Bandwidth efficient channel estimation for full duplex communication systems

Koohian, Abbas; Mehrpouyan, Hani; Ahmadian, M.; Azarbad, Mohammad

doi:10.1109/icc.2015.7249067

Cited by 12 publications

(11 citation statements)

References 16 publications

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“…Recently, self-interference cancellation techniques have been developed with great promise [1]- [3]. With these techniques, the self-interference can be canceled by estimating the self-interference channels [4]- [6] in FD mode, or be suppressed with null-space methods in MIMO systems [7]. However, despite these advances, residual self-interference (RSI) still exists after the self-interference cancellation [3], [7]- [9].…”

Section: Introductionmentioning

confidence: 99%

Optimal Training for Residual Self-Interference for Full-Duplex One-Way Relays

Tepedelenlioğlu

Şenol

2018

IEEE Trans. Commun.

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Full-duplex relays, residual self-interference, maximum likelihood estimation, optimal training sequence, Toeplitz matrix, frequency-selective channels, multiple relays AbstractChannel estimation and optimal training sequence design for full-duplex one-way relays are investigated.We propose a training scheme to estimate the residual self-interference (RSI) channel and the channels between nodes simultaneously. A maximum likelihood estimator is implemented with Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. In the presence of RSI, the overall source-to-destination channel becomes an intersymbol-interference (ISI) channel. With the help of estimates of the RSI channel, the destination is able to cancel the ISI through equalization. We derive and analyze the Cramer-Rao bound (CRB) in closed-form by using the asymptotic properties of Toeplitz matrices. The optimal training sequence is obtained by minimizing the CRB. Extensions for the fundamental one-way relay model to the frequency-selective fading channels and the multiple relays case are also considered. For the former, we propose a training scheme to estimate the overall channel, and for the latter the CRB and the optimal number of relays are derived when the distance between the source and the destination is fixed. Simulations using LTE parameters corroborate our theoretical results.Xiaofeng Li and Cihan Tepedelenlioglu are with the

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Section: Introductionmentioning

confidence: 99%

Optimal Training for Residual Self-Interference for Full-Duplex One-Way Relays

Tepedelenlioğlu

Şenol

2018

IEEE Trans. Commun.

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“…Hence, the residual interference after the RF canceller is still higher than the receiver noise floor and needs to be cancelled via digital processing at baseband [4], [5], [9]. However, effective self-interference cancellation at baseband requires accurate knowledge of the digital channels, which are the channels observed by the receiver at baseband after the passive and RF cancellation stages [10]. Consequently, for reliable FD communication first the digital channels are estimated and then the received signal is processed for data detection [5], [6], [11].…”

Section: Introductionmentioning

confidence: 99%

Residual self-interference cancellation and data detection in full-duplex communication systems

Koohian

Mehrpouyan

Nasir

et al. 2017

2017 IEEE International Conference on Communications (ICC)

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Abstract-Residual self-interference cancellation is an important practical requirement for realizing the full potential of full-duplex (FD) communication. Traditionally, the residual selfinterference is cancelled via digital processing at the baseband, which requires accurate knowledge of channel estimates of the desired and self-interference channels. In this work, we consider point-to-point FD communication and propose a superimposed signaling technique to cancel the residual self-interference and detect the data without estimating the unknown channels. We show that when the channel estimates are not available, data detection in FD communication results in ambiguity if the modulation constellation is symmetric around the origin. We demonstrate that this ambiguity can be resolved by superimposed signalling, i.e., by shifting the modulation constellation away from the origin, to create an asymmetric modulation constellation. We compare the performance of the proposed detection method to that of the conventional channel estimation-based detection method, where the unknown channels are first estimated and then the data signal is detected. Simulations show that for the same average energy over a transmission block, the bit error rate performance of the proposed detection method is better than that of the conventional method. The proposed method does not require any channel estimates and is bandwidth efficient.

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“…Consequently, for (21) to hold for ∀y a i , the coefficient of x a i should be zero, i.e., θ (1) = θ (1). Knowing that θ (1) = θ(1) and equating (19) and (20), we have…”

Section: Appendixmentioning

confidence: 99%

“…However, blind estimators can only estimate the channel up to a scaling factor and cannot recover the channel phases [23]. The necessary and sufficient conditions for ambiguity-free blind estimation can be determined using identifiability analysis, which determines whether a parameter can be uniquely estimated without any ambiguity [19,23,[28][29][30]. To the best of our knowledge, bandwidth efficient and accurate channel estimation methods for FD systems are still an important open area of research.…”

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Superimposed signaling inspired channel estimation in full-duplex systems

Koohian

Mehrpouyan

Nasir

et al. 2018

EURASIP J. Adv. Signal Process.

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Residual self-interference (SI) cancellation in the digital baseband is an important problem in full-duplex (FD) communication systems. In this paper, we propose a new technique for estimating the SI and communication channels in a FD communication system, which is inspired from superimposed signaling. In our proposed technique, we add a constant real number to each constellation point of a conventional modulation constellation to yield asymmetric shifted modulation constellations with respect to the origin. We show mathematically that such constellations can be used for bandwidth efficient channel estimation without ambiguity. We propose an expectation maximization (EM) estimator for use with the asymmetric shifted modulation constellations. We derive a closed-form lower bound for the mean square error (MSE) of the channel estimation error, which allows us to find the minimum shift energy needed for accurate channel estimation in a given FD communication system. The simulation results show that the proposed technique outperforms the data-aided channel estimation method, under the condition that the pilots use the same extra energy as the shift, both in terms of MSE of channel estimation error and bit error rate. The proposed technique is also robust to an increasing power of the SI signal.

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Bandwidth efficient channel estimation for full duplex communication systems

Cited by 12 publications

References 16 publications

Optimal Training for Residual Self-Interference for Full-Duplex One-Way Relays

Optimal Training for Residual Self-Interference for Full-Duplex One-Way Relays

Residual self-interference cancellation and data detection in full-duplex communication systems

Superimposed signaling inspired channel estimation in full-duplex systems

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