Adding noise and channel to OFDM

[sumeshkp03]

Hello,

I have created an ofdm VI (Transmitter and receiver). Now I want to add a noise and to apply it to a random channel. Please help me to do this. The output of the ofdm is 1D array of double complex.So whenever I try to add noise to this the wires becomes broken. 

[NAGARJUNA473]

could you attach the  subVIs used in the program,

so that we can check it out