A mobile terminal (302, 304) wakes up from a low power state and initiates a frame exchange in a wireless local area network that supports voice traffic by transmitting a polling frame (602). If the mobile terminal had voice data to send, it is included in the polling frame. In response to receiving the polling frame, the access point transmits a delay frame (604) to acknowledge receipt of the polling frame. If the access point has data for the polling mobile terminal, it transmits a non-delay frame (606) including the voice data, otherwise it transmits a null frame (702). The mobile terminal acknowledges the data from the access point (608), and goes back to sleep until the beginning of the next service interval.