Joint synchronization and demodulation by forward filtering

In a typical receiver, symbol synchronization must be established before symbol demodulation. This paper discusses synchronization for an isolated symbol from a filter-bank type multicarrier system. It is shown that accurate symbol timing for a single multicarrier symbol can be obtained using forward-only processing. The proposed receiver computes continuous-time symbol likelihoods along with a timing metric and its time derivative. The timing metric shows a sharp concentration that is used to produce a trigger to sample the matched filter outputs. The paper proposes baseband processing using message passing algorithms derived from factor graphs. Suitable system parameters for which near-optimum synchronization is obtained are identified using computer simulations.