Abstract
Molecular signaling is ubiquitous across scales in nature and finds useful applications in precision medicine and heavy industry. Characterizing noise in communication systems is essential to understanding its information capacity. To date, research in molecular nano communication (MNC) primarily considers the molecular dynamics within the medium, where various forms of stochastic effects generate noise. However, in many real-world scenarios, external effects can also influence molecular dynamics and cause noise. Here, the noise due to the temperature fluctuations from incident electromagnetic (EM) radiation is considered, with applications ranging from cell signaling to chemical engineering. EM radiation and subsequent molecular absorption cause temperature fluctuations which affect molecular dynamics and can be considered as an exogenous noise source for MNC. In this paper, the probability density function of the radiation absorption noise (RAN) is analyzed and to demonstrate applicability, we include characteristics of different tissues of the human body. Furthermore, the closed-form expression of error probability (EP) for MNC under the radiation noise is derived. Numerical analysis is demonstrated on different tissues of the human body: skin, brain, and blood, as well as the polarization factor of incident EM radiation is demonstrated. The coupling relationship between the radiation frequency and the intrinsic impedance of the human body on the PDF of radiation absorption noise is presented. This is useful for understanding how mutual information changes with external radiation sources.
Highlights
Extreme environments present a significant challenge to conventional wireless signals that are used for monitoring, control, and communications
The parameters used for analysis are as follows: Stefan’s proportionality constant (σ ) is equal to 5.670373 x 103 W m−2K −4 [23], intrinsic impedance (η, in ) of body tissues can be calculated from [27] for THz and [21], [28] for MHz frequency range and value of emissivity ( ) is taken from [31]
Either increase in intrinsic impedance or increase in polarization factor shifts the noise peak towards LHS
Summary
Extreme environments present a significant challenge to conventional wireless signals that are used for monitoring, control, and communications. Authors in [8] analyses the effect of molecular absorption noise which has been carried out for different tissues of the human body such as fat, blood, skin, etc., but from EMNC point of view. It is noticeable that as per the authors’ best knowledge, to date, none of the literature has presented analytical expressions of the RAN as function of temperature due to the absorption of EM energy by the molecules of the medium and its effect on Molecular information transfer (MIT). 2) Novel closed form expression for the PDF of the proposed RAN is presented which includes the impedance of the human body tissues (skin, brain, and blood), the polarization factor of incident and frequency of incident EM wave. Substituting PF from Eq (22) and PD form Eq (24) into Eq (25) we get final expression of error probability under
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