A Method of BER Estimation for OTFS MP Receiver

This work studies how to estimate the bit error rate (BER) performance of the message-passing (MP) receiver for the orthogonal time frequency space (OTFS) modulation over doubly-selective fading channels. We first derive the equivalent signal models of the MP receiver after convergence and establish the definition formula for calculating the BER and transform it into a more convenient form for calculation. Then we divide the whole BER curve of the MP receiver into three regions with different characteristics and derive BER estimation formulas for three regions separately. All these formulas need to obtain the probability density function of the real part of the complex output of the MP receiver. We assume the random variable of interest follows the stable distribution, and then use the Monte Carlo method to estimate the parameters to obtain the needed function. Simulation results verify that the proposed method of BER estimation is effective.