On the Robustness of Widely Linear Processing for FBMC-OQAM System with Short Prototype Filter

In this paper, we study the impact of the prototype filter length on FBMC-OQAM equalization. This waveform is still considered as a promising candidate for beyond 5G and Narrow Band Internet of things systems thanks to the well localized prototype filter providing high spectral efficiency, low side-lobes radiations and better robustness to users asynchronism, when compared to OFDM. As far as the prototype filter length gets shorter, the Inter-Carrier-Interferences level increases. In this context, we will demonstrate how the FBMC-OQAM prototype filter length impacts the performances of linear and widely linear processing. This work confirms the outstanding capability of widely linear processing in mitigating interference effects for non second order circular signals.