The room with the coordinator is just

free-space propagation with RSSI from 0 to -50 dBm.

For

free-space propagation, the received power [P.sub.r] and free-space loss [L.sub.fs] can be written as

To mitigate this problem, one can apply the zoning technique whereby parts of the lens are removed when their phase variation with respect to

free-space propagation is an integer multiple of 2[pi] [35-37].

The paper titled '

Free-space propagation of high dimensional structured optical fields in an urban environment' can be viewed through this link.

The test network has 90 nodes, all of which follow random direction mobility model and

free-space propagation model.

In the above set of equations, [mu] and [epsilon] are, respectively, the permeability and the permittivity of the medium, [omega] is the angular frequency in the unbounded medium, [beta] is the propagation constant in the medium, [k.sub.0] is the

free-space propagation constant, v is the azimuthal mode index, and primes represent differentiation with respect to the arguments of field functions.

Also, the parameters u and w are, respectively, defined as u = [square root of [([n.sub.1][k.sub.0]).sup.2] - [[beta].sup.2]] and w = [square root of [[beta].sup.2] - [([n.sub.2][k.sub.0]).sup.2]] with [beta] as the axial propagation constant and k as the

free-space propagation constant.

It also seemed odd that the computed values of [u.sub.RS.sup.(p)] and [u.sub.RS.sup.(s)] were consistently different in the near zone but the same in the mid zone, without any indication how the degree of polarization could change during the

free-space propagation of light.

As shown in Figure 1, the

free-space propagation (also sometimes called line-of-sight) model is appropriate for propagation in which there are no significant reflection paths.

The results shown assume isotropic transmit and receive antennas, and

free-space propagation conditions (path loss exponent = 2).

Namely, 5G radio frequency (RF) propagation is affected by various phenomena that more or less deteriorate the original transmitted signal arriving at the receiver (

free-space propagation, object penetration, reflection, scattering, diffraction, and absorption caused by atmospheric gases, fog, and precipitation).

with [[DELTA].sup.2.sub.t] as the Laplacian operator in the cylindrical coordinate system; [n.sub.[rho]], [n.sub.[phi]] and [n.sub.z] as the RI values along the [rho]-, [phi]- and z-directions, respectively, and [k.sub.0] as the

free-space propagation constant.