If you live in an area with plenty of other neighbouring WLAN networks it might be worth trying if changing the "channel" setting on your own WLAN router/access point happens to improve the WLAN signal strength (overlapping WLAN networks may cause interference, lowering your signal quality).
Also note that Bluetooth (on your phone or some other BT devices in vicinity) and other wireless devices operating at the 2.4GHz frequency range (wireless telephones, baby monitors, wireless PC mouse/keyboard etc.) can cause interference for WLAN signal.