27 chapters · 120+ message-accurate diagrams · 3GPP Rel-19

5G NR Protocols, decoded to the bit — for test, dev & optimization engineers

The advanced engineer's guide to the entire NR signalling stack — SDAP, PDCP, RLC, MAC, RRC and NAS, then the interfaces that hold a disaggregated network together: NGAP, F1AP, E1AP and XnAP. Every layer traced message by message, IE by IE, timer by timer — grounded in 3GPP Release 19 and written for the three engineers who live in these protocols.

27chapters · 7 parts
120+colour diagrams
133GPP specs decoded
lifetime access
$6.99$29.99
SDAP PDCP RLC MAC PHY THE ADVANCED ENGINEERING GUIDE 5G NR Protocols decoded to the bit · Rel-19 RRC · NAS · NGAP · F1AP · E1AP · XnAP Abhijeet Kumar CafeTele Engineering Book Series
Message-accurate to 3GPP Release 19 Instant online access Lifetime — one-time payment Free 3-chapter preview
What's inside

Not a survey — a decoder for the whole stack

Every protocol is built from its one job upward: the PDU byte layout, the state machine, the procedures with their timers, and the exact IEs on the wire — then the part most books skip: how to test it, decode it in a live trace, and tune it. Every chapter ends with a summary and interview-grade review questions.

SDAP · PDCP

QoS-flow→DRB mapping (TS 37.324), then PDCP sequencing, ciphering, integrity, ROHC and reordering (38.323) — header layouts and the security maths.

RLC · MAC

TM/UM/AM, segmentation and the AM ARQ state machine (38.322); MAC multiplexing, HARQ, the MAC PDU and subheaders, RACH/BSR/PHR/DRX (38.321).

RRC, end to end

States, the ASN.1 message framework, connection setup/reconfig/re-establishment, system information, paging, measurements, mobility and AS security (38.331).

NAS — 5GMM & 5GSM

Registration and mobility, authentication, ciphering and integrity, and PDU-session management with QoS signalling — all of TS 24.501, decoded.

NGAP · F1AP · E1AP · XnAP

The interfaces that make a split, multi-vendor gNB work — and where most real integration bugs hide. Plus LTE 36.331/413/423 for EN-DC/NSA.

Test · Decode · Optimize

A whole part for engineers: conformance testing, reading PCAP/signalling traces, and the parameter-to-KPI map for tuning latency, throughput and signalling load.

Try before you buy

Read all of Part I — free

Chapters 1–3 are completely free, no signup: the full protocol-stack map, the channel/bearer model, and the skill of reading 3GPP and ASN.1. Open the Kindle-style reader, switch between light, sepia and dark, and judge the depth before you spend $6.99.

A reader that feels like Kindle, reads like a senior protocol engineer

Fixed chapter sidebar, three reading themes, font sizing, reading progress, and 120+ colour diagrams that re-theme with the page and colour-code every layer. Built for long, focused reading — on desktop and mobile.

light · sepia · dark120+ SVG diagramsreview questionsmobile-ready
Open free preview
Table of contents

27 chapters across 7 parts

Plus 5 appendices: an ASN.1 & PER primer, a per-protocol message reference catalog, a timers & constants reference, an IE cross-reference, and a full abbreviations + 3GPP spec map.

PART I

The Protocol Architecture · FREE

  • The 5G NR protocol stack — map of the territory
  • Channels, bearers, QoS flows & the data path
  • Reading 3GPP — releases, ASN.1 & message anatomy
PART II

User-Plane Radio Protocols

  • SDAP — QoS-flow→DRB mapping (37.324)
  • PDCP — sequencing, security, header compression (38.323)
  • RLC — TM/UM/AM, segmentation & ARQ (38.322)
  • MAC — multiplexing, HARQ, the MAC PDU; RACH/BSR/PHR/DRX (38.321)
PART III

Control Plane — RRC

  • RRC states, architecture & message framework (38.331)
  • Connection control — setup, reconfig, re-establishment, release
  • System information & paging
  • Measurements, mobility & handover; AS security & beam mgmt
PART IV

Control Plane — NAS

  • NAS & 5GMM — registration and mobility (24.501)
  • NAS security — authentication, ciphering & integrity
  • 5GSM — PDU session management & QoS signalling
PART V

RAN-Internal & Core Interfaces

  • NGAP — the N2 interface (38.413)
  • F1AP — the CU/DU split (38.473)
  • E1AP — the CU-CP/CU-UP split (38.463)
  • XnAP (38.423) · LTE interworking — EN-DC, S1AP, X2AP
PART VI

End-to-End Procedures

  • Power-on to connected — initial access & registration
  • PDU session establishment — every layer
  • Handover — Xn, N2 & intra-gNB, signalling-complete
PART VII

Test, Development & Optimization

  • Protocol testing & conformance
  • Log & trace analysis — decoding the live stack
  • Implementation & optimization — building and tuning
APPENDICES

Reference

  • ASN.1 & PER primer · message reference catalog
  • Timers & constants · IE cross-reference
  • Abbreviations & 3GPP spec map
Who it's for

Written for the three engineers who live in these protocols

Test & conformance engineersMessage validity, mandatory/optional/conditional IEs, criticality, timers and exact pre/post-conditions of every procedure.
Stack developersPDU byte layouts, state machines, the encode/decode hot path and where the spec leaves implementation freedom to exploit.
Optimization engineersThe parameter-to-KPI map: which knob in which layer moves latency, throughput, BLER, retransmissions and signalling load — and its cost.
RAN & core engineersA message-level model of the disaggregated gNB and the N2/F1/E1/Xn interfaces that connect it.
ArchitectsWhere the layers live across CU-CP/CU-UP/DU/RU, and why the cut between layers is where multi-vendor bugs hide.
Students & interview-prepA structured, accurate model plus review questions written the way design reviews and interviews actually ask them.
Get the book

One book. Lifetime access. ₹599 / $6.99

A one-time payment, instant online access, free updates. Read the free preview first to confirm the depth fits.

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5G NR Protocols — full access

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Questions

Frequently asked

Can I preview it first?

Yes — all of Part I (chapters 1 to 3) is completely free with no signup. Open the reader, try all three themes, and confirm the message-level depth before you buy.

How deep does it actually go?

To the bit. PDU and header byte layouts, ASN.1/IE structures, state machines, procedures with their exact timers, and the reject/ignore/notify criticality of interface IEs — grounded in 3GPP Release 19 (TS 37.324, 38.321/322/323/331, 24.501, 38.413/423/463/473, and 36.331/413/423 for LTE interworking).

How do I read it after I buy?

Instant online access. After payment via Razorpay the full 27-chapter Kindle-style reader unlocks immediately in your browser — chapter sidebar, three themes, font sizing, progress tracking — with lifetime access. No subscription.

₹599 or $6.99 — which do I pay?

₹599 if you pay from India, $6.99 internationally. Pick your currency on the buy panel above. One-time payment, lifetime access and updates.

Do I need deep prior knowledge?

You should be comfortable with basic 5G architecture (gNB, AMF, UPF). Part I then builds the protocol foundations — stack, channels/bearers and how to read 3GPP/ASN.1 — so the layer chapters land. It is an advanced book, but it bootstraps you.

What's the refund policy?

Because it's a digital product with instant access and a free 3-chapter preview, sales are final once unlocked. Please read the free preview first to confirm it fits your needs.

Stop guessing at traces. Read the stack to the bit.

27 chapters, 120+ colour diagrams, a Kindle-style reader and lifetime access — message-accurate to 3GPP Rel-19, for less than a coffee.

Get the book — $6.99 / ₹599