Design of soft-output Viterbi decoders with hybrid trace-back processing

This paper presents a novel VLSI architecture for soft output Viterbi algorithm (SOVA) based on hybrid track-back of transverse paths. In order to achieve very high speed of decoding, majority of SOVA designs in the past use simple register-exchange method that nevertheless suffers from both complex routing and high switching activities. In this paper, a hybrid approach that combines both the trace-back and register exchange schemes has been applied to the design of SOVA. The resulted architecture not only exhibits better regularity due to less routing, but it can also lead to lower power consumption because of reduced switching activities.