stations in standby mode periodically wake up to check for buffered data at the access points . traditionally , the information is available by checking the periodic beacon frame for a traffic indication map . unfortunately , the length of beacons has steadily increased with the progression of the various wireless standards requiring stations to wake up for longer periods to merely check for buffered data . several approaches are disclosed which address this shortcoming , including the broadcast of tim frames , the partial reception of beacon frames and the use of an embedded tim frame within a beacon frame .