DC in champion selection

Hi everyone:

Its been a long time I have been facing this issue. I always (100%) dc in champion selection. Sometimes I am lucky and I actually got into the games. But recently, I am facing this thing over and over. I reboot my routers already, did the "initial repair" in the client, and none of those worked. Can someone plz tell me how to fix this?

P.S. This issue only happens to one of my account. The other one never ever dc during the champion selection :(