A system and method are provided for traffic signaling in wireless or sensor networks. The system and method use information or bits in a Signal Field (SIG) of Physical Layer (PHY) preamble in a packet to provide traffic control information. An embodiment method implemented by a network component comprises indicating a traffic direction and a traffic type for traffic control in a SIG in a frame and transmitting the frame including the SIG. Another method comprises receiving in a frame a SIG for traffic control that indicates a transmission type and decoding the SIG field to determine whether to process remaining information in the frame if the frame comprises data payload or a Media Access Control (MAC) header.