A New Hardware Design Scheme of Symbol Synchronization for an Underwater Acoustic Receiver

Abstract — Conventional time domain symbol synchronizers typically use channel noise models to set static synchronization thresholds. However, static thresholds may prove insufficient in the underwater environment as the underwater acoustic channel can be highly variable and plagued by multipath, variable noise levels, path-loss, Doppler shifts, and long propagation delays. The paper provides a new hardware scheme using real time orthogonal sliding correlation as an adaptive threshold to build a symbol synchronizer suitable for an underwater FSK acoustic receiver. The design has been implemented and evaluated on an FPGA board. Both the simulation and real data experimental results show that the design provides accurate synchronization while consuming only 9 % of the FPGA’s slice resources. I