Viterbi algorith for trellis traceback

Hello,

i am trying to simulate GSM and i have s function called FCN_VITERBI that generate table for trellis, metrics and metric differences and then trys to find the last state and traceback the trellis based on viterbi algorithm.

At the end i am trying to show the trellis by using the following function:

function [C] = showTrellis(S,bEst,sTrace)

len = 10;

figure(30)

clf

C = [0 1 0; 0 1 0; 0 1 0; 0 1 0;1 0 0; 1 0 0; 1 0 0; 1 0 0];

%plot([1,2],[(1:8)',S(:,1)]','-o');

hold on

for i = 0:len - 2

P = plot([2,1]+i,[(0:7)',S(:,2+i)-1]','-o','Linewidth',3); %the error position

%plot([2,1]+i,[(0:7)',S(:,2+i)-1]','-o','Linewidth',3);

for j = 1:8

P(j).Color = C(j,:);

end

text(i + 1.4,-.5,num2str(bEst(i+1)),'FontSize',14);

end

plot(sTrace(1:len)-1,'--k','Linewidth',3);

title('Trellis Diagram');

end

but i get the following error:

Error using horzcat

Dimensions of arrays being concatenated are not consistent.

Error in showTrellis (line 10)

P = plot([2,1]+i,[(0:7)',S(:,2+i)-1]','-o','Linewidth',3);

%some infos

length(S) = 62

length(h) = 6

length(y) = 66

L = 5

length( r ) = 64

length(ini_S) = 1

tail_R = [111]

can someone please help?

Thanks

Answer 1

[Gaurav Garg]

Hi Mohamad,

You should try printing individual arrays [2,1]+i and [(0:7)',S(:,2+i)-1]' and ensure that the array sizes are same.

[Mohamad Khalil]

They are not, thank you so much