Multiple transmitter localization via single receiver in 3-D molecular communication via diffusion

Molecular communications have proven as a viable technology to enable information exchange at the nanoscale, where conventional communication paradigms fail. However, the diffusion-based characteristics of molecular communications hamper applying traditional approaches to problems like transmitter localization, which is a critical issue in in-body applications. The problem becomes even more complex when there are multiple transmitters in the environment. In this paper, a solution for localizing multiple point transmitters of molecules that are absorbed by a spherical and fully-absorbing receiver in a 3-D diffusion-based medium is proposed. In order to localize multiple point transmitters, absorbing coordinates of the molecules on the receiver's surface are used. Then, these coordinates (spherical data) are clustered via clustering algorithms, such as K-Means, Gaussian mixture model, or Bayesian mixture model. Using the average coordinate values of the clusters, direction-of-arrival (DoA) for each cluster is estimated. Additionally, from the size of the data in each cluster and the hitting probability of the molecules with respect to time, receiver radius, and the distances between the spherical receiver and each point transmitter are estimated.