achievable data rate, cell-free massive mimo system, internet of things, spatial correlation, wireless power transfer, Telecommunication, TK5101-6720, Electronics, TK7800-8360

The massive multiple-input multiple-output (mMIMO) approach is promising for the Internet of Things (IoT) owing to its massive connectivity and high data rate. We introduce a wireless-powered cell-free mMIMO system, in which ground IoT devices transmit pilot and uplink information by harvesting down-link power from multiantenna access points. Considering the spatial correla-tion, we derive closed-form expressions for the average harvested power with a nonlinear energy-harvesting model per IoT device and achievable data rate according to the random matrix theory. The analytical expressions show that spatial correlation has a negative effect on the data rate owing to the increas-ing interference power. In contrast, the average received power improves with increasing spatial correlation. Simulation results demonstrate that the derived analytical expressions are consistent with results from the Monte Carlo method.