Impact of Pilot Spoofing Attack on Superimposed Pilots in Cell-Free Massive MIMO

This letter investigates the impact of the pilot spoofing attack (PSA) on the uplink cell-free massive multi- input multi-output (mMIMO) system with superimposed pilots (SPs). A closed-form expression of the uplink achievable rate in the presence of the PSA is derived. In particular, a performance analysis concerning key system parameters, including the length and transmit power of training pilots, the number of access points (APs), and the eavesdropping power, is carried out. Furthermore, a comparison is made between the uplink achievable rates of the SP and regular pilots (RPs) schemes to characterize their differences in the PSA scenario.