“…Besides, they can also be categorized in terms of the quantization schemes, e.g., fixed-level quantizer and uniform quantizer. In particular, for FIR models with finite quantization levels, there are empirical measure approach [9,17] which has good properties of unbiasedness and strong consistency, EM algorithm [10,11] which has a exponent convergent speed under certain conditions, kernel-based method [12], and quadratic programming-based method [13].…”