Afonso Ferreira, Rui Dinis, and Paulo Montezuma
Power amplification, Nonlinear distortion, LINC transmitters, Multi-antenna systems
LINC transmitters (LInear amplification with Nonlinear Components are suitable for the power amplification of variable-envelope signals, since they allow the use of low-cost, highly-efficient strongly-nonlinear power amplifiers. However, the combination of the outputs of the LINC's two amplifiers has is the weak part of it: the combiner losses offset the amplification efficiency gains inherent to the use of highly-efficient power amplifiers and/or it might have linearity requirements.
In this paper we consider a LINC transmitter structure for OFDM systems (Orthogonal Frequency Division Multiplexing) that does not require a combiner, since the output of each amplifier is sent to a different antenna, with the channels being combined at the channel level. Therefore, our transmitter outperforms conventional LINC transmitters. We propose an analytical model for the study of the impact of phase errors on the performance. It is shown that the proposed multi-antenna LINC (MA-LINC) is robust to estimation impairments.