One of the most common grievances about this problem is that each time a neighbor puts up a wireless network your wireless network is slower or you get booted off.
The easiest thing you can due is change your channel on your wireless router. Almost all wireless networks have default channel of 6. Change your wireless network channel to something try channel 11 first.
If you have the money purchases a MIMO wireless router. This will overpower one radio access points. The most common complaint regarding wireless interference is dropped packets. MIMO wireless routers let you transfer and receive at twice the rate because they have two transmitters and two receivers…or two radios!! This gives you a better quality signal and better coverage.
Another tip lies in the placement of your wireless router. If you have a wireless router in one of your edge bedrooms half you signal is being sent out of your house with the default dipole antennas.
If you are going to keep your default Di-pole antennas then you need place your router in the middle of your house away from large metal objects.