In recent years wake-up receivers have shown to be a promising technique to achive ultra-low power communication in wireless sensor networks. In this project we study the feasibility of using this technique to make Wireless LAN (WLAN) more power efficient. Instead of using the duty-cycling approach of the normal power save mode, we add an additional wake-up receiver to the mobile stations. If an accesspoint gets new data for a station in sleep mode, it can use this receiver to wake the station up and immediately send the packets. This technique achieves lower power consumption and lower delays compared to existing solutions. We study our proposed system by building hardware prototypes in conjunction with extensive simulations.