Transmitter and Receiver Architectures for Molecular
Total Page:16
File Type:pdf, Size:1020Kb
1 Transmitter and Receiver Architectures for Molecular Communications: A Survey on Physical Design with Modulation, Coding and Detection Techniques Murat Kuscu, Student Member, IEEE, Ergin Dinc, Member, IEEE, Bilgesu A. Bilgin, Member, IEEE, Hamideh Ramezani, Student Member, IEEE, Ozgur B. Akan, Fellow, IEEE, Abstract—Inspired by Nature, molecular communications infrastructure [1], [2]. In that respect, MC is promising for (MC), i.e., use of molecules to encode, transmit and receive infor- novel applications especially towards information and commu- mation, stands as the most promising communication paradigm nication technology (ICT)-based early diagnosis and treatment to realize nanonetworks. Even though there has been exten- sive theoretical research towards nanoscale MC, there are no of diseases, such as continuous health monitoring, smart drug examples of implemented nanoscale MC networks. The main delivery, artificial organs, and lab-on-a-chips [3], [4] (see reason for this lies in the peculiarities of nanoscale physics, Fig. 1(a)). It bears a significant potential as an alternative to challenges in nanoscale fabrication and highly stochastic nature conventional wireless communication in environments where of biochemical domain of envisioned nanonetwork applications. the latter may fail, e.g., intrabody medium [5] and confined This mandates developing novel device architectures and com- munication methods compatible with MC constraints. To that channels like pipe networks [6], [7]. end, various transmitter and receiver designs for MC have Discrete nature of information carrying agents, i.e., been proposed in literature together with numerable modulation, molecules, and peculiarities arising from the nanophysical and coding and detection techniques. However, these works fall into biochemical processes, and computational and energy-based domains of a very wide spectrum of disciplines, including but limitations of communicating nanomachines give rise to novel not limited to information and communication theory, quan- tum physics, materials science, nanofabrication, physiology and challenges that cannot be always tackled by the conventional synthetic biology. Therefore, we believe it is imperative for the ICT methods, which are mostly tailored for electromagnetic progress of the field that, an organized exposition of cumulative means of communications with macroscale components. This knowledge on subject matter be compiled. Thus, to fill this gap, requires rethinking of the existing ICT tools and devising in this comprehensive survey we review the existing literature new ones for MC in the light of envisioned applications on transmitter and receiver architectures towards realizing MC amongst nanomaterial-based nanomachines and/or biological and considering especially available material and fabrication entities, and provide a complete overview of modulation, coding technologies, which basically set the limitations. and detection techniques employed for MC. Moreover, we identify MC has been extensively studied from various aspects the most significant shortcomings and challenges in all these over the last decade. The research efforts are mainly cen- research areas, and propose potential solutions to overcome some tered around developing information theoretical models of of them. MC channels [8], [9], devising modulation and detection Index Terms—Molecular communications, Nanonetworks, In- techniques [10], [11], and system-theoretical modeling of MC ternet of Nano Things, Transmitter, Receiver, Modulation, Cod- applications [12], [13]. For the physical design of MC trans- ing, Detection mitter (Tx) and receiver (Rx), mainly two approaches have arXiv:1901.05546v1 [cs.ET] 16 Jan 2019 been envisioned: biological architectures based on engineered I. INTRODUCTION bacteria enabled by synthetic biology, and nanomaterial-based OLECULAR communications (MC) is a bio-inspired architectures, as shown in Fig. 1(b) [1]. However, none of M communication method that uses molecules for en- these approaches could be realized yet, and thus, there is no coding, transmitting and receiving information, in the same implementation of any artificial micro/nanoscale MC system way that living cells communicate [1]. Since it is inherently to date. As a result, the overall MC literature mostly relies bio-compatible, energy-efficient and robust in physiological on assumptions isolating the MC channel from the physical conditions, it has emerged as the most promising method to processes regarding the transceiving operations, leading to a realize nanonetworks and Internet of Nano Things (IoNT), i.e., plethora of ICT techniques, feasibility and performance of artificial networks of nanoscale functional units, such as nano- which could not be validated. biosensors and engineered bacteria, integrated with the Internet Our objective in this paper is to tackle this discrepancy between the theory and practice by providing a comprehensive The authors are with the Internet of Everything (IoE) Group, Electrical account of the recent proposals for the physical design of Engineering Division, Department of Engineering, University of Cambridge, MC-Tx/Rx and the state-of-the-art in the theoretical MC re- UK, CB3 0FA (e-mail: fmk959, ed502, bab46, hr404, [email protected]). This work was supported in part by the ERC projects MINERVA (ERC- search covering modulation, coding and detection techniques. 2013-CoG #616922), and MINERGRACE (ERC-2017-PoC #780645). We provide an overview of the opportunities and challenges 2 (a) (b) Engineered Bacteria-based Biological MC-Tx/Rx MC-based Alzheimer & Epilepsy Monitoring and Brain Stilmulation Networks MC-based Information Body-Area Nanosensor Molecules Networks Transmitter MC Channel Receiver Heart Transmitted Received Monitoring Signal Signal INTERNET MC Networks Information Molecules Cancer Monitoring/ Drug Delivery MC Networks Healthcare Nano/Macroscale Provider (or Bio-Cyber) Interface Electrical Stimuli-responsive Graphene Biosensor-based Hydrogel/Graphene MC-Tx MC-Rx Fig. 1: (a) An intrabody continuous healthcare application of IoNT enabled by MC nanonetworks [1]. (b) Components of an MC system with biological and nanomaterial-based MC-Tx/Rx design approaches, which are reviewed in Section II and Section III. regarding the implementation of Tx/Rx and corresponding MC receiver. It is shown that field effect transistor (FET)- ICT techniques which are to be built on these devices. based biosensors (bioFETs) satisfy the requirements of an MC Although we mostly focus on diffusion-based MC in this receiver, i.e., nanoscale dimension, in-situ, label free, contin- review, we also partly cover other MC configuration, such as uous and selective detection of information carriers. Thus, in MC with flow, microfluidic MC, bacteria conjugation-based this paper, we mostly focus on the operation principles of MC, and molecular-motor powered MC. We first investigate bioFETs and their main design parameters that must be se- the fundamental requirements for the physical design of mi- lected to optimize performance of the device as an MC-Rx. We cro/nanoscale MC-Tx and MC-Rx, e.g., those regarding the review the possible types of bioreceptors, e.g., natural receptor energy and molecule consumption, computational complexity proteins, aptamer/DNAs, which act as the interface between and operating conditions. In light of these requirements, both the MC channel and the receiver. We also study available of the design approaches previously proposed for MC-Tx/Rx, options for the nanomaterials, e.g., silicon nanowire (SiNW) i.e., artificial Tx/Rx designs enabled by the discovery of new and graphene, used as the transducer channel, and evaluate nanomaterials, e.g., graphene, and biological Tx/Rx architec- their feasibility and potential to be a part of MC receiver tures based on the engineering tools provided by synthetic in terms of mechanical, electrical and chemical properties biology, are covered. and associated fabrication challenges. We then provide an overview of studies focusing on the modeling and performance The literature on physical design of micro/nanoscale artifi- evaluation of bioFETs from MC perspective. cial MC-Tx is almost nonexistent, except for a few approaches focusing on standalone drug delivery systems [14] and mi- Regarding biological architectures, there are more opportu- crofluidic neural interfaces with chemical stimulation capabil- nities enabled by the synthetic biology tools in engineering ities [15], [16], which, however, do not address the commu- bacteria with artificial MC-Tx/Rx functionalities. Biological nication theoretical challenges of MC. Therefore, regarding device architectures, in general, have the advantage of bio- the MC-Tx architecture, we mostly investigate and propose compatibility, a necessary condition for many MC applications several potential research directions towards nanomaterial- within healthcare and Internet of Bio-Nano Things (IoBNT) based implementation of MC-Tx based on recent advance- paradigm [1], as well as availability of already existing molec- ments in nanotechnology, novel materials and microfluidics. ular machinery for sensing, transmitting and propagation at We will particularly focus on the utilization of nanoporous micro/nanoscale, all of which are prone to be utilized for MC graphene membranes in microfluidic settings to control the nanonetworking. In terms of Tx architectures, biological-based release of information molecules through electric field. For approaches also prove advantageous thanks to the