Wireless Nanonetworks Research Articles

Toward Modeling and Assessing the Disorientation and Misalignment Effect in Optical Wireless Nano-Networks

Toward Modeling and Assessing the Disorientation and Misalignment Effect in Optical Wireless Nano-Networks

Self-configuring asynchronous sleeping in heterogeneous networks

Nowadays, the heterogeneous wireless nano-network topology becomes a need for diverse applications based on heterogeneous networks composed of regions of different node densities. In Wireless Nano-networks (WNNs), nodes are of nano-metric size and can be potentially dense in terms of neighbouring nodes. Nano-nodes have limited resources in terms of processing, energy and memory capabilities. In nano-network(s), even in a communication range limited to tens of centimeters, thousands of neighbours can be found. We proposed a fine-grained duty-cycling method (sleeping mechanism), appropriate to nanonodes, which aims to reduce the number of receptions seen by a node during data packet routing. The present study reveals the usefulness of implementing the sleeping mechanism in heterogeneous networks, as well as configuring a dynamic awaken duration for nodes based on a density estimation algorithm. We also proposed an algorithm that helps in increasing the reliability of the packet received by the destination node.

Optimal Resource Allocations for Statistical QoS Provisioning to Support mURLLC Over FBC-EH-Based 6G THz Wireless Nano-Networks

One of most important techniques for enabling the sixth-generation (6G) mobile wireless network lies in how to efficiently guarantee various stringent quality-of-service (QoS) performance-metrics to support the emerging massive Ultra-Reliable Low-Latency Communications (mURLLC) in 6G. Correspondingly, finite blocklength coding (FBC) has been developed as an effective technique to significantly improve various QoS indices for mURLLC through implementing short-packet communications. On the other hand, Terahertz (THz) band wireless nano-communications have been widely envisioned as a promising 6G technique to efficiently support utra-high data-rate (up to 1 Tbps). One of the major constraints over THz-band nano-networks is the severely limited energy that can be accessed by nano devices. Towards this end, various novel energy harvesting (EH) mechanisms have been proposed to remedy the energy scarcity problem. However, how to accurately characterize the relationships among THz wireless channels, energy consumption, and EH models for FBC based nano communications remains a challenging problem to support statistical delay and error-rate bounded QoS provisioning over FBC based 6G THz wireless nano-networks. To overcome these challenges, in this paper we propose optimal resource allocation policies to achieve the maximum ε-effective capacity in the THz band over FBC-EH-based nano-networks. Particularly, we establish nano-scale system models and characterize wireless channel models in the THz band using FBC. In order to support statistical delay and error-rate bounded QoS provisioning, we formulate and solve the ε-effective capacity maximization problem under several different EH constraints for our proposed schemes. Simulation results are included, which validate and evaluate our proposed schemes in the finite blocklength regime.

Fractal Graphene Patch Antennas and the THz Communications Revolution

Fractal antennas have and are continuing to receive attention in regard to the future of wireless communications. This is because of their wide- and multi-band capabilities, the opportunity of fractal geometries to drive multiple resonances, and, the ability to make smaller and lighter antennas with fewer components and radiative elements with higher gains. Small scale (i.e. on the micro- and nano-scale) and ultra high frequency (in the Terahertz or THz range) fractal antennas composed of Graphene have the potential to enhance wireless communications at a data rate that is unprecedented, i.e. ∼ 1012 bits per second. A Fractal Graphene antenna is a high-frequency tuneable antenna for radio communications in the THz spectrum, enabling unique applications such as wireless nano-networks. This is because (mono-layer) Graphene is a one-atom-thick two-dimensional allotrope of Carbon with the highest known electrical conductivity that is currently unavailable in any other material, including metals such as Gold and Silver. Thus, combining the properties of Graphene with the self-affine characteristics of a fractal at the micro- and nano-scale, provides the potential to revolutionise communications, at least in the near field (the order of a few metres) for low power systems. In this paper, we consider the basic physics and some of the principle mathematical models associated with the development of this new disruptive technology in order to provide a guide to those engaged in current and future research, a fractal Graphene antenna being an example of an advanced material for demanding applications. This includes some example simulations on the THz field patterns generated by a fractal patch antenna composed of Graphene whose conductivity is taken to scale with the inverse of the frequency according to a ‘Drude’ model. The approach to generating THz sources using Graphene is also explored based on Infrared laser pumping to induce a THz photo-current.

Exploring network-level performances of wireless nanonetworks utilizing gains of different types of nano-antennas with different materials

Wireless nanonetworks are not a simple extension of traditional communication networks at the nano-scale. Owing to being a completely new communication paradigm, existing research in this field is still at an embryonic stage. Furthermore, most of the existing studies focus on performance enhancement of nanonetworks via designing new channel models and routing protocols. However, the impacts of different types of nano-antennas on the network-level performances of the wireless nanonetworks remain still unexplored in the literature. Therefore, in this paper, we explore the impacts of different well-known types of antennas such as patch, dipole, and loop nano-antennas on the network-level performances of wireless nanonetworks. We also investigate the performances of nanonetworks for different types of traditional materials (e.g., copper) and for nanomaterials (e.g., carbon nanotubes and graphene). We perform rigorous simulation using our customized ns-2 simulation to evaluate the network-level performances of nanonetworks exploiting different types of nano-antennas using different materials. Our evaluation reveals a number of novel findings pertinent to finding an efficient nano-antenna from its several alternatives for enhancing network-level performances of nanonetworks. Our evaluation demonstrates that a dipole nano-antenna using copper material exhibits around 51% better throughput and about 33% better end-to-end delay compared to other alternatives for large-size nanonetworks. Furthermore, our results are expected to exhibit high impacts on the future design of wireless nanonetworks through facilitating the process of finding the suitable type of nano-antenna and suitable material for the nano-antennas.

EEWNSN: Energy Efficient Wireless Nano Sensor Network MAC Protocol for Communications in the Terahertz Band

Wireless Nano Sensor Networks (WNSNs) are a dense deployment of nano sensors that communicate through electromagnetic waves over the Terahertz band (0.1–10 THz). The extreme energy, processing power and memory capacity limitation of nano-scale devices and the peculiarities of high operating frequency introduce the requirement to design novel communication paradigm and light MAC protocols for WNSNs. In this paper, we present a new Energy Efficient Wireless Nano Sensor Network MAC protocol (EEWNSN-MAC) for mobile multi-hop wireless nanonetworks. The proposed protocol takes advantage of the clustering mechanism and TDMA scheduling scheme to alleviate the mobility effects and transmission collisions. We evaluate performance of the EEWNSN-MAC protocol compared with a similar previously proposed nano-MAC protocol called “Smart-MAC”. For this purpose, we utilize a new NS-3 simulator module named nano-sim. This evaluation is done for three critical metrics in WNSN, namely, the total energy that is consumed per sent/received packet on the network, the packet loss ratio (PLR) and scalability. Finally, the simulation results demonstrate that the EEWNSN-MAC protocol improves the network performance in terms of energy consumption and PLR and it is more scalable compared to the “Smart-MAC” algorithm.

Large scale MEMS robots cooperative map building based on realistic simulation of nano-wireless communications

The Claytronics project has produced interesting hardware components like cylindric micro-robots called catoms and software models to enable the concept of programmable matter. One application is the use of several catoms linked together so that they can “walk”. These walkers can explore an area and thanks to electromagnetic wireless nano-networks, they can communicate with each other sharing the map of the place to explore. In this paper, we study the different parameters influencing the transmission quality of the map to a sink which uses both traditional wireless and wireless nano-communication networks.

Optimizing Energy Consumption in Terahertz Band Nanonetworks

In this paper, we develop a technique for achieving the maximum utilization of harvested energy in perpetual wireless nanonetworks, where nanonodes communicate in the THz frequency band. Because of their nano-scale sizes, nanonodes cannot store large amounts of energy. Compounding the problem, the arrival of energy is not constant, but follows a stochastic process. Therefore, an optimum design for the consumption of this limited amount of energy is required. We model the problem as a Markov decision process, where we include the energy for both reception and transmission of packets. We analyze the performance of the energy harvesting and consumption processes for very low energy harvesting rates and small energy storage capacity. We compare the performance of the optimal policy with intuitive energy consumption policies. Next, since solving an optimized problem of this sort is too compute-intensive for nanonodes with limited resources, we propose a light-weight heuristic method that can perform close to optimal. Simulation results show that our heuristic model and the optimal model can serve as a framework for the design of nanonodes that operate in low rate stochastic energy harvesting conditions with limited energy storage.

Channel Modeling and Capacity Analysis for Electromagnetic Wireless Nanonetworks in the Terahertz Band

Nanotechnologies promise new solutions for several applications in the biomedical, industrial and military fields. At the nanoscale, a nanomachine is considered as the most basic functional unit which is able to perform very simple tasks. Communication among nanomachines will allow them to accomplish more complex functions in a distributed manner. In this paper, the state of the art in molecular electronics is reviewed to motivate the study of the Terahertz Band (0.1-10.0 THz) for electromagnetic (EM) communication among nano-devices. A new propagation model for EM communications in the Terahertz Band is developed based on radiative transfer theory and in light of molecular absorption. This model accounts for the total path loss and the molecular absorption noise that a wave in the Terahertz Band suffers when propagating over very short distances. Finally, the channel capacity of the Terahertz Band is investigated by using this model for different power allocation schemes, including a scheme based on the transmission of femtosecond-long pulses. The results show that for very short transmission distances, in the order of several tens of millimeters, the Terahertz channel supports very large bit-rates, up to few terabits per second, which enables a radically different communication paradigm for nanonetworks.