References & Further Reading

References

  1. H. Q. Ngo, A. Ashikhmin, H. Yang, E. G. Larsson, and T. L. Marzetta, Cell-Free Massive MIMO Versus Small Cells, 2017

    The foundational paper on cell-free massive MIMO. Derives the UatF SINR bound with conjugate beamforming and shows that cell-free outperforms small cells in fairness (95%-likely rate). The full cell-free formulation analyzed here is the starting point for Chapter 12.

  2. E. Bjornson and L. Sanguinetti, Scalable Cell-Free Massive MIMO Systems, 2020

    Introduces the formal definition of scalable cell-free massive MIMO and the user-centric clustering framework. Derives achievable rates under bounded per-AP load and proposes the LLSF clustering algorithm. The primary technical reference for Sections 12.1–12.2 and 12.4.

  3. O. T. Demir, E. Bjornson, O. Y. Bursalioglu, and G. Caire, Fog Massive MIMO: A User-Centric Seamless Hot-Spot Architecture, 2019

    The CommIT contribution establishing the Fog Massive MIMO architecture. Introduces the master AP concept, derives the achievable rates with user-centric clustering and distributed power control, and demonstrates seamless coverage through simulation. The primary reference for Section 12.3.

  4. S. Buzzi and C. D'Andrea, Cell-Free Massive MIMO: User-Centric Approach, 2017

    One of the first papers to propose the user-centric approach to cell-free massive MIMO. Shows that serving each user with a subset of nearby APs provides most of the performance of full cell-free at much lower cost.

  5. G. Interdonato, E. Bjornson, H. Q. Ngo, P. Frenger, and E. G. Larsson, Ubiquitous Cell-Free Massive MIMO Communications, 2019

    Comprehensive overview of cell-free massive MIMO including pilot assignment strategies, power control, and practical deployment considerations. Bridges the gap between theoretical analysis and practical 5G implementation.

  6. E. Bjornson and L. Sanguinetti, Making Cell-Free Massive MIMO Competitive with MMSE Processing and Centralized Implementation, 2020

    Shows that MMSE processing (instead of MRC) can significantly improve cell-free performance. Analyzes centralized and distributed MMSE and their fronthaul requirements — a natural extension of the MRC analysis in this chapter.

  7. O. T. Demir, E. Bjornson, and L. Sanguinetti, Foundations of User-Centric Cell-Free Massive MIMO, 2021

    A comprehensive monograph covering the full theory of user-centric cell-free massive MIMO. Chapters 3–5 extend the analysis presented here to MMSE processing, downlink precoding, and multi-antenna APs.

  8. E. Nayebi, A. Ashikhmin, T. L. Marzetta, H. Yang, and B. D. Rao, Precoding and Power Optimization in Cell-Free Massive MIMO Systems, 2017

    Develops precoding strategies for cell-free massive MIMO downlink and optimizes power allocation for max-min fairness — the power control framework used in the Fog MIMO analysis.

  9. Z. Chen and E. Bjornson, Channel Hardening and Favorable Propagation in Cell-Free Massive MIMO with Stochastic Geometry, 2018

    Rigorous analysis of channel hardening and favorable propagation in cell-free networks using stochastic geometry. Shows that these properties hold under random AP placement — important for validating the UatF bound used throughout this chapter.

  10. H. A. Ammar, R. Adve, S. Shahbazpanahi, G. Boudreau, and K. V. Srinivas, Downlink Resource Allocation in Multiuser Cell-Free MIMO Networks with User-Centric Clustering, 2022

    Addresses downlink resource allocation in user-centric cell-free, including joint power control and cluster optimization. Extends the uplink analysis to the downlink scenario.

Further Reading

For readers who want to go deeper into specific topics from this chapter.

  • Comprehensive treatment of user-centric cell-free massive MIMO

    Demir, Bjornson, and Sanguinetti, *Foundations of User-Centric Cell-Free Massive MIMO*, 2021

    The definitive monograph covering the full theory. Chapters 3–5 extend the MRC analysis in this chapter to MMSE processing, downlink precoding, and multi-antenna APs. Essential reading for anyone working on cell-free research.

  • Scalable distributed processing algorithms

    Bjornson and Sanguinetti, 'Scalable Cell-Free Massive MIMO Systems,' IEEE Trans. Commun., 2020

    The primary technical reference for the scalability framework in Sections 12.1–12.2. Contains detailed proofs and simulation results not reproduced in this chapter.

  • O-RAN and cell-free implementation

    O-RAN Alliance Technical Reports, especially WG1 (Use Cases) and WG4 (Fronthaul)

    Provides the practical framework for implementing Fog Massive MIMO within the O-RAN architecture. The 7.2x functional split maps directly onto the AP/master-AP hierarchy described in Section 12.3.

  • Graph coloring and pilot assignment

    Bjornson et al., 'Cell-Free Massive MIMO,' in *Massive MIMO Networks*, Cambridge University Press, 2024

    Chapter 7 provides a more detailed treatment of the graph-coloring-based pilot assignment framework, including extensions to weighted coloring and fractional coloring.

  • Stochastic geometry analysis of cell-free networks

    Chen and Bjornson, 'Channel Hardening and Favorable Propagation in Cell-Free Massive MIMO,' IEEE Trans. Commun., 2018

    Uses stochastic geometry to rigorously justify the UatF bound under random AP placement — validates the core analytical framework used throughout this chapter.

ExercisesCh 13 →