The Generalized Frequency Division Multiplexing (GFDM) has been proposed as a flexible modulation scheme for future cellular systems. It extends the traditional OFDM concept to a general framework by trading the orthogonality for the flexibility of employing different pulse shapes, which allows to improve the frequency localization feature.
Nevertheless, considering its practical usage, the complexity issue has to be addressed. In this paper, we present a low complexity algorithm for the GFDM implementation which, under certain conditions, yields less computational complexity. Furthermore, we introduce a Span-Factor Manipulation (SFM) concept that can possibly compensate for the orthogonality loss, eventually turning the GFDM into an orthogonality improved system.