Measuring Distance From Single Spike Feedback Signals in Molecular Communication

Systems of bionanomachines may benefit future applications which require interaction with biological systems at the nano- to microscale. Molecular communication is a suitable communication mechanism for autonomous bionanomachines which are limited in size and capability and for interfacing with biological systems. In molecular communication, a bionanomachine transmits information to a receiver bionanomachine by modulating the concentration of molecules in the environment. One promising direction for molecular communication is for a bionanomachine to measure the distance to another bionanomachine in order to perform location-based functionality or to adapt communications using the measured distance. In this paper, a bionanomachine measures the distance to another bionanomachine by requesting the other bionanomachine to transmit a feedback signal of many molecules transmitted over a short time interval (i.e., a single spike of molecules). Upon receiving the feedback signal, the bionanomachine which requested the feedback signal then estimates distance by measuring the Round Trip Time (RTT) or Signal Attenuation (SA) of the received feedback signal. The propagation of molecules and the receiving of molecules are modeled to investigate how distance impacts measured RTT and SA. Simulations are performed to measure the accuracy of the distance measurement, the time required to measure distance, and how the number of molecules transmitted affects accuracy.