Legitimate Pilot Contamination Attack in Intelligent Multi-Access Networks

In this correspondence, we investigate the legitimate surveillance of a suspicious intelligent multi-access (MA) network via pilot contamination attack (PCA). Specifically, the base station (BS) can switch between orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) to achieve the optimal sum rate for the paired two users. The monitor sends PCA signals to distort the channel estimation and misleads the mode selection at the BS, i.e., from OMA to NOMA. As thus, the monitor can replace the stronger user in the NOMA pair by itself and wiretap the information of both users, owing to the superimposed signals in NOMA. To this end, the PCA power is minimized subject to the sum-rate requirement and eavesdropping condition, which guarantees that the information can be successfully recovered by the monitor. Simulation results confirm the effectiveness of our PCA scheme in achieving the surveillance in intelligent MA networks.