Spatial Precoding in Frequency Domain for Multi-User MIMO Affine Frequency Division Multiplexing

This paper deals with the potential of affine frequency division multiplexing (AFDM) to operate within a multi-user multi-input multi-output (MU-MIMO) system, facilitated by spatial precoding preformed in frequency domain. To this end, we take advantage of the fact that AFDM based on discrete affine Fourier transform (DAFT) can be rewritten as a discrete Fourier trans-form (DFT)-based precoded orthogonal frequency division multiplexing (OFDM) waveform. By considering the well-known zero-forcing (ZF) precoder and white noise, we show that MU-MIMO AFDM achieves the same performance as MU-MIMO OFDM in terms of both sum rate and bit error rate (BER).