Trace back techniques adapted to the surviving memory management in the M algorithm

A new architecture for survivor memory management in the M algorithm is presented. So far, classical implementations of the survivor memory management employ the register exchange procedure. The architecture presented here is based on the trace back procedure used in the Viterbi algorithm. Using a new pointer which indicates the number of the surviving path given by the sorting operation during the path metric updating operation, all the trace back techniques that have been proposed for the Viterbi algorithm can be employed for the M algorithm. This architecture is specially attractive for large values of M and L in which case the register exchange approach is impractical due to power consumption and to the area required for wiring. In addition, a combination of the register exchange and the trace back procedures is also presented. The combination of these algorithms reduces both the information to be stored and the processing time.