Widely linear precoding with interference exploitation for improper signals in MU-MISO systems

The evolution of dedicated power communication networks requires higher capacity and reliability for services like high-definition video and real-time data transmission. Traditional systems assume proper (circularly symmetric) signals, but improper signals-prevalent in modulations such as binary phase shift keying (BPSK) and amplitude shift keying (ASK)-offer asymmetric statistics that can be exploited for improved performance in multi-user multiple-input single-output (MU-MISO) systems. This paper addresses the gap by proposing widely linear precoding and reception techniques that integrate interference exploitation for improper signals. Two schemes are introduced: Widely Linear Zero-Forcing (WLZF) and Widely Linear Minimum Mean Square Error (WLMMSE), paired with optimal widely linear receivers. Simulations show significant improvements in signal-to-noise ratio (SNR) and bit error rate (BER) over conventional methods, providing valuable insights for high-reliability, low-latency networks.