Outage Performance Analysis of Improper Gaussian Signaling for Two-User Downlink NOMA Systems with Imperfect Successive Interference Cancellation

The improper Gaussian signaling (IGS) technique can improve the achievable rate of an interference-limited network by fully exploiting second-order statistics complex signaling. This paper addresses outage performance analysis a two-user downlink non-orthogonal multiple access (NOMA) system using IGS in presence imperfect successive interference cancellation (SIC). strong channel user (SU) adopts IGS, while weak (WU) traditional proper (PGS). Considering practical scenario where transmitter has obtained coefficients instead instantaneous state information (CSI), expressions rates both users under residual due to SIC are derived, together with their probabilities, subject predetermined target and statistics. Given fixed transmit power WU, degree impropriety SU optimized minimize probability constraint WU. Numerical results provided assess benefits proposed IGS-based NOMA system, which consistent analysis.