Can anybody tell me how to change value of a parameter which is not given in input ports of that block during each iteration of 'while' or 'for' loop in any block in simulink for example, if i want to plot 'throughput' against 'SNR' which is a parameter in 'awgn channel' block (which takes only data to be transmitted as input, I change 'SNR' parameter manually) how can it be done automatically with loop iterations?