A single-chip Viterbi decoder for a binary convolutional code using an adaptive algorithm

By using an adaptive algorithm, we design a single-chip Viterbi decoder for a rate 1/2 binary convolutional code. The adaptive algorithm is realized by threshold checking at each stage. The survivor paths that are less likely are ignored and hence the number of states at each decoding stage to be computed is reduced significantly in comparison with the conventional Viterbi decoder. Therefore, the decoding speed can be increased. A single-chip hard-decision decoder for a rate 1/2 convolutional code with constraint length K=6 (64 states) has been fabricated in 1.2 μm CMOS technology. Experimental results show that this improved algorithm can achieve a data throughput rate about 3 times faster than that using a conventional algorithm without sacrificing the decoding reliability