Low complexity implementation of per-survivor processing for carrier-phase tracking in uncertain environments

Performance of Maximum Likelihood Sequence Estimation (MLSE) in receivers highly depends on the reliability of the channel parameters estimation. Traditionally, the channel parameters are estimated based on the tentative decisions before the MLSE detector. Per-survivor Processing (PSP) technique, as compared to traditional Viterbi algorithm, was shown to improve the performance of MLSE in uncertain environments. The PSP technique mainly comes from the idea that the estimation of unknown channel parameters can be embedded into the Viterbi decoder. The higher performance of the technique is achieved at the expense of higher complexity. In this paper we introduce a modification to the PSP algorithm to reduce the number of per-survivors and therefore the associated parameter updating modules. This modification was shown to lower the implementation complexity of the algorithm while keeping the performance at an acceptable level. The performance of phase tracking based on the PSP technique was also compared to traditional phase trackers through simulation.