Security and performance improvement in OFDM transmission using chaotic precoding

We propose and demonstrate signal encryption schemes using digital chaos for orthogonal frequency division multiplexing (OFDM) signals, where discrete Fourier transform (DFT) and Walsh-Hadamard transform (WHT) are applied as chaotic precoder for peak-to-average power ratio (PAPR) reduction. The physical-layer security during transmission is enhanced, where a huge key space is created by digital chaos. Moreover, the OFDM transmission performance is jointly improved due to the effective PAPR reduction benefited from pseudo-random properties of digital chaos.