A Secure Coded MIMO System Under Imperfect Channel Estimation

There have been many researches on physical layer security (PLS) schemes using dynamic channel information, but most of them assumed the perfect channel information, which is difficult to obtain in practical systems. This paper proposes an efficient PLS scheme for coded multi-input multi-output (MIMO) systems operating under imperfect channel estimation conditions. Since coded MIMO systems are typically equipped with an interleaver for bit-interleaved coded modulation (BICM), which is associated with soft iterative decoding, the scheme proposed herein adopts a random interleaving index, which is a function of the legitimate channel. This scheme also includes a novel strategy to prevent the performance degradation caused by channel estimation error through the combination of ancillary forward error correction (AFEC). This innovative concept can archive an advanced level of security protection without requiring any additional power. We also derive the secrecy rate of the proposed scheme. The simulation results presented in this paper demonstrate that the proposed scheme effectively protects the transmitted data without any information leakage to the eavesdropper.