Integration of a GFDM secondary system in an OFDM primary system

Concepts of cognitive radio are yet in an early stage of development. They aim at improving the efficiency of spectrum utilization by exploiting locally and temporally vacant parts of the spectrum. When hierarchical spectrum access is considered, secondary users are authorized to use spectrum white spaces on a non-interfering basis, where minimal impact on the primary systems has to be ensured. GFDM is a digital multi-carrier transceiver concept that employs pulse shaping filters to provide control over the transmitted signal's spectral properties, a cyclic prefix that enables an efficient FFT-based frequency domain equalization scheme as well as tail biting as a way to make the prefix independent of the filter length. In this paper, two setups of uncoded AWGN transmission are analyzed through simulation. Both setups have in common that an OFDM primary system is overlaid by a secondary system. For that purpose, resources are made free artificially. First, a non-synchronized OFDM system is inserted into the white space. Then, the results are compared to the case when the secondary system operates with the GFDM scheme. Both setups are reviewed under the aspect of bit error performance in dependence of guard bands and various pulse shaping filter parameters. Conclusions for the primary and secondary system are drawn.