Comparison of ITU models performance in predicting Malaysia′s tropical Rainfall Rate and Rain Attenuation at 26GHz mm-wave propagation

Comparative study of the performance of different ITU model in predicting Malaysia tropical climate properties.

Comparison of ITU models performance in predicting Malaysia′s tropical Rainfall Rate and Rain Attenuation at 26GHz mm-wave propagation

Comparative study of the performance of different ITU model in predicting Malaysia tropical climate properties.

Investigation of accuracy of rain-rate and rain-attenuation prediction models in satellite communications based on meteorological skills

Rainfall is a major destructive factor which severely reduces the quality and reliability of propagated signals in satellite communications. Hence, rain-attenuation prediction plays a vital role in the satellite radio link planning and engineering. The accuracy of the rain-attenuation prediction models depends on two things; (i) the accuracy of rain-rate information and (ii) the area of study. Therefore, selecting an appropriate rain-attenuation prediction model for a new site without having any specific prediction model and experimental measured rain-rate would be challenging. In this regard, this letter takes advantage of climatology skills to find an accurate model for such kind of areas. To do so, we study the Urmia-site (37.55° N, 45.1° E) and its communication link with the Eutelsat 25A (25.5° E), where there is no available experimental measured data and specific prediction models for that site. Therefore, based on the meteorological skills, the Yong-in site in South-Korea (37.43° N, 126.93° E) was chosen, as a homogeneous area with Urmia, which has available measured data of rainfall and rain-attenuation. Afterward, the most common used global prediction models are applied to Yong-in and the results are compared with the existing measurements. Consequently, the more accurate rain-rate and rain-attenuation prediction models are investigated and generalized to Urmia, which are the ITU-R P.837-5 model with 34% r.m.s. and the Joo-Hwan model with 18% r.m.s., respectively. Finally, the amount of rain-attenuation in different useful frequency bands (10-50 GHz) is investigated for Urmia by the Joo-Hwan model.

Dynamic Beam Hopping Time Slots Allocation Based on Genetic Algorithm of Satellite Communication under Time-Varying Rain Attenuation

Beam hopping technology is considered to provide a high level of flexible resource allocation to manage uneven traffic requests in multi-beam high throughput satellite systems. Conventional beam hopping resource allocation methods assume constant rainfall attenuation. Different from conventional methods, by employing genetic algorithm this paper studies dynamic beam hopping time slots allocation under the effect of time-varying rain attenuation. Firstly, a beam hopping system model as well as rain attenuation time series based on Dirac lognormal distribution are provided. On this basis, the dynamic allocation method by employing genetic algorithm is proposed to obtain both quantity and arrangement of time slots allocated for each beam. Simulation results show that, compared with conventional methods, the proposed algorithm can dynamically adjust time slots allocation to meet the non-uniform traffic requirements of each beam under the effect of time-varying rain attenuation and effectively improve system performance.

Development of a new rain attenuation model for tropical location

This study proposes a new rain attenuation prediction model (RAM) based on the rain cell concept for tropical locations. The new model addresses the research gap in the international telecommunications union (ITU) model. Results obtained show that the proposed RAM predicted the possibility of signal across seven (7) out of thirteen (13) stations monitored. The predicted attenuation values were 18.3427 dB, 18.8106 dB, 18.3921 dB, 13.8062 dB, 20.8803 dB, 9.4519 dB, and 19.6018 dB for Jalingo, Jos, Makurdi, Mubi, Otukpo, Sokoto, and Abuja respectively. However, the RAM predicted outage across six stations with predicted attenuation values of 31.7040 dB, 26.8302 dB, 28.6635 dB, 29.6562 dB, 28.8827 dB, and 30.0614 dB for Akwa-Ibom, Benin, Donga, Port-Harcourt, Owerri, and Aba respectively. The proposed RAM hence suggests an additional Ku-band spot beam power of at least 331.97 watts for Nigeria's Nigerian communication satellite-1 (NIGCOMSAT-1R) Ku-band transponder to overcome the predicted attenuation across the six stations which recorded signal outage. The results from this study can be used by network engineers for the implementation of fade mitigation techniques (FMTs) such as site diversity and power control to aid telecommunication networks anticipate changes and allocate resources accordingly.