Capacity of Backscatter Communication under Arbitrary Fading Dependence

TL;DR

This paper investigates how arbitrary dependence between forward and backward links affects backscatter communication capacity, revealing that positive dependence enhances capacity at low SNR, while dependence is negligible at high SNR.

Contribution

It introduces a novel analysis using Copula theory to quantify the impact of arbitrary fading dependence on backscatter channel capacity, surpassing traditional correlation-based methods.

Findings

Capacity increases with positive dependence at low SNR.

Fading dependence has minimal impact at high SNR.

Fading severity influences capacity growth in low SNR regimes.

Abstract

We analyze the impact of arbitrary dependence between the forward and backward links in backscatter communication systems. Specifically, we quantify the effect of positive and negative dependence between these fading links on channel capacity, using Copula theory. The benefits of this approach are highlighted over the classical framework of linear dependence based on Pearson's correlation coefficient, which is also analyzed. Results show that for a fixed transmit power budget, capacity grows with positive dependence as well as with fading severity in the low signal-to-noise ratio (SNR) regime. Conversely, fading dependence becomes immaterial in the high SNR regime.