On the Application of MIMO Space-Time Coding to Physical Layer Security in sub-6 GHz 5G

This paper investigates the application and performance improvement of MIMO Space Time Block Coding (STBC) for Physical Layer Security. The paper analyzes a Precoder Matrix Index (PMI) based scheme called Private Random Precoding (PRP). Key-based Physical Layer Security protects against eavesdroppers in wireless communication links, invaluable in emerging 5G and IoT networks. This paper derives improvements in PRP based on STBC. Also presented are simulation results which show as much as 7 dB improvement in Key bit Error Rate performance vs SINR of the enhanced PRP-STBC scheme for a 1-bit codebook at the cost of decreased transmission rate. In addition, the paper derives a closed form expression for the Key bit Error Rate for both the PRP and enhanced PRP-STBC schemes as a function of dense 5G cellular geometries. Furthermore, we present the effective information rate of the PRP key based communication framework in low SNR scenarios.