In-Band Distortion Compensation for Peak Cancellation-Based PAPR Reduction in Massive MIMO-OFDM With Uniform Planar Array

Peak limiter-based techniques such as peak canceler (PC) have been investigated as simple solutions for reducing the peak-to-average power ratio (PAPR) in massive multi-input multi-output (mMIMO) orthogonal frequency division multiplexing (OFDM) systems. An important shortcoming of using peak limiter strategies is degradation of the transmitted signal quality, such as the bit error rate (BER), because of in-band distortion caused by peak limiting. To address this shortcoming, an in-band distortion compensation method has been proposed. With this method, a subset of transmit antennas at the base station is dedicated to mitigate in-band distortion caused by peak cancellation. However, the success of this approach depends on the spatial arrangement of the antennas and the precoder design. As described herein, we propose an improved in-band distortion compensation method for PC-based PAPR reduction in uniform planar array (UPA) mMIMO OFDM systems. Using the proposed method, the distortion compensation accuracy can be improved by properly determined placement of in-band distortion compensation antennas. We demonstrate that the proposed method using a minimum mean square error (MMSE) precoder achieves lower in-band distortion effectively and that it consequently provides better BER performance while maintaining comparable PAPR reduction capabilities to those of conventional methods.