Comparison of Optimization Criteria for Preprocessing for Physical-Layer Security in Multi-Carrier-THz-MIMO Systems

We consider physical-layer security for MIMO communication in the THz-frequency band using multi-carrier transmission. Two different approaches to design preprocessing are considered for this scenario. One is classical preequalization, which aims at minimizing the error ratio at Bob and does not take an eavesdropper into account. In contrast to this, preprocessing can also be designed according to the secrecy capacity, where knowledge about the eavesdropper is used. We consider two approaches for dealing with multiple eavesdroppers and compare the results. Additionally, a new variant is suggested that enables a trade-off between security and the performance of the legitimate receiver. Numerical simulations are conducted and the results are shown to compare the preprocessing variants.