A network interface of a wireless network device generates a cyclic redundancy check (CRC) sequence using information bits of a signal field of a physical layer (PHY) preamble of a PHY data unit, including generating the CRC sequence using a CRC polynomial. The network interface generates a CRC field to be included in the signal field, including generating the CRC field to include a portion of the CRC sequence. The network interface generates the PHY data unit to include the PHY preamble, the PHY preamble having the signal field, the signal field having the information bits and the CRC field that includes the portion of the CRC sequence, where the PHY data unit is generated such that the signal field does not include the entire CRC sequence. The network interface generates a transmission signal for transmission in the wireless network, the transmission signal corresponding to the PHY data unit.