Stochastic Approach to a Rain Attenuation Time Series Synthesizer for Heavy Rain Regions

In this work, a new rain attenuation time series synthesizer based on the stochastic approach is presented. The model combines a well-known interest-rate prediction model in finance namely the Cox-Ingersoll-Ross (CIR) model, and a stochastic differential equation approach to generate a long-term gamma distributed rain attenuation time series, particularly appropriate for heavy rain regions. The model parameters were derived from maximum-likelihood estimation (MLE) and Ordinary Least Square (OLS) methods. The predicted statistics from the CIR model with the OLS method are in good agreement with the measurement data collected in equatorial Malaysia while the MLE method overestimated the result. The proposed stochastic model could provide radio engineers an alternative solution for the design of propagation impairment mitigation techniques (PIMTs) to improve the Quality of Service (QoS) of wireless communication systems such as 5G propagation channel, in particular in heavy rain regions

Survival probability of precipitations and rain attenuation in tropical and equatorial regions

This contribution presents a stochastic model useful for the generation of a long-term tropospheric rain attenuation time series for Earth space or a terrestrial radio link in tropical and equatorial heavy rain regions based on the well-known Cox-Ingersoll-Ross model previously employed in research in the fields of finance and economics. This model assumes typical gamma distribution for rain attenuation in heavy rain climatic regions and utilises the temporal dynamic of precipitation collected in equatorial Johor, Malaysia. Different formations of survival probability are also discussed. Furthermore, the correlation between these probabilities and the Markov process is determined, and information on the variance and autocorrelation function of rain events with respect to the particular characteristics of precipitation in this area is presented. The proposed technique proved to preserve the peculiarities of precipitation for an equatorial region and reproduce fairly good statistics of the rain attenuation correlation function that could help to improve the prediction of dynamic characteristics of rain fade events

Spectrum

Abstract � HAPS is a new technology in the wireless communications field. The straightforwardness with which HAPS gets along with service providers will make this system a unique feature of future wireless networks. Most of the HAPS criteria have been well documented by the International Telecommunication Union (ITU) or subscribed to in World Radio Conferences (WRCs) periodicals. This procedure will prolong to function for various frequency ranges in future, most notably in WRC-12. Here, the emphasis is on HAPS spectrum sharing with FSS in the Frequency range 5850-7075 MHz. To clarify, FSS links are planted in the C-Band frequency range for tropical and subtropical regions, with high amounts of rain, which serve to condense the propagation attenuation. Furthermore, FSS uplink frequency ranges between 5925 and 6725 MHz. Therefore, FSS uplink intervenes with HAPS frequency range causing interference. This paper will assess and clarify the prospects of implementing HAPS gateway links in co- and adjacent channels of FSS uplink regarding MD and NFD techniques. 1

Adjacet channel interference (ACI) assessment between high altitude platform (HAP) and fixed satellite service (FSS) in frequency range 5850-7075 mhz

HAPS is a new technology in the wireless communication field.The straightforwardness with which HAPS gets along with service providing,makes this system a unique feature of future wireless networks