Leakage Rate Analysis for Artificial Noise Assisted Massive MIMO with Non-coherent Passive Eavesdropper in Block-fading

Abstract: Massive MIMO is one of the salient techniques for achieving high spectral efficiency in next generation wireless networks. Recently, a combined strategy of the massive MIMO and the artificial noise (AN), namely, {\it AN assisted massive MIMO (ANAM)} has recently been actively investigated for security enhancement. However, most of previous studies on the ANAM have been built upon the full channel state information (CSI) assumption at the eavesdropper (ED), which may be too pessimistic to provide meaningful information on the security since the channel uncertainty of the ED may degrade its decoding ability. In this paper, we provide more sophisticated investigation on the performance of the ANAM system assuming that the CSI of the ED channels are unknown to both the BS and the ED or partially known to the ED. We measure the secrecy in terms of both the leakage rate to the ED and the secrecy rate to the legitimate users, and characterize their upper and lower bounds in the high SNR regime as a function of the number of ED antennas, the number of data and AN signal dimensions, and coherence time. Finally, from numerical results, we demonstrate the accuracy of our analysis and highlight the security potential of the ANAM system against the passive eavesdropping attack.