Multiple Antenna Physical Layer Security Against Passive Eavesdroppers: A Tutorial

The increasing use of network-connected devices places a higher risk on security and privacy of data. The characteristics of the wireless channel can be employed to provide secrecy in wireless communication, in the form of Physical Layer Security (PLS). This review paper provides a tutorial on practical PLS based on multiple antenna and relay network systems, and identifies current challenges in this important research area. The emphasis is also put on the crucial step of secure channel estimation, as well as discriminatory channel estimation (DeE), without which the practical application of PLS remains limited.