In this paper, real measurements were conducted to investigate the impact of rain on the propagation of millimeter waves at 26 GHz. The measurements were accomplished using a microwave fifth generation radio link system with 1.3 km path length implemented at Universiti Teknologi Malaysia Johor Bahru, Malaysia. The implemented system consisted of Ericsson CN500 mini E-link, radio unit, rain gauge, and data logger. The measurements were attained and logged daily for a continuous year, with 1-min time intervals. Next, the MATLAB software was used to process and analyze the annual rain rate and rain attenuation, including for the worst month. From the analyzed results, it was found that at 0.01% percentage of time, the rain rate was 120 mm/hr; while the specific rain attenuation was 26.2 dB/km and the total rain attenuation over 1.3 km was 34 dB. In addition, the statistics acquired from the measurements for the worst month were lower than what was predicted by the international telecommunication union (ITU) model; around 51% and 34% for the rain rate and rain attenuation, respectively. The average percentage of error calculated between the measurements and predicted results for the rain rate and rain attenuation were 143% and 159%, respectively. Thus, it can be concluded that the statistics for the worst month in Malaysia is lower than what was predicted by the ITU model.

Real Measurement Study for Rain Rate and Rain Attenuation Conducted Over 26 GHz Microwave 5G Link System in Malaysia

Rain is a major source of attenuation for microwave propagation above 10 GHz. In tropical and equatorial regions, the rain intensity is high. Therefore, designing terrestrial and Earth-to-satellite microwave links is very critical and challenging. The raindrop-size distribution and the rain-rate distribution are two important parameters used for attenuation prediction. Both are proposed based on measured data and the rain-rate conversion technique. In this paper, rain attenuation was directly measured at different frequencies for terrestrial and Earth-to-satellite links, in order to investigate prediction models. The reduction factor and frequency scaling were investigated and proposed to predict total attenuation. Worst-month and annual statistics were also analyzed, based on measurements. Moreover, this paper summarizes all contributions related to rain-caused attenuation for microwave propagation in Malaysia's tropical climate.

Review of Rain Attenuation Studies in Tropical and Equatorial Regions in Malaysia: An Overview

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

Attenuation due to rainfall is one of the most fundamental constraints on the performance of satellite links above 10 GHz. This work presents the results of rain attenuation measurement using radar data collected from MMD and DIDM, Malaysia. The results were compared with newly improved ITU-R P530-16 and four other selected tropical rain attenuation prediction models. The statistical analysis showed that ITU-R P 530-16 has significantly addressed the problem of rain attenuation underestimation prediction as presented by the older version of the recommendation. Although point accuracy is far-fetched in reality, more improvement is needed on the model so as to address its insufficiency in tropical and equatorial rain attenuation estimation.

Validation of New ITU-R Rain Attenuation Prediction Model over Malaysia Equatorial Region

Rain seriously influences the performance of a communications satellite link. A good knowledge of the statistical behavior of rain attenuation in a particular region is vital. Radio propagation research has been undertaken at University Science Malaysia (USM) to study the effect of rain on satellite-Earth communications link. The worst-month analysis for rain attenuation and rain rate is presented. The probability relation between the annual and worst-month statistics follows a power law relation. The values of A and /spl beta/ obtained suggests that the global values proposed by ITU is not suitable for Malaysia which is situated in the tropical region.

Worst-month rain attenuation statistics for satellite-Earth link design at Ku-band in Malaysia

Attenuation due to rain is an important constraint in microwave radio link design especially at frequencies above 10 GHz in temperate climates. However, it has been shown in some literature that rain also plays an important role in radio signal attenuation below 10 GHz in tropical and equatorial climates which experience higher precipitation rates. Due to the scarcity of rain attenuation data for the tropical region, a definitive attenuation model can only be derived from long term data collection in this region. In this paper, the results of two years rain rate data and six months radiometer data are presented. The rain data is measured using a tipping bucket type (0.5 mm) rain gauge with one minute integration time. The radiometer data were taken for 45 and 90 degrees elevation using a dual channel unbalanced Dicke radiometer. Both the rain gauge and radiometer data were analysed in event and statistical terms. The attenuation derived from radiometer measurements gives a higher value of attenuation compared to rain gauge measurements. It was also found that at for 0.01% of the time, the rain rate is lower than that given by the ITU (formerly CCIR) for P region climate.

M.M.M. Yusoff

Papers

Rain attenuation prediction at 6.75 GHz in Malaysia using rain gauge and radiometer measurements