OTFS: A New Modulation Scheme for High-Mobility Use Cases

Ramachandran, M.; Surabhi, G. D.; Chockalingam, A.

doi:10.1007/s41745-020-00167-4

Cited by 44 publications

(27 citation statements)

References 31 publications

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“…Prominently, almost all of the existing treatises employ a DD-domain guard for pilot placement, which leads to a reduction of the resultant bandwidth efficiency. Most of the DD-domain CSI estimation techniques consider either an ideal-biorthogonal [2], [10] signalling pulse or an approximate model for the practical rectangular pulse that relies on the relationship developed in [4]. The above-mentioned impediments motivate us to develop a novel DD-domain sparse CSI estimation scheme for OTFS systems that can overcome the shortcomings of the approaches presented in the open literature.…”

Section: A Literature Reviewmentioning

confidence: 99%

“…Let h(τ, ν) denote the DD-domain representation of the wireless channel, which is a 2D function of the delay variable τ and Doppler variable ν. Since typically, only a few dominant reflectors are exhibited by a wireless channel, the DD-domain channel can be formulated as [1], [4], [10]…”

Section: B Dd-domain Wireless Channel Modelmentioning

confidence: 99%

“…Considering these K snapshots of the DD-domain CSI h k well within the geometric-coherence time [10], for which their support-set, i.e., the L p -indices of the non-zero locations of the sparse DD-domain CSI h k , do not change, the resultant CSI matrix H exhibits simultaneous-sparsity, since its columns h k share an identical sparsity profile. As described in our technical report [18], one can readily derive an efficient MMV-BL (M-BL) framework, which exploits the multiple pilot outputs and the simultaneous-sparse nature of the CSI matrix H, yielding a superior estimation performance.…”

Section: A Multiple Measurement Vector (Mmv)-extensionmentioning

confidence: 99%

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Bayesian Learning Aided Sparse Channel Estimation for Orthogonal Time Frequency Space Modulated Systems

Srivastava

Singh

Jagannatham

et al. 2021

IEEE Trans. Veh. Technol.

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A novel sparse channel state information (CSI) estimation scheme is proposed for orthogonal time frequency space (OTFS) modulated systems, in which the pilots are directly transmitted over the time-frequency (TF)-domain grid for estimating the delay-Doppler (DD)-domain CSI. The proposed CSI estimation model leads to a reduction in the pilot overhead as well as the training duration required. Furthermore, it does not require a DD-domain guard interval between the pilot and data symbols, hence increasing the bandwidth efficiency. A novel Bayesian learning (BL) framework is proposed for CSI acquisition, which exploits the DD-domain sparsity for improving the estimation accuracy in comparison to the conventional minimum mean squared error (MMSE)-based scheme. A lowcomplexity linear MMSE detector is used in the subsequent data detection phase. Our simulation results demonstrate the performance improvement of the proposed BL-based scheme over the conventional MMSE-based scheme as well as over other existing sparse estimation schemes. Index Terms-OTFS, delay-Doppler domain channel, sparsity, channel estimation, BCRLB, high-mobility I. INTRODUCTIONGiven the continuously evolving diverse range of applications, it is of paramount importance to explore novel modulation techniques that are resilient to both the delay-spread and to the Doppler-shifts introduced by the wireless propagation medium. To this end, a novel delay-Doppler (DD)-domain modulation technique, originally proposed by R. , termed as the orthogonal time frequency space (OTFS) arrangement, deserves further exploration in highmobility scenarios. An important aspect of OTFS modulation is that it relies on the DD-domain representation of the wireless

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Section: A Literature Reviewmentioning

confidence: 99%

Section: B Dd-domain Wireless Channel Modelmentioning

confidence: 99%

Section: A Multiple Measurement Vector (Mmv)-extensionmentioning

confidence: 99%

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Bayesian Learning Aided Sparse Channel Estimation for Orthogonal Time Frequency Space Modulated Systems

Srivastava

Singh

Jagannatham

et al. 2021

IEEE Trans. Veh. Technol.

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“…To demodulate the interference affected signal, receiver designs have been proposed in the literature which include linear equalizers [15], [16] and non-linear equalizers [17]- [20]. The works [18] and [19] describes a belief propagation receiver for OTFS. In [17] Markov chain Monte Carlo sampling based on the low-complexity OTFS signal detection scheme is presented.…”

Section: Introductionmentioning

confidence: 99%

Time Domain Channel Estimation and Equalization of CP-OTFS Under Multiple Fractional Dopplers and Residual Synchronization Errors

et al. 2021

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“…To demodulate the interference affected signal, the works [16] and [17] describes a belief propagation receiver for OTFS. In [18] Markov chain Monte Carlo sampling based on the lowcomplexity OTFS signal detection scheme is presented.…”

Section: Introductionmentioning

confidence: 99%

Estimation and Equalization of residual synchronization errors in CP-OTFS

Tiwari¹,

Rangamgari²,

Das³

et al. 2020

Preprint

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In this work, we analyze the effect of residual frame timing offset and carrier frequency offset along with the presence of fractional Doppler on the bit error rate performance of OFTS system. We show in this work that channel equalization with appropriate channel estimates can compensate for the combined effect of the time-varying multipath channel (TVMC) as well as residual synchronization errors. We<br>also present a unique time-domain channel estimation method for OTFS, which can be used along with the above-mentioned channel equalization. It is seen from the extensive Monte Carlo simulation results of the LDPC coded OTFS system that the estimation and compensation methods presented here provide necessary resilience properties to OTFS against the effects of TVMC channel and residual<br><div>synchronization errors. A unified signal processing flow for OTFS and OFDM is also described in this work to motivate studies on coexistence between the two as well as to encourage investigations on a seamless transition from OFDM based system to OTFS based systems for future air interface design.</div><div><br></div><div><b>This Work is submiited to an IEEE Journal for possible future publication.</b><br></div>

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OTFS: A New Modulation Scheme for High-Mobility Use Cases

Cited by 44 publications

References 31 publications

Bayesian Learning Aided Sparse Channel Estimation for Orthogonal Time Frequency Space Modulated Systems

Bayesian Learning Aided Sparse Channel Estimation for Orthogonal Time Frequency Space Modulated Systems

Time Domain Channel Estimation and Equalization of CP-OTFS Under Multiple Fractional Dopplers and Residual Synchronization Errors

Estimation and Equalization of residual synchronization errors in CP-OTFS

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