Implementation of preamble based GFDM prototype for robust 5G systems

Generalized frequency division multiplexing (GFDM) is a flexible block-structured multi-carrier scheme recently proposed for next-generation wireless communication systems. There are various approaches suggested for its analysis and implementation via simulations but testing in real-time environments is not heavily investigated. This paper carries out the real-time implementation of the GFDM system utilizing software-defined radio (SDR) by emphasizing mainly channel estimation and synchronization. Symbol timing, frequency offset, and channel estimate algorithms are applied using a windowed preamble with two identical halves to satisfy low egress noise requirements. Time and frequency estimation is evaluated in terms of residual offsets along with symbol error rate over frequency selective channels. This algorithm is extended to a preamble composed of multiple identical parts. This facilitates a large frequency estimation range at the cost of complexity. For practical validation of the above concepts, the National Instruments (NI) universal software radio peripheral (USRP) 2953R is employed as hardware and it is interfaced with LabVIEW.