Rainfall and Diffraction Modeling for Millimeter-Wave Wireless Fixed Systems

Abstract

Rain attenuation is the main practical problem that confronts wireless signals specifically when it uses millimeter-waves for fifth-generation (5G) communication systems. In addition, due to that the urban environments are characterized by many high buildings act as diffraction objects can block the signal path and produce non-line of sight (NLOS) situations. These diffraction materials can cause further considerable losses that disturb the received power at the 5G receiver. This paper proposes a new model can investigate the influence of both precipitation and diffraction phenomena on wireless point to point (PPT) communication systems. This new research work utilizes measured rainfall data and actual scenarios in an urban environment to simulate the wireless PPT system and examine the influence of rainfall and knife-edge diffraction (KED) on the performance of the PPT system and signal strength at the receiver. Several durations of exceedances of rain rates and various operation scenarios have been employed to study and analyze the status of 5G wireless system links. The results indicated that there is an exchange of the effect of rain and KED diffraction in the lower millimeter-waves compared to the higher millimeter-waves. This study declares that at higher frequency bands the rain attenuation is observed to be greater, the diffraction loss is higher, and the path loss is also larger compared to the effect of these three factors seen at lower frequency bands. Furthermore, specific carrier frequencies, as in the case of 60 GHz, undergo extra huge atmospheric absorption loss which can diminish the communication coverage of the PPT system link.

Keywords

• Rain rate
• rain attenuation
• millimeter-waves
• KED mechanism
• antenna height
• 5G