Comments on “Local Partial Zero-Forcing Combining for Cell-Free Massive MIMO Systems”

There are major errors in [1] in the derivation of closed-form expressions for the spectral efficiency (SE) and large-scale fading decoding (LSFD) using different zero-forcing combining schemes for cell-free massive MIMO networks. In this comments paper, we first highlight those errors and then provide corresponding corrected expressions for the spectral efficiency and LSFD with these combining schemes. Furthermore, we provide numerical simulations to validate the proposed corrections by comparing the uplink SE with that obtained using the precoding vectors from [2] as combining vectors.