Joint Power Control and LSFD for Wireless-Powered Cell-Free Massive MIMO

This paper considers wireless uplink information and downlink power transfer in cell-free massive multiple-input multiple-output systems. The single-antenna user equipments (UEs) utilize the energy harvested to transmit pilot signals multiple-antenna access points (APs). We consider Rician fading maximum ratio processing based on either linear minimum mean-squared error (LMMSE) or least-squares (LS) channel estimation. derive average by using a practical non-linear harvesting circuit model for both coherent non-coherent transmission schemes. Furthermore, spectral efficiency (SE) is derived all considered methods max-min fairness problem cast where optimization variables are AP UE control coefficients together with large-scale decoding vectors. objective maximize SE of UEs’ under APs’ constraints. A novel alternating algorithm guaranteed convergence improvement at each step proposed solve highly-coupled non-convex problem.