Secure Transmission in Cell-Free Massive MIMO Network with Phase Noise

Abstract

This paper investigates the secure transmission for cell-free massive MIMO network under active eavesdropping by taking into consideration of phase noise. By utilizing MMSE approach and distributed conjugate beamforming technique, the tractable deterministic achievable secrecy rate expression has been derived with respect to phase noise, network configuration and power allocation scheme. Analytical results reveal that phase noise at the users has a greater influence on the system secrecy performance than that at the APs. Besides, it is illustrated that the considered cell-free network can achieve superior security than collocated massive MIMO architecture. Moreover, constraint of active eavesdropping imposed on the achievable secrecy capacity is also revealed. Finally, all derived findings are corroborated by numerical results.