References & Further Reading

References

1. 3GPP, NR; Physical channels and modulation (TS 38.211), 2023. [Link]

   The normative specification of the NR physical layer: frame structure, slot format, reference signals (SSB, CSI-RS, SRS, DMRS, PT-RS), and modulation. Clauses 4 (frame structure), 6.4 (uplink reference signals including SRS), and 7.4 (downlink reference signals including CSI-RS and SSB) are the primary sources for Sections 22.1-22.4.

2. 3GPP, NR; Multiplexing and channel coding (TS 38.212), 2023. [Link]

   Defines the UCI (uplink control information) formats that carry CSI reports from the UE to the gNB, including the Type I and Type II PMI field encoding. The codebook payload numbers in Section 22.3 come from Clause 6.3.

3. 3GPP, NR; Physical layer procedures for control (TS 38.213), 2023. [Link]

   Specifies the PDCCH-related procedures: beam management (Clause 6), beam failure recovery (Clause 6), and the timing and measurement rules for SS burst sets. Primary reference for Section 22.4.

4. 3GPP, NR; Physical layer procedures for data (TS 38.214), 2023. [Link]

   Specifies the CSI reporting framework (Clause 5.2), codebook configuration for Type I/II/eType II (Clause 5.2.2.2), and the multi-TRP operation procedures (Clause 5.1.6A). Primary reference for Sections 22.3 and 22.5.

5. 3GPP, NR; Base Station (BS) radio transmission and reception (TS 38.104), 2023

   Defines FR1 and FR2 band plans (Clause 5.2), EIRP limits, and base-station conformance requirements. Source for the FR1/FR2 classification in Section 22.1 and the practical deployment constraints in Section 22.6.

6. E. Dahlman, S. Parkvall, J. Skold, 5G NR: The Next Generation Wireless Access Technology, Academic Press (Elsevier), 2nd edition, 2020

   The industry-standard textbook on 5G NR by three of the key Ericsson contributors to the standard. Chapters 6-7 (frame structure and numerology), 11 (multi-antenna transmission), and 12 (beam management) are the most relevant to this chapter. Written from a system-design perspective, it fills in the narrative around the 3GPP TS documents.

7. X. Lin et al. (Qualcomm), 5G New Radio: Unveiling the Essentials of the Next Generation Wireless Access Technology, 2019

   A concise overview by the Qualcomm standardization team, covering numerology, reference signals, MIMO, and beam management. Especially useful for the CSI-RS / SRS design rationale and the P1/P2/P3 procedure description. Primary secondary reference for Sections 22.2-22.4.

8. X. Lin et al., An Overview of 5G Advanced Evolution in 3GPP Release 18, 2022

   The Release 18 (5G Advanced) overview, including eType II enhancements, Rel-18 multi-TRP CJT study, and AI/ML CSI feedback. Source for the eType II and ML-codebook discussion in Section 22.3 and the CJT Rel-18 study mention in Section 22.5.

9. M. Giordani, M. Polese, A. Roy, D. Castor, M. Zorzi, A Tutorial on Beam Management for 3GPP NR at mmWave Frequencies, 2019

   A thorough tutorial on NR beam management at mmWave, covering the P1/P2/P3 procedures, beam correspondence, beam failure recovery, and measurement design. The primary external reference for Section 22.4 beyond the 3GPP TS.

10. E. Björnson, J. Hoydis, L. Sanguinetti, Massive MIMO Networks: Spectral, Energy, and Hardware Efficiency, 2017

    The definitive monograph on massive MIMO theory. Chapter 3 (channel estimation) is the source of the TDD pilot-budget analysis of Section 22.1; Chapter 4 (UatF bound) is the basis of the field-trial gap analysis of Section 22.6. Every section of this chapter cross-references it.

11. T. L. Marzetta, E. G. Larsson, H. Yang, H. Q. Ngo, Fundamentals of Massive MIMO, Cambridge University Press, 2016

    The book-length treatment by the original massive MIMO team, emphasizing TDD reciprocity and the pilot-contamination problem. Chapter 4 on TDD reciprocity is the primary source for the SRS-reciprocity argument of Section 22.2.

12. H. Asplund, D. Astely, P. von Butovitsch, T. Chapman, M. Frenne, F. Ghasemzadeh, M. Hagstrom, B. Hogan, G. Jongren, J. Karlsson, F. Kronestedt, E. Larsson, E. Sjoland, Advanced Antenna Systems for 5G Network Deployments: Bridging the Gap Between Theory and Practice, Academic Press (Elsevier), 2022

    Field-trial results from Ericsson's 5G AAS deployments across multiple continents. Chapter 9 reports measured SE and coverage numbers for 64T64R AAUs. The primary source for the field-trial numbers in Section 22.6 and the practical-theoretical gap decomposition.

13. P. Wang, Y. Li, L. Song, B. Vucetic, Multi-Gigabit Millimeter Wave Wireless Communications for 5G: From Fixed Access to Cellular Networks, 2020

    Commercial mmWave deployment review covering 2019-2020 Chinese and Korean 64T64R deployments at 3.5 GHz and initial 28 GHz trials. Primary reference for the 2019 commercial-launch historical note and the measured cell SE values in Section 22.6.

14. H. Q. Ngo, G. Caire, E. Björnson, E. G. Larsson, Ultra-Dense Cell-Free Massive MIMO for 6G: Technical Overview and System Perspectives, 2024

    CommIT contribution: positions cell-free massive MIMO as the asymptotic limit of multi-TRP cooperation and argues that each Rel-16 through Rel-18 NR feature is a partial step toward the cell-free architecture. Source for the commit_contribution block in Section 22.5.

15. G. Caire, S. Shamai, H. Q. Ngo, Massive MIMO: A Retrospective at the Commercial Deployment Horizon, 2022

    CommIT contribution: retrospective identifying the three dominant sources of the practical-theoretical gap (pilot contamination residual, scheduler heterogeneity, CSI ageing) and arguing that cell-free architectures are the logical remedy. Source for the commit_contribution block in Section 22.6.

16. A. Adhikary, J. Nam, J.-Y. Ahn, G. Caire, Joint Spatial Division and Multiplexing — The Large-Scale Array Regime, 2013

    The CommIT JSDM paper referenced in Section 22.3 as a structurally different approach to FDD massive MIMO. The Rel-15 Type II codebook design borrows the "linear combination of DFT beams" idea that JSDM introduced five years earlier as a statistics-aware precoder.

17. R. Rogalin, O. Y. Bursalioglu, H. C. Papadopoulos, G. Caire, A. F. Molisch, A. Michaloliakos, V. Balan, K. Psounis, Scalable Synchronization and Reciprocity Calibration for Distributed Multiuser MIMO, 2014

    CommIT contribution on TDD reciprocity calibration. Primary reference for the engineering note on RF calibration in Section 22.2. The paper develops a distributed calibration algorithm that commercial BS equipment later adopted in simplified form.

18. 3GPP, Study on channel model for frequencies from 0.5 to 100 GHz (TR 38.901), 2022

    The 3GPP channel model for sub-6 GHz through FR2. Defines the spatial channel model (SCM) and the geometry-based stochastic model used in system-level simulations. Reference for the path-loss and beam-coherence parameters in Section 22.4.

19. R. Irmer, H. Droste, P. Marsch, M. Grieger, G. Fettweis, S. Brueck, H.-P. Mayer, L. Thiele, V. Jungnickel, Coordinated Multipoint: Concepts, Performance, and Field Trial Results, 2011

    The canonical CoMP paper that precedes 5G NR multi-TRP. Primary source for the historical note on CoMP-to-multi-TRP evolution in Section 22.5 and for the low-SNR CJT advantage argument.

20. E. Björnson, L. Sanguinetti, Making Cell-Free Massive MIMO Competitive with MMSE Processing and Centralized Implementation, 2019

    Source for the CJT-vs-NCJT rate analysis in Section 22.5 and the multi-TRP coordination-quality argument. The paper frames CJT as cell-free in miniature.

21. V. Va, T. Shimizu, G. Bansal, R. W. Heath Jr., Millimeter Wave Vehicular Communications: A Survey, 2016

    Survey on mmWave vehicular channels and beam tracking at high mobility. Reference for the beam-tracking engineering note in Section 22.4.

Further Reading

• Full 5G NR PHY textbook treatment

  E. Dahlman, S. Parkvall, J. Skold, *5G NR: The Next Generation Wireless Access Technology*, 2nd ed., Academic Press, 2020

  The most complete textbook treatment of 5G NR from a system-design perspective. Its chapters 6, 7, 11, and 12 expand nearly every section of this chapter with additional protocol detail, signaling procedures, and deployment context that go beyond what is needed for the massive MIMO perspective taken here.

• Massive MIMO theory as taught by Björnson-Hoydis-Sanguinetti

  E. Björnson, J. Hoydis, L. Sanguinetti, *Massive MIMO Networks: Spectral, Energy, and Hardware Efficiency*, Now Publishers, 2017

  The theoretical foundation that 5G NR MIMO is built on. Section 22.6 cites its UatF bound as the clean-theory reference; readers who want to understand exactly why commercial deployments fall short should study its chapter 4 in depth.

• Beam management at mmWave

  M. Giordani et al., 'A Tutorial on Beam Management for 3GPP NR at mmWave Frequencies,' IEEE Commun. Surveys & Tutorials, 2019

  The most accessible external treatment of NR beam management, with simulation results calibrated against the 3GPP TR 38.901 channel model. Complements Section 22.4 with quantitative latency and coverage analyses.

• Field-trial measurement methodology

  H. Asplund et al., *Advanced Antenna Systems for 5G Network Deployments*, Academic Press, 2022

  Ericsson's field-trial book documents the measurement methodology and interpretation framework used to benchmark commercial massive MIMO deployments. Essential reading for anyone designing 6G studies, since the bar for new architectures is set by these measurements.

• AI/ML for CSI feedback and prediction

  J. Guo, C.-K. Wen, S. Jin, G. Y. Li, 'Overview of Deep Learning-Based CSI Feedback in Massive MIMO Systems,' IEEE Trans. Commun., 2022

  Survey of ML-based CSI compression and prediction techniques being considered for Rel-19 and 6G. The Rel-18 CSI study item cites many of the methods in this paper; read it before Chapter 25 for context on how AI/ML fits into the NR CSI framework.

• Cell-free massive MIMO as a 6G framework

  H. Q. Ngo, G. Caire, E. Björnson, E. G. Larsson, 'Ultra-Dense Cell-Free Massive MIMO for 6G,' IEEE Commun. Mag. (invited overview), 2024

  The CommIT-led argument for cell-free architectures as the 6G successor to NR multi-TRP. Connects Section 22.5 of this chapter to Chapters 11-15 of the book and is the cleanest articulation of how the 5G NR gap can be closed.