Is Antenna Reservation Superior to Increasing Input Back-off in 5G Massive MIMO Base Stations?

The power amplifiers (PAs) used in the transmitter chains of 5G Massive MIMO (multiple-input multiple-output) base stations can account for a significant portion of the network energy consumption. A peak-to-average power ratio (PAPR) reduction mechanism can be used to enable operating the PAs at smaller input back-offs (IBOs) from their peak power capabilities, improving their energy efficiency operating points. In this paper, the performance of the iterative clipping and filtering (ICF) combined with the antenna reservation (AR) is explored, for transmission in spatially correlated frequency-selective line-of-sight (LoS) and non-line-of-sight (NLoS) channels. The simulation results show that for the single-user scenarios the distortion compensation performance of the AR for LoS is significantly worse than for NLoS (by about 2.6 dB, in the cases tested here). For multi-user transmission, a relatively large variation of the performance depending on the spatial scenario for both LoS and NLoS was observed, compared with the behavior in spatially uncorrelated channels. Additionally, an attempt at estimation of the power consumption of the ICF with and without the AR is made.