Decoding Message in Matlab with soft decision

Hi guys,

i'm trying to encode and decode a simple message using Matlab , Im trying to implement in matlab viterbi decoder with k=7 , r=1/2 .

so I coded message which it's [0 0 1] in the encoder k=7 , r=1/2 . so the output of the encoder I entered it to my viterbi decoder that I decoded but the decoded

message isn't the same as input message , it means the decoded message should be the same as [0 0 1].

my code in matlab is:

msg=[1 1 0]; %input

constlen = 7;

codegen = [171, 133]; % G1=171 , G2=133. this is parameters for k=7 , r=1/2 .

trellis = poly2trellis(constlen, codegen);

coded=convenc(msg,trellis);

ViterbiDecoderMsg=vitdec(coded, trellis, length(msg),'cont','soft',1);

the output (decoded message) isn't the same input message, it means that my viterbi decoder isn't properly working and I get wrong decoded message.

Note: the output of the encoder is two bits (a0, a1).

any help please how do I update/fix my code in order to get correct decoded message as the input message?

[Jimmy cho]

@Walter Roberson

could you please at your free time help me here in this thread? Im stuck about two weeks on this problem to implement /use soft viterbi decoder of matlab.

Appreciated !

[Jimmy cho]

@Walter Roberson

Any help please?