Comparison between Analog Differential Architecture and Analog Feed Forward Differential Architecture for Analog Viterbi Decoder
사 마헤스워, 양창주, Sung Woo Kim, 김형석 · 제어로봇시스템학회 합동학술대회 논문집 · 2009
The Decoding performance of analog differential Viterbi decoder and analog feed forward differential Viterbi decoder has been investigated. In Viterbi decoder, the optimal path from the specific starting state of the decoding stage to a state of output stage needs to be computed. The starting state in analog differential viterbi decoder is varied depending on previous decoding information at the output stage, the structure requires more complicated circuits in determination and designation of starting state. The feed forward differential architecture comes from the idea that decoding is mainly done through first state to several stages by allowing the optimum path from multiple nodes of trellis diagram. The optimal path computed from multiple starting states on the decoding stage to a state on the output stage is simpler in hardware. We found that the performance of the circuits with the feed forward differential architecture is similar to that with the analog differential structure when the constraint (size) of the Viterbi decoder is small. In this paper, the size at which the decoder can still be used is investigated through simulations.