In recent years, progresses in nanotechnology have established the foundations for implementing nanomachines capable of carrying out simple but significant tasks. Under this stimulus, researchers have been proposing various solutions for realizing nanoscale communications, considering both electromagnetic and biological communications. Their aim is to extend the capabilities of nanodevices, so as to enable the execution of more complex tasks by means of mutual coordination, achievable through communications. However, although most of these proposals show how devices can communicate at the nanoscales, they leave in the background specific applications of these new technologies. Thus, this paper shows an overview of the actual and potential applications that can rely on a specific class of such communications techniques, commonly referred to as molecular communications. In particular, we focus on health-related applications. This decision is due to the rapidly increasing interests of research communities and companies to minimally invasive, biocompatible, and targeted health-care solutions. Molecular communication techniques have actually the potentials of becoming the main technology for implementing advanced medical solution. Hence, in this paper we provide a taxonomy of potential applications, illustrate them in some detail, along with the existing open challenges for them to be actually deployed, and draw future perspectives.
Designing an optimum receiver for diffusion-based molecular communication in nano-networks needs a well justified channel model. In this paper, we present a linear and time invariant signal propagation model and an additive noise model for the diffusion-based molecular communication channel. These models are based on Brownian motion molecular statistics. Using these models, we develop the first optimal receiver design for diffusion-based molecular communication scenarios with and without inter-symbol interference. We evaluate the performance of our proposed receiver by investigating the bit error rate for small and large transmission rates.
The increasing demand for higher bandwidth and higher speed wireless communication motivates the exploration of higher frequency bands. The Terahertz (THz) band (0.06–10 THz) is envisioned as one of the key players to meet the demand for such higher bandwidth and data rates. However, the available bandwidth at THz frequencies comes with the cost of a much higher propagation loss. Due to the power limitations of compact solid-state THz transceivers, this results in very short communication distances of approximately one meter. In this paper, the concept of Ultra-Massive Multiple Input Multiple Output (UM MIMO) communication is introduced as a way to increase the communication distance and the achievable capacity of THz-band communication networks. The very small size of THz plasmonic nano-antennas, which leverage the properties of nanomaterials and metamaterials, enables the development of very large plasmonic arrays in very small footprints. For frequencies in the 0.06–1 THz range, metamaterials enable the design of plasmonic antenna arrays with hundreds of elements in a few square centimeters (e.g., 144 elements in 1 cm at 60 GHz). In the 1–10 THz band, graphene-based plasmonic nano-antenna arrays with thousands of elements can be embedded in a few square millimeters (e.g., 1024 elements in 1 mm at 1 THz). The resulting arrays can be utilized both in transmission and in reception (e.g., UM MIMO at 1 THz) to support different modes, from razor-sharp UM beamforming to UM spatial multiplexing, as well as multi-band communication schemes. After introducing the main properties of plasmonic nano-antenna arrays, the working modes of UM MIMO are presented, and preliminary results are provided to highlight the potential of this paradigm. Finally, open challenges and potential solutions to enable UM MIMO communication are described.
Nanonetworks will enable advanced applications of nanotechnology in the biomedical, industrial, environmental and military fields, by allowing integrated nano-devices to communicate and to share information. Due to the expectedly very high density of nano-devices in nanonetworks, novel Medium Access Control (MAC) protocols are needed to regulate the access to the channel and to coordinate concurrent transmissions among nano-devices. In this paper, a new PHysical Layer Aware MAC protocol for Electromagnetic nanonetworks in the Terahertz Band (PHLAME) is presented. This protocol is built on top of a novel pulse-based communication scheme for nanonetworks and exploits the benefits of novel low-weight channel coding schemes. In PHLAME, the transmitting and receiving nano-devices jointly select the optimal communication scheme parameters and the channel coding scheme which maximize the probability of successfully decoding the received information while minimizing the generated multi-user interference. The performance of the protocol is analyzed in terms of energy consumption, delay and achievable throughput, by taking also into account the energy limitations of nano-devices. The results show that PHLAME, by exploiting the properties of the Terahertz Band and being aware of the nano-devices’ limitations, is able to support very densely populated nanonetworks with nano-devices transmitting at tens of Gigabit/second.
The expectedly very limited communication distance of nanoscale machines in the Terahertz Band (0.1–10 THz) is one of the main factors narrowing the scope of the nanonetworking applications. In this paper, the use of the transparency windows in the THz Band, which provide molecular-absorption-free transmission, is proposed as a way to extend the communication distance of nanomachines. The trade-offs between the signal-to-noise (SNR) ratio, channel capacity, transmission bandwidth and communication distance for these windows are identified. The results suggest that, by focusing on the first transparency window (0.1–0.54 THz), reliable communication up to 10 m is feasible when using just 0.1 aJ per symbol to achieve a capacity of up to 10 Mbps. For the same energy per symbol, when using the entire THz Band, the capacity is up to 2 Tbps, but only for distances below a few centimeters. Motivated by these results, the achievable link throughput of a simple binary digital modulation scheme based on the transmission of width-adaptive pulses is investigated. The results show that, due to the relaxation time of molecular absorption noise, additional pauses between pulse transmissions are required, but reliable communication is possible even for very small SNR values. These results extend the application scope of nanonetworks and illustrate that they are not limited to small coverage areas but can also be used to carry traffic generated by both low-rate transactional and bandwidth-greedy applications at small-to-medium distances.
Packet routing in nanonetworks requires novel approaches, which can cope with the extreme limitations posed by the nano-scale. Highly lossy wireless channels, extremely limited hardware capabilities and non-unique node identifiers are among the restrictions. The present work offers an addressing and routing solution for static 3D nanonetworks that find applications in material monitoring and programmatic property tuning. The addressing process relies on virtual coordinates from multiple, alternative anchor point sets that act as . Each viewport offers different address granularity within the network space, and its selection is optimized by a packet sending node using a novel heuristic. Regarding routing, each node can deduce whether it is located on the linear segment connecting the sender to the recipient node. This deduction is made using integer calculations, node-local information and in a stateless manner, minimizing the computational and storage overhead of the proposed scheme. Most importantly, the nodes can regulate the width of the linear path, thus trading energy efficiency (redundant transmissions) for increased path diversity. This trait can enable future adaptive routing schemes. Extensive evaluation via simulations highlights the advantages of the novel scheme over related approaches.
This paper focuses on molecular absorption noise caused by molecular absorption in the higher frequency bands, such as THz band (0.1–10 THz). This transmission induced noise has been predicted to exist in the THz band, since the conservation of energy requires the conservation of the absorbed energy in the medium. There exist multiple models for the molecular absorption noise. Most of them focus only on the transformation of the absorbed energy directly into antenna temperature. This paper aims at giving additional perspectives to the molecular absorption noise. It is shown that the molecular absorption noise can be investigated with multiple different approaches, strongly affecting on the predicted strength and behavior of the noise. The full molecular absorption noise model is not given in this paper. Instead, we study the molecular absorption noise from different perspectives and give their derivations and the general ideas behind the noise modeling.
Circuit switched network is a fundamental component to transmit the input signal among different users within a distributed communication networks. This paper demonstrates the design of a novel fault-tolerant circuit switched network based on Quantum-Dot Cellular Automata (QCA). The design is achieved in a single layer. To design this communication network, a novel crossbar switch is proposed in this paper. The proposed circuit switched network has the major building blocks as multiplexer, demultiplexer and crossbar switch. Stuck-at-fault at the inputs as well as at the outputs is explored to design fault free circuit for crossbar switch. How the communication through crossbar switch as well as circuit switched network is disrupted due to control signal, is also demonstrated. All those proposed QCA layouts have low energy dissipation, which is shown by exploring the dissipated energy by the layouts. The designs are evaluated in terms of area, latency and logic gates. The designs are verified through matching up the results with the truth tables.
This paper presents measurements and statistical characterization to compare three potential bands of the low-THz channel, namely, the 300 to 319 GHz, 340 to 359 GHz and 380 to 399 GHz bands. From the large set of measurements performed in line-of-sight (LoS) and non-LoS (NLoS) environments, parameters for path loss model with shadowing are evaluated. Our results show that the path loss exponents for the band around 310 GHz, 350 GHz, and 390 GHz is 2.07, 1.90 and 1.96, respectively. The impacts of different materials acting as surfaces in LoS channels and reflectors in NLoS environments are also examined. Additionally, the statistical analysis due to temporal, spatial and multipath propagation is performed to determine the best fit distributions. Finally, we look at some networking scenarios in THz Band communication to derive the expressions for the number of connections a user can make based on antenna characteristics, data rate requirements and antenna mobility as well as network density. Our results suggest fundamental parameters that can be used in future THz Band analysis with applications in both macro and micro scale Internet of Things (IoT).
Quantum-dot Cellular Automata (QCA) has emerged as an attractive alternative to Complementary Metal Oxide Semiconductor (CMOS) technology in the nanoscale era. In designing arithmetic circuits, an efficient adder can play a significant role. The next generation of digital systems will be used QCA as desired technology. The QCA computational and arithmetic systems will be facilitated using an efficient QCA-based full-adder. The defects of manufacturing and variations still remain as a problem in QCA-based circuits. Being unreliable and error-prone are the weaknesses of these circuits. Therefore, in this paper, a novel QCA-based fault-tolerant full-adder design using cells redundancy is suggested. Three elements such as misalignment, missing and dislocation cells are important in analyzing the fault properties. Further, this paper aims to study the functionality and the fault-tolerant property of the proposed full-adder in the presence of QCA deposition faults. The obtained results using QCADesigner have demonstrated the proposed full-adder has better performance in terms of latency, complexity, and area in comparison to the previous full-adder designs. Also, the redundant version of full-adder has simple and strong structure compared to standard styles.
Quantum dot Cellular Automata (QCA) is one of the most commendable approach besides the other alternative approaches, which has the proficiency to replace a well-known CMOS approach in near future. QCA technology possess small size, high speed of operation, high integration density capacity and ultra-low power consumption at nano-scale level. Various design paradigms of logic circuits related with QCA have been extensively studied in the recent past. A basic design of an Inverter and 3-input majority gate serves the purpose of the fundamental logic gates to design most of the QCA circuits with accuracy. In this presentation, a new design prototype of 3-input majority gate has been proposed, which is best suited to design QCA based circuits in variety of ways according to one’s own need. The proposed 3-input majority gate has the flexibility to change the position of its input as well as output QCA cells location from one place to another according to the need of a particular design. Physical proof and power dissipation analysis is derived for the proposed 3-input majority gate. Simulation results have been obtained by implementing various circuits based on the proposed 3-input majority gate and their output is verified using QCADesigner 2.0.3 tool.
Molecular communication is a novel approach for conveying information at the nano- or micro-scale. The modulation and demodulation schemes for fixed transmitter and receiver nanomachine have been studied in previous literature. However, it is still a big challenge to perform the demodulation when the transmitter and/or the receiver is mobile. In this paper, a simple and effective demodulation scheme for a mobile receiver is investigated for 3-D scenario with drift. Inter-symbol interference (ISI) mitigation, bit alignment scheme and an adaptive threshold mechanism are proposed for correct demodulation. The parameters such as symbol interval and flow/receiver velocity ratio are simulated and analyzed in terms of bit error rate. (C) 2019 Elsevier B.V. All rights reserved.
In this paper, a micro-stereo sensor is proposed using two-identical Panda-ring resonators, which are coupled by jointed drop ports. When light from the identical coherent sources is fed into the system via the input ports, the coupling outputs are obtained at the drop port at the resonant condition. These are mixed signals in the form of stereo signals. By using different input power between the right and left systems, the phase difference generated by the Kerr-Effect in the non-linear medium leads to the shift in the coupling outputs. The shift in the center wavelength is the primary measurement of interest along with coupling crosstalk signals that are also visible at the output. The measurement self-calibration of the two channels is confirmed by the mixed channel signals. In the manipulation, the crosstalk signals can be used to interpret the cross-communication of bio-cells. The crosstalk results have shown the optical crosstalks of 2.0 and 2.5 dB are calculated and obtained, respectively. The stereo sensor sensitivity of 5.70 nmW is noted.
Communication between nanoscale devices is an area of considerable importance as it is essential that future devices be able to form nanonetworks and realise their full potential. Molecular communication is a method based on diffusion, inspired by biological systems and useful over transmission distances in the nm to range. The propagation of messenger molecules via diffusion implies that there is thus a probability that they can either arrive outside of their required time slot or ultimately, not arrive at all. Therefore, in this paper, the use of a error correcting codes is considered as a method of enhancing the performance of future nanonetworks. Using a simple block code, it is shown that it is possible to deliver a coding gain of ∼1.7 dB at transmission distances of . Nevertheless, energy is required for the coding and decoding and as such this paper also considers the code in this context. It is shown that these simple error correction codes can deliver a benefit in terms of energy usage for transmission distances of upwards of for receivers of a radius.