Secure Transmission with Large Numbers of Antennas and Finite Alphabet Inputs

TL;DR

This paper addresses secure transmission in large-scale MIMO systems with finite alphabet inputs, proposing a novel PG-GSVD design that outperforms traditional GSVD methods, especially at high SNR, with lower computational complexity.

Contribution

It introduces a new PG-GSVD design for secure MIMO transmission with finite alphabet inputs, reducing complexity and improving performance over existing GSVD-based methods.

Findings

PG-GSVD outperforms GSVD at high SNR.

Proposed method has significantly lower computational complexity.

Numerical results show substantial performance gains in large-scale systems.

Abstract

In this paper, we investigate secure transmission over the large-scale multiple-antenna wiretap channel with finite alphabet inputs. First, we investigate the case where instantaneous channel state information (CSI) of the eavesdropper is known at the transmitter. We show analytically that a generalized singular value decomposition (GSVD) based design, which is optimal for Gaussian inputs, may exhibit a severe performance loss for finite alphabet inputs in the high signal-to-noise ratio (SNR) regime. In light of this, we propose a novel Per-Group-GSVD (PG-GSVD) design which can effectively compensate the performance loss caused by the GSVD design. More importantly, the computational complexity of the PG-GSVD design is by orders of magnitude lower than that of the existing design for finite alphabet inputs in [1] while the resulting performance loss is minimal. Then, we extend the PG-GSVD design to the case where only statistical CSI of the eavesdropper is available at the transmitter. Numerical results indicate that the proposed PG-GSVD design can be efficiently implemented in large-scale multiple-antenna systems and achieves significant performance gains compared to the GSVD design.