Synchronization Algorithms and Receiver Structures for Multiuser Filter Bank Uplink Systems

We address the synchronization problem in an uplink multiuser filter bank system. The system differs from orthogonal frequency division multiple access (OFDMA) since it deploys subchannel frequency confined pulses. User multiplexing is still accomplished by partitioning the tones among the active users. Users are asynchronous such that the received signals experience independent time offsets, carrier frequency offsets, and multipath fading. We first consider the synchronization problem in conventional receivers that implement an analysis filter bank with precompensation of the subchannel time and frequency offsets followed by recursive least square linear subchannel equalization. Several correlation metrics that use data training are described. Then, we consider the synchronization problem in a novel multiuser receiver that comprises two efficiently implemented fractionally spaced analysis filter banks. In this receiver, time/frequency compensation can be jointly done for all the users. Despite its lower complexity, we show that it approaches the performance of single-user transmission.