start there. The rest unlocks with enrollment.

Ch 1

What is a Radio Access Network?

FREE

A short, cinematic story to set the stage: the four blocks of a mobile network, why the air is the hard part, cells & handover, and how the base station became the gNodeB.

the radio problemcells & handoverNodeB → gNodeB
Ch 2

Architecture & the gNodeB

🔒 ENROLL

Five lessons on disaggregation: LTE→5G, the CU/DU/RU split and why it lands where it does, functional splits (Option 2 & 7-2x), the fronthaul timing nightmare, and NSA vs SA.

CU/DU/RUOption 2 · 7-2xfronthaulNSA · SA
Ch 3

The Complete Architecture

🔒 ENROLL

Five lessons wiring the radio to the core: NG-RAN and its three directions, the 5G Core network functions, the service-based architecture and the NRF, reference points, and slicing.

AMF · SMF · UPFSBA · NRFN2/N3/N4slicing
Ch 4

The Protocol Stack

🔒 ENROLL

Fourteen lessons, every layer to IE level — SDAP, PDCP (×2), RLC (×2), MAC (×6), RRC (×3): security, ordering, ARQ, the scheduler, HARQ, RACH and DRX. This is the heart of the course.

SDAP · PDCPRLC · ARQMAC · HARQRRC
Book

The Theory Companion — written, illustrated reference

FREE

The book behind the videos: ~9,000 words with 57 hand-drawn blue-and-white diagrams, deep-dive boxes and spec citations. Free to read — it's how I'd want a colleague to learn this.

57 diagramsTS 38.300 seriesdeep dives
Exam

100-Question Mastery Quiz

🔒 ENROLL

A hundred MCQs across all four chapters with instant feedback and explanations — the honest test of whether it stuck. Full, shuffle, quick-20 or per-chapter.

100 questionsexplanationsscored

By the end, you can

Read a real architecturePlace every node and interface — CU-CP/CU-UP, F1, E1, Xn, NG — and say what rides each.
Defend a split choiceExplain why Option 2 and 7-2x won, and what the fronthaul costs you.
Trace a connectionWalk registration and a PDU session through the service-based core, function by function.
Talk the stack fluentlyExplain SDAP's QFI marking, PDCP COUNT & ciphering, RLC ARQ, MAC scheduling and HARQ — at IE level.
Reason about the airNumerology, the frame, SSB & beam management, MU-MIMO and link adaptation.
Cite the specBack what you say with the right TS — 38.321/322/323/331, 37.324, 23.501.

Questions people ask

Is this for me?

If you work near the radio — RF, RAN, integration, a core engineer who wants the RAN side, or a fresher trying to get past memorising acronyms — yes. If you've never seen a cellular network at all, start with Chapter 1 (it's free) and see how it feels.

How much can I see before paying?

Chapter 1 (the full cinematic intro) and the entire theory book are free — no login, no card. That's a real slice of the course, not a trailer. Chapters 2–4 and the exam unlock when you enroll.

What do I actually get?

Lifetime access to all four narrated chapters (25 lessons), the 57-diagram theory book, and the 100-question exam — plus every future update, free. One payment, no subscription.

What if it's not for me?

30-day money-back, no questions. If it didn't teach you something you didn't know, email us and we'll refund it.

Is the content accurate?

It's built from the 3GPP 38-series and 23.501, and every non-obvious claim names the governing TS. Where the spec distinguishes a TR (study) from a TS (normative), so do we.

CT

Made by the CafeTele team. We build telecom courses for working engineers — the kind we wanted ourselves: spec-accurate, visual, and honest about the hard parts. If something here is wrong or unclear, tell us; we fix it and you get the update for free.

5G RAN Masterclass · ₹499 / $4.99 · lifetime access · 30-day money-back  ·  Enroll →  ·  All courses