PMI-Based MIMO OFDM PHY Integrated Key Exchange (P-MOPI) Scheme
In this paper, the authors have proposed the MIMO-OFDM PHY Integrated (MOPI) scheme for achieving physical-layer security in practice without using any cryptographic ciphers. The MOPI scheme uses channel sounding and Physical-layer Network Coding (PNC) to prevent eavesdroppers from learning the Channel State Information (CSI). Nevertheless, due to the use of multiple antennas for PNC at transmitter and beamforming at receiver, it is not possible to neither have spatial multiplexing nor use space-time codes in their previous MOPI scheme. In this paper, they propose a variant of the MOPI scheme, called P-MOPI that works with a cryptographic cipher and utilizes Precoding Matrix Index (PMI) as an efficient key-exchange mechanism.