Principle of Parallelism in Information Transmission via an Unsecured Communication Channel

Transmission of information over an unprotected radio channel can be carried out in two ways: either using a powerful source operating in a short time interval, or using low-power sources operating in a continuous mode. In both the first and second cases, the energy of the transmitted signal can be the same. One of the main problems of information transmission is related to the properties of the medium through which the electromagnetic signal propagates. In this regard, it is necessary to study the transfer function of the medium, which can be determined using noise-like signals. This approach is known in determining the impulse transfer function of various devices, considered as a ``black box'' model. However, in the case of radio communications, it is necessary to consider the electrodynamic problem of propagation of the electromagnetic field in the atmosphere, on the surface of the earth with complex terrain, in buildings and underground structures, etc. In this case, it is necessary to use Maxwell's equations, including both the dielectric constant and the electrical conductivity of the material medium.