On the secure degrees of freedom of the K user MIMO MAC with statistical CSI

Abstract

We investigate the secure degrees of freedom (SDoF) of the K-user MIMO multiple access channel (MAC) in the vicinity of an eavesdropper which is trying to decode the messages sent by the transmitters. The eavesdropper is equipped with NE antennas and fading channels. The transmitters and the legitimate receiver are assumed to be oblivious of the eavesdropper channels values. We derive an upperbound on the sum SDoF of such K-user MAC channel and present an achievable scheme that partially meets the derived upperbound.