72 research outputs found
Analytical modelling of the effect of noise on the terahertz in-vivo communication channel for body-centric nano-networks
The paper presents an analytical model of the terahertz (THz) communication channel (0.1 - 10 THz) for in-vivo nano-networks by considering the effect of noise on link quality and information rate. The molecular absorption noise model for in-vivo nano-networks is developed based on the physical mechanisms of the noise present in the medium, which takes into account both the radiation of the medium and the molecular absorption from the transmitted signal. The signal-to-noise ratio (SNR) of the communication channel is investigated for different power allocation schemes and the maximum achievable information rate is studied to explore the potential of THz communication inside the human body. The obtained results show that the information rate is inversely proportional to the transmission distance. Based on the studies on channel performance, it can be concluded that the achievable transmission distance of in-vivo THz nano-networks should be restrained to approximately 2 mm maximum, while the operation band of in-vivo THz nano-networks should be limited to the lower band of the THz band. This motivates the utilisation of hierarchical/cooperative networking concepts and hybrid communication techniques using molecular and electromagnetic methods for future body-centric nano-networks
Analytical characterisation of the terahertz in-vivo nano-network in the presence of interference based on TS-OOK communication scheme
The envisioned dense nano-network inside the human body at terahertz (THz) frequency suffers a communication performance degradation among nano-devices. The reason for this performance limitation is not only the path loss and molecular absorption noise, but also the presence of multi-user interference and the interference caused by utilising any communication scheme, such as time spread ON—OFF keying (TS-OOK). In this paper, an interference model utilising TS-OOK as a communication scheme of the THz communication channel inside the human body has been developed and the probability distribution of signal-to-interference-plus-noise ratio (SINR) for THz communication within different human tissues, such as blood, skin, and fat, has been analyzed and presented. In addition, this paper evaluates the performance degradation by investigating the mean values of SINR under different node densities in the area and the probabilities of transmitting pulses. It results in the conclusion that the interference restrains the achievable communication distance to approximate 1 mm, and more specific range depends on the particular transmission circumstance. Results presented in this paper also show that by controlling the pulse transmission probability and node density, the system performance can be ameliorated. In particular, SINR of in vivo THz communication between the deterministic targeted transmitter and the receiver with random interfering nodes in the medium improves about 10 dB, when the node density decreases one order. The SINR increases approximate 5 and 2 dB, when the pulse transmitting probability drops from 0.5 to 0.1 and 0.9 to 0.5
A Holistic Investigation on Terahertz Propagation and Channel Modeling Toward Vertical Heterogeneous Networks
User-centric and low latency communications can be enabled not only by small
cells but also through ubiquitous connectivity. Recently, the vertical
heterogeneous network (V-HetNet) architecture is proposed to backhaul/fronthaul
a large number of small cells. Like an orchestra, the V-HetNet is a polyphony
of different communication ensembles, including geostationary orbit (GEO), and
low-earth orbit (LEO) satellites (e.g., CubeSats), and networked flying
platforms (NFPs) along with terrestrial communication links. In this study, we
propose the Terahertz (THz) communications to enable the elements of V-HetNets
to function in harmony. As THz links offer a large bandwidth, leading to
ultra-high data rates, it is suitable for backhauling and fronthauling small
cells. Furthermore, THz communications can support numerous applications from
inter-satellite links to in-vivo nanonetworks. However, to savor this harmony,
we need accurate channel models. In this paper, the insights obtained through
our measurement campaigns are highlighted, to reveal the true potential of THz
communications in V-HetNets.Comment: It has been accepted for the publication in IEEE Communications
Magazin
Wake-Up Transceiver Architectures with Novel Symbol Time Synchronization Schemes for ElectroMagnetic NanoNetworks
Projecte final de carrera fet en col.laboració amb Georgia Institute of
TechnologyEnglish: The work we present on this thesis covers unresolved PHY-Layer topics for Electromagnetic Nanonetworks that covers the transceiver architecture, frequency estimation for symbol synchronization and a wake-up receiver module for node synchronziation. Solving these PHY-Layer topics leads to stablish a base to propose and design network protocols on top of a well-defined architecture.Castellano: El trabajo que se presenta en este proyecto cubre temas de capa física no resueltos para Electromagnetic Nanonetworks. Se propone una arquitectura de transceiver, la estimación de frecuencia para la sincronización del tiempo de símbolo y además se propone un modulo wake-up para sincronización entre nodos. Solucionar estos temas de capa física propone establecer una base para el diseño de futuros protocols de redes diseñados sobre bajo dichas consideracionesCatalà: El traball presentat cobreix temes de capa física no resolts per a Electromagnetic Nanonetworks. Es proposa una arquitectura de transceiver, una estimació de freqüència per a la sincronització del temps de símbol i un mòdul wake-up per a sincronització entre nodes. Donant solució a aquests temes de capa física permet establir una base per al diseny de futurs protocols de xarxes dissenyats sota aquestes consideracions
Modelling of the Terahertz Communication Channel for In-vivo Nano-networks in the Presence of Noise
This paper focuses on the modelling of communication channel noise inside human tissues at the THz band (0.1-10THz). A novel model is put forward based on the study of the physical mechanism of the channel noise in the medium, which takes into account both the radiation of the medium and the molecular absorption from the transmitted signal. The derivation and the general concepts of the noise modelling is detailed in the paper. The results show that the channel noise power spectral density at the scale of several micrometres is at acceptable levels and the value tends to decrease with the increase of both distance and frequency. In addition, the channel noise is also related to the composition of the human tissues, with the result of higher channel noise in tissues with higher water concentration. The conclusion drawn from the conducted study and analysis paves the way for more comprehensive characterisation of the electromagnetic channel within in-vivo nano-networks
- …