According to various aspects of the present disclosure, medium access control (MAC) sublayer logic of a device or a system may generate and implement a preamble structure of a data unit including a signal field which includes a four-bit cyclic redundancy check sequence providing a Hamming distance of two. The signal field portion of the preamble structure may include information related to a plurality of physical layer parameters used for wireless communication of the data unit. The preamble structure may be stored on a machine-accessible medium. The preamble may be generated by a data unit builder of the device, which may further receive a frame including a data payload, and encapsulate the frame with the preamble portion to generate the data unit. A transmitter coupled with the data unit builder may then wirelessly transmit the data unit using an antenna array.