This disclosure provides systems, devices, apparatus and methods, including computer programs encoded on storage media, for generating wake-up radio (WUR) frames formats and implementing WUR communications between transmitting and receiving wireless devices. A transmitting wireless device may identify one or more intended receiving wireless devices for which to send a WUR frame. The transmitting wireless device may generate the WUR frame, where the WUR frame has a first portion that includes a first field. The first field may indicate whether the WUR frame is a fixed length frame or a variable length frame. The transmitting wireless device may also determine a frame check sequence (FCS) type for use with a WUR frame for transmission. The FCS portion may be capable of being one of a plurality of FCS types. The transmitting wireless device may transmit the WUR frame to the one or more intended receiving wireless devices.