Channel impulse response-based source localization in a diffusion-based molecular communication system

Molecular source localization finds its applications in future healthcare systems, including proactive diagnostics. This work localizes a molecular source in a diffusion based molecular communication (DbMC) system via a minimal set of passive anchor nodes and a fusion center. Two methods are presented which both utilize (the peak of) the channel impulse response measurements to uniquely localize the source, under the assumption that the molecular source of interest lies within the open convex-hull of the sensor/anchor nodes. The first method is a one-shot, triangulation-based approach which estimates the unknown location of the molecular source using least-squares method. The second method is an iterative approach, which utilizes the gradient-descent control law to minimize a non-convex cost function. The corresponding Cramer-Rao bound (CRB) is also derived. Simulation results reveal that: (a) the gradient-descent method outperforms the triangulation method (in terms of mean squared error performance) for a wide range of values of signal-to-noise ratio; (b) the gradient-descent method converges to the true source location uniformly (in less than 100 iterations).