Analysis of cyclostationary GFDM signal properties in flexible cognitive radio

Generalized Frequency Division Multiplexing (GFDM) is a recent multicarrier modulation technique with extremely low out-of-band radiation that makes it an attractive choice for the PHY layer of cognitive radio. GFDM has a flexible pulse shaping technique which reduces the out of band leakage. It also has an innovative tail biting cyclic prefix (CP) which shows unique circular detection properties. Compared to OFDM, only the GFDM signal presents side peaks characteristics in the cyclostationary autocorrelation function (CAF). Following this observation, in this paper we analyze the impact of the roll-off factor on the detection result when the cyclostationary detector uses the CAF side peaks. We have also studied the trade-off between the length of the CP and the roll-off factor for the detection performance. The results show that if the roll-off factor is properly designed, it can increase the detection capability even when the CP is very low, thus allowing to transmit more useful data in the same time without decreasing the detection performance.