Efficient Sampling of Bacterial Signal Transduction for Detection of Pulse-Amplitude Modulated Molecular Signals.

The sampling of the bacterial signal transduction is investigated for molecular communication (MC). It is assumed that the finite-duration amplitude modulated, i.e., pulse-amplitude modulated (PAM), concentration of a certain type of molecule is used for information transmission. The bacterial signaling pathway is modified to transduce the input molecules to the output signal, i.e., produce green fluorescent protein (GFP). The bacterial signal transduction is composed of a set of biochemical reactions which impose randomness on the response. Therefore, the input-output relation, the timing issues, and the noise effects for the bacteria response are characterized based on both analytical and experimental observations. Sampling schemes for the raw bacteria response are proposed based on the total response duration, the peak value, the ramp-up slope, and the ramp-down slope. Each sampling scheme is shown to be providing a one-to-one and monotonic function of the input. The sampling based on the ramp-up slope is shown to be statistically favorable for the detection of PAM molecular signals. Accordingly, the time interval selection and non-coherent sampling are studied for the efficient calculation of the ramp-up slope from the raw bacteria response. This work provides a basis for the sampling of the raw bacteria response and enables accurate detection of PAM molecular signals via bacterial response for MC and sensing applications.