Relative angle estimation of an interferer in a diffusion-based molecular communication system

The design of molecular communication systems over a diffusive channel has been extensively studied under the hypothesis of a point-wise transmitter and one receiving cell that absorbs molecules from the environment. Recent works have extended this scenario by including also the effect of one, or more, interfering cells that introduce a perturbation in the number of molecules absorbed by the target receiving cell. In this paper we exploit such a perturbation to estimate the relative angle under which the receiver sees the interferer with respect to the transmitter. The mean-squared error of the relative angle estimation is reported for different distances between interferer and receiver. As a main result, we show that the interfering cell introduces two effects, namely "blocking" and "shadowing", that strongly affect the angle assessment. Simulation results are supported by the derivation of an analytical model that is able to make a good prediction of the average number of molecules absorbed by the target receiver as a function of the position of the interferer. Our numerical results show that, for the selected hypotheses, the best performance for the angle estimation is achieved when it is around 30o.