An Efficient In-Place VLSI Architecture for Viterbi Algorithm

This paper presents a novel design of Viterbi decoder based on in-place state metric update and hybrid survivor path management. By exploiting the in-place computation feature of the Viterbi algorithm, the proposed design methodology can result in high-speed and modular architectures suitable for those Viterbi applications with large constraint length. This feature is not only applied to the design of highly regular ACS units, but also exploited in the design of trace-back units for the first time. The proposed hybrid survivor path management based on the combination of register-exchange and trace-back schemes cannot only reduce the number of memory operations, but also the size of memory required. Compared with the general hybrid trace-back structure, the overhead of register-exchange circuit in our architecture is significantly less. Therefore, the proposed architecture can find promising applications in digital communication systems where high-speed large state Viterbi decoders are desirable.