Optimal Channel Equalizer for mmWave Massive MIMO Using 1-bit ADCs in Frequency-Selective Channels

Millimeter wave (mmWave) massive multiple-input and multiple-output (mMIMO) is a key technology for increasing the capacity of the future wireless communication systems. However, high-resolution ADCs are costly and infeasible for mmWave mMIMO systems due to high power consumption. Hence, there is a lot of interest in low-resolution ADCs including ultra-low-precision 1-bit ADCs. Such ADCs can be implemented with very low power consumption and hardware cost. However, new channel equalization algorithms are required to compensate the severe nonlinear distortion caused by such low-resolution ADCs. In this work, we analytically derive the maximum likelihood sequence estimation (MLSE) channel equalizer for MIMO systems in frequency-selective fading channels using 1-bit ADCs.