Diffusive MIMO Molecular Communications: Channel Estimation, Equalization and Detection

In diffusion-based communication, as for molecular systems, the achievable data rate is low due to the stochastic nature of diffusion which exhibits a severe inter-symbol-interference (ISI). Multiple-Input Multiple-Output (MIMO) multiplexing improves the data rate at the expense of an inter-link interference (ILI). This paper investigates training-based channel estimation schemes for diffusive MIMO (D-MIMO) systems and corresponding equalization methods. Maximum likelihood and least-squares estimators of mean channel are derived, and the training sequence is designed to minimize the mean square error (MSE). Numerical validations in terms of MSE are compared with Cramer-Rao bound derived herein. Equalization is based on decision feedback equalizer (DFE) structure as this is effective in mitigating diffusive ISI/ILI. Zero-forcing, minimum MSE and least-squares criteria have been paired to DFE, and their performances are evaluated in terms of bit error probability. Since D-MIMO systems are severely affected by the ILI because of short transmitters inter-distance, D-MIMO time interleaving is exploited as countermeasure to mitigate the ILI with remarkable performance improvements. The feasibility of a block-type communication including training and data equalization is explored for D-MIMO, and system-level performances are numerically derived.Comment: Accepted paper at IEEE transaction on Communicatio

Analyzing Large-Scale Multiuser Molecular Communication via 3D Stochastic Geometry

arXiv admin note: text overlap with arXiv:1605.08311arXiv admin note: text overlap with arXiv:1605.08311Information delivery using chemical molecules is an integral part of biology at multiple distance scales and has attracted recent interest in bioengineering and communication theory. Potential applications include cooperative networks with a large number of simple devices that could be randomly located (e.g., due to mobility). This paper presents the first tractable analytical model for the collective signal strength due to randomly-placed transmitters in a three-dimensional (3D) large-scale molecular communication system, either with or without degradation in the propagation environment. Transmitter locations in an unbounded and homogeneous fluid are modelled as a homogeneous Poisson point process. By applying stochastic geometry, analytical expressions are derived for the expected number of molecules absorbed by a fully-absorbing receiver or observed by a passive receiver. The bit error probability is derived under ON/OFF keying and either a constant or adaptive decision threshold. Results reveal that the combined signal strength increases proportionately with the transmitter density, and the minimum bit error probability can be improved by introducing molecule degradation. Furthermore, the analysis of the system can be generalized to other receiver designs and other performance characteristics in large-scale molecular communication systems

Nano/Bio-Receiver Architectures and Detection Methods for Molecular Communications

Internet of Nano Things (IoNT) is an emerging technology, which aims at extending the connectivity into nanoscale and biological environments with collaborative networks of artificial nanomachines and biological entities integrated into the Internet. To enable the IoNT and its groundbreaking applications, such as real-time intrabody health monitoring, it is imperative to devise nanoscale communication techniques with low-complexity transceiver architectures. Bio-inspired molecular communications (MC), which uses molecules to transfer information, is the most promising technique to realise IoNT due to its inherent biocompatibility and reliability in physiologically-relevant environments. Despite the substantial body of work concerning MC, the implications of an interface between MC channel and practical MC transceiver architectures are largely neglected, leading to a major gap between theory and practice. As the first step to remove this discrepancy, in this thesis, I develop a realistic analytical ICT model for microfluidic MC with surface-based receivers as a convection-diffusion-reaction system. In the second part, I focus on biological MC receivers, which can be implemented in living cells using synthetic biology tools. In this direction, I theoretically develop low-complexity and reliable MC detection methods exploiting the various statistics of the stochastic ligand-receptor interactions at the membrane of biological MC receivers. The estimation and detection theoretical analysis of these detection methods demonstrate that even single type of receptors can provide sufficient statistics to overcome the receptor saturation problem, cope with the interference of non-cognate molecules, and simultaneously sense the concentration of multiple types of ligands. I also propose synthetic receptor designs for the transduction of decision statistics into a representation by concentration of intracellular molecules, and design chemical reaction networks performing decoding with intracellular reactions. Finally, I fabricate a micro/nanoscale MC receiver based on graphene field-effect transistor biosensors and perform its ICT characterisation in a custom-designed microfluidic MC system with the information encoded into the concentration of DNAs. This experimental platform is the first practical demonstration of micro/nanoscale MC, and can serve as a testbed for developing realistic MC methods

NASA's Microgravity Research Program

This fiscal year (FY) 1997 annual report describes key elements of the NASA Microgravity Research Program (MRP) as conducted by the Microgravity Research Division (MRD) within NASA's Office of Life and Microgravity, Sciences and Applications. The program's goals, approach taken to achieve those goals, and program resources are summarized. All snapshots of the program's status at the end of FY 1997 and a review of highlights and progress in grounds and flights based research are provided. Also described are major space missions that flew during FY 1997, plans for utilization of the research potential of the International Space Station, the Advanced Technology Development (ATD) Program, and various educational/outreach activities. The MRP supports investigators from academia, industry, and government research communities needing a space environment to study phenomena directly or indirectly affected by gravity

Channel Coding in Molecular Communication

This dissertation establishes and analyzes a complete molecular transmission system from a communication engineering perspective. Its focus is on diffusion-based molecular communication in an unbounded three-dimensional fluid medium. As a basis for the investigation of transmission algorithms, an equivalent discrete-time channel model (EDTCM) is developed and the characterization of the channel is described by an analytical derivation, a random walk based simulation, a trained artificial neural network (ANN), and a proof of concept testbed setup. The investigated transmission algorithms cover modulation schemes at the transmitter side, as well as channel equalizers and detectors at the receiver side. In addition to the evaluation of state-of-the-art techniques and the introduction of orthogonal frequency-division multiplexing (OFDM), the novel variable concentration shift keying (VCSK) modulation adapted to the diffusion-based transmission channel, the lowcomplex adaptive threshold detector (ATD) working without explicit channel knowledge, the low-complex soft-output piecewise linear detector (PLD), and the optimal a posteriori probability (APP) detector are of particular importance and treated. To improve the error-prone information transmission, block codes, convolutional codes, line codes, spreading codes and spatial codes are investigated. The analysis is carried out under various approaches of normalization and gains or losses compared to the uncoded transmission are highlighted. In addition to state-of-the-art forward error correction (FEC) codes, novel line codes adapted to the error statistics of the diffusion-based channel are proposed. Moreover, the turbo principle is introduced into the field of molecular communication, where extrinsic information is exchanged iteratively between detector and decoder. By means of an extrinsic information transfer (EXIT) chart analysis, the potential of the iterative processing is shown and the communication channel capacity is computed, which represents the theoretical performance limit for the system under investigation. In addition, the construction of an irregular convolutional code (IRCC) using the EXIT chart is presented and its performance capability is demonstrated. For the evaluation of all considered transmission algorithms the bit error rate (BER) performance is chosen. The BER is determined by means of Monte Carlo simulations and for some algorithms by theoretical derivation

Macro-Scale Molecular Communications

The use of electromagnetic (EM) waves to transmit information has allowed our society to collaborate and share information on a scale that was unimaginable just a few decades ago. But as with any technology, there are areas where EM-based communications do not function well. For example, underwater and underground communications where EM waves experience high attenuation. This limitation has generated interest in an alternative mode of information transmission, molecular communications. In this thesis, after giving a survey of micro- and macro-scale molecular communications, the two most important aspects of molecular communications are identified: macroscale molecular communications and the experimental analysis of molecular communications. Molecular communication has been dominated so far by interest in the nano-scale, where the application focus is on drug-delivery and DNA communications, etc. Studies in the macro-scale are relatively rare compared to nano- and micro-scale research. This thesis looks closely at macro-scale molecular communication and attempts to improve our understanding of this novel communication paradigm. To achieve this, a mathematical model was developed, based on the advective-diffusion equation (ADE). The model was compared with experimental results, and showed a strong correlation. In addition, a model was developed to simulate molecular communication in both 1D and 3D environments. To generate the modulated chemicals and transmit them in the environment, an inhouse- built odour generator was used, and to detect the chemicals in the environment a mass spectrometer (MS) with a quadrupole mass analyser (QMA) was employed. Mass spectrometers have the ability to distinguish multiple chemicals in the environment concurrently, making them ideal detectors for use in molecular communications. Based on the experimental setup, various aspects of the communication paradigm are investigated in the three main sections. The first section focuses on the fundamental parameters that govern the propagation of molecules in a flow. The second section delves into the communication properties of this new form of information transfer. The final section studies aspects of simultaneous multiple-chemical transmission. Based on this multiple-chemical transmission, modulation methods are developed that exploit this new approach for use in molecular communications

NASA's Microgravity Science Research Program

The ongoing challenge faced by NASA's Microgravity Science Research Program is to work with the scientific and engineering communities to secure the maximum return from our Nation's investments by: assuring that the best possible science emerges from the science community for microgravity investigations; ensuring the maximum scientific return from each investigation in the most timely and cost-effective manner; and enhancing the distribution of data and applications of results acquired through completed investigations to maximize their benefits

Art and Technology: coherence, connectedness, and the integrative field

Merged with duplicate record 10026.1/690 on 03.04.2017 by CS (TIS)This thesis is a theoretical and practical intervention in the field of art and technology. It proceeds from the re-examination of four specific domains that in the past 40 years have considerably informed the invention of new aesthetic forms. They are: art, science, nature and technology. We have identified that each one of these domains and the way they inform one another reflects the influence of a Western analytical tradition based on fragmentation, dichotomies and dualities. In consequence of this, art of the last decades has suffered from a sort of mechanistic thought which results from a predominantly weary aesthetic model, founded in dualities such as: object/process, form/behaviour, meaning/information. The main question that the present study addresses is how to overcome this predominantly reductionist inheritance and to develop an aesthetic model able to interconnect in an integrative fashion those disparate domains, respective discourses and practices? The answer to this question, developed throughout this thesis, is an aesthetic principle built upon the notions of resonance, coherence and field models, rooted in an integrative view of living organisms based on the theory of biophotons. This constitutes the main contribution of the thesis to new knowledge. The theoretical approach of this thesis is developed upon the revision of the concept of form, supported by a Gestalt analysis as provided by Rudolf Arnheim, and has involved the consideration of the ideas of Gilbert Simondon (the concept of "concretisation") and Vilem Flusser (the concept of "apparatus"), in order to gain a deeper insight into the nature of technology. In conclusion, the practice-based methodology of this thesis has been to develop artworks based on the confluence of living organisms (plants) and artificial systems in order to permit empirical observation and reflection on the proposed theory. The major outcome of the practice is the artwork "Breathing", a hybrid creature made of a living organism (a plant) and an artificial system. The creature responds to its environment through movement, light and the noise of its mechanical parts and interacts with the observer through his/her act of breathing. This work is the result of an investigation into plants as sensitive agents for the creation of art. The intention was to explore new forms of artistic experience through the dialogue of natural and artificial processes

Advanced Trends in Wireless Communications

Physical limitations on wireless communication channels impose huge challenges to reliable communication. Bandwidth limitations, propagation loss, noise and interference make the wireless channel a narrow pipe that does not readily accommodate rapid flow of data. Thus, researches aim to design systems that are suitable to operate in such channels, in order to have high performance quality of service. Also, the mobility of the communication systems requires further investigations to reduce the complexity and the power consumption of the receiver. This book aims to provide highlights of the current research in the field of wireless communications. The subjects discussed are very valuable to communication researchers rather than researchers in the wireless related areas. The book chapters cover a wide range of wireless communication topics