Multiple Antennas Secure Transmission under Pilot Spoofing and Jamming Attack

TL;DR

This paper introduces a random channel training scheme for secure downlink transmission in TDD systems with multiple antennas, effectively mitigating pilot spoofing and jamming attacks to improve secrecy rates.

Contribution

It proposes a novel RCT framework with multiple orthogonal pilot sequences, enabling the BS to identify the legitimate user's pilot and estimate channels under attack.

Findings

Secrecy performance significantly improved over conventional schemes.

Analytical expressions for the probability of incorrect pilot detection.

Closed-form secure beamforming vectors optimized for enhanced secrecy.

Abstract

Transmitter-side channel state information (CSI) of the legitimate destination plays a critical role in physical layer secure transmissions. However, channel training procedure is vulnerable to the pilot spoofing attack (PSA) or pilot jamming attack (PJA) by an active eavesdropper (Eve), which inevitably results in severe private information leakage. In this paper, we propose a random channel training (RCT) based secure downlink transmission framework for a time division duplex (TDD) multiple antennas base station (BS). In the proposed RCT scheme, multiple orthogonal pilot sequences (PSs) are simultaneously allocated to the legitimate user (LU), and the LU randomly selects one PS from the assigned PS set to transmit. Under either the PSA or PJA, we provide the detailed steps for the BS to identify the PS transmitted by the LU, and to simultaneously estimate channels of the LU and Eve. The probability that the BS makes an incorrect decision on the PS of the LU is analytically investigated. Finally, closed-form secure beamforming (SB) vectors are designed and optimized to enhance the secrecy rates during the downlink transmissions. Numerical results show that the secrecy performance is greatly improved compared to the conventional channel training scheme wherein only one PS is assigned to the LU.