Asynchronous Uplink Access with FBMC-PAM for Future Wireless Systems

FBMC-PAM is a recently introduced filter bank multicarrier technique which exploits pulse amplitude modulation and operates at the same symbol rate as OFDM, unlike FBMC-OQAM which operates at twice that symbol rate. The scheme is efficiently implemented in the frequency domain and, in the system, the receiver is equipped with a frequency domain equalizer. In the present paper, uplink access is considered, focusing on two issues, single carrier modulation and preamble-based channel estimation. It is shown that the scheme can handle asynchronous users, thanks to the spectral separation brought by the filter bank and flexible frequency domain equalizers, and the performance is demonstrated by simulations. An FBMC-PAM-based physical layer can be envisaged for the uplink of future wireless systems.