Author Q&A with Sassan Ahmadi: 5G NR: Architecture, Technology, Implementation, and operation of 3GPP New Radio Standards.

By: , Posted on: July 26, 2019

We take 5 minutes to with Sassan Ahmadi the author of recently published 5G NR: Architecture, Technology, Implementation, and operation of 3GPP New Radio Standards to talk about the new book and where he sees the industry evolving in the next 5 years.


1 – As with your previous books, your new book on 5G NR takes a system approach. Can you describe how you take this approach and what benefits it provides the reader?

I took a systems approach for my previously-published book, LTE-Advanced, which was born out of the idea of giving the reader in-depth insight into each system function/protocol/procedure/feature while helping the reader understand how the individual elements fit into the system as whole and operate within that framework. Encouraged by very positive feedback and reviews for the previous books, I have taken the same approach for my new book on 5G NR. From my perspective, a systems approach is a structured and systematic way of describing the theory and operation of a complex system comprising many interconnected logical/physical entities and functions, which is very suitable for system analysis and design. It starts with studying the high-level architecture, network entities and interfaces, interaction/inter-operation among network elements, etc. and then continues with detailed examination of each functional entity and its physical realization and characterization. The organization of the book content is also based on such top-down approach.

As an example, the book starts with high-level description of the 5G core and access networks and then each network is further broken down into individual elements and each element is analyzed at functional and protocol levels. The functions and protocols are further scrutinized at algorithm and operation levels. At each stage, the theoretical and practical issues are described and discussed.

2 – You are unique in giving detailed information on the RAN protocol layers, transport, network architecture and services. What kind of information do you provide on these?

The book provides detailed theoretical and practical information that is required for in-depth understanding, design and implementation of access and core network protocols, transport systems, services, and entities in software and hardware.

As an example, the disaggregated base station model is first discussed at network architecture level before it is broken down into components and interfaces. Then each functional entity and protocol as well as interface including the fronthaul and backhaul interfaces are examined, and theoretical and practical information and example implementations are provided.


3 – For someone looking for information on implementation and deployment issues, what types of information can the reader gain from this book?

The information includes practical insights, design techniques and limitations, certain implementation and deployment considerations in the choice of hardware components or in the selection of system parameters, etc.

In my current position, I have contributed to, advised, architected and overseen various 5G commercial system designs and implementations by prominent network equipment vendors and operators, which have helped me to learn and reflect my learnings in this book. Those include several techniques for realization of disaggregated base station hardware and software which are captured in meticulous detail in chapters 1 to 5.

Furthermore, some of the key features and procedures are compared with their counterparts in 3GPP LTE systems to help the readers familiar with the legacy systems to quickly learn 3GPP NR improvements/features.

4- How do you see 5G evolving in the next 5 years?

The official 5G standardization process is still ongoing in 3GPP and ITU-R, expected to be concluded by  mid-2020. Nevertheless, prominent vendors and network operators have already started design, implementation and deployment of the Rel-15 features. This trend will grow and continue in the next 5 years when the 5G systems will gain more footprint and maturity. We should be expecting more new service offerings, more advanced services, more deployments, etc. in the next few years.

5- To what extent do you cover Rel-15? Do you cover the features added as part of Rel-16?

The 3GPP NR Rel-15 is completely covered in detail and some of the important features of Rel-16 such as V2X, NR-U, URLLC, 2-step RACH, IAB, MR-DC as well as the physical layer enhancements are covered up to and including April 2019 meetings of 3GPP. While it is hard to predict the final functional and design details of Rel-16 features, I have made my best effort to provide insights into their development path and underlined the practical considerations for feature development and deployment.


About the book

  • Provides a strong focus on practical considerations, implementation and deployment issues
  • Takes a top-down approach to explain system operation and functional interconnection
  • Covers all functional components, features, and interfaces based on clear protocol structure and block diagrams
  • Describes RF and transceiver design considerations in sub-6 GHz and mmWave bands
  • Covers network slicing, SDN/NFV/MEC networks and cloud and virtualized RAN architectures

The book is available now on ScienceDirect. Want your own copy? Order via the Elsevier store and enter code STC319 at the checkout to save up to 30%

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