Performance Analysis for Physical Layer Security in Multi-Antenna Downlink Networks with Limited CSI Feedback

TL;DR

This paper analyzes how limited CSI feedback affects physical layer security in multi-antenna downlink networks, focusing on the ergodic secrecy sum-rate and its asymptotic behavior, supported by theoretical and numerical results.

Contribution

It provides a quantitative analysis of ergodic secrecy sum-rate with limited CSI feedback and explores its asymptotic properties in multi-antenna downlink networks.

Findings

Secrecy sum-rate increases with more CSI feedback.

Asymptotic behaviors are characterized in extreme feedback cases.

Numerical results confirm theoretical predictions.

Abstract

Channel state information (CSI) at the transmitter is of importance to the performance of physical layer security based on multi-antenna networks. Specifically, CSI is not only beneficial to improve the capacity of the legitimate channel, but also can be used to degrade the performance of the eavesdropper channel. Thus, the secrecy rate increases accordingly. This letter focuses on the quantitative analysis of the ergodic secrecy sum-rate in terms of feedback amount of the CSI from the legitimate users in multiuser multi-antenna downlink networks. Furthermore, the asymptotic characteristics of the ergodic secrecy sum-rate in two extreme cases is investigated in some detail. Finally, our theoretical claims are confirmed by the numerical results.