Adding convolutional coding in "LTE PHY Downlink with Spatial Multiplexing"

Ia m using MATLAB 2013a(64bit WIN7). In the matlab code for LTE PHY Downlink with Spatial Multiplexing, I tried to add a convolution coder decoder by putting first

    hConEnc = comm.ConvolutionalEncoder;
    hDec = comm.ViterbiDecoder('InputFormat','Hard');

    encodedData1 = step(hConEnc,scramOut1);
    encodedData2 = step(hConEnc,scramOut2);

    modOut1 = step(hMod, encodedData1);
    modOut2 = step(hMod, encodedData2);

At the demodulator side I did

    decodedData1 = step(hDec,demodOut_1);
    decodedData2 = step(hDec,demodOut_2);

    demodOut1 = step(hDemod, cwOut1, nVar1);
    demodOut2 = step(hDemod, cwOut2, nVar2);

But when I am running it. it throws following error

Subscripted assignment dimension mismatch.

Error in lteREMapper (line 165) tmp(dtIdx_subframe, :) = in;

Error in commExamplePrivate (line 128) [varargout{1:nargout}] = lteREMapper(varargin{2:end});

Error in dwnlink_LTE_ADEL (line 296) txGrid = commExamplePrivate('lteREMapper', preOut, csr, nS, ...

I tried digging the code of lteREMapper but no success so far.

What dimensions I need to change ?

[sumit kumar]

I suddenly found that I as doing wrong. Channel coding is already there in the demo .. {face palm} Now my issue is that I cant edit the file lteTbChannelCoding.m

[sumit kumar]

LoL .. Just found that I dont have to edit that file. I just made a copy of main file and edit the line

prmLTEDLSCH.trellis = poly2trellis(4, [13 15], 13);

for user defined trellis

[hussain ali]

give code to exchange