###### Abstract  
Various destructive weather and physical phenomena affect many parameters in the radio layer (i.e., affecting the wireless paths Over-The-Air (OTA)) of many outdoor-to-outdoor wireless systems. These destructive effects create polarization torsion and rotation of the signals propagating in space and cause the scattering of wireless spatial paths. The direct meaning is a significant degradation in system performance, especially in the Quality-of-Service (QoS). Under these challenging scenarios, intelligent utilization of advanced Multiple-Input-Multiple-Output (MIMO) techniques such as polarization-diversity and time-diversity at the transmitter, as well as at the receiver, and intelligent use of the Cross-Polarization-Isolation (XPI) mechanism, are essential. We prove that combining these techniques with the tuning of the XPI of the antennas creates optimal conditions in the wireless MIMO channels. This combination does not only improve the system's performance, but also turns the destructive physical phenomena in the spatial-domain, into an advantage. In this article, we focus on formulating a wireless communication MIMO model in millimeter-Wave (mmWave) channels under rain distortions. We demonstrate the optimal use of combining Orthogonal-Space-Time-Coding (OSTBC) and Maximal-Ratio-Receive-Combiner (MRRC) with cross-polarization diversity techniques, that utilize the tuning of the XPI. An analytical exact optimal solution is proposed, that allows the tuning of the leading parameters to achieve global optimal performance, in terms of channel-capacity and Bit-Error-Rate (BER). In addition, we propose a process of approximation of feedback-closed-loop-MIMO. The feedback is employed between the transmitter and the receiver, in the scenario of changes in the channel-response-matrix in-between successive symbol-times. The feedback was designed to acheive global-maximum channel-capacity, while preserving the channel-path orthogonality in order to minimize the BER. a 20  
* formulating a communication model that takes into account the physical phenomena and the system mechanisms (e.g., antenna parameters, channel estimation, decoding algorithms and interference-cancellation algorithms);
* finding optimal solutions regarding ultra-capacity and minimal BER performance. When transmitting considerable amounts of information on wireless channels under random physical destruction such as rich-scattering environments [5; 6], multi-interference [7], path-loss Rayleigh-Fading environments, atmospheric and weather phenomena-the proposed method is desirable. Examples of these effects are rain distortion and scattering in urban environments [8] that cause severe attenuation of the transmitted signals in addition to significant fading effects at the receiver. Moreover, these effects cause transformation of the polarization components of the propagating electromagnetic wave in the media [9; 10; 11; 12], including the outcome of None-Line-of-Site (NLOS). Considering rain distortions or urban objects means taking into account that a relationship exists between the input and the output linear depolarizing electric field components, propagating from the raindrop or the scattering objects in the medium. To illustrate the destructive rain phenomenon, it is possible to see the Figure 2e at [13], and the diagram at [9]. The effects of these phenomena on wireless communication systems based on orthogonal Dual-Polarization (DP) components, cause a deterioration in system performance, due to the sensitivity of orthogonality between polarized-signals and spatial-paths. The most important phenomenon is scattering due to impact of the electromagnetic signal with random scattering objects or raindrops, under rich scattering environments, or under heavy rain, hail and snow events. To our best knowledge, the vast literature, in the case of heavy rain, hail, and snow, does not suggest any MIMO techniques that deal with these challenging scenarios.