Per-survivor timing recovery for uncoded partial response channels

Abstract

Abstract-A conventional receiver performs timing recovery and equalization separately. Specifically, conventional timing recovery is based on a phase-locked loop that relies on the decision provided by its own symbol detector. We propose a new timing recovery scheme based on per-survivor processing (PSP) that jointly performs timing recovery and equalization for uncoded partial response channels. In the proposed scheme, each survivor of the Viterbi algorithm maintains its own estimate of the timing offset, and this estimate is updated according to the history data associated with the survivor path. As compared to conventional timing recovery at BER = 10 −4 , the proposed scheme can provide a 0.5 dB gain in SNR.

Effect of Preamplifier on Timing Recovery in Magnetic Recording Channels

“…As future work, we shall look at the performance other timing recovery algorithms such as interpolated timing recovery [7] and per-survivor processing [8]. …”

Per-survivor iterative timing recovery for coded partial response channels

“…Again, per-survivor iterative timing recovery still performs similar to the genieaided receiver and loses approximately a 0.35 dB relative to the system with perfect timing at BER = 10 −5 . One reason that per-survivor iterative timing recovery outperforms the NBM scheme when σ w /T is large might be because the front-end PLL used in the NBM scheme does not work as well as PSP-based timing recovery [8]. Additionally, per-survivor iterative timing recovery can automatically correct a cycle slip (without a cycle slip detection and correction technique as employed in the NBM scheme [1]) much more efficiently than the NBM scheme.…”

“…It has been employed in many applications, including channel identification, adaptive ML sequence detection, and phase/carrier recovery [5]- [7]. In [8], we applied PSP to develop the PSP-based timing recovery implemented based on a Viterbi algorithm [9], which performs timing recovery and ML equalization jointly.…”

Reduced-Complexity Per-Survivor Iterative Timing Recovery for Coded Partial Response Channels

“…3 shows the PSP-SOVA algorithm, where the lines starting with * are the additional steps beyond the conventional SOVA. It should be noted that PSP-SOVA works in a same manner as PSP-based timing recovery 1 [9] does (i.e, from (A-1) to (A-10)), except that 1 It is implemented based on the Viterbi algorithm.…”

“…Following the notations in [9], at each k-th stage, the metric difference for state q at time k + 1, ∆ k+1 (q), is computed by (A-11). Then, the tentative LLR is updated based on (A-12), whereL k (q) is the k-th LLR associated with state q,â (m) j (Ψ j+1 ) is the j-th estimated data bit associated with the m-th path that passes Ψ j+1 , and m ∈ {1, 2} is used to indicate the two paths that merge in state q (where m = 1 represents a correct path and m = 2 represents a wrong path).…”