Secure Communication for Spatially Correlated Massive MIMO with Low-Resolution DACs

TL;DR

This paper analyzes the impact of low-resolution DACs on the secrecy performance of massive MIMO systems over spatially correlated channels, revealing conditions where low-resolution DACs can enhance security.

Contribution

It derives a tight lower bound for the secrecy rate with artificial noise in correlated channels and evaluates the effects of spatial correlation and DAC resolution on security.

Findings

Low-resolution DACs can improve secrecy performance in highly correlated channels.

Spatial correlation influences the effectiveness of low-resolution DACs for security.

Optimal power allocation further enhances secrecy rates.

Abstract

In this paper, the performance of a secure massive multiple-input multiple-output (MIMO) system adopting low-resolution digital-to-analog converters (DACs) is analyzed over spatially correlated wireless channels. A tight lower bound for the achievable secrecy rate is derived with artificial noise (AN) transmitted in the null space of the user channels. Using the analytical results, the impact of spatial correlation on the secrecy rate is explicitly evaluated in the presence of low-resolution DACs. The analytical observations reveal that using low-resolution DACs can be beneficial to the secrecy performance compared with ideal DACs, when the channels are strongly correlated and optimal power allocation is not employed.