Secure Communication over Fading Channels with Statistical QoS Constraints

TL;DR

This paper analyzes secure data transmission over fading channels under statistical QoS constraints, deriving optimal power control policies and revealing how eavesdropper CSI impacts secure throughput.

Contribution

It introduces effective secure throughput as a metric and derives optimal power control strategies considering the availability of eavesdropper CSI under QoS constraints.

Findings

Optimal power control policies depend on eavesdropper CSI availability.

QoS constraints limit waiting strategies when eavesdropper CSI is known.

Eavesdropper CSI becomes less useful under stringent QoS constraints.

Abstract

In this paper, the secure transmission of information over an ergodic fading channel is investigated in the presence of statistical quality of service (QoS) constraints. We employ effective capacity, which provides the maximum constant arrival rate that a given process can support while satisfying statistical delay constraints, to measure the secure throughput of the system, i.e., effective secure throughput. We assume that the channel side information (CSI) of the main channel is available at the transmitter side. Depending on the availability of the CSI of the eavesdropper channel, we obtain the corresponding optimal power control policies that maximize the effective secure throughput. In particular, when the CSI of the eavesdropper channel is available at the transmitter, the transmitter can no longer wait for transmission when the main channel is much better than the eavesdropper channel due to the introduction of QoS constraints. Moreover, the CSI of the eavesdropper channel becomes useless as QoS constraints become stringent.