problem with wifi model and the throughput results

[Doaa Terri]

Hi all 

I want to simulate effect of nodes which modify the value of their contention window. 

I have four nodes, I 've changed the contention window value for the first node (node 0).  I should notice an increase in the throughput of the of this node but this is not the case. 

I have tried a lot to figure out the problem that leads to an incorrect results but unable to do so. 

(ie: I've changed the node configuration in order to make all the nodes in the same transmission range, I've changed the the some of the channel parameters) 

I have also checked that cw value for node 0 is modified using config store text file. 

Can someone tell me why I am having such results or what is missing in my script. Or if some one can tell me how to debug such problem (ie: how to know where is the problem)

attached is my script and the obtained results. 

Thanks 

[Doaa Terri]

any hints please?