See Wi-Fi bridge
A device that connects two LAN segments together via infrared or microwave transmission. A wireless bridge is often used to span buildings and provides a more economical method than laying cable or leasing a private line. Long distance wireless bridges often require line-of-sight between transmitter and receiver; however, bridges used inside a home or building that add remote devices to a Wi-Fi network do not (see Wi-Fi bridge
Spanning Geographic Areas
A wireless bridge is used to span buildings or areas where laying cable or leasing lines is prohibitive.
Securing Hotspot Access
A wireless bridge can also be used to secure a local wireless network that accesses the Internet via a public hotspot. By wiring the bridge into the WAN port of the router, it serves as a gateway between the private encrypted network and the hotspot, which is not encrypted.