Chaotic Encryption for Belief Propagation Decoding in Massive MIMO Systems

In this paper, belief propagation (BP) iterative estimation of chaos-modulated signals is considered in massive multiple-input multiple-output (MIMO) systems. We show that signals encrypted by a certain class of chaos algorithms cannot be decoded accurately by BP decoding. To address this, we reconstruct the algorithm to allow BP decoding to be applied to the data transmitted across the massive MIMO system. Numerical results show that the proposed encryption successfully improves the bit error ratio performance. Moreover, no significant difference in the computation time required by the BP decoding is observed between the proposed encryption and the binary phase-shift keying. This suggests that the proposed encryption is practical to use with the BP method and that this approach may enhance the security of massive MIMO systems.