A weighted fractional Fourier transform (WFRFT) scheme is proposed for the orthogonal frequency division multiplexing (OFDM) system to combat impulsive noise (IN) in substation communications. According to the central limit theorem, the analytic expression of the real-valued IN probability density function (PDF) after WFRFT is derived and for ease of calculation, the closed form expression of the approximate PDF is also put forward. The PDF of IN shows that WFRFT makes IN more concentrated to the small amplitudes in the fractional Fourier transform domain than in the frequency domain at the receiver. As a result, the WFRFT scheme achieves a better bit error rate (BER) performance than the conventional OFDM system. In addition, the proposed scheme is also compatible with other existing IN mitigation techniques, such as dynamic peak-based threshold estimation-lookup table (DPTE-LUT) blanking. Simulation results have verified that the derived analytic and closed form PDF expressions of IN after WFRFT and the advantage of the proposed scheme over the counterpart OFDM system in the IN channels at high SNR with and without the DPTE-LUT blanking.
Application of WFRFT in Impulsive Noise Channels of Substation Communications
2017-06-01
305923 byte
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
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