Active Attack on User Load Achieving Pilot Design in Massive MIMO Networks

TL;DR

This paper reveals vulnerabilities in user load-achieving pilot design in massive MIMO networks and proposes an active attack strategy that significantly reduces the network's ability to meet SINR requirements.

Contribution

It identifies specific vulnerabilities in pilot sequence design and develops an active attack method that compromises network performance.

Findings

Active attack reduces per-cell user load region

SINR guarantees are broken under attack

Worst affected users cannot meet SINR even with infinite antennas

Abstract

In this paper, we propose an active attacking strategy on a massive multiple-input multiple-output (MIMO) network, where the pilot sequences are obtained using the user load-achieving pilot sequence design. The user load-achieving design ensures that the signal-to-interference-plus-noise ratio (SINR) requirements of all the users in the massive MIMO networks are guaranteed even in the presence of pilot contamination. However, this design has some vulnerabilities, such as one known pilot sequence and the correlation among the pilot sequences, that may be exploited by active attackers. In this work, we first identify the potential vulnerabilities in the user load-achieving pilot sequence design and then, accordingly, develop an active attacking strategy on the network. In the proposed attacking strategy, the active attackers transmit known pilot sequences in the uplink training and artificial noise in the downlink data transmission. Our examination demonstrates that the per-cell user load region is significantly reduced by the proposed attacking strategy. As a result of the reduced per-cell user load region, the SINR requirements of all the users are no longer guaranteed in the presence of the active attackers. Specifically, for the worst affected users the SINR requirements may not be ensured even with infinite antennas at the base station.