Dynamic power optimization of the trace-back process for the Viterbi algorithm

This paper presents an architecture for the trace-back unit of a Viterbi decoder, whose decoding window length can be adjusted dynamically during runtime, allowing power to be saved by turning off the unused stages. Power savings of up to 62% are reported, using two different technology libraries to validate the results. An algorithm is also provided, which determines the optimum value for the trace-back window length that ensures a target BER of the decoded stream, for an estimated quality of the communication channel.