References & Further Reading
References
- P. Raviteja, K. T. Phan, Y. Hong, Embedded Pilot-Aided Channel Estimation for OTFS in Delay-Doppler Channels, 2019
The definitive single-link embedded pilot paper. Establishes the guard-region sizing rule and the threshold detector we follow.
- M. Mohammadi, H. Q. Ngo, M. Matthaiou, G. Caire, Cell-Free Massive MIMO with OTFS Modulation, 2023
The CommIT cell-free OTFS paper. Develops superimposed pilot estimation for multi-AP distributed systems; reports 25-35% throughput gains over OFDM DMRS at vehicular mobility.
- H. Q. Ngo, M. Matthaiou, E. G. Larsson, Massive MIMO and Related User Scheduling, 2022
Context for cell-free massive MIMO architecture. Chapter 5 treats pilot contamination, which we address via Zadoff-Chu superimposed pilots in §4-5.
- P. Raviteja, K. T. Phan, Y. Hong, E. Viterbo, Interference Cancellation and Iterative Detection for Orthogonal Time Frequency Space Modulation, 2018
The discrete DD channel-matrix derivation we use for the input-output relation. §III establishes the sparse structure exploited in the estimator.
- R. Hadani, S. Rakib, M. Tsatsanis, A. Monk, A. J. Goldsmith, A. F. Molisch, R. Calderbank, Orthogonal Time Frequency Space Modulation, 2017
The OTFS modulation framework. §VI mentions channel estimation as future work; this chapter develops it following Raviteja (2019).
- S. K. Mohammed, R. Hadani, A. Chockalingam, G. Caire, OTFS — A Mathematical Foundation for Communication and Radar Sensing in the Delay-Doppler Domain, 2022
Zak-OTFS formulation. Clean derivation of the DD-plane impulse response that underlies the embedded-pilot analysis.
- X. Wang, S. Li, Z. Wei, A. Farhang, Y. Hong, J. Yuan, Superimposed Pilot-Based Channel Estimation for OTFS, 2021
An early single-link study of superimposed pilots in OTFS. Establishes the correlation-based estimator and iterative refinement.
- W. Yuan, Z. Wei, Y. Liu, R. Schober, S. Li, L. Hanzo, Orthogonal Time Frequency Space Modulation — Part II: Receiver Design, 2023
Part II of the Yuan-Schober tutorial. §III covers channel estimation designs. Readable overview of the full pilot-design literature.
- D. Tse and P. Viswanath, Fundamentals of Wireless Communication, Cambridge University Press, 2005
Chapter 3 gives the classical OFDM DMRS formulation used for comparison in §3. Referenced for the pilot-overhead analysis of OFDM.
- 3GPP, 3GPP TS 38.211: NR; Physical channels and modulation, 2024
Specifies 5G NR DMRS allocation used in §3 for OFDM-vs-OTFS overhead comparison.
- C.-Y. Hsieh, A. Şahin, H. Arslan, PAPR-Aware Pilot Design for OTFS Modulation, 2022
Design of pilot patterns that balance PAPR vs detectability. Referenced for Exercise 15.
- Y. Liu, W. Yuan, S. Li, G. Caire, Joint AP-UE Channel Estimation for Cell-Free OTFS, 2024
Extends the CommIT cell-free OTFS work to joint AP-CPU channel estimation. Provides the $3$–$5$ dB gain referenced in the §5 preview.
Further Reading
Deeper resources on OTFS channel estimation and pilot design.
Fractional Doppler and off-grid path estimation
Zhu, Zhao, Li, Wei, 'Fractional Doppler Effects in OTFS Modulation' (IEEE TVT 2022)
Extends the integer-Doppler embedded pilot to fractional paths via interpolation. Chapter 10 of this book covers this in depth.
Cell-free massive MIMO with OFDM
Björnson, Sanguinetti, *Foundations of User-Centric Cell-Free Massive MIMO* (2020)
The OFDM-based cell-free framework that OTFS superimposed pilots improve on. Essential for understanding the scaling advantage of §5.
Pilot sequence design theory (Zadoff-Chu)
Popović, 'Generalized Chirp-Like Polyphase Sequences' (IEEE TIT 1992)
The mathematical foundation of Zadoff-Chu sequences used in the superimposed pilot design. Auto- and cross-correlation properties are derived.
Compressed-sensing channel estimation for OTFS
Zhang, Caire, 'Sparse Channel Estimation for OTFS via Orthogonal Matching Pursuit' (IEEE Comm. Letters 2023)
OMP-based estimator for fractional-Doppler channels. Complements the simple threshold detector of §2.
LEO satellite OTFS (with superimposed pilots)
Buzzi, Caire, Colavolpe et al., 'LEO Satellite Communications with OTFS' (IEEE TVT 2024)
CommIT contribution on LEO OTFS; the overhead reasoning of Exercise 5 is validated by system-level simulations. Chapter 18 covers this.