Physical-Layer Encryption Using Digital Chaos for Secure OFDM Transmission

Abstract

Due to the broadcasting nature of passive optical network ({PON}), data security is challenging. For the transmission of orthogonal frequency division multiplexing ({OFDM}) signals, the high peak-to-average power ratio ({PAPR}) is considered as one of the major drawbacks. This chapter reviews the digital chaos-based secure {OFDM} data encryption schemes, where the transmission performance is improved via {PAPR} reduction. The digital chaos is incorporated into the signal scrambling approaches: selective mapping ({SLM}), partial transmit sequence ({PTS}); and precoding approaches: discrete Fourier transform ({DFT}) and {WalshHadamard} transform ({WHT}) for {PAPR} reduction. Multi-fold data encryption is achieved with a huge key space provided by digital chaos, to enhance the physical-layer security for {OFDM}-{PON}, while the pseudo-random properties of digital chaos are applied for {PAPR} reduction, which consequently improves the transmission performance. The evidences of these encryption approaches are presented in terms of theories, simulations, as well as experimental demonstrations. The chaotic data encryption schemes could be promising candidates for next-generation {OFDM}-{PON}.