Your IP is responsible for delivering an Internet connection to your home. Given that every building varies in its construction, there are many different kinds of wifi adaptors, and differing levels of local interference, they can't be expected to take responsibility for the wireless link between your router and each of your individual devices.
As Eliipsis says, you might want to consider a wireless repeater, or you could also consider an ethernet over mains connection, or a combination of ethernet over mains coupled with a wireless repeater.
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