arXiv:1409.5583
On the degrees of freedom of the MIMO Wiretap and MIMO broadcast channels with unknown eavesdroppers.
Mohamed Amir, Tamer M. Khattab, Tarek Elfouly, Amr Mahmoud Salem Mohamed
Abstract
We determine the secure degrees of freedom region of the point to point and the two-transmitter Gaussian broadcast wiretap channels with multiple antennas at the legitimate receivers and the eavesdroppers with unknown eavesdroppers' CSI. The existence of unknown number of eavesdroppers is assumed but with maximum number of antennas at any eavesdropper is limited to a known value $N_E$. The channel matrices between the transmitters and the receiver is available everywhere, while the legitimate pair have no information about the eavesdroppers channels. A new upperbound is established and The DoF region is characterized. It is important to note that the same problem was studied with arbitrarily varying eavesdropper channels, our region is larger than their upperbound. It is important to note that the same problem has been studied recently with arbitrarily varying eavesdropper channels and an upperbound has been derived. However, our achievable sum secure DoF exceeds their previously derived upperbound. Consequently, we revisited the uppperbound derivation and we re-derived a new mathematically robust upperbound.