Decision-Directed Timing Recovery Based on Maintaining Multiple Phase Trajectories

Jaekyun Moon, Jaewook Lee

Abstract: A decision-directed timing recovery scheme is proposed that maintains and updates a separate phase estimate path for each survivor data path in the maximum-likelihood sequence detection of intersymbol interference channels. For each survivor path, the phase estimate is updated recursively using symbol- decisions implied in the path. Unlike in the existing per-survivor timing recovery approach, there exists a single global timing loop that operates on a single stream of phase sequence released from the phase-estimating maximum-likelihood detector that is associated with the merged survivor path or the best up-to-date survivor path. The timing error detector itself is derived as a recursive formulation of the least square solution that minimizes error between the observation sequence and the clean expected signal sequence. Jitter analysis, stability analysis and tracking time simulation validate the proposed approach.