Quasi-rectilinear (MSK, GMSK, OQAM) co-channel interference mitigation by three inputs widely linear fresh filtering

Widely linear (WL) filters have the capability to perform single antenna interference cancellation (SAIC) of one rectilinear (R) or quasi-rectilinear (QR) co-channel interference (CCI). The SAIC technology for QR signals is operational in GSM handsets but requires enhancements for both VAMOS standard, an evolution of GSM/EDGE standard, and FBMC-OQAM networks, which are candidate for 5G mobile networks. For this reason, we propose and analyze in this paper, for QR signals, a SAIC/MAIC enhancement based on the concept of three inputs WL FRESH filtering, exploiting almost exhaustively both the non-circularity and the cyclostationarity of QR signals, contrary to classical approaches which only exploit very partially these properties.