Prediction of Time Diversity Gain – Comparison Between ITU-R P.618-13 Using a Concept of Rain Rate with Delay and Synthetic Storm Technique

Abstract

Future satellite companies will use higher Ka and V bands. Rain fade is the most important issue in establishing reliable communication between Earth and satellites outside the 10 GHz band. The problem is exacerbated in the tropics by significant rainfall throughout the year. One way to deal with rainfall attenuation is to use a time-diversity strategy. Real-time rainfall attenuation data is needed to analyze time variability. However, data from higher frequency bands such as Ka and V bands cannot be used. As a result, the Synthetic Storm Technique (SST) was proposed to convert the measured real time rainfall data into rainfall attenuation data and predict the time diversity gain. The measured rainfall data was converted to rainfall attenuation data using the traditional SST method. Time diversity gains were predicted using Converted rainfall attenuation and the Matriciani model, and the measurements were significantly overestimated. A new concept of realtime rainfall with and without time delay is proposed and used to predict time diversity gain using ITU-R P. 618-13 and the measured rainfall distribution with delay. Therefore, the proposed method recommends using the measured long-term precipitation data to predict the gain from time diversity at the desired frequency.

Prediction of Time Diversity Gain for Earth-to-Satellite Microwave Link Design Based on Real Time Rain Intensity Measurement

“…1 shows that calculated SST attenuation and rain rate time series have similar features. In earlier analysis, SST technique [28], [29] was implemented with different velocities from 1 to 20 m/s where it was found that the predicted rain attenuation characteristics match well with that of the measured rain rate at storm velocity of 11 m/s. The most important finding is that utilizing SST as a function of observed rainfall rate, attenuation rises quickly.…”

“…One minute integration time is needed to analyze data captured in 10 second integration time intervals. A conversion from mm/10 second to mm/hr is required [29]. As a result, the integration times were represented graphically using the…”

“…With time delays of 1, 3, 5, 10, 15, 20, 25, and 30 minutes, the observed time diversity gain for both frequencies is calculated and compared to those predicted by the model. From August 1996 to July 1997, [29] and USM for 2009 [31], the cumulative distribution of recorded real time rain rate is utilized to calculate R % P. Also, time delays of 1, 3, 5, 10, 15, 20, 25, and 30 minutes were utilized to validate the cumulative distribution of recorded rain attenuation at two sites in Malaysia are compared to the equation's predictions (23). Fig.…”