Optimization of Probabilistic Constellation Shaping for Improving Secrecy Performance of O...

Physical layer security (PLS) is an attractive paradigm for protecting information confidentiality without the use of traditional key-based cryptography. This paper proposes a design of probabilistic constellation shaping to improve the PLS performance of optical wireless channels using M-ary pulse amplitude modulation (M-PAM) with the signal-dependent noise model. Specifically, the proposed design aims to maximize the reliability (i.e., minimization of the bit error rate - BER) of the legitimate user’s channel while guaranteeing that the modulation-constrained secrecy capacity is at least equal to that achieved by the uniform signaling. For this purpose, a novel upper bound for the BER of M-PAM constellation with signal-dependent noise channels with arbitrary input distribution is derived. Simulation results reveal that the proposed PCS design achieves a considerably lower BER of the legitimate user’s channel while attaining the same secrecy capacity as the uniform signaling.

Optimization of Probabilistic Constellation Shaping for Improving Secrecy Performance of Optical Wireless Channels with Signal-Dependent Noise

Thanh V. Pham, Shizuoka Univeristy; Susumu Ishihara, Shizuoka University