Description
Mastery on L2-PDCP – 3GPP Rel-18 is a deep-dive, specification-aligned, and example-driven e-book designed to help telecom professionals gain complete command over the PDCP (Packet Data Convergence Protocol) layer in 5G NR, as defined in 3GPP TS 38.323 (Release 18).
This e-book goes beyond high-level theory and explains how PDCP actually works in live 5G networks, covering user plane and control plane processing, security, header compression, sequence numbering, reordering, duplication, routing, and handover scenarios with clear flows and numerical examples.
🔍 What This E-Book Covers
✅ PDCP Functionalities in 5G (TS 38.323 §4.4)
A clear explanation of all PDCP responsibilities including data transfer, SN maintenance, ROHC, ciphering, integrity protection, discard mechanisms, routing, duplication, and reordering—each explained with practical VoLTE, VoNR, eMBB, and URLLC examples (Pages 4–14).
✅ PDCP Functional View (TS 38.323 §4.2.2)
Step-by-step transmit and receive side PDCP processing, showing where compression, ciphering, integrity, duplication, and reordering occur, supported by a functional block diagram (Page 16).
✅ PDCP Services (TS 38.323 §4.3.1 / §4.3.2)
Detailed coverage of:
Services provided to RRC and SDAP
Services expected from RLC, SRAP, and N3C
PDCP SDU and Control PDU size limits
(Pages 18–19)
✅ ROHC – Robust Header Compression (TS 38.323 §5.7)
In-depth explanation of ROHC profiles and modes:
U-mode, O-mode, and R-mode
High-level flows with IR, SO, IR-DYN, ACK/NACK
Use-case mapping for VoNR, eMBB, and URLLC
ROHC decompression order during receive processing
(Pages 20–28)
✅ Ciphering & Deciphering (TS 38.323 §5.8)
A complete numerical example covering:
COUNT calculation
Key usage (KUPenc / KRRCenc)
Keystream generation
XOR-based ciphering and deciphering
Difference between LTE and 5G (MAC-I ciphering)
(Pages 29–34)
✅ Integrity Protection & Verification (TS 38.323 §5.9)
Explains:
What is protected and where integrity applies
MAC-I generation and verification
COUNT formula with HFN and PDCP SN
Detailed step-by-step integrity calculation example
Failure and attack detection scenarios
DAPS bearer integrity handling
(Pages 35–43)
✅ PDCP Data & Control PDU Structure (TS 38.323 §6.2)
Covers:
PDCP Data PDU formats for SRB and DRB
PDCP Control PDUs (Status Report, ROHC feedback)
FMC, bitmap, and PDU type fields
(Pages 44–46)
✅ PDCP Structure Parameters (TS 38.323 §6.3)
Detailed explanation of:
PDCP SN length (12 / 18 bits)
COUNT composition
MAC-I presence rules
SDU types and ROHC applicability
(Pages 47–51)
🎯 Who Should Read This Book
5G L2 / PDCP / Protocol Engineers
5G Test, Validation & Interop Engineers
R&D and System Engineers
Telecom Trainers & Advanced Learners
Professionals preparing for 5G protocol interviews
⭐ Why This E-Book Stands Out
✅ Strictly aligned with 3GPP TS 38.323 Rel-18
✅ Explains why, how, and where PDCP functions operate
✅ Includes real numerical examples & protocol flows
✅ Covers VoNR, eMBB, URLLC, Dual Connectivity & DAPS
✅ Ideal for log analysis, troubleshooting, and interviews
Internal Links
External Links
Abhishek Kumar –
This e-book gives an excellent breakdown of the PDCP layer. The explanations of ROHC, ciphering, and integrity protection with numerical examples made TS 38.323 very easy to understand.
Shreya Banerjee –
A very practical and well-structured guide. The PDCP transmit and receive flow diagrams helped me clearly understand how packets are processed in real 5G networks.
Nitin Sharma –
This book bridges the gap between specification and implementation. The detailed explanation of COUNT calculation, MAC-I generation, and integrity verification is extremely useful for protocol engineers.
Kavya Rao –
Excellent coverage of ROHC modes and PDCP security. The VoNR and URLLC examples helped me relate PDCP behavior to real-world services and log analysis.
Sandeep Verma –
A must-read for anyone working on 5G L2 protocols. The explanation of PDCP reordering, duplication, routing, and DAPS bearers is very clear and aligned with Rel-18 behavior.
Mehul Patel –
Very informative and industry-oriented content. This e-book helped me gain confidence in PDCP-related interview questions and real-time troubleshooting scenarios.
Nikhil Raj –
This book explains PDCP concepts with excellent clarity. Ciphering, deciphering, COUNT calculation, and HFN handling are explained step-by-step with numerical examples, which made PDCP much easier to understand.
Swati Deshpande –
The explanation of ROHC modes (U-mode, O-mode, R-mode) and context handling is outstanding. The way packet loss and context refresh are explained helped me understand real network behavior.
Kunal Mehra –
This is one of the best resources available for PDCP layer learning. Security procedures, integrity protection, and interaction with RLC are clearly mapped to 3GPP Rel-18 specifications.
Ayesha Khan –
The numerical examples for COUNT = (HFN << SN length) + SN and ciphering flow diagrams are extremely helpful. This book is perfect for both interview preparation and protocol log analysis.
Ramesh Iyer –
A very practical and well-structured e-book. PDCP retransmission triggers, duplication handling, and split bearer concepts are explained in a simple yet standards-compliant way.