Improving energy efficiency in massive MIMO: joint digital beam-steering and tone-reservation PAPR reduction
Résumé
In this study, the authors propose a novel architecture based on the combination of peak-to-average power ratio (PAPR) reduction with digital beamforming (BF) for mm-wave massive multiple-input multiple-output (MIMO) systems. In order to keep the power amplifiers (PAs) working at the same input back-off thus maximising the system power efficiency, they propose to perform time-domain transmit beam-steering by adding progressive time delays to the signals at each antenna element, while keeping the amplitude weights unitary. They show that these time delays can be obtained with a finite impulse response filter implementation of time-domain fractional delay filter structures such as Lagrange interpolation polynomials. They also introduce an analysis on the PAPR of the interpolated signals, where they derive an upper bound to it and show that its value is similar to that of the signal at the input of the interpolation filters, showing the feasibility of the proposed method. In addition, they present a detailed analysis where they show that a significant reduction in computational complexity is obtained when compared to frequency-domain BF. Simulation results validate that the novel proposed scheme combining PAPR reduction and digital BF offers high-precision beam-steering maintaining reduced PAPR in the delayed signals fed to the antennas.
Mots clés
polynomials
interpolation
array signal processing
FIR filters
OFDM modulation
MIMO communication
delay filters
computational complexity
millimetre wave power amplifiers
millimetre wave communication
millimetre wave antenna arrays
energy efficiency
massive MIMO
joint digital beam-steering
peak-to-average power ratio reduction
digital beamforming
mm-wave massive multiple-input multiple-output systems
power amplifiers
system power efficiency
time-domain transmit beam-steering
progressive time delays
amplitude weights
finite impulse response filter implementation
time-domain fractional delay filter structures
Lagrange interpolation polynomials
interpolated signals
interpolation filters
frequency-domain BF
PAPR reduction
digital BF
high-precision beam-steering
delayed signals
tone-reservation PAPR reduction