Physical layer security for multiuser transmission techniques of massive MIMO relay networks with linear processing
Abstract
In this paper, we consider the problem of secure multiuser transmission in a massive multiple input multiple output (MIMO) relaying system, wherein a base station equipped with many antennas transmits simultaneously its message to multiuser at the destination via help of a relay equipped with massive antenna arrays. Decode and forward (DF) protocol is considered by using the maximum ratio combining/maximum ratio transmission ( MRC = MRT ) or zero-forcing reception/zero-forcing transmission ( ZFR = ZFT ) to process signals at the relay under imperfect channel state information (CSI). As a result, exact and asymptotic expressions for user rate and outage secrecy rate for a given secure outage probability of eavesdropper links are derived. Furthermore, we have proposed the asymptotic analysis in various special cases. It is disclosed that the majority of eavesdropper rates is eliminated when a number of relay antennas go to infinity, and simultaneously the transmit power at the base station and the relay can be scaled down significantly by factor 1 = p N while maintaining secure system performance. Finally, numerical results confirm the validity of our analysis.