Implementation and Performance Measurement of Flexible Radix-2 GFDM Modem

Recent researches indicate that generalized frequency division multiplexing (GFDM) can be regarded as a physical layer waveform core. With proper configuration, it can be used to generate different type of the state of the art waveforms. The GFDM modulation can be realized by means of several discrete Fourier transform (DFT) transforms, a complex multiplier and several memory blocks. However, the conventional implementations of GFDM were limited by the consideration of real-valued symmetric prototype pulse shapes, where even numbers of subcarriers and subsymbols produce singular modulation matrix. The new design of GFDM prototype pulse shape allows all combinations of the parameters, which facilitates an efficient radix-2 implementation. In this paper, we realize a new field programmable gate array (FPGA) implementation of GFDM considering radix-2 parameters. We show that our modem significantly reduces the hardware resource consumption in comparison with conventional implementations. Moreover, it provides high throughput, maintains low-latency, and achieves high accuracy with small fixed-point bit width. Beside that, this implementation is unified for both the time and frequency domains. Furthermore, the hardware design provides additional degrees of freedom with run-time reconfiguration features.