1. hard decision viterbi decoder ----- input is (1/0) here we use hamming distance for metric calculation.
2. soft decision viterbi decoder ------- input is soft decision ie 2 or 3 or ........9 . it depends on the demapper which is before your viterbi decoder block. and the out put is hard ie (1/0) .
3. soft output viterbi decoder ............ here you will get input as soft data and output also soft.
i had implemented hard and soft decision viterbi decoder in verilog sucessfully for constraint length 1/2,1/3.... for ASIC .
I need your help. I need viterbi algorithm in c++ with realize algorithm of Trellis code decoding . if somebody have or found this algorithm i will be happy . I am from poland and I dont know good english .