Hi Shshbaz
for plotting the graphs you need to change the one of the values either power,distance.However received power and BEr change for each iteration value..So you can select any two values and plot the graph in your case it is Rx power and LOG[BER}.I think you are plotting the input power Vs LOG[BER} values.Otherwise the graph should be like waerfall.A screen shot of this plot attached by Essakamuthu in other forum topic.https://optiwave.com/forums/topic/back-to-back-ber-measurement/