Patent attributes
A first field of a preamble of a physical layer (PHY) data unit is generated to include a first set of one or more information bits indicating a duration of the data unit and is formatted to conform to a first communication protocol such that the first field allows a receiver device conforming to a second communication protocol to determine the duration of the data unit. A second field of the preamble is generated to include a second set of one or more information bits indicating to a receiver device conforming to the first communication protocol that the data unit conforms to the first communication protocol. The second field is convolutionally coded using a tail biting technique, and the first field and the second field are modulated using a modulation scheme specified for a field corresponding to the first field and the second field, respectively, by the second communication protocol.