MDPI - Publisher of Open Access Journals

20 pages, 5419 KiB

Open AccessArticle

On the Physical Layer Security Peculiarities of Wireless Communications in the Presence of the Beaulieu-Xie Shadowed Fading

by Aleksey S. Gvozdarev and Tatiana K. Artemova

Mathematics 2022, 10(20), 3724; https://doi.org/10.3390/math10203724 - 11 Oct 2022

Cited by 4 | Viewed by 1690

Abstract

The article presents an analysis of the physical layer security of a wireless communication system functioning in the presence of multipath fading and a wiretap. Under the assumption of the equal propagation conditions (both for the legitimate receiver and the eavesdropper) described by the shadowed Beaulieu–Xie model, a closed-form expression for the secrecy outage probability was derived. The correctness of the obtained expression was numerically verified via comparison with the direct numerical integration. The truncated version of the obtained expression was analyzed for various channel parameters to establish the requirements for numerically efficient implementation (in terms of the number of summands delivering the desired precision). An in-depth study of the secrecy outage probability dependence from all the possible channel parameters for different fading scenarios was performed, including heavy fading and light fading, with and without strong dominant and multipath components. The performed research demonstrated the existence of the secrecy outage probability non-uniqueness with the respect to the average signal-to-noise ratio in the main channel and the relative distance between the legitimate and wiretap receivers. Full article

(This article belongs to the Special Issue Mathematical Methods for Computer Science)

► Show Figures

Figure 1

8 pages, 250 KiB

Open AccessArticle

On Nonuniqueness of Quantum Channel for Fixed Input-Output States: Case of Decoherence Channel

by Congjie Ou and Sumiyoshi Abe

Symmetry 2022, 14(2), 214; https://doi.org/10.3390/sym14020214 - 22 Jan 2022

Viewed by 2307

Abstract

For a fixed pair of input and output states in the space

H_{A}

of a system A, a quantum channel, i.e., a linear, completely positive and trace-preserving map, between them is not unique, in general. Here, this point is discussed specifically [...] Read more.

For a fixed pair of input and output states in the space

H_{A}

of a system A, a quantum channel, i.e., a linear, completely positive and trace-preserving map, between them is not unique, in general. Here, this point is discussed specifically for a decoherence channel, which maps from a pure input state to a completely decoherent state like the thermal state. In particular, decoherence channels of two different types are analyzed: one is unital and the other is not, and both of them can be constructed through reduction of B in the total extended space

H_{A} \otimes H_{B}

, where

H_{B}

is the space of an ancillary system B that is a replica of A. The nonuniqueness is seen to have its origin in the unitary symmetry in the extended space. It is shown in an example of a two-qubit system how such symmetry is broken in the objective subspace

H_{A}

due to entanglement between A and B. A comment is made on possible relevance of the present work to nanothermodynamics in view of quantum Darwinism. Full article

(This article belongs to the Special Issue Thermodynamics for Finite-Size and Time-Dependent Behavior: Small Systems, Fluctuations, Correlations, and Internal Heterogeneity)

Search Results (2)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (2)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI