Patent attributes
A preamble of a physical layer (PHY) data unit that conforms to a first communication protocol is generated. The preamble includes a legacy field that is formatted according to a second communication protocol, and a signal field having a first orthogonal frequency division multiplexing (OFDM) symbol and a second OFDM symbol. The first OFDM symbol (i) immediately follows the legacy field and (ii) is modulated using binary phase shift keying (BPSK) modulation, whereas a third communication protocol specifies that an OFDM symbol, defined by the third communication protocol, that immediately follows the legacy field is modulated using BPSK modulation rotated by 90 degrees (Q-BPSK). The second OFDM symbol (i) immediately follows the first OFDM symbol and (ii) is modulated using Q-BPSK to indicate to a receiver device that conforms to the first communication protocol that the data unit conforms to the first communication protocol.
