Eigendecomposition-Based GFDM for Interference-Free Data Transmission and Pilot Insertion for Channel Estimation

This paper proposes a new generalized frequency division multiplexing (GFDM) system that eliminates the effects of intrinsic interference and makes it possible to insert a pilot for channel estimation without interference. We express inter-subsymbol interference (ISI) and inter-carrier interference (ICI), which represent the intrinsic interference in GFDM systems, in a matrix form. The proposed GFDM system can remove the ISI through pre-processing and post-processing, which are done by eigendecomposition. We analytically derive the sufficient condition for the ICI removal. In this way, the proposed GFDM system is able to eliminate the effects of both the ISI and ICI. Furthermore, we investigate the prototype filter structures of the proposed GFDM system transformed by pre-processing and post-processing. We verify that the changed prototype filter structures are able to insert pilot symbols that are orthogonal to data symbols. Hence, the pilot symbols for channel estimation can be clearly observed. Simulation results demonstrate that the proposed system has better BER performance than conventional GFDM systems when the channel estimation process is considered.