Wireless router problem?

RF signals face interference. The signal could experience scatter, deflection, refraction, absorption and attenuation. The further away the computer is from the wireless access point, the signal strength starts to weaken more and more that is attenuation. When the signal goes through the ceiling and floor the signal does become weaker and more difficult for the two devices to communicate. Also you have to find a common channel on all devices including the wireless router. If all are using the 802.11g and just one devices is using 802.11b, the router will change all devices to use the 802.11b channel which only runs 11mbps unlike the other channel which can run at 54 mbps. So that is another position you should be aware of. 300mbps is ideal, and unless you are running 4G connection or WiMax you might not get higher than 5-10 mbps.