On design of improper signaling for ser minimization in K-user interference channel

The rate maximization for the K-user interference channels (ICs) has been investigated extensively in the literature. However, the dual problem of minimizing the error probability with given signal constellations and/or data rates of the users is less exploited. In this paper, by utilizing the additional degrees of freedom attained from the improper signaling (versus the conventional proper signaling), we optimize the precoding matrices for the K-user single-input single-output (SISO) ICs to achieve minimal transmission symbol error rate (SER). Compared to conventional proper signaling as well as other state-of-the-art improper signaling designs, our proposed improper signaling scheme is shown to achieve notable SER improvement in SISO-ICs by simulations. Our study provides another viewpoint for optimizing transmissions in ICs and further justifies the practical benefit of improper signaling in interference-limited communication systems.