Single and multi-user capacity of communication by silence in terahertz band

Abstract

Nanotechnology utilizes the operation of nano-sensors also called nano-machines. Nano-machines are very small in size, about a few hundreds of nanometers. At the nanoscale, single nano-machine has very limited functionalities so it is able to perform only a simple task. However, the group of nano-machine can perform complex tasks when they communicate among themselves. The tasks performed by those machines have applications in the field of biomedical, environmental, and military. There are various models of communication among nano machines, like electromagnetic wireless communication, molecular communication, acoustic communication, nano-mechanical communication model. In this studies, electromagnetic wireless communication model is used with the latest advancement in graphene based electronic. Graphene and its derivatives points that the frequency range of operation of future electronic nano-machines is terahertz band (0.1 – 10.0 THz). This band of frequency is still unlicensed and it can theoretically support a very large transmission speed. Nano-machines, due to its small size have resource constrain. Nano-machines with nano-batteries are typically characterized by a limited energy supply. Hence, to overcome the power limitation, there is a need of an energy-efficient communication paradigm. Such an energy-efficient communication paradigm is communication through silence (CtS) strategy. This strategy enables energy-efficient information transfer within the nano-machines. In CtS, information is transmitted using silence period which makes this strategy energy-efficient. This thesis is focused in this new communication paradigm, CtS. The performance from this strategy is evaluated in terms of channel capacity for both single and multiple user cases in terahertz band. A propagation model for terahertz band based on radiative transfer theory is used to calculate the total path loss and the molecular absorption noise that a travelling wave suffers. Chanel capacity was formulated in this studies using those parameters. Analytical result in this studies shows that the performance is very high for both lower distance like, 1 meter and lower number of water vapour (H2O) molecules