Phase index-based receive spatial modulation PHY security against supervised pattern recognition

Receive Spatial Modulation (RSM) uses the index of the receive antenna to convey additional information bits, which reduces the receiver complexity and improves spectral efficiency. Additionally, it provides inherent physical layer security using the Zero-forcing (ZF) precoding technique. However, the channel becomes vulnerable to eavesdropper (Eve) if the channel impulse response is assumed to be time-invariant or stationary through coherent block intervals. In this paper, a physical layer secure scheme is proposed based on phase index RSM to combat eaves-droppers that use k-nearest neighbors (KNN) supervised pattern recognition. The average bit error rate (BER) performance shows the ability of the proposed scheme to provide a suitable level of security while degrading the average BER performance of Eve.