Synthesis of the Joint Estimation Algorithm of the OFDM Signal Distortions based on Polynomial Approximation

The synthesis of the algorithm for estimating the distortion of the OFDM signal is presented in the article, which are brought in by the channel and the direct conversion receiver. The aim of the work is to improve the noise immunity of communication systems. The estimation of unknown parameters is carried out by the minimum least squares method (MLS) using polynomial approximation. The choice of MLS is due to its simplicity and the ability to solve the problem posed in conditions of a priori uncertainty regarding the laws of distribution of phase noise and observation noise. The proposed approximating construction allows us to combine the estimation and interpolation procedures for the channel factors, and to simplify the algorithm. The synthesized algorithm can work on both pilot OFDM symbols and unknown information OFDM symbols, but it does not require any changes. The computational experiment showed that if the order of the approximating polynomial in the time and frequency domains and the number of reference symbols are correct, the error probability tends to the probability obtained with precisely known signal parameters.