A Phase Increment-Based Frequency Estimator for General PSAM in Burst Communications
In this paper, a two-stage phase-increment-based frequency estimator with a general pilot-symbol-assisted- modulation (PSAM) structure is proposed for burst-mode communications. We derive the true Cramer-Rao bounds (CRBs) under the general PSAM structure for pure data-aided (DA) estimator. The proposed phase increment-based estimator is a pure DA estimator and implemented via two stages. In the first stage, a joint auto-correlation with one-symbol delay (AC-1) and simplified L&R (S-L&R) estimator is employed for the coarse estimation. In another stage, a two-step simplified cross-correlation algorithm with three disjoint pilot blocks is proposed for the fine estimation, where the problem of phase ambiguity is solved in the first stage such that wide estimation range as large as half of symbol rate can be guaranteed, and the fine estimation improves overall estimation accuracy. It is shown that the proposed estimator exhibits wide operating range while providing both high accuracy and moderate complexity, and efficient pilot utilization.