A Simple Two-Stage Equalizer for OTFS With Rectangular Windows

Jin, Chenxi; Bie, Zhisong; Lin, Xuehong; Xu, Wenjun; Gao, Hui

doi:10.1109/lcomm.2020.3043841

Cited by 24 publications

(9 citation statements)

References 8 publications

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“…where a, b ∈ {1, 2, ..., M }. Moreover, h(a, a−b) denotes the corresponding doubly dispersive channel impluse at a-th time interval with delay a − b, where L represents the maximum delay spread of the channel [26], [27]. Similar to (17), the received signal rn j of the j-th receive antenna can be given by…”

Section: Proposed Gsm-otfsmentioning

confidence: 99%

Generalized Approximate Message Passing Detector for GSM-OTFS Systems

et al. 2022

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Orthogonal Time Frequency Space (OTFS) as a two-dimensional modulation scheme designed in the delay-Doppler domain, is realized by inverse Symplectic Finite Fourier Transform (ISFFT) and Symplectic Finite Fourier Transform (SFFT) operation, for combating the high Doppler channels toward future wireless communications. Meanwhile, generalized spatial modulation (GSM) offers an efficient implementation for multi-input multi-output (MIMO) systems, by activating only part of the transmit antennas to alleviate inter-channel interference (ICI). In this paper, the combination of the above two concepts is exploited, for bridging their unique advantages. On the other hand, an iterative detector based on generalized approximate message passing (GAMP) is also developed for GSM-OTFS. Simulation results demonstrate that the proposed GAMP detector can achieve better performance than the conventional minimum mean square error (MMSE) detector.INDEX TERMS Generalized spatial modulation, orthogonal time frequency space, generalized approximate message passing.

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Section: Proposed Gsm-otfsmentioning

confidence: 99%

Generalized Approximate Message Passing Detector for GSM-OTFS Systems

et al. 2022

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“…According to the way of inserting CP, there are two versions of OTFS. Letting N denote the number of slots occupied by an OTFS symbol and calling N slots as a frame, the first version is to insert one CP per frame which is also known as the reduced-CP OTFS, for example, [11][12][13]; the second version is to insert one CP per slot which is also known as the full-CP OTFS, for example, [14][15][16]. These two versions have their own advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

Partial and statistical CSI based precoding for reduced‐CP OTFS with inter‐slot‐interference pre‐cancellation

Zhang

Wang

2022

IET Communications

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This work studies the precoding methods for the reduced cycle-prefix (CP) orthogonal time frequency space (OTFS) modulation to simplify the receiver design. First, a system model is established which shows that there are both intra-slot-interference and inter-slotinterference in the reduced-CP OTFS system. Then, the precoding operation is proposed to pre-cancel the inter-slot-interference in the reduced-CP OTFS system so that the bit error rate (BER) performance can be greatly improved. According to how much channel state information (CSI) needs to be fed back, precoding methods for two different cases are proposed: the partial CSI feedback case and the partial and statistical CSI feedback case. Among them, the partial and statistical CSI based precoding method has very small feedback burden. Simulation results of the BER performance of the proposed precoding methods for reduced-CP OTFS are reported and compared under different system parameters.

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“…Finally, OTFS modulation was 38 studied using Zak transform principles in [20] and [21] and 39 summarized in [22]. 40 On the other hand, OTFS detection has attracted a lot 41 research attention and many solutions have been proposed 42 such as zero-forcing (ZF) detection, minimum mean square 43 error (MMSE) detection, decision feedback equalization 44 (DFE), message passing algorithm (MPA), and other lin-45 ear/nonlinear equalization methods (see [1], [3], [4], [22], 46 [23], [24], [25], [26], [27], [28], [29] and references therein). 47 More recently, variants of MPA were proposed to improve 48 performance over standard MPA or partially reduce com-49 plexity.…”

Section: Introductionmentioning

confidence: 99%

General I/O Relations and Low-Complexity Universal MRC Detection for All OTFS Variants

2022

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Orthogonal time frequency space (OTFS) is a recently proposed modulation scheme which multiplexes information symbols in the delay-Doppler domain to combat severe Doppler shifts in high mobility wireless communications. In this paper, we classify all the OTFS variants depending on whether a cyclic prefix (CP) or zero padding (ZP) is added to each block or to the entire frame. We then present the general input-output relations for integer and fractional delays and Doppler shifts. Further, we present a low-complexity universal maximum ratio combining (MRC) detector for all OTFS variants, which has the lowest complexity among other known OTFS detection schemes at no loss of performance. Finally, we derive the input-output relation for overspread channels, where the channel delay spreads can exceed the OTFS block duration. Simulation results demonstrate that the MRC detection offers same performance for all OTFS variants and can also be effectively used for overspread channels. 11 12 157 III. TIME-DOMAIN INPUT-OUTPUT RELATION 224 In this section, we present the time-domain input-output 225 relation in matrix form for RZP-OTFS and RCP-OTFS, 226 where RZP/RCP-OTFS appends/prepends a ZP/CP of length 227 L ≥ l max to an OTFS frame, as shown in Fig. 2 (a). 228 Both integer and fractional delays and Doppler shifts are 229 considered. Further, we present the general forms of channel 230 matrix G, valid for integer and fractional delays and Doppler 231 shifts. For simplicity, we do not include CP (or ZP) in the 232 derivation. Also, we omit noise term in the rest of the paper. 233 The time domain input-output relation in matrix form is 234 given as 235 r = G • s, (20) 236 where the time-domain channel matrix G ∈ C NM ×NM has 237 mostly zero entries except the diagonal entries 1238239 for all q and the l-th subdiagonal entries) 241 where b = NM − 1. 242 Next, we study the structure of matrix G for RZP-OTFS 243 and RCP-OTFS for integer and fractional delay and Doppler 244 shifts.

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A Simple Two-Stage Equalizer for OTFS With Rectangular Windows

Cited by 24 publications

References 8 publications

Generalized Approximate Message Passing Detector for GSM-OTFS Systems

Generalized Approximate Message Passing Detector for GSM-OTFS Systems

Partial and statistical CSI based precoding for reduced‐CP OTFS with inter‐slot‐interference pre‐cancellation

General I/O Relations and Low-Complexity Universal MRC Detection for All OTFS Variants

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