I just got back from outside and have read what you said in the attached file. But actually I did not use that equation in my calculation, albeit I do think it is equal when those variables are optimal. Please read my calculation process carefully.
I am doing research on macroeconomic issues at the University of Tokyo and my supervisor is Kosuke Aoki. I aspire to become an economics teacher, so I am pretty glad to discuss economics problems with you. If you have any further question, please let me know. Good luck.

不会

Hi，I have one question:how to understand the payoff in the text,which is Xi-XiT(X1+..+Xn).I think these two could not be minus because they are different.The Xi is the volume of transimitted data,the XiT is the time.The units of them are different.

could you give me some ideas?