Hardware Efficient Low-Latency Architecture for High Throughput Rate Viterbi Decoders

Abstract—By optimizing the number of look-ahead steps of the first layer of the previous low-latency architectures for M-step look-ahead high-throughput rate Viterbi decoders, this paper improves the hardware efficiency by large percentage with slight increase or even further decrease of the latency for the add-com-pare-select (ACS) computation. This is true especially when the encoder constraint length (K) is large. For example, when and M varies from 21 to 84, 20.83 % to 41.27 % of the hardware cost in previous low latency Viterbi method can be saved with only up to 12 % increase or 4 % decrease of the latency of the conventional M-step look-ahead viterbi decoder. The proposed architecture also relaxes the constraint on the look-ahead level M to be a multiple of K as was needed in the previous work. For example, when and M (indivisible by K) varies from 40 to 80, 60.27 % to 69.3 % latency of conventional M-step look ahead Viterbi architecture can be reduced at the expense of 148.62 % to 320.20 % extra hardware complexity. Index Terms—Add-Compare-Select (ACS), high-throughput rate Viterbi decoder, look-ahead implementation, low latency viterbi decoder. I