Secrecy Coding Analysis of Short-Packet Full-Duplex Transmissions with Joint Iterative Channel Estimation and Decoding Processes
Résumé
This paper studies the secrecy coding analysis achieved by the self-jamming technique in the
presence of an eavesdropper by considering a short-packet Full-Duplex (FD) transmission developed
based on iterative blind or semi-blind channel estimation and advanced decoding algorithms. Indeed,
the legitimate receiver and eavesdropper can simultaneously receive the intended signal from the
transmitter and broadcast a self-jamming or jamming signal to the others. Unlike other conventional
techniques without feedback, the blind or semi-blind algorithm applied at the legitimate receiver can
simultaneously estimate, firstly, the Self-Interference (SI) channel to cancel the SI component and,
secondly, estimate the propagation channel, then decode the intended messages by using 5G Quasi-
Cyclic Low-Density Parity Check (QC-LDPC) codes. Taking into account the passive eavesdropper
case, the blind channel estimation with a feedback scheme is applied, where the temporary estimation
of the intended channel and the decoded message are fed back to improve both the channel estimation
and the decoding processes. Only the blind algorithm needs to be implemented in the case of a
passive eavesdropper because it achieves sufficient performances and does not require adding pilot
symbols as the semi-blind algorithm. In the case of an active eavesdropper, based on its robustness
in the low region of the Signal-to-Noise Ratio (SNR), the semi-blind algorithm is considered by
trading four pilot symbols and only requiring the feedback for channel estimation processes in
order to overcome the increase in noise in the legitimate receiver. The results show that the blind
or semi-blind algorithms outperform the conventional algorithm in terms of Mean Square Error
(MSE), Bit Error Rate (BER) and security gap (Sg). In addition, it has been shown that the blind
or semi-blind algorithms are less sensitive to high SI and self-jamming interference power levels
imposed by secured FD transmission than the conventional algorithms without feedback.