Generalized frequency division multiplexing in the two-way-relay channel

The increasing demand for data traffic has driven the development of current mobile communication standards 3G and 4G. Future mobile radio standards might have additional demands, e. g. influenced by Internet of Things. Due to the strong sensitivity to distortions, many research projects propose to abandon conventional orthogonal multi carrier schemes. Instead, non-orthogonal waveforms might be utilized. Within this thesis the fundamental benefit of the good localization of the Gaussian waveform in cooperative wireless networks has been addressed. The application of the Gaussian impulse shape is proposed to decrease the susceptibility to synchronization offsets in cooperative wireless networks with more than two nodes. Considering interference as additional noise, mutual information for the multiple access phase of a physical layer network coding system is analyzed for Gaussian as well as discrete input alphabets, and different detection schemes at the relay. Afterwards it is shown for the point-to-point as well as the two way relay channel that the impact of carrier frequency and timing offsets in an orthogonal system can be reduced significantly if the Gaussian waveform is used instead of a rectangular prototype filter. If the non-orthogonal system is disturbed by synchronization offsets, the robustness of the Gaussian waveform ensures that the degradation of the system performance is significantly smaller than in the orthogonal system. However, the gain in robustness comes at the expense of a performance degradation in the synchronized case. To improve the performance of the non-orthogonal system basically three approaches are considered.