Robust Power Allocation and Outage Analysis for Secrecy in Independent Parallel Gaussian Channels

TL;DR

This paper analyzes the secrecy outage probability in parallel Gaussian channels with uncertain eavesdropper CSI and proposes a robust power allocation scheme to minimize outage probability in low SNR regimes.

Contribution

It introduces a robust power allocation method that accounts for eavesdropper CSI uncertainty, improving secrecy performance over conventional schemes.

Findings

Proposes a linear fractional program for power allocation under CSI uncertainty.

Effectively reduces outage probability compared to traditional methods.

Provides bounds on secrecy outage probability in uncertain conditions.

Abstract

This letter studies parallel independent Gaussian channels with uncertain eavesdropper channel state information (CSI). Firstly, we evaluate the probability of zero secrecy rate in this system for (i) given instantaneous channel conditions and (ii) a Rayleigh fading scenario. Secondly, when non-zero secrecy is achievable in the low SNR regime, we aim to solve a robust power allocation problem which minimizes the outage probability at a target secrecy rate. We bound the outage probability and obtain a linear fractional program that takes into account the uncertainty in eavesdropper CSI while allocating power on the parallel channels. Problem structure is exploited to solve this optimization problem efficiently. We find the proposed scheme effective for uncertain eavesdropper CSI in comparison with conventional power allocation schemes.