Local Convexity Inspired Low-Complexity Noncoherent Signal Detector for Nanoscale Molecular Communications

TLDR

Molecular communications via diffusion (MCvD) is a promising nanoscale wireless technology, but its long‑tailed channel causes severe inter‑symbol interference and coherent detection is impractical due to the need for accurate channel estimation and high computational cost. This work introduces a low‑complexity, noncoherent detector that leverages the local convexity of the diffusive channel response. The detector employs a blind threshold‑estimation mechanism that adapts to channel variations without requiring explicit channel knowledge. Numerical results show that the scheme achieves high data rates, effectively suppresses ISI from many preceding symbols, and reduces complexity to simple summation operations, making it suitable for energy‑constrained nanoscale applications.

Abstract

Molecular communications via diffusion (MCvD) represents a relatively new area of wireless data transfer with especially attractive characteristics for nanoscale applications. Due to the nature of diffusive propagation, one of the key challenges is to mitigate inter-symbol interference (ISI) that results from the long tail of channel response. Traditional coherent detectors rely on accurate channel estimations and incur a high computational complexity. Both of these constraints make coherent detection unrealistic for MCvD systems. In this paper, we propose a low-complexity and noncoherent signal detector, which exploits essentially the local convexity of the diffusive channel response. A threshold estimation mechanism is proposed to detect signals blindly, which can also adapt to channel variations. Compared to other noncoherent detectors, the proposed algorithm is capable of operating at high data rates and suppressing ISI from a large number of previous symbols. Numerical results demonstrate that not only is the ISI effectively suppressed, but the complexity is also reduced by only requiring summation operations. As a result, the proposed noncoherent scheme will provide the necessary potential to low-complexity molecular communications, especially for nanoscale applications with a limited computation and energy budget.