Iterative Timing Recovery with the Split-Preamble Strategy for Coded Partial Response Channels

This paper proposes a modified per-survivor iterative timing recovery scheme, which exploits a new split-preamble strategy in conjunction with a per-survivor processing soft-output Viterbi algorithm (PSP-SOVA). The conventional split-preamble strategy places a preamble at the beginning of a data sector and uses it to run a phase-locked loop during acquisition to find an initial phase/frequency offset. However, the proposed scheme splits the preamble into two parts. The first part is placed at the beginning of the data sector, whereas the second part is divided into small clusters, each of which is then embedded uniformly within the data stream. This split preamble is utilized to adjust the branch metric calculation in PSP-SOVA to ensure that the survivor path occurs in a correct direction. Results indicate that the proposed scheme yields a better performance than a conventional receiver with separate timing recovery and turbo equalization, and the iterative timing recovery scheme proposed in [1],[2], especially when the timing jitter is large. In addition, we also show that the proposed scheme can automatically correct a cycle slip much more efficiently than the others.