On Fuzzy Estimation of Channel Noise Characteristics in MIMO Communication Systems

In wireless communications, the signals are affected by channel fading and additive noise generated by different Gaussian or non-Gaussian noise sources. In practical situations, channel characteristics are only estimated with more or less uncertainties, depending on the signal-to-noise ratio (SNR) of the received signals. The noise characteristics, like power level, and distribution parameters, are important for management system, regarding either transmitter or receiver state. In this paper, fuzzy logic approach is used for power level estimation of channel noise, based on a much smaller subset from the set of estimated values of the received symbols determined by decoder. Some expert rules are generated, and a fuzzy structure is proposed for SNR estimation. Several fuzzy systems were tested, using different sets of membership functions and rule bases. Simulation results and the output performances are presented. Accurate estimation of SNR is obtained with lower computational complexity.