Hard- and soft-output trellis-based conflict resolution for bidirectional decision feedback equalization

Wong, Chan Wong; Shea, John M.; Lee, Yumin

doi:10.1109/twc.2009.081064

Cited by 5 publications

(3 citation statements)

References 19 publications

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“…The work in [23] introduces an arbitration mechanism with filtering to exploit the error distributions at the outputs of the normal and time-reversed DFEs. Later, the bidirectional structure is applied in trellis-based delayed decision feedback soft-output turbo equalizers [20], [21] which combines the soft symbols of the two DFEs in each iteration and feeds the combined symbols to the decoder. More recently, a low-complexity soft-input soft-output bidirectional DFE (Bi-DFE) [22] combines extrinsic information instead of soft symbols of the two DFEs.…”

Section: Introductionmentioning

confidence: 99%

Bidirectional Soft-Decision Feedback Turbo Equalization for MIMO Systems

Duan

Zheng

2016

IEEE Trans. Veh. Technol.

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This paper proposes a bidirectional soft-decision feedback Turbo equalizer (Bi-SDFE) for severe triply-selective fading channels. The proposed Bi-SDFE uses a time-reversed soft-decision feedback equalizer (SDFE) in conjunction with a normal SDFE to harvest time-reverse diversity and mitigate error propagation. A simple and effective linear combining scheme is derived for combining the extrinsic information of the two SDFEs for multiple-input multiple-output (MIMO) systems with both Binary Phase Shift Keying (BPSK) and multilevel modulation. The Bit-Error-Rate (BER) simulation results show that the proposed Bi-SDFE exhibits a lower Signal-to-Noise-Ratio (SNR) threshold than the original SDFE and outperforms the well-known Exact Turbo Minimum Mean Square Error (MMSE) Linear Equalizers at medium-to-high SNRs. Moreover, both Extrinsic Information Transfer (EXIT) chart analysis and BER simulation results show that the Bi-SDFE achieves better performance than the original SDFE while the Bi-SDFE uses only half the number of iterations of the SDFE. Therefore, the total computational complexity of the Bi-SDFE is similar to that of the original SDFE, which is a linear function of the channel length, MIMO size, and modulation constellation size. The performance gain of the proposed Bi-SDFE is also verified through an underwater acoustic communication experiment with tough channel conditions.Index Terms-Bidirectional soft-decision feedback equalizer (Bi-SDFE), turbo equalization, multiple-input multiple-output (MIMO), underwater acoustic communication.

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Section: Introductionmentioning

confidence: 99%

Bidirectional Soft-Decision Feedback Turbo Equalization for MIMO Systems

Duan

Zheng

2016

IEEE Trans. Veh. Technol.

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“…Then, the two outputs are compared, and if the decoded bits are different for the two streams (i.e., conflicting decisions), the more likely bit is chosen comparing the corresponding Euclidean metrics. In [6], an improved receiver structure is proposed by trellis-based conflict resolution. Time reversal is also used in the context of antenna arrays [7], multiple-input multiple-output systems [8], and space-time block coding [9].…”

Section: Introductionmentioning

confidence: 99%

“…The techniques proposed in [4,5] and [6] do not consider matched filtering. Therefore, precursor ISI cancellation is not considered.…”

Section: Introductionmentioning

confidence: 99%

Precursor inter-symbol interference removal by block transmission-based time-reversed equalization

Forouzan

Moonen

Timmers³

et al. 2013

EURASIP J. Adv. Signal Process.

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Single-carrier transmission is considered in the general finite impulse response inter-symbol interference (ISI) channel. In an ISI channel with a matched filter, the folded spectrum of the received pulse can be factored into a minimum phase causal part and a maximum phase anticausal part corresponding to the postcursor and precursor ISI, respectively. In this paper, zero-forcing ISI cancellation is considered. In a direct implementation, the precursor equalization is carried out based on truncating and delaying the ideal anticausal precursor equalizer impulse response. In the proposed scheme, a block transmission is adopted, and the precursor equalization is carried out by a time reversal within each block and using a practical minimum phase filter. We show that the ISI can be removed perfectly using the proposed scheme. By means of a numerical example, it is shown that the proposed scheme achieves improved performance compared to the truncate-and delay-based equalizer in terms of transmission rate, delay, and implementation complexity.

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Message Feedback Interference Cancellation Aided UAMP Iterative Detector for OTFS Systems

Li,

Wang,

et al. 2024

IEEE Wireless Commun. Lett.

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Hard- and soft-output trellis-based conflict resolution for bidirectional decision feedback equalization

Cited by 5 publications

References 19 publications

Bidirectional Soft-Decision Feedback Turbo Equalization for MIMO Systems

Bidirectional Soft-Decision Feedback Turbo Equalization for MIMO Systems

Precursor inter-symbol interference removal by block transmission-based time-reversed equalization

Message Feedback Interference Cancellation Aided UAMP Iterative Detector for OTFS Systems

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