SNR-Walls in Eigenvalue-based Spectrum Sensing

TL;DR

This paper investigates the impact of noise coloring uncertainty on the eigenvalue-based MME spectrum sensing detector, revealing the existence of an SNR-wall and deriving a lower bound for it, supported by simulations.

Contribution

It demonstrates that noise coloring uncertainty causes an SNR-wall in the MME detector, which was previously unaffected by noise power uncertainty.

Findings

Uncertainty in noise coloring leads to an SNR-wall in MME detection.

A lower bound on the SNR-wall is derived and evaluated.

Numerical simulations support the theoretical results.

Abstract

Various spectrum sensing approaches have been shown to suffer from a so-called SNR-wall, an SNR value below which a detector cannot perform robustly no matter how many observations are used. Up to now, the eigenvalue-based maximum-minimum-eigenvalue (MME) detector has been a notable exception. For instance, the model uncertainty of imperfect knowledge of the receiver noise power, which is known to be responsible for the energy detector's fundamental limits, does not adversely affect the MME detector's performance. While additive white Gaussian noise (AWGN) is a standard assumption in wireless communications, it is not a reasonable one for the MME detector. In fact, in this work we prove that uncertainty in the amount of noise coloring does lead to an SNR-wall for the MME detector. We derive a lower bound on this SNR-wall and evaluate it for example scenarios. The findings are supported by numerical simulations.