WHY the throughput in the beginning of the simulation rises very fast and then drop fast

[Ian]

I use ns-3.17 to simulate the wifi cognitive radio environment, i set up some primary users in order to test the throughput of the wifi node. 

However, the throughput rises very fast to 10 Mbps in the beginning of the simulation. After about 500 seconds, the throughput drops to about 7 Mbps and never rises again.

So, why CANNOT the throughput rises to 10 Mbps in the subsequent time?

The throughput plot is shown in the picture. I AM SO CONFUSED... 

[Ian]

ummm, to be clear, sometimes the throughput rises up to 10 Mbps, the plot shown in my question is the average plot.

在 2017年3月4日星期六 UTC+8下午2:29:27，Ian写道：

[Tommaso Pecorella]

It's called transient phase. It is normal and you should be able to cope with it.

If you don't know what it is and how to correctly minimize its effects, then go grab a good book about computer simulations because you need it desperately.

T.