Analysis of Cumulative Distribution Function of 2-year Rainfall Measurements in Ogbomoso, Nigeria

Abstract: The conversion of most available hourly rainfall data to 1-minute integration time rain rate statistic is imperative for accurate estimation of attenuation due to rain employed in the design of both terrestrial and earth-to-space microwave systems. 2-year rainfall data collected at Ogbomoso, South-west region of Nigeria, between the periods of 2009 and 2010 was used in the analysis. Result shows that a power law relationship exists between the equiprobable rain rates of two different integration times. The regression coefficients a and b obtained are slightly different from the ITU-R recommendation. The conversion factor obtained at Ogbomoso is lower compared to Ile-Ife, in the South-west region of the country. The disagreement is attributed to the effect of global warming hitting the whole universe most especially the tropical regions. This study also reveals that different conversion factors are required for different locations even within the same climatic region

Statistical analysis of rain height over Malaysia

Rain height is one of the key parameters in rain attenuation prediction. However, few studies on it had been carried out due to unavailability of data especially over tropics. Presented here is the result of eleven years zero degree isotherm height for eight locations over Malaysia. The studies had been carried out over two main seasons in the country (Northeast and Southwest Monsoon). The result shows that rain height is grossly under estimated by ITU-R P. 839-3

Performance evaluation of an improved ITU-R rain attenuation prediction model over Malaysia equatorial region

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 older version of the recommendation

Performance of multiple antenna beamforming in higher constellation PSK signaling schemes

The quality of reception of radio signals at the destination is greatly influenced by the type of signaling schemes used and the use of multiple antennas at the output of transmitter and the input of receiver. However, this configuration usually causes InterCarrier Interference (ICI), which leads to distortions. In this paper, the performance of 6×6 multiple antenna beamforming in offset 16, 32 and 64-Phase Shift Keying (PSK) schemes is evaluated using the system model for the received signal developed to reduce distortions. The beamforming is performed on the offset signaling schemes by weighing the transmitted streams with the eigenvalues of the 6×6 antenna channel before the transmission through the 6 multiple antennas over the Rayleigh channel. The distorted signals received are demodulated and filtered by using the square root raised cosine receive filter. These signals are detected and compared with the transmitted bits to evaluate the performance using Bit Error Rate (BER). The results obtained show that as the constellation size of offset PSK schemes increases, the BER values increase and provide better performance than the corresponding conventional schemes

Prediction of rain attenuation trend due to climate change in some locations of Southwestern Nigeria

Climate change has become a phenomenon of global concern and it has resultant effect on the variability of radio propagation. In recent times, the issue of climate change has been a global phenomenon having its resultant effect on the variability of radio propagation. High-capacity radio signal fades due to absorption by atmospheric gases and scattering by hydrometeors which limits the link availability. This study is aimed at investigating the effects of climate change trend via rain attenuation along the satellite-earth path over Nigeria’s climate. Rain rates computed by using the compensated function on Semire and Rosmiwati model were utilized to estimate rain attenuations and effective path lengths using ITU-R P.618-13 model on NIGCOMSAT-1R satellite at 0.01% exceedance for selected frequencies within Ku- and K-bands. Linear trend models for annual rain attenuation were also developed. At 0.01% time unavailability, the prediction of rain attenuation on NIGCOMSAT-1R link using ITU-R P.618-13 model ranged from 14 to 28 dB at Ku-band, and rose beyond 40 dB at K-band. This study inferred that trends of rain rate distributions corresponded to the trends in attenuation due to rain and then concluded that the rising trends of yearly signal outage along earth-space path as a result of increasing rainfall intensity was due to climate change in the study area. This outcome can be explored for better communication planning and design in order to provide reliable links in order to satisfy customers’ demand for high quality radio communication