Impact of Phase Noise on Secrecy Performance of Cell-Free Massive MIMO Networks with Multi-Antenna Users

This paper studied the effect of phase noise on secrecy performance of the cell-free massive MIMO network with multi-antenna user terminals, where a multi-antenna eavesdropper will actively contaminate the uplink training. Specifically, using discrete-time Wiener model and random matrix theory, tractable expression for the achievable secrecy rate is derived, which can provide precise evaluation of key factors including phase noise, multi-antenna and arbitrary system configuration. Analytical results illustrate that strong phase noise and high wiretapping power would lead to performance degradation while the network can acquire multiplexing gain by equipping multiple antennas. Also, it indicates that phase noise at the user terminals imposes more rigorous influence than that on access points (APs). Simulations are presented to corroborate the derived results.