Why OFDM signal has different plot at different simulation steps?

My matlab code is meant for the generation of 16QAM-OFDM signal. I observe different plots of OFDM signal everytime I run the simulation. Can anyone help me understand why this happens?

Answer 1

[Walter Roberson]

Simulations often use random number generation. You should consider using rng() to set the same random seed for each run.