OTFS Channel Estimation and Detection for Channels with Very Large Delay Spread
Abstract: In low latency applications and in general, for overspread channels, channel delay spread is a large percentage of the transmission frame duration. In this paper, we consider OTFS in an overspread channel exhibiting a delay spread that exceeds the block duration in a frame, where traditional channel estimation (CE) fails. We propose a two-stage CE method based on a delay-Doppler (DD) training frame, consisting of a dual chirp converted from time domain and a higher power pilot. The first stage employs a DD domain embedded pilot CE to estimate the aliased delays (due to modulo operation) and Doppler shifts, followed by identifying all the underspread paths not coinciding with any overspread path. The second stage utilizes time domain dual chirp correlation to estimate the actual delays and Doppler shifts of the remaining paths. This stage also resolves ambiguity in estimating delays and Doppler shifts for paths sharing same aliased delay. Furthermore, we present a modified low-complexity maximum ratio combining (MRC) detection algorithm for OTFS in overspread channels. Finally, we evaluate performance of OTFS using the proposed CE and the modified MRC detection in terms of normalized mean square error (NMSE) and bit error rate (BER).
- R. Hadani et al., “Orthogonal Time Frequency Space Modulation,” in Proc. IEEE Wireless Commun. Net. Conf., San Francisco, CA, USA, 2017, pp. 1–6.
- P. Raviteja, K. T. Phan, Y. Hong, and E. Viterbo, “Embedded Delay-Doppler Channel Estimation for Orthogonal Time Frequency Space Modulation,” in Proc. IEEE 88th Veh. Tech. Conf., Chicago, IL, USA, 2018, pp. 1–5.
- P. Raviteja, K. T. Phan, and Y. Hong, “Embedded Pilot-Aided Channel Estimation for OTFS in Delay–Doppler Channels,” IEEE Trans. Veh. Tech., vol. 68, no. 5, pp. 4906–4917, 2019.
- W. Shen, L. Dai, J. An, P. Fan, and R. W. Heath, “Channel Estimation for Orthogonal Time Frequency Space (OTFS) Massive MIMO,” IEEE Trans. Sig. Proc., vol. 67, no. 16, pp. 4204–4217, 2019.
- O. K. Rasheed, G. D. Surabhi, and A. Chockalingam, “Sparse Delay-Doppler Channel Estimation in Rapidly Time-Varying Channels for Multiuser OTFS on the Uplink,” in Proc. IEEE 91st Veh. Tech. Conf., Antwerp, Belgium, 2020, pp. 1–5.
- P. Raviteja, K. Phan, Y. Hong, and E. Viterbo, “Orthogonal Time Frequency Space (OTFS) Modulation Based Radar System,” in 2019 IEEE Radar Conference (RadarConf), Boston, MA, USA, 2019, pp. 1–6.
- Y. Liu, S. Zhang, F. Gao, J. Ma, and X. Wang, “Uplink-Aided High Mobility Downlink Channel Estimation Over Massive MIMO-OTFS System,” IEEE Journal Sel. Areas Commun., vol. 38, no. 9, pp. 1994–2009, 2020.
- L. Zhao, W.-J. Gao, and W. Guo, “Sparse Bayesian Learning of Delay-Doppler Channel for OTFS System,” IEEE Commun. Lett., vol. 24, no. 12, pp. 2766–2769, 2020.
- D. Shi, W. Wang, L. You, X. Song, Y. Hong, X. Gao, and G. Fettweis, “Deterministic Pilot Design and Channel Estimation for Downlink Massive MIMO-OTFS Systems in Presence of the Fractional Doppler,” IEEE Trans. Wireless Commun., vol. 20, no. 11, pp. 7151–7165, 2021.
- S. Srivastava, R. K. Singh, A. K. Jagannatham, and L. Hanzo, “Bayesian Learning Aided Sparse Channel Estimation for Orthogonal Time Frequency Space Modulated Systems,” IEEE Trans. Veh. Tech., vol. 70, no. 8, pp. 8343–8348, 2021.
- S. R. Mattu and A. Chockalingam, “Learning based Delay-Doppler Channel Estimation with Interleaved Pilots in OTFS,” in 2022 IEEE 96th Vehicular Technology Conference (VTC2022-Fall), 2022, pp. 1–6.
- A. Naikoti and A. Chockalingam, “Signal detection and channel estimation in OTFS,” ZTE Communications, vol. 19, no. 4, pp. 16–33, 2021.
- H. B. Mishra, P. Singh, A. K. Prasad, and R. Budhiraja, “OTFS Channel Estimation and Data Detection Designs With Superimposed Pilots,” IEEE Trans Wireless Commun., vol. 21, no. 4, pp. 2258–2274, 2022.
- F. Jesbin, S. Rao Mattu, and A. Chockalingam, “Sparse Superimposed Pilot Based Channel Estimation in OTFS Systems,” in 2023 IEEE Wireless Communications and Networking Conference (WCNC), 2023, pp. 1–6.
- T. Thaj, E. Viterbo, and Y. Hong, “Orthogonal Time Sequency Multiplexing Modulation: Analysis and Low-Complexity Receiver Design,” IEEE Transactions on Wireless Communications, vol. 20, no. 12, pp. 7842–7855, 2021.
- A. Thomas, K. Deka, P. Raviteja, and S. Sharma, “Convolutional Sparse Coding Based Channel Estimation for OTFS-SCMA in Uplink,” IEEE Transactions on Communications, vol. 70, no. 8, pp. 5241–5257, 2022.
- L. Li, H. Wei, Y. Huang, Y. Yao, W. Ling, G. Chen, P. Li, and Y. Cai, “ simple two-stage equalizer with simplified orthogonal time frequency space modulation over rapidly time-varying channels,” in available in arXiv, 2017.
- T. Zemen, M. Hofer, and D. Loeschenbrand, “Low-complexity equalization for orthogonal time and frequency signaling (OTFS),” in available in arXiv, 2017.
- P. Raviteja, K. T. Phan, Y. Hong, and E. Viterbo, “Interference Cancellation and Iterative Detection for Orthogonal Time Frequency Space Modulation,” IEEE Trans. Wireless Commun., vol. 17, no. 10, pp. 6501–6515, 2018.
- S. Tiwari, S. Das, and V. Rangamgar, “Low complexity LMMSE receiver for OTFS,” IEEE Commun. Lett., vol. 23, no. 12, p. 2205–2209, 2019.
- G. D. Surabhi and A. Chockalingam, “Low-Complexity Linear Equalization for OTFS Modulation,” IEEE Commun. Lett., vol. 24, no. 2, pp. 330–334, 2020.
- B. C. Pandey, S. K. Mohammed, P. Raviteja, Y. Hong, and E. Viterbo, “Low Complexity Precoding and Detection in Multi-User Massive MIMO OTFS Downlink,” IEEE Trans. Veh. Tech., vol. 70, no. 5, pp. 4389–4405, 2021.
- T. Zou, W. Xu, H. Gao, Z. Bie, Z. Feng, and Z. Ding, “Low-complexity linear equalization for OTFS systems with rectangular waveforms,” in Proc. IEEE Int. Conf. Commun. Workshops (ICC Workshops), Montreal, QC, Canada, 2021, pp. 1–6.
- Y. Ge, Q. Deng, P. C. Ching, and Z. Ding, “Receiver Design for OTFS with a Fractionally Spaced Sampling Approach,” IEEE Trans. Wireless Commun., vol. 20, no. 7, pp. 4072–4086, 2021.
- L. Xiang, Y. Liu, L.-L. Yang, and L. Hanzo, “Gaussian Approximate Message Passing Detection of Orthogonal Time Frequency Space Modulation,” IEEE Trans. Veh. Tech., vol. 70, no. 10, pp. 10 999–11 004, 2021.
- Y. Zhang, Q. Zhang, L. Zhang, C. He, and X. Tian, “A Low-Complexity Approximate Message Passing Equalizer for OTFS system,” in Proc. IEEE/CIC Int. Conf. Commun. China, Xiamen, China, 2021, pp. 449–454.
- H. Li, Y. Dong, C. Gong, Z. Zhang, X. Wang, and X. Dai, “Low Complexity Receiver via Expectation Propagation for OTFS Modulation,” IEEE Commun. Lett., vol. 25, no. 10, pp. 3180–3184, 2021.
- Z. Yuan, F. Liu, W. Yuan, Q. Guo, Z. Wang, and J. Yuan, “Iterative Detection for Orthogonal Time Frequency Space Modulation With Unitary Approximate Message Passing,” IEEE Trans. on Wireless Commun., vol. 21, no. 2, pp. 714–725, 2022.
- T. Thaj and E. Viterbo, “Low Complexity Iterative Rake Detector for Orthogonal Time Frequency Space Modulation,” in Proc. IEEE Wireless Commun. Networking Conf., Seoul, Korea (South), 2020, pp. 1–6.
- ——, “Low Complexity Iterative Rake Decision Feedback Equalizer for Zero-Padded OTFS Systems,” IEEE Trans. Veh. Tech., vol. 69, no. 12, pp. 15 606–15 622, 2020.
- T. Thaj, E. Viterbo, and Y. Hong, “General I/O Relations and Low-Complexity Universal MRC Detection for All OTFS Variants,” IEEE Access, vol. 10, pp. 96 026–96 037, 2022.
- P. Priya, E. Viterbo, and Y. Hong, “Low Complexity MRC Detection for OTFS Receiver with Oversampling,” IEEE Transactions on Wireless Communications, pp. 1–1, 2023.
- A. Naikoti and A. Chockalingam, “Low-complexity Delay-Doppler Symbol DNN for OTFS Signal Detection,” in Proc. IEEE 93rd Veh. Tech. Conf., Helsinki, Finland, 2021, pp. 1–6.
- Y. K. Enku, B. Bai, F. Wan, C. Guyo, I. N. Tiba, C. Zhang, and S. Li, “Two-dimensional convolutional neural network-based signal detection for OTFS systems,” IEEE Wireless Commun. Lett., vol. 10, no. 11, p. 2514–2518, 2021.
- Z. Zhou, L. J. Liu, J. Xu, and R. Calderbank, “Learning to Equalize OTFS,” IEEE Transactions on Wireless Communications, vol. 21, no. 9, pp. 7723 – 7736, 2022.
- Z. Zhang, L. Heng, W. Qianli, and P. Fan, “A Survey on Low Complexity Detectors for OTFS SystemsDetectors for OTFS Systems,” ZTE Communications, vol. 4, no. 19, pp. 3–15, 2021.
- X. Geng, Z. Liu, and H. Wu, “Timing synchronization based on Radon–Wigner transform of chirp signals for OTFS systems,” Physical Communication, p. 102161, 2023.
- S. K. Mohammed, “Time-domain to delay-doppler domain conversion of otfs signals in very high mobility scenarios,” IEEE Transactions on Vehicular Technology, vol. 70, no. 6, pp. 6178–6183, 2021.
- “LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Base Station (BS) radio transmission and reception,” 3GPP TS 36.104 version 14.3.0 Release 14, 2017.
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