Papr reduction for mimo transmission

Abstract

A method is disclosed for reduction of peak-to-average power ratio (PAPR) of transmission of a multiple-input multiple-output (MIMO) signal from a transmitter, wherein the transmission comprises a number of MIMO layers. The method comprises determining a clipping signal for the MIMO signal, and generating a PAPR reduced MIMO signal for transmission by combining the MIMO signal with a projection of the clipping signal onto a null space of an effective channel. The effective channel comprises a propagation channel between the transmitter and one or more receivers (wherein the receivers have an amount of receiver antenna ports) as affected by receiver combining matching transmitter precoding. A setting of the transmitter precoding is varied over frequency, which induces frequency selectivity of the effective channel. The method is particularly useful when the propagation channel is relatively flat in frequency. Corresponding computer program product, apparatus, radio access node, user device, control node, and system are also disclosed.

Dependencies are inferred from the claim text.