Pilot-symbol assisted iterative carrier synchronization for burst transmission

This contribution considers the joint estimation of the carrier phase and the frequency offset from a noisy linearly modulated burst signal containing random data symbols (DS) as well as known pilot symbols (PS). The corresponding Cramer-Rao lower bound (CRB) is derived. This bound indicates that it is potentially more accurate to estimate carrier phase and frequency from such a 'hybrid' burst than from a burst without PS or from the limited number of PS only. The new bound is then compared with the performance of new and existing carrier synchronizers. We present the iterative Soft-Decision-Directed estimator with combined Data-Aided/Nondata-Aided initialization, which performs closely to the CRB, and provides a large improvement over the classical Nondata-Aided estimator at low and moderate Signal-to-Noise Ratio.