Cross-correlation based approach for counting nodes of undersea communications network considering limited bandwidth

Abstract

The limited bandwidth (BW) of undersea communication presents a significant challenge to the node counting technique based on cross-correlation (CC), which traditionally use Gaussian signals with infinite BW. To address this, a band-limited Gaussian signal is employed for counting nodes, impacting the cross-correlation function (CCF) and the derived estimation parameters. To correlate the estimation parameters for finite and infinite BW scenarios, a scaling factor (S_F) is determined for a specific BW by averaging their ratios across different node counts. Efficient estimation in a band-limited condition is feasible if the S_F for that BW is known. Previous investigations have been limited to 5 kHz and 10 kHz BW. Given the typical undersea BW range of 1–15 kHz, it is important to establish a relationship between the S_F and BW. This relationship, derived and validated through simulation in this study, allows for determining the S_F and achieving accurate node count under any band-limited condition within the 1–15 kHz range.