Digital carrier frequency estimation for multilevel CPM signals

This paper analyzes a feedforward synchronization scheme for carrier frequency recovery in continuous phase modulation. The algorithm is non-data-aided and non-clock-aided and can be implemented in digital form. It operates with general multilevel partial response signaling. Because of its feedforward structure, its estimation time is independent of the frequency offset. Its estimation range is large, on the order of the symbol rate. Performance is investigated theoretically and is checked by simulation.