Comparative Analysis on Interference Suppressive Transmission Schemes for White Space Radio Access

With opening up of the TV white spaces for opportunistic access, designing a flexible physical layer (PHY) scheme has become an important focus for cognitive radio (CR) systems. Two possible PHY design solutions proposed are: generalized frequency division multiplexing (GFDM) and interference avoidance by partitioned frequency and time domain transmission (IA-PFT). Both of these methods extend the orthogonal frequency division multiplexing (OFDM) scheme to be applicable as a flexible CR PHY solution in a fragmented spectrum. In GFDM, introduction of pulse shaping filters reduces the out-of-band radiation of the opportunistic signals into the frequency band of the incumbent users; while in IA-PFT, simultaneous cancellation carrier insertion and time windowing technique suppress spectral leakage into the incumbent band of operation. In this paper, these two different approaches are compared in terms of interference suppression, transmission performance and processing complexity.