Filter design for MIMO Gaussian wiretap channel

In wireless communication, the broadcast nature of the medium has made information security a very important concern. This nature allows the unauthorized receivers to observe and eavesdrop the signals sent by the transmitter to an authorized receiver if it lies within the transmission range. This paper considers the transmit and receive filter design for multiple input multiple output (MIMO) Gaussian wiretap channel. The optimal transmit filter design requires prior knowledge of the type of filters used at the receivers. Here, we assume that the valid receiver and the eavesdropper employ Zero-Forcing (ZF) criteria at their receivers. We also assume that the transmitter, intended receiver and eavesdropper are equipped with two antennas and channel information is known to all parties. The transmit and receive filters are designed with an objective to minimize the mean-square error (MSE) between authenticated parties, while ensuring that the eavesdropper MSE goes beyond a certain level. Performances of the designed filters are analyzed using numerical simulation.