Frequency-Domain Decoupling for MIMO-GFDM Spatial Multiplexing

Generalized frequency division multiplexing (GFDM) is considered a non-orthogonal waveform and known to encounter difficulties when using in the spatial multiplexing mode of multiple-input-multiple-output (MIMO) scenario. In this paper, a class of GFDM prototype filters, under which the GFDM system is free from inter-subcarrier interference, is investigated, enabling frequency-domain decoupling in the processing at the GFDM receiver. An efficient MIMO-GFDM detection method based on depth-first sphere decoding is then proposed with such class of filters. Numerical results confirm a significant reduction in complexity, especially when the number of subcarriers is large, compared with existing methods presented in recent years. Keywords—Frequency-domain (FD) decoupling, multiple-inputmultiple-output generalized frequency division multiplexing (MIMO-GFDM), spatial multiplexing (SM), depth-first sphere decoding (DFSD), sorted QR decomposition (SQRD), symbol error rate (SER).