Linear Precoding for Broadcast Channels with Confidential Messages under Transmit-Side Channel Correlation

TL;DR

This paper investigates the performance of regularized channel inversion precoding in MISO broadcast channels with confidential messages, deriving deterministic equivalents for secrecy rates and optimizing regularization under transmit-side channel correlation.

Contribution

It introduces a deterministic equivalent analysis for secrecy rates in correlated MISO channels and identifies the optimal regularization parameter for RCI precoding.

Findings

Deterministic equivalents for secrecy rates derived

Optimal regularization parameter identified

Validation through finite-size system simulations

Abstract

In this paper, we analyze the performance of regularized channel inversion (RCI) precoding in multiple-input single-output (MISO) broadcast channels with confidential messages under transmit-side channel correlation. We derive a deterministic equivalent for the achievable per-user secrecy rate which is almost surely exact as the number of transmit antennas and the number of users grow to infinity in a fixed ratio, and we determine the optimal regularization parameter that maximizes the secrecy rate. Furthermore, we obtain deterministic equivalents for the secrecy rates achievable by: (i) zero forcing precoding and (ii) single user beamforming. The accuracy of our analysis is validated by simulations of finite-size systems.