Trace-back method and apparatus for use in a viterbi decoder

摘要

A trace-back apparatus to select a most likely path for use in a Viterbi decoder comprises one or more processing elements to carry out tracing-back based on a sequence of decision vectors coupled among themselves in a pipeline fashion. In each processing element, N number of decision vectors are delayed during a predetermined period to generate 1-step to N-step delayed decision vectors; and an input state is stored during the predetermined period to generate an 1-step delayed state; and multiplexing means multiplexs sequentially the 1-step to N-step delayed decision vectors based on the 1-step delayed state to provide an N-step trace-back state to the next processing element. <IMAGE>