High-speed reduced-state sequence estimation

Reduced-state sequence estimation (RSSE) is a suboptimal modification of the Viterbi algorithm (VA) which reduces the computational complexity of maximum likelihood sequence estimation. However, the maximum achievable throughput of RSSE may be significantly lower than the VA, as in addition to the add-compare-select function the critical path comprises branch metric computation, survivor memory operations, and decision-feedback calculation, This paper shows that precomputation of branch metrics can shorten the critical path of RSSE such that its delay becomes of the same order as the VA