Multistage interconnection networks for parallel Viterbi decoders

We propose new multistage interconnection networks (MIN) for scalable parallel Viterbi decoder architectures. The architecture consists of the desired number of processing elements (PE) connected by the suggested MINs, thus allowing a tradeoff between complexity and speed. The structure of the MIN is derived first by transforming the de Bruijn interconnection-based Viterbi algorithm trellis into the equivalent trellis with a perfect shuffle interconnection, and then applying a new decomposition of the perfect shuffle operator. This results in an efficient modular system and data flow is formed by the shuffling in a local PE memory and data exchange through a fixed interconnection between PEs. We suggest several solutions for 1/n and k/n rate codes, where k denotes the number of input bits shifting into k shift registers of the encoder and, at each cycle, the encoder produces n output bits as linear combinations of certain bits in the shift registers.