Viterbi decoder using decreasing length tracebacks.

摘要

A communication system (e.g., 10) including a Viterbi decoder for tracing a path through a trellis of individual state information and method of operation are disclosed. The traceback determines a decoded symbol. A matrix of surviving branch data is stored in an array of registers. Operating the system includes initiating a first traceback from a storage register at a first symbol instant. The traceback traces a path back through the trellis a first predetermined number of symbol instants to determine a first decoded symbol. The length of the traceback is changed and another traceback is executed. This process is repeated until all remaining final decoded symbols are decoded. In an alternate embodiment, the traceback length is repreatedly decremented by one less than the constraint length, with each traceback obtaining multiple decoded symbols. <IMAGE>