Sparse Superimposed Pilot Based Channel Estimation in OTFS Systems

Jesbin, F and Rao Mattu, S and Chockalingam, A (2023) Sparse Superimposed Pilot Based Channel Estimation in OTFS Systems. In: 2023 IEEE Wireless Communications and Networking Conference, WCNC 2023, 26 March - 29 March 2023, Glasgow.

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Abstract

Traditional orthogonal time frequency space (OTFS) channel estimation schemes dedicate an entire frame or a part of the frame for accommodating pilot and guard symbols to avoid pilot-data interference, which compromises spectral efficiency. This spectral efficiency loss can be avoided using superimposed pilots, where delay-Doppler (DD) bins in the OTFS frame carries both data and pilot symbols. In this paper, we propose a sparse superimposed pilot scheme for channel estimation, where all the DD bins in a frame carry data symbols and pilot symbols are superimposed over some of them, sparsely. The proposed scheme does not suffer spectral efficiency loss due to pilot/guard symbols. It also has the advantage of more localized pilot-data interference profile that leads to better performance. We derive the minimum mean square error (MMSE) channel estimator for the proposed scheme. We obtain optimum number of pilot symbols per frame and power distribution among data and pilot symbols through simulations. Simulation results show that the proposed scheme achieves better performance at a lesser complexity compared to existing superimposed pilot scheme. An iterative scheme that further improves performance is also proposed.

Item Type:	Conference Poster
Publication:	IEEE Wireless Communications and Networking Conference, WCNC
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Channel estimation; Frequency estimation; Mean square error, Data symbols; Delay-dopple channel estimation; Doppler channels; Minimum mean square error estimate; Orthogonal time frequency space modulation; Pilot arrangement; Pilot symbols; Spectral efficiencies; Superimposed pilots; Time-frequency space, Spectrum efficiency
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	15 Jun 2023 09:49
Last Modified:	15 Jun 2023 09:49
URI:	https://eprints.iisc.ac.in/id/eprint/82049

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