Survivor Sequence Memory Management in Viterbi Decoders

In a Viterbi Decoder, there are two known memory organization techniques for the storage of survivor sequences from which the decoded information sequence is retrieved. The register erchange method is the simplest conceptually but suffers from the disadvantage that every bit in the memory must be read and rewritten for each information bit decoded. The alternative is the traceback method where the interpretation of the symbols as pointers removes the necessity to move data in the memory. Thi#paper extends previously known traceback approaches and describes a new one-pointer traceback algorithm for survivor sequence memory management that is particularly well-suited to a VLSI implementation. Memory size, latency and implementational complexity of the survivor sequence management are analyzed for both uniprocessor and multiprocessor realiza tions of Viterbi Decoders.