Department of Physics.
Permanent URI for this communityhttp://itsupport.cu.edu.ng:4000/handle/123456789/28754
Welcome to the Department of Physics.
Browse
Search Results
Item Global Transmission Margins Determination and Cloud Attenuation Models at Satellite Bands(Scientific Research, New Technologies and Applications Vol. 7, 2024) Adewusi, O. M.; Ometan, O. O.; Akinwumi, S. A.; Omotosho, T. V.; Akinyemi, M. I.Considering the fact that various dimensions of disturbances occur in the atmospheric layers randomly, which often have consequential footprints on the troposphere where mankind naturally lives, there is an obvious need for periodic determination of effective transmission margins consistently for most geographic locations on Earth. The need for the achievement of an effective wireless transmission margin and larger bandwidth at a relatively lower cost precipitates the importance of hydrometeor models’ roles in satellite transmissions. Also, the almost perpetual existence of clouds in tropical climates makes cloud models all the more fundamental. Details of four years of station spectrum analyzer data, five years of climatological data and fifty – eight years of radiosonde data used in this research at tropical test station - Ota, southwest Nigeria - were earlier published. At the station, total cloud attenuation data were measured and logged every minute using the spectrum analyzer. The large data was used to deduce the station cloud attenuation cumulative distribution, which was used to derive the station's new cloud attenuation algorithm. This cumulative distribution was compared with the station cloud attenuation cumulative distribution of each of the other existing cloud models. The radiosonde data was used to derive each existing cloud model’s predicted cloud attenuation cumulative distribution respectively for the tropical station. These sets of distributions were used to deduce the station's new cloud attenuation algorithm’s parameters through a written and published simulation program, which defined the cloud attenuation model for the station. Thus, the generation of any new station cloud attenuation model only fundamentally requires the station’s radiosonde data. The integrity of the radiosonde data renders cloud cover data and all others for a station only for graphical comparisons and corroboration. Thus, the new cloud attenuation algorithm can be used to develop the cloud attenuation model for any geographic location by using the methodology reviewed above and whose details were earlier published. Subsequently, the collected spectrum analyzer data, climatological data and acquired radiosonde data were used to compute projected attenuation values for each cloud attenuation model at propagation signal frequencies between 12 GHz to 50 GHz. The predicted values were extracted and analysed statistically. Spectrally, the station's new cloud attenuation model’s cumulative distribution proportionally averaged the other model’s characteristic cumulative distributions as shown by the graphical figures. The results show that convergence of the range of predicted attenuation values by each of the cloud models increases directly with frequency. Hence, global hydrometeor transmission margins for any set of locations can be determined through the explained method, at an effective frequency.Item Path Loss Prediction on Earth-Space Link Using Statistical and Time Series Approach at Ka-Band in Abuja, North Central Nigeria(ICSAEES-2024, Lagos, Nigeria, 2024) Arijaje, T. E.; Omotosho, T. V.; Aizebeokhai, A. P.Predictive path loss modelling is essential in designing wireless communication systems. However, the empirical methods of path loss prediction are inaccurate as the empirical models cannot be implemented outside the area or region where they are developed. This study focuses on improving the prediction of path loss using statistical approaches such as multiple linear regression (MLR) and time series models using eight (2014 – 2021) data retrieved from the global precipitation measuring mission (GPM) at Ka-band. The step-wise selected method was adopted for the multiple linear regression (MLR). In the exponential smoothing method, weighting is carried out exponentially, decreasing in the direction of the older values. The MLR analysis revealed that the MLR model performs well, with an accuracy of 99.52%. The R2 value of 99.52% indicated a strong correlation between the estimated and predicted path loss in the model. PL = 18.706 0.98459 − Pr +1.60027Pt + 0.99808Gr The P-value of the regression model is 0.000, indicating that the model estimated by the MLR procedure is statistically significant at a level of 0.05. Also, the results showed that the transmitted antenna gain is the most contributed predictor in the path loss with a value of 1.60027 dB. Likewise, the results from the exponential smoothing models revealed that the single exponential smoothing (SES) model performs better than the double exponential smoothing model with a mean absolute percentage error (MAPE) of 14.47%, indicating that the model's performance is good because the MAPE value falls within 10 – 20%. The mean absolute deviation (MAD), mean square deviation (MSD), and smoothing constant are 0.3215, 0.2313, and 0.9685, respectively. Striking a balance, the application of MLR and the SES models will improve wireless communication systems in Abuja, the North Central region of Nigeria, at Ka-band. Therefore, engineers and policymakers in the Nigerian telecommunication industry should assess the impacts of path loss within the study locations towards sustainable telecommunications and infrastructure (SDG goal 9) for planning and setting radiowave propagation technologies in the study locations and Nigeria at large.Item Seasonal Variation of Total Attenuation between Airborne Platform and Earth Station in South-West Region, Nigeria(7th International Conference on Science and Sustainable Development and Workshop, 2024) Arijaje, T. E.; Omotosho, T. V.; Aizebeokhai, A. P.; Akinwumi S. A.The seasonal variation of total attenuation in the southwest region of Nigeria has been computed using eight (8) years dataset at Ku- and Ka-band of the transmitted power of the radar, transmitted antenna gain and the received antenna gain of the satellite retrieved from the archived of the GPM. The results obtained fluctuates between the seasons at Ku- and Ka-band. From the results obtained at Ku-and Ka-band, the results from analysis showed that the peak total attenuation was recorded between the early (MAM) and late wet (JJA) season when the intensity of rainfall is maximum in the South-West region. As a result, the effect on the airborne-earth station link will be severe which may further lead to signal outage. However, the state where the highest total attenuation was consistent is Lagos state. These seasons and Lagos state must be taking into consideration by engineers and radiowave propagation group when planning and sitting radiowave propagation in the study area.