Wifi range not working on iOS 7

I would like to know if anyone can answer how to solve the wifi range problem with iOS 7. I have to be 2 meters away (or less) to my router in order to my iPhone 4 to get that network...

I have tried the following:

- Reset network settings (with airplane mode on)

- Install iOS 7.0.2 version

- Restarting my iPhone and my router (even changing the router's channel settings)

Nothing of these procedures have worked for me... Please help! I'm getting frustrated with iOS 7 😢