Diffusive Mobile MC With Absorbing Receivers: Stochastic Analysis and Applications

Abstract

This paper presents a stochastic analysis of the time-variant channel impulse response (CIR) of a three dimensional diffusive mobile molecular communication (MC) system where the transmitter, the absorbing receiver, and the molecules can freely diffuse. In our analysis, we derive the mean, variance, probability density function (PDF), and cumulative distribution function (CDF) of the CIR. We also derive the PDF and CDF of the probability p that a released molecule is absorbed at the receiver during a given time period.The obtained analytical results are employed for the design of drug delivery and MC systems with imperfect channel state information. For the first application, we exploit the mean and variance of the CIR to optimize a controlled-release drug delivery system employing a mobile drug carrier. We evaluate the performance of the proposed release design based on the PDF and CDF of the CIR. We demonstrate significant savings in the amount of released drugs compared to a constant-release scheme and reveal the necessity of accounting for the drug-carrier's mobility to ensure reliable drug delivery. For the second application, we exploit the PDF of the distance between the mobile transceivers and the CDF of p to optimize three design parameters of an MC system employing on-off keying modulation and threshold detection. Specifically, we optimize the detection threshold at the receiver, the release profile at the transmitter, and the time duration of a bit frame. We show that the proposed optimal designs can significantly improve the system performance in terms of the bit error rate and the efficiency of molecule usage.

Membrane Fusion-Based Transmitter Design for Static and Diffusive Mobile Molecular Communication Systems

“…We further assume that the TX and RX are perfectly synchronized since several practical synchronization schemes for MC have been studied and proposed in [23]. For demodulation of b w at the RX, we adopt a widely-investigated threshold detector that compares the number of molecules absorbed during the wth bit interval with a detection threshold [13]. In this paper, we consider the threshold of the detector is fixed for simplicity.…”

“…2) Mobile MC: In Fig. 9(b), we plot the average BER Q m versus the fixed detection threshold ξ as in [13] for mobile MC, where different TX and RX diffusion coefficients and the number of molecules stored within each vesicle are applied to investigate their impacts on the average BER.…”

“…However, these studies considered a mobile ideal point TX that releases molecules instantaneously while moving. [12] and [13] considered a mobile transparent RX that does not interact with molecules and a mobile non-transparent RX, respectively, where statistical properties of the time-varying channel were derived. For bit transmission, [12] assumed that the distance between the TX and the RX is known when bits are transmitted, and [13] ignored the inter-symbol interference (ISI) when performing the error probability analysis.…”

“…[12] and [13] considered a mobile transparent RX that does not interact with molecules and a mobile non-transparent RX, respectively, where statistical properties of the time-varying channel were derived. For bit transmission, [12] assumed that the distance between the TX and the RX is known when bits are transmitted, and [13] ignored the inter-symbol interference (ISI) when performing the error probability analysis. [14] derived the distribution of the number of molecules observed at a mobile transparent RX.…”

Modulation and Signal Detection for Diffusive-Drift Molecular Communication with a Mobile Receiver

“…It is generally applied in applications like health monitoring [11] and water quality monitoring [12] where nanomachines are static. In MMC, however, nanomachines can move directionally or randomly to perform certain tasks such as target searching [13] and drug delivering [14,15]. is illustrates a great potential of MMC in long-distance communication and cancer treatment [16,17].…”