Iterative Synchronization for Multiuser Filtered Multitone Systems

We address the synchronization problem in a filtered multitone (FMT) modulated system. An FMT based system differs from the popular OFDM scheme in the deployment of sub-channel shaping filters. We assume a multiuser uplink scenario where sub-channels are partitioned among the active users. Users are asynchronous such that the received signals experience independent time offsets, carrier frequency offsets, and multipath fading. We propose to recover symbol/frame timing and carrier frequency for each active user by exploiting the sub-channel separability with an iterative procedure that uses training sequences. Two synchronization metrics are described, detection uses simple linear sub-channel equalizers with RLS training