Received Signal and Channel Parameter Estimation in Molecular Communications

Molecular communication (MC) is a paradigm that employs molecules as information carriers, hence, requiring unconventional transceivers and detection techniques for the Internet of Bio-Nano Things (IoBNT). In this study, we provide a novel MC model that incorporates a spherical transmitter and receiver with partial absorption. This model offers a more realistic representation than receiver architectures in literature, e.g., passive or entirely absorbing configurations. An optimization-based technique utilizing particle swarm optimization (PSO) is employed to accurately estimate the cumulative number of molecules received. This technique yields nearly constant correction parameters and demonstrates a significant improvement of 5 times in terms of root mean square error (RMSE) compared to the literature. The estimated channel model provides an approximate analytical impulse response; hence, it is used for estimating channel parameters such as distance, diffusion coefficient, or a combination of both. The iterative maximum likelihood estimation (MLE) is applied for the parameter estimation, which gives consistent errors compared to the estimated Cramer-Rao Lower Bound (CLRB).