Hi all, 

I am doing a project on trellis coding of 64 QAM.. Now i am  stuck in constlen and codegen..
How to write it ? As it is shown below for 16-QAM:

%% Encoding bits with a Convolution Code for 1/2 coderate and 16 QAM
%---------------------------------------

%Declare Variables
%-----------------

%codeRate = 1/2;                               % Code Rate
%constlen = 7;                                 % constraint Length
%codegen = [171 133];                          % Generator Polynomials
%trellis = poly2trellis (constlen, codegen);   % Create Trellis Structure
 
%Encode transmitted sequence
%xEnc = convenc (x, trellis);

So on above code I ddnt get how 7 and [171 133] comes..

For my case it is as below.. 

%% Encoding bits with a Convolution Code for 5/6 coderate and 64 QAM
%---------------------------------------

%Declare Variables
%-----------------

M=64;
k = log2(M);
n = 1e6;
x= randint (n*k,1);
codeRate = 5/6;                               % Code Rate
constlen =[21 22 25 54 30];                                 % constraint Length
codegen = [22
32 33 34 23 36;23 0 25 26 27 3;21 16 0 20 21 22;26 10 11 0 13 14;5 12
13 14 15 30];                          % Generator Polynomials
trellis = poly2trellis(constlen, codegen);   % Create Trellis Structure
xEnc = convenc(x, trellis)

but I wrote random value as:
constlen =[21 22 25 54 30];                               
codegen = [22
32 33 34 23 36;23 0 25 26 27 3;21 16 0 20 21 22;26 10 11 0 13 14;5 12
13 14 15 30];                         
Can anyone tell me what should be there in MATRIX..any clue..??

Thanks in advance.

Hardik Makhaniya