LS algorithm for PAR Reduction in OFDM based Massive MIMO Broadcast systems

This manuscript accosts peak-to-average ratio (PAR) reduction in OFDM based massive Multi-Users (MU) MIMO systems. We propose an iterative Least-Squares (LS) approximation algorithm for limiting the peak exceedance values. In MU MIMO-OFDM broadcast systems, as the dimensionality of the MIMO system grows, the probability of an inactive user increases, resulting in redundant channels. In the LS algorithm, we exploit these redundant channels to limit the peak excursions on the remaining active channels. The algorithm approximates the peak excursions on the active channels utilizing the redundant carriers in a Least-Squares fashion. The PAR on the remaining active channels in then limited by adding this model function to the transmit signal. To attain a target limiting threshold for the peak excursions, the algorithm is performed iteratively. As shown through simulation, the proposed algorithm results in a gain of approximately 4.6 dB with as few as 8 iterations.