In upcoming years, the advancement in nanotechnologies is expected to accelerate the development of integrated devices with the size ranging from one to a few hundred nanometers. With the aim of developing miniaturised classical machines and creating nano-devices with new functionalities, nanotechnologies have produced and continued creating some novel nano-materials and nano-particles with new behaviours and properties that are not observed at the microscopic level. The links and connectivity between nano-devices distributed through collaborative efforts lead to the envision of nano-networks, followed by the nano-communication proposal. The limited capabilities of nano-machines in terms of processing power, complexity and range of operations can be expanded by this collaborative communication. It is sustaining the revolutionary transition from the Internet of things to the Internet of nano-things.

Nanotechnology is providing the engineering community with a new set of tools to create miniature machines, which has a few cubic micrometers in size, and functions including sensing, actuation, computation, and data storing [1]. A large number of such nanomachines can accomplish more complex tasks collaboratively, with the capability of wireless communications. In light of this direction, nanonetworks, i.e., networks of nanomachines, can enable transformative and promising applications in the biomedical, environmental, security, defense, and consumer fields, as revealed by Akyildiz et al. [2].

In this chapter, the authors will introduce a general system model for nano electromagnetic communication networks based on the NS-3 framework and explain each element in the context of drug delivery application. Finally, we will also describe an experimental platform that can be used to validate the simulation model.

In this chapter, an overview of wearable antennas operating in the terahertz frequency range made from two-dimensional materials such as graphene is presented. The antenna designs are analyzed in realistic environments in the proximity of human skin. Characteristics such as highly miniaturized and flexible substrate materials of the antennas coupled with excellent antenna performance make these wearable antennas a strong candidate in applications of short-range wireless communication near the human body. The resonant properties of the two-dimensional materials are investigated using their electronic properties. Wireless communication in the terahertz frequency, high-resolution imaging for bio-sensing and disease management, and spectroscopy are anticipated to be some of the early beneficiaries of wearable and flexible antennas. Further investigations in this area of research provide interesting opportunities not only for antenna engineers but also for material scientists and physicists.

This chapter mainly focuses on various sensing technologies that have been employed to detect food and water contamination. It has been found that these conventional sensing technologies appear to be unfeasible and impractical to meet with the challenging growth of population. In this aspect, THz sensing is discussed in detail and deemed to be more effective due to its strong penetration feature, high resolution, and sensitivity to monitor the molecular changes in fruits. This chapter also introduces a novel technique of fruits contamination detection by monitoring MC and observe the transmission and path loss response of fruits. It also investigates an important parameter such as the absorption coefficient and shows some significant results and correlation of MC with transmission response and absorption coefficient. Upon close analysis, these results give meaningful information about the composites present in fruits such as carbohydrates and proteins. Toward the end, this chapter emphasizes on the advancement and development of terahertz technology applications and found that the THz sensing is a promising candidate and has a potential to change a paradigm in the plant science sector.

In this chapter, the path loss and molecular absorption noise models for the in vivo THz communication are introduced. Moreover, the analytical results on SNR and information rate with flat and Gaussian pulse-based power allocation scheme are presented. It indicates that the maximum achievable transmission distance of in vivo THz communication should be restrained to approximately 1-2 mm, and more specific transmission distance limitation depends on the composition of the transmission medium, especially the water concentration of the medium. The operation band of iWNSNs is limited to the frequencies lower than 1 THz. The information rate decreases steadily with the increase in the transmission distance regardless of the type of the medium and can reach several Gbps when the transmission distance is 0.5 mm. Afterwards, an interference model for iWNSNs with the utilisation of TS-00K is developed based on the mathematical apparatus of stochastic geometry. The performance of the multi-user communication inside human blood, skin and fat is comparatively illustrated, showing that blood is the worst performing scenario because of higher water concentration than skin and fat. In all three kinds of tissues, the obtained results show that high node density and pulse transmission probability would potentially decrease SINR of the system and impair the system performance. Flat and Gaussian-pulse based power distribution scheme behaves differently in different tissues in the THz frequencies. Therefore, a proper power allocation should be selected based on the specific application. The presented results provide an important basis for more practical network-level modelling, stimulating further research on simple, reliable and energy efficient communication protocols and coding schemes.

This chapter aims to provide insights into the modulation and coding schemes (MCS) tailored for-and synchronization issues faced by-the nano-scale electromagnetic communication systems operating in the terahertz (THz) band. The MCS is of paramount importance for the works dealing with rate and power adaptation by the transmitter when channel state information at transmitter (CSIT) of the link is available. Synchronization, on the other hand, refers to frequency, phase, and timing synchronization and is the pre-requisite for many modern signal processing operations, advanced multi-antenna techniques, and advanced modulation techniques. Some prominent examples that require synchronization include decoding at the receiver, multi-input, multi-output (MIMO) systems, beamforming, and orthogonal frequency division multiplexing (OFDM).

Nano-electromagnetic communication networks, namely, wireless nano networks (WNNs), are wireless communication networks composed of interacting nanonodes (sizes ranging from a few hundred cubic nanometers to micrometers). The extremely limited capabilities and resources of nanonodes, as well as the severe path loss of terahertz band communication in WNNs, represent a challenge to the communication distance among nanonodes and the overall network performance. Therefore, appropriate routing protocols are necessary for guaranteeing multihop communication in WNNs. In this chapter, the existing routing protocols for WNNs are comprehensively analyzed and classified into three categories: limit-flood-areabased routing protocols, dynamic-infrastructure-based (DIF-based) routing protocols, and single-path-based routing protocols. Based on the peculiarities of WNNs, especially the constrained resources and limited energy supply, the features of each protocol are presented through a detailed comparison. Finally, by integrating the features of WNNs and the problems of existing routing technologies, we present our views on the future research directions of routing techniques in WNNs.

Nanonetworks consist of nano-sized communication devices that perform simple tasks such as computation, data storage, and actuation at the nanoscale. However, communication in nanonetworks is constrained by error-prone wireless links due to severe path loss in the terahertz band (0.1-10.0 THz) and the very limited energy storage capacity of nanodevices. Therefore, efficient and effective error-control protocols are required for nanonetworks in the THz band. In this chapter, first, the related works on error control for nanonetworks are presented and investigated by considering the corresponding features. Second, a new error-control strategy with probing (ECP) mechanism for nanonetworks powered by energy harvesting is proposed. In particular, each data packet will not be transmitted until the communication of one probing packet is successful. Third, an energy state model is presented by considering the energy-harvesting-consumption process based on the extended Markov chain approach. Moreover, a probabilistic analysis of overall network traffic and multiuser interference is used by the proposed energy state model to capture dynamic network behavior. Following that, the impact of the energy consumption of different packets on state transition and the state probability distribution of nanonodes based on the above model are comprehensively investigated. Finally, the performance of the ECP mechanism is investigated and evaluated in terms of end-to-end successful packet delivery probability, end-to-end packet delay, achievable throughput, and energy consumption by comparing with other four different error-control strategies, such as automatic repeat request (ARQ), forward error correction (FEC), error prevention code (EPC), and a hybrid EPC (HEPC).

The performances of the nano-EM communication network are thoroughly investigated with the inclusion of the overview of the current development of terahertz (THz) technologies, which is generally considered as the most promising candidate of the frequency choices. At the same time, a profound growth has been seen by the wireless interaction of the human bodies with the nano devices in the past few years. Such growth would cause the global wearable devices market increasing from 20 million in 2015 to 187.2 million annually by 2020, which also emphasizes the importance of such studies in the book.