Orthogonally Precoded Massive MIMO for High Mobility Scenarios

Zemen, Thomas; Löschenbrand, David; Hofer, Markus; Pacher, Christoph; Rainer, Benjamin

doi:10.1109/access.2019.2941316

Cited by 15 publications

(26 citation statements)

References 24 publications

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“…More recently, we have proposed a sparse WH waveform in [10], where we have shown that the equal-gain is achieved with sparse spreading, which can be implemented with lower complexity. In summary, our results in [4], [5], [10] and the analysis of [8], [9] are complementary approaches that lead to the same conclusion: data symbols should experience the same channel gain to maximize performance. In this paper, we denote this condition as equal gain criterion (EGC).…”

Section: Introductionmentioning

confidence: 67%

“…where the matrixH(n ini , N UW ) ∈ C NUW×NUW is defined in (9) in the bottom of next page, and is a quasi-circulant 1 channel matrix due to CP insertion. The quantity n ini represents the initial channel sample and T = N UW in ( 9) is due to the UW length.…”

Section: Receiver Structurementioning

confidence: 99%

“…A novel modulation scheme called orthogonal time frequency space (OTFS) has been proposed in [6], where the data symbols are modulated in the delay-Doppler domain [7]. Also, the works [8], [9] have investigated waveforms with equal-gain and iterative equalization. In particular, it has been shown that Walsh-Hadamard (WH) waveform spreads overall time and frequency resources, ultimately achieving the same performance as OTFS.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Robust Baseband Transceiver Design for Doubly-Dispersive Channels

Bomfin

Chafii

Nimr

et al. 2021

IEEE Trans. Wireless Commun.

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In this paper, we investigate three different concepts for robust link-level performance under doubly-dispersive wireless channels, namely, i) channel estimation, ii) cyclic prefix (CP)free transmission, and iii) waveform design. We employ a unique word-based channel estimation, where we decouple the channel related errors into channel estimation error (CEE) and Doppler error (DE). Then, we show that a trade-off between CEE and DE emerges in the frame design, where the system can be optimized to achieve the minimum composite channel error. Another strategy to improve the link-level performance is to suppress the CP of the sub-blocks. This allows for better channel estimation due to the reduced transmission time, with the penalty of requiring the CP-restoration processing at the receiver. Furthermore, we propose the waveform design based on the equal-reliability criterion (ERC), leading to the block multiplexing-orthogonal chirp division multiplexing (BM-OCDM). This waveform is advantageous in the CP-free transmission mode, where the data symbols have equally distributed interference from adjacent sub-blocks. Our framework is a generalization of the recently proposed orthogonal time frequency space (OTFS), which fails to achieve the ERC. The link-level simulations show that at high modulation and coding scheme, the proposed BM-OCDM provides superior link-level performance than OTFS.

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Section: Introductionmentioning

confidence: 67%

Section: Receiver Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Robust Baseband Transceiver Design for Doubly-Dispersive Channels

Bomfin

Chafii

Nimr

et al. 2021

IEEE Trans. Wireless Commun.

View full text Add to dashboard Cite

show abstract

“…Different from those contributions, our work is interested in the impact of aged CSIT on the massive-MIMO-enabled URSST. Unlike the work in [19], [20] which consider deterministic time-varying channel models for the aged CSIT, our investigation is mainly based on the first-order Markov model of the aged CSIT, which is more appropriate for wireless environments that are rich in scattering. It is perhaps worth noting that MIMO (or massive-MIMO) beamforming with aged CSIT has already received intensive investigation for throughput-oriented systems and for the average performance (e.g., [21]- [23]), while our work targets on the reliability for every single shot.…”

Section: Introductionmentioning

confidence: 99%

Massive-MIMO MF Beamforming with or without Grouped STBC for Ultra-Reliable Single-Shot Transmission Using Aged CSIT

Wang,

Ma,

et al. 2021

Preprint

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The technology of using massive transmit-antennas to enable ultra-reliable single-shot transmission (URSST) is challenged by the transmitter-side channel knowledge (i.e., CSIT) imperfection. When the imperfectness mainly comes from the channel time-variation, the outage probability of the matchedfilter (MF) transmitter beamforming is investigated based on the first-order Markov model of the aged CSIT. With a fixed transmit-power, the transmitter-side uncertainty of the instantaneous signal-to-noise ratio (iSNR) is mathematically characterized. In order to guarantee the outage probability for every single shot, a transmit-power adaptation approach is proposed to satisfy a pessimistic iSNR requirement, which is predicted using the Chernoff lower bound of the beamforming gain. Our numerical results demonstrate a remarkable transmit-power efficiency when comparing with power control approaches using other lower bounds. In addition, a combinatorial approach of the MF beamforming and grouped space-time block code (G-STBC) is proposed to further mitigate the detrimental impact of the CSIT uncertainty. It is shown, through both theoretical analysis and computer simulations, that the combinatorial approach can further improve the transmit-power efficiency with a good tradeoff between the outage probability and the latency.

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“…Recently in [15], the authors have proposed a large-antenna array based low-complexity receiver for decoding the downlink OTFS signal transmitted from a single-antenna BS. However, the authors ignore inter-carrier interference (ICI) and intersymbol interference (ISI) as they assume ideal pulse shaping transmit and receiver waveforms which satisfy the biorthogonality condition (see equation (17) in [15]). Such ideal pulses however do not exist.…”

Section: Introductionmentioning

confidence: 99%

Low Complexity Precoding and Detection in Multi-user Massive MIMO OTFS Downlink

Pandey¹,

Mohammed²,

Raviteja³

et al. 2020

Preprint

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We consider the problem of degradation in performance of multi-carrier multi-user massive MIMO systems when channel induced Doppler spread is high. Recently, Orthogonal Time Frequency Space (OTFS) modulation has been shown to be robust to channel induced Doppler spread. In OTFS based systems, information symbols are embedded in the delay-Doppler (DD) domain where they are jointly modulated to generate the time-domain transmit signal. Due to the multi-path delay and Doppler shifts, the DD domain information symbols need to be jointly demodulated at the receiver. For multi-carrier based communication (e.g., Orthogonal Frequency Division Multiplexing (OFDM)), massive MIMO systems have been shown to achieve high spectral and energy efficiency with low complexity multiuser precoding in the downlink. Extending the same to OTFS based downlink multi-user massive MIMO systems is challenging due to the requirement for joint demodulation of all information symbols at the user terminal (UT). In this paper, we solve this problem by proposing a novel OTFS based multi-user precoder at the base station (BS) and a corresponding low complexity detector (LCD) at the user terminals (UTs), which allows for separate demodulation of each DD domain information symbol at the UT. The complexity of the proposed precoder increases only linearly with increasing number BS antennas Q and the number of UTs. We show, through analysis, that as Q increases (with total transmitted power decreased linearly with Q), the proposed low complexity detector achieves a sum spectral efficiency close to that achieved with optimal joint demodulation at each UT. Numerical simulations confirm our analysis and also show that the spectral efficiency and error rate performance of the proposed OTFS based massive MIMO precoder (with the proposed LCD detector at each UT) is significantly more robust to channel induced Doppler spread when compared to OFDM based multiuser massive MIMO systems.

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Orthogonally Precoded Massive MIMO for High Mobility Scenarios

Cited by 15 publications

References 24 publications

A Robust Baseband Transceiver Design for Doubly-Dispersive Channels

A Robust Baseband Transceiver Design for Doubly-Dispersive Channels

Massive-MIMO MF Beamforming with or without Grouped STBC for Ultra-Reliable Single-Shot Transmission Using Aged CSIT

Low Complexity Precoding and Detection in Multi-user Massive MIMO OTFS Downlink

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