Sinalização FTN tempo-frequência para o GFDM: sphere decoder e avaliação de desempenho

Abstract

This dissertation proposes a way to improve the spectral efficiency of generalized frequency division multiplexing (GFDM) through the principles of faster than Nyquist (FTN) signaling, without error rate penalties. This is obtained by undersampling the time-frequency grid, introducing controlled interference to the system. At the receiver, a detection scheme based on the sphere decoder (SD) algorithm is proposed, and its performance is evaluated in terms of bit error rate (BER) under different channel models. The proposed SD has a computational complexity smaller than the maximum likelihood (ML), without presenting significant BER performance loss, even in high interference scenarios, proving that the FTN-GFDM scheme is able to achieve high spectral efficiency in the channels analyzed.