Broadcast precoding for massive MIMO subject to an instantaneous total power constraint

We design a new precoding scheme for massive multiple-input multiple-output (MIMO) systems subject to an instantaneous total power constraint. Unlike the classical way of designing precoders, we use a more realistic model for power amplifiers by considering their maximum power. The considered power constraint is applicable in the single-RF MIMO transmitter which has been proposed recently for massive MIMO systems. For sake of analysis, i.i.d. Gaussian signals are considered. It is shown that the designed precoding scheme results in a good performance in terms of signal to interference plus noise ratio (SINR) at the receivers and power efficiency at the transmitter. It is shown that the power efficiency utilizing this precoding scheme is almost equal to the case of constant envelope signals. Since the proposed precoding limits the total transmit power, there is no need for peak-to-average power ratio (PAPR) reduction algorithms.