Publications
We often attend conferences around the world in order to present and spread our knowledge. Below we list some of our papers within international journals or international conferences.
Joint Semi-Blind Self-Interference Cancellation and Equalisation Processes in 5G QC-LDPC-Encoded Short-Packet Full-Duplex Transmissions
Authors: Bao Quoc Vuong; Roland Gautier; Hien Quang Ta; Lap Luat Nguyen; Anthony Fiche and Mélanie Marazin
MDPI Sensors : Published online (March 2022)
The paper proposes a joint semi-blind algorithm for simultaneously cancelling the self-interference component and estimating the propagation channel in 5G Quasi-Cyclic Low-Density Parity-Check (QC-LDPC)-encoded short-packet Full-Duplex (FD) transmissions. To avoid the effect of channel estimation processes when using short-packet transmissions, this semi-blind algorithm was developed by taking into account only a small number (four at least) pilot symbols, which was integrated with the intended information sequence and used for the feedback loop of the estimation of the channels. The results showed that this semi-blind algorithm not only achieved nearly optimal performance, but also significantly reduced the processing time and computational complexity. This semi-blind algorithm can also improve the performances of the Mean-Squared Error (MSE) and Bit Error Rate (BER). The results of this study highlight the potential efficiency of this joint semi-blind iterative algorithm for 5G and Beyond and/or practical IoT transmission scenarios.
Joint Iterative Blind Self-Interference Cancellation, Propagation Channel Estimation and Decoding Processes in Full-Duplex Transmissions
Authors: Bao Quoc Vuong; Roland Gautier; Anthony Fiche; Mélanie Marazin; Hien Quang Ta; Lap Luat Nguyen
IEEE Access : Published online (February 2022)
The paper proposes a joint blind iterative Self-Interference (SI) cancellation, propagation channel estimation and decoding algorithm in Full-Duplex (FD) transmissions via feedback of channel estimates and decoded messages combined with the process of Digital Self-Interference Cancellation (DSIC). Different from the conventional algorithm, the proposed blind algorithm simultaneously estimates the self-interference and propagation channels and decodes messages in each decoding iteration of 5G Quasi-Cyclic Low Density Parity Check (QC-LDPC) codes. The temporary propagation channel estimate and decoded message are fed back to improve the self-interference cancellation and also the channel estimation as well as decoding in the next iteration. The results show that the proposed algorithm outperforms the conventional algorithm, especially at high signal to noise ratio (SNR) and small number of symbols, and requires much less processing time and computational complexity while achieving the convergence performance. The results also show that the proposed algorithm is less sensitive to SI level than the conventional algorithm. The paper further proposes a partial feedback scheme, which only use few feedback symbols for channel estimation, to significantly reduce the processing time and computational complexity while maintaining the performance. These good properties seem quite suitable for a use of this proposed blind iterative algorithm for short-length packet FD transmissions in Internet-of-Things (IoT) applications and green communications.
Covert Communications over Multiple Overt Channels
Authors: Sang Wu Kim, Ta Quang Hien
IEEE Transactions on Communications : Published online (November 2021)
We explore leveraging the multiplicity of overt (public) messages, destined for different receivers through different channels, for hiding the transmission of a covert (private) message. The transmitter hides the covert message against a warden by superimposing it onto an overt message. We determine the optimum rule for choosing the overt message to maximize the total detection error probability (sum of the probability of false alarm and missed detection) at the warden. In addition, the channel variation is exploited to minimize the throughput loss on the overt message caused by the superimposition of the covert message. We show that the maximum total detection error probability converges fast to 1 as the number of overt messages (channels) increases; the total detection error probability is independent of the transmission power; and that a positive covert rate (bits per channel use) can be achieved while keeping the total detection error probability arbitrarily close to 1. These findings indicate that the multiplicity of overt messages (channels) and channel variations can be exploited to achieve a positive covert rate.
Modulated Wideband Converter Compressed Sensing Spectrum Reconstruction in Multi-Level Power of Transmitters Signal Scenarios
Authors: Nguyen Lap Luat, Anthony Fiche, Roland Gautier
In proceedings of 2021 International Conference on Advanced Technologies for Communications (ATC), Ho Chi Minh City, Viet Nam, 2021
This paper studies the impacts of transmitters power levels on spectrum reconstruction performances in order to monitor a wideband spectrum. A sub-Nyquist blind sampling scheme based on the Modulated Wideband Converter (MWC) has been considered to achieve this task. Reconstruction performances are evaluated in simulation in terms of correct reconstruction and false alarm rates by studying several multi-level power scenarios. The study shows that the performance of reconstruction depends on the In-Band Signal-to-Noise ratio (IBSNR) of each transmitter. Based on these results, a threshold of In-Band Signal-to-Noise ratio to ensure the correct reconstruction is proposed.
Impacts of chaotic mixing sequence on the Compressed Sensing blind spectrum reconstruction
Authors: Nguyá»…n Láºp PhÆ°Æ¡ng Uyên, Vo Tan Phuoc , Nguyen Lap Luat, Nguyá»…n Huỳnh PhÆ°Æ¡ng Bảo
In proceedings of 2021 International Conference on Advanced Technologies for Communications (ATC), Ho Chi Minh City, Viet Nam, 2021
This paper studies the impacts of chaotic mixing sequence on the Modulated Wideband Converter blind spectrum sensing and reconstruction scheme. The Modulated Wideband Converter is a sub-Nyquist sampling scheme which comprises a multi-branch of mixer, lowpass filter and analog-to-digital converter. The mixing sequences play an important role in performance of the Modulated Wideband Converter blind spectrum sensing and reconstruction. Under the Compressed Sensing hypothesis, several approaches and the selection of chaotic mixing sequence for the Modulated Wideband Converter which is obtained from a chaotic system will be presented. This study also evaluates the Modulated Wideband Converter performance based on chaotic mixing sequences and several existing mixing sequences in the simulation.
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