Patent ID: 7225393
Filing Date: 2007-05-29
Classification: H03M

Abstract:
1. A Viterbi decoder for decoding a trellis-coded modulated signal, comprising: a subset selector section for receiving a reception signal, selecting a transmission symbol having a highest likelihood with respect to a reception symbol point for each subset, and outputting branch metrics corresponding to the selected transmission symbol and subset select signals for specifying the selected transmission symbol; delays for delaying the subset select signals for a predetermined time; an add-compare-select (ACS) section for receiving the branch metrics, performing arithmetic operation to obtain path metrics in accordance with a trellis diagram, and outputting path select signals for selecting paths having high likelihood; a trace-back memory for storing the path select signals; a trace-back section for tracing back the path select signals stored in the trace-back memory by a predetermined trace-back length from a start node number as a start point; a subset number generator section for outputting, using a number of a first node through which a most likely path passes obtained by the trace-back section and in accordance with a trellis diagram, coding bits relating to transition to the first node and a subset number; a selector section for receiving the subset number and the subset select signals output from the delays and outputting a noncoding bit relating to the transition to the first node; and a LIFO memory for storing the coding bits output from the subset number generator section and the noncoding bit output from the selector section in combination and outputting the stored bits as a decoded signal.