Embedded Pilot-Aided Channel Estimation for OTFS in Delay–Doppler Channels

By Patchava Raviteja, Khoa Tran Phan, Yi Hong. IEEE Transactions on Vehicular Technology, 2018

843 citations recorded by the source corpus.

Orthogonal time frequency space (OTFS) modulation was shown to provide significant error performance advantages over orthogonal frequency division multiplexing (OFDM) in delay–Doppler channels. In order to detect OTFS modulated data, the channel impulse response needs to be known at the receiver. In this paper, we propose embedded pilot-aided channel estimation schemes for OTFS. In each OTFS frame, we arrange pilot, guard, and data symbols in the delay–Doppler plane to suitably avoid interference between pilot and data symbols at the receiver. We develop such symbol arrangements for OTFS over multipath channels with integer and fractional Doppler shifts, respectively. At the receiver, channel estimation is performed based on a threshold method and the estimated channel information is used for data detection via a message passing algorithm. Thanks to our specific embedded symbol arrangements, both channel estimation and data detection are performed within the same OTFS frame with minimum overhead. We compare through simulations the error performance of OTFS using the proposed channel estimation and OTFS with ideally known channel information and observe only a marginal performance loss. We also demonstrate that the proposed channel estimation in OTFS significantly outperforms OFDM with known channel information. Finally, we present extensions of the proposed schemes to multiple-input multiple-output (MIMO) and multi-user uplink/downlink.

Subfields: Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/9eabd61cbfda9cff6dd02522cb47bfa4aabee156

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Citations in the corpus

Off-grid Channel Estimation with Sparse Bayesian Learning for OTFS Systems (2021, methodology): “Moreover, we can observe that our proposed schemes may incur a higher computational complexity than the conventional single pilot impulse-based CE approach [6] when the delay and Doppler spreads of channels are large.”
Channel Estimation for Orthogonal Time Frequency Space (OTFS) Massive MIMO (2019, methodology): “The impulse-based scheme is extended to OTFS MIMO systems by transmitting several impulses with proper guard between two adjacent impulses to distinguish different BS antennas [36], [38].”
Orthogonal Time-Frequency Space Modulation: A Promising Next-Generation Waveform (2021, methodology): “At the receiver side, a cascaded combination of multi-carrier demodulation and 2D orthogonal decoding transforms the received signal back into the DD domain and retrieves the transmitted symbols in the DD domain using an appropriate channel estimator [11] and equalizer [12].”
Integrated Sensing and Communication-Assisted Orthogonal Time Frequency Space Transmission for Vehicular Networks (2021, methodology): “The NMSE performances for channel estimation scheme [31] with and without guard space are plotted as reference.”
Low Complexity Iterative Rake Decision Feedback Equalizer for Zero-Padded OTFS Systems (2020, methodology): “Moreover, in OTFS, the ZP can be used as guard band for the pilot in the delay-Doppler domain [10], and hence reduction in detector complexity can be achieved at little cost, which is convenient for the ZP-OTFS system.”
On the Effectiveness of OTFS for Joint Radar Parameter Estimation and Communication (2020, background): “An efﬁcient pilot-aided CSI acquisition is a problem of independent interest that we postpone to future work (see also [26], [27], [44]).”
A Primer on Rate-Splitting Multiple Access: Tutorial, Myths, and Frequently Asked Questions (2022, background): “The DD domain symbol multiplexing enables a direct coupling of the transmitted symbols with the channel’s delay-Doppler spread function, which has nice properties, such as quasi-static, compact, and sparse, to be exploited to achieve a low channel estimation overhead and full channel diversity with ”