Intelligent techniques to maintain QoS at SHF and EHF satellite systems network in a subtropical climate

Abstract

In the recent time and due to ever-increasing demand by the end-users, bandwidth are now being increased (high frequency bands) to boost the market for satellite solutions so that the growing capacity requirements can be met. However, frequencies greater than 10 GHz leads to signal fading due to physical phenomena related to the propagation of radio waves through the atmosphere. In this paper, we present an intelligent weather aware technique (IWAT) based on Fuzzy logic which can be adopted to maintain the QoS at satellite communication systems operating in the Super High Frequency (SHF) to Extremely High Frequency (EHF) spectral region in a heavy rainfall subtropical region. In order to insure the proper QoS against various transmissions and other impairments at these spectral regions, not only rain attenuation, which is recognized to be the most significant impairment is considered, extra fading due to tropospheric constituents, like snow, water vapor, clouds, gaseous and scintillations caused by air turbulence are also considered. Rain induced-attenuation (AM) at the given carrier frequency in an average year is estimated by the synthetic storm technique (SST) and an associated formula that links RIA to frequency for fixed probabilities while extra fading due to tropospheric constituents is estimated by applying the ITU-R formulae. Outcomes are given using the three-dimensional techniques based on the point rainfall rate, propagation angle and rain-induced attenuation; satellite signal power, modulation and coding rates are controlled by efficient fuzzy intelligent weather aware schemes. The techniques are then adopted to adjust the Signal to Noise Ratio (SNR) values that can give an optimum uplink/downlink signal performances under severe subtropical weather conditions.