Mohammad Upal Mahfuz

On the characterization of binary concentration-encoded molecular communication in nanonetworks

Abstract In this study, nanoscale communication networks have been investigated in the context of binary concentration-encoded unicast molecular communication suitable for numerous emerging applications, for example in healthcare and nanobiomedicine. The main focus of the paper has been given to the spatiotemporal distribution of signal strength and modulation schemes suitable for short-range, medium-range, and long-range molecular communication between two communicating nanomachines in a nanonetwork. This paper has principally focused on bio-inspired transmission techniques for concentration-encoded molecular communication systems. Spatiotemporal distributions of a carrier signal in the form of the concentration of diffused molecules over the molecular propagation channel and diffusion-dependent communication ranges have been explained for various scenarios. Finally, the performance analysis of modulation schemes has been evaluated in the form of the steady-state loss of amplitude of the received concentration signals and its dependence on the transmitter–receiver distance.

Characterization of intersymbol interference in concentration-encoded unicast molecular communication

This paper characterizes intersymbol interference (ISI) in a unicast molecular communication between a pair of nanomachines in a nanonetwork. Correspondingly, a transmission-controlled approach based on reduced pulse-width transmission has been proposed in order to mitigate ISI. Binary amplitude modulation has been assumed for the concentration-encoded signaling. Characteristics of interference signal strength (as a fraction of total available signal strength at the location of receiving nanomachine) have been explained in terms of communication range, pulse-width, and data rate of the system. Performance evaluation has been explained in the form of improvement by reducing interference with a reduced pulse-width approach. Results based on numerical analyses with three suitable propagation media (air, water, and human blood plasma) have been shown for the sake of potential applications in the field of nano-bio-communication and healthcare nanomedicine. Finally, it is concluded that ISI is a significant issue in molecular communication, and the proposed reduced pulse-width based approach saves signal energy and improves ISI performance in concentration-encoded molecular communication.

A comprehensive study of sampling-based optimum signal detection in concentration-encoded molecular communication.

In this paper, a comprehensive analysis of the sampling-based optimum signal detection in ideal (i.e., free) diffusion-based concentration-encoded molecular communication (CEMC) system has been presented. A generalized amplitude-shift keying (ASK)-based CEMC system has been considered in diffusion-based noise and intersymbol interference (ISI) conditions. Information is encoded by modulating the amplitude of the transmission rate of information molecules at the TN. The critical issues involved in the sampling-based receiver thus developed are addressed in detail, and its performance in terms of the number of samples per symbol, communication range, and transmission data rate is evaluated. ISI produced by the residual molecules deteriorates the performance of the CEMC system significantly, which further deteriorates when the communication range and/or the transmission data rate increase(s). In addition, the performance of the optimum receiver depends on the receivers ability to compute the ISI accurately, thus providing a trade-off between receiver complexity and achievable bit error rate (BER). Exact and approximate detection performances have been derived. Finally, it is found that the sampling-based signal detection scheme thus developed can be applied to both binary and multilevel (M-ary) ASK-based CEMC systems, although M-ary systems suffer more from higher BER.

Strength-based optimum signal detection in concentration-encoded pulse-transmitted OOK molecular communication with stochastic ligand-receptor binding

Abstract In this paper, a strength-based optimum signal detection scheme for binary concentration-encoded molecular communication (CEMC) system has been presented. In CEMC, a single type of information molecule is assumed to carry the information from the transmitting nanomachine (TN), through the propagation medium, to the receiving nanomachine (RN) in the form of received concentration of information molecules at the location of the RN. We consider a pair of nanomachines communicating by means of on–off keying (OOK) transmission protocol in a three-dimensional ideal (i.e. free) diffusion-based unbounded propagation environment. First, based on stochastic chemical kinetics of the reaction events between ligand molecules and receptors, we develop a mathematical receiver model of strength-based detection scheme for OOK CEMC system. Using an analytical approach, we explain the receiver operating characteristic (ROC) curves of the receiver thus developed. Finally, we propose a variable threshold-based detection scheme and explain its communication range and rate dependent characteristics. We show that it provides an improvement in the communication ranges compared to fixed threshold-based detection scheme. (Part of this paper has been peer-reviewed and published in BWCCA-2012 conference in Victoria, BC, 12–14 November, 2012 [20] .)

Spatiotemporal distribution and modulation schemes for concentration-encoded medium-to-long range molecular communication

Spatiotemporal distribution and modulation schemes suitable for medium-to-long range molecular communication and networks have been investigated in this paper. This research has basically focused on bio-inspired transmission techniques for concentration-encoded nanoscale molecular communication system. Spatiotemporal distribution of a carrier signal in the form of concentration of diffused molecules and diffusion-dependent ranges are explained. Finally, the performance of modulation schemes has been evaluated in the form of steady state loss of amplitude of received concentration signals and its dependence to transmitter-receiver distance.

A comprehensive study of concentration-encoded unicast molecular communication with binary pulse transmission

In this paper we present a set of performance metrics for a pulse-based concentration-encoded unicast molecular communication system between a pair of nanomachines. We have also evaluated the performance of these metrics in the form of desired signal and interference signal strengths, transient loss, intersymbol interference (ISI) characteristics, and detection sensitivity of a binary amplitude-modulated scheme. The performance metrics are found to have a significant dependence on data rate of the system and communication distance between the transmitter and the receiver.

A Comprehensive Analysis of Strength-Based Optimum Signal Detection in Concentration-Encoded Molecular Communication With Spike Transmission

In this paper, a comprehensive analysis of strength-based optimum signal detection model has been presented for concentration-encoded molecular communication (CEMC) with spike (i.e., impulsive) transmission based on amplitude-shift keying (ASK) and on-off keying (OOK) modulations. Strength-based optimum signal detection problem in diffusion-based CEMC system has been investigated in detail in the presence of both diffusion noise and intersymbol interference (ISI). The receiver for optimum signal detection has been developed theoretically and explained with both analytical and simulation results of binary signal detection. Results show that the receiver thus developed can detect CEMC symbols effectively; however, the performance is influenced by three main factors, namely, communication range, transmission data rate, and receiver memory. For both ASK and OOK receivers, exact and approximate detection performances have been derived analytically depending on the probabilistic nature of molecular availability and the relationship between mean and variance of signal strengths. Correspondingly, bit error rate (BER) performance of the optimum receiver in a single CEMC link is further evaluated under various scenarios through extensive simulation experiments.

On the characteristics of concentration-encoded multi-level amplitude modulated unicast molecular communication

In this paper we have investigated into a multi-level amplitude modulation (M-AM) scheme for concentration-encoded unicast molecular communication between a transmitting nanomachine (TN) and a receiving nanomachine (RN) in a nanonetwork. The performance of M-AM scheme has been evaluated on the basis of signal strength in the form of average loss of concentration of received molecules at the location of RN, and interference strength in the form of concentration of undesired molecules that originate at previous symbol but provide additional concentration of molecules over the transmission rate, and interfere with the detection of current symbol. In order to evaluate signal strength and interference strength characteristics two performance metrics have been proposed and explained by observing their behavior as a function of communication range and number of amplitude levels. In addition, results of M-AM scheme have been compared with conventional binary scheme in order to show the corresponding improvement and/or drawbacks when a random sequence of bits is transmitted.

Strength Based Receiver Architecture and Communication Range and Rate Dependent Signal Detection Characteristics of Concentration Encoded Molecular Communication

In this paper for the first time ever a strength (energy) based receiver architecture of binary pulse amplitude modulated (PAM) concentration-encoded molecular communication (CEMC) system between communicating nanomachines has been presented. We also analyze the communication range and data rate dependent signal detection characteristics of a PAM CEMC system in a three dimensional ideal (free) diffusion based unbounded propagation environment. A unicast CEMC channel with a single type of information molecules has been assumed to carry the information from the transmitting nanomachine (TN), through the propagation medium, to the receiving nanomachine (RN) in the form of received concentration of information molecules at the location of the receptor of the RN. We develop a mathematical model of strength based detection method for a PAM CEMC system, explain its dependence on communication range and transmission data rate, compare it with a single pulse transmission case, and determine the impacts of intersymbol interference (ISI) contributed by all the previous bits of information to the current bit duration.

Transient characterization of concentration-encoded molecular communication with sinusoidal stimulation

In this paper we present an analysis of transient loss and detection noise margin of a molecular communication system based on sinusoidal stimulation. The molecular propagation channel is based on ideal diffusion of molecules. A set of possible performance metrics has been proposed and their characteristics have been analyzed for various operating frequencies of the stimulation. Transient loss and detection noise margin have shown a significant dependence on communication range and operating frequency in a noiseless channel. Finally, the effectiveness of the metrics in a frequency-shift keying (FSK) modulated scheme has been explained.