A low-complex peak-to-average power reduction scheme for OFDM based massive MIMO systems

An Orthogonal Frequency-Division Multiplexing (OFDM) based multi-user massive Multiple-Input Multiple-Output (MIMO) system is considered. The problem of high Peak-to-Average Ratio (PAR) in OFDM based systems is well known and the large number of antennas (RF-chains) at the Base Station (BS) in massive MIMO systems aggravates this further, since large numbers of these Power Amplifiers (PAs) are used. High PAR necessitates linear PAs, which have a high hardware cost and are typically power inefficient. In this paper we propose a low-complex approach to tackle the issue. The idea is to deliberately clip signals sent to one set of antennas, while compensating for this by transmitting correction signals on a set of reserved antennas (antenna-reservation). A reduction of 4dB in PAR is achieved by reserving 25% of antennas, with only a 15% complexity overhead.