Comparison of measured rain attenuation and ITU-R predictions on experimental microwave links in Malaysia

Abstract

This paper presents the results of direct rain attenuation measurements carried out on four experimental microwave links, installed at UTM, Malaysia. The links operate at frequencies of 15, 22, 26, and 38 GHz and the cumulative distribution function for different rain rates have been generated from the measured 4-year rain gauge data. The experimentally measured attenuation data have been compared with International Telecommunication Unior-R rain attenuation predictions; and it has been found that the latter have underestimated the measured values, especially at higher rain rates. The deviations have been modeled as a function of rain rate exceedances R%p. It is hoped that the study will provide useful information for estimation of rainfall attenuation on microwave links in tropical regions that have similar situation to Malaysia.

Rain attenuation and worst month statistics verification and modeling for 5G radio link system at 26 GHz in Malaysia

“…As clarified in the last paragraph, rain characteristics in tropical regions may cause a real obstacle against the propagation of mm‐wave signals. Raindrops may interact with the propagated signal by imposing various physical effects such as scattering, reflection, absorption, depolarization, and rain temperature . Each raindrop will act as an obstacle facing the microwave signal, particularly, when raindrop size is comparable to the signal wavelength as depicted in Figure .…”

Rain attenuation of millimetre wave above 10 GHz for terrestrial links in tropical regions

“…The effect increases further with higher frequency bands, rainfall rates, longer path length, and larger raindrop sizes. This attenuation, caused by rain, reduces the reliability, systems availability, reception of signal‐to‐interference‐plus‐noise ratio (SINR), and overall performance of the communications link . As a result, rain attenuation is a real and concerning issue facing the implementation of mm‐waves, especially in tropical regions with consistent heavy rainfall such as Malaysia.…”

“…Rainfall is a significant impediment that obstructs the propagation of mm‐wave signals from transmitter to receiver. Millimeter‐wave signals can be absorbed, scattered, depolarized, and diffracted by rain . This can restrict the propagation of mm‐wave signals, causing high signal attenuation loss through the effective propagation path length (km) measured in dB/km.…”

“…Rain attenuation harshly increases when the frequency, rain density, or effective length are increased. This attenuation reduces the reliability, availability, and degraded the overall performance of the communications link . As a result, rain attenuation is a real and concerning issue facing the implementation of mm‐waves, especially in tropical regions with consistent heavy rainfall.…”

“…Several rain attenuation studies have been conducted to investigate the effect of rain on the propagation of mm‐wave bands in different environments while considering several scenarios. A number of these studies succeeded in conducting measurements . They gave indications about the behavior of mm‐wave band propagation during precipitation.…”