Adaptive detection and ISI mitigation for mobile molecular communication

Current studies on modulation and detection schemes in molecular communication mainly focus on the scenarios with static transmitters and receivers. However, mobile molecular communication is needed in many envisioned applications, such as target tracking and drug delivery. Until now, investigations about mobile molecular communication have been limited. In this paper, a static transmitter and a mobile bacterium-based receiver performing random walk are considered. In this mobile scenario, the channel impulse response changes due to the dynamic change of the distance between the transmitter and the receiver. Detection schemes based on fixed distance fail in signal detection in such a scenario. Furthermore, the intersymbol interference (ISI) effect becomes more complex due to the dynamic character of the signal which makes the estimation and mitigation of the ISI even more difficult. In this paper, an adaptive ISI mitigation method and two adaptive detection schemes are proposed for this mobile scenario. In the proposed scheme, adaptive ISI mitigation, estimation of dynamic distance and the corresponding impulse response reconstruction are performed in each symbol interval. Based on the dynamic channel impulse response in each interval, two adaptive detection schemes, concentration-based adaptive threshold detection (CATD) and peak-time-based adaptive detection (PAD), are proposed for signal detection. Simulations demonstrate that, the ISI effect is significantly reduced and the adaptive detection schemes are reliable and robust for mobile molecular communication

Nonnegative Code Division Multiple Access Techniques in Molecular Communication

In molecular communication, two types of multiple access have been studied: time division and molecule division. In this work, we consider code division multiple access. However, unlike code division multiple access that has been used for electromagnetic signals, we investigate optical code division multiple access: since molecular signals have the same non-negativity feature as optical signals, this scheme is a promising solution for molecular communication. In this thesis, we perform experiments and set up simulation models which match these experiments. Moreover, using simulations, we find the features of optical code division multiple access for molecular communication. Our results include an optimal information transmission scheme, and an algorithm to decode molecular information signals. Finally, we demonstrate reliable communication with multiple access by using this scheme

A comprehensive survey of recent advancements in molecular communication

With much advancement in the field of nanotechnology, bioengineering and synthetic biology over the past decade, microscales and nanoscales devices are becoming a reality. Yet the problem of engineering a reliable communication system between tiny devices is still an open problem. At the same time, despite the prevalence of radio communication, there are still areas where traditional electromagnetic waves find it difficult or expensive to reach. Points of interest in industry, cities, and medical applications often lie in embedded and entrenched areas, accessible only by ventricles at scales too small for conventional radio waves and microwaves, or they are located in such a way that directional high frequency systems are ineffective. Inspired by nature, one solution to these problems is molecular communication (MC), where chemical signals are used to transfer information. Although biologists have studied MC for decades, it has only been researched for roughly 10 year from a communication engineering lens. Significant number of papers have been published to date, but owing to the need for interdisciplinary work, much of the results are preliminary. In this paper, the recent advancements in the field of MC engineering are highlighted. First, the biological, chemical, and physical processes used by an MC system are discussed. This includes different components of the MC transmitter and receiver, as well as the propagation and transport mechanisms. Then, a comprehensive survey of some of the recent works on MC through a communication engineering lens is provided. The paper ends with a technology readiness analysis of MC and future research directions

Molecular Communication: From Theory to Practice

Always-on, always-available digital communication has changed the world – allowing us to collaborate and share information in ways unimaginable not long ago. Yet many of the physical principles used in everyday digital communication break down as the size of the devices approach micro- or nano-scale dimensions. As a result, tiny devices, with dimensions of microns or less, need to do something different in order to communicate. Moreover, at meter scales there are areas where use of radio signals is not possible or desirable. An emerging biomimetic technique called molecular communication, which relies on chemical signaling is a promising solution to these problems. Although biologists have studied molecular communication extensively, it is very poorly understood from a telecommunication engineering perspective. Engineering molecular communication systems is important since micro- and nano-scale systems are the key to unlocking a realm of futuristic possibilities such as: self-repairing machines, micro- and nano-scale robotics, synthetic biological devices, nanomedicine, and artificial immune systems that detect and kill cancer cells and pathogens. All these transformative applications have one feature in common: they involve not just single devices working independently, but swarms of devices working in concert. Besides solving the communication problem at small scales, use of molecular communication in areas such as robotics, and infrastructure monitoring can unlock new applications in smart cities and disaster search and rescue. In this dissertation, after providing a comprehensive survey of the field, two areas of study with high potential impact are identified: on-chip molecular communication, and experimental platforms for molecular communication. First, on-chip molecular communication is investigated towards the goal of networking components within lab-on-chip devices and point-of-care diagnostic devices. This has numerous applications in medicine, environmental monitoring systems, and the food industry. Then in the second part of the dissertation, a tabletop demonstrator for molecular communication is designed and built that could be used for research and experimentation. In particular, no macroscale or microscale molecular communication platform capable of reliably transporting sequential data had existed in the past, and this platform is used to send the world's first text message ("O Canada") using chemical signals