Evaluating the efficiency of the OFDM signals parameters optimal measurement algorithm

 

E. A. Spirina

Kazan National Research Technical University of A.N.Tupolev  (KNRTU-KAI)

 

The paper is received on June 22, 2016, after correction - on September 8, 2016

 

Abstract. This article presents the analysis of parameters estimations for the OFDM channel signals under asynchronous operation of the equipment on various frequency channels for two demodulation algorithms: standard FFT algorithm and optimal measuring by maximum likelihood estimation algorithm. It contains expressions for deviation estimations of the measured signal parameters of their true values for the general case. Also it considers detail analysis of transmitting signals on two subcarriers with known frequency and time delay. For the latter case, paper presents a comparison of the deviation dispersions to depend on the signal parameters and the type of algorithm used, which showed that both algorithms provide unbiased estimates of the receiving signal quadrature components at the first subcarrier. Thus on receiving the first subcarrier variance estimates algorithms except white Gaussian noise include standard algorithm for receiving intra-system interference power from signals transmitted on the second subcarrier, and the algorithm for optimal measurement white Gaussian noise on the second subcarrier. This difference leads to the assumption that the benefits of applying the optimal measurement algorithm at high S/N ratio characteristic of broadband wireless access networks.

Key words: OFDM, FFT, demodulation, optimal measurement, maximum likelihood estimation.

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