Viterbi algoritms for STTC

Hi all,
Can anybody please tell me if there is any different between the viterbi
algorithm for Convoluntional code and that for Space time trellis codes.
I have tried using the decoding approach for convoluntional and trellis
coded modulation (TCM) to decode my 2 states BPSK  space time trellis code
but the ber that  is producing is quite embarasing.
Can anybody please help me out.
I am writing my code in C++.
It will be aprreciated if someone can lend a helping hand here.