Physical layer frame format for WLAN

An apparatus comprising:

• a network interface device having one or more integrated circuit (IC) devices configured to:
• generate a physical layer (PHY) preamble of a PHY protocol data unit, wherein the PHY preamble is generated to include:
• a first field that includes a first set of one or more information bits that indicate a duration of the PHY protocol data unit, the first field being formatted such that the first field is decodable by a receiver device that conforms to a second communication protocol, but does not conform to the first communication protocol, to determine the duration of the PHY protocol data unit based on the first field, and
• a second field that includes a second set of one or more information bits that indicate to a receiver device that conforms to the first communication protocol that the data unit conforms to the first communication protocol, and wherein generating the PHY preamble includes one or both of (i) generating the second set of one or more information bits according to an error detection scheme that does not conform to the second communication protocol and (ii) generating the second set of one or more information bits to indicate a PHY mode not supported by the second communication protocol;
• wherein the one or more IC devices are further configured to:
• modulate the PHY preamble onto a first plurality of orthogonal frequency division multiplexing (OFDM) symbols, and
• generate a PHY data portion of the PHY protocol data.

A method, comprising:

• receiving, at a wireless network interface device, a physical layer (PHY) protocol data unit;
• decoding, at the wireless network interface device, a field of a PHY preamble of the PHY protocol data unit, including decoding a received cyclic redundancy check (CRC) included in the field;
• generating, at the wireless network interface device, a first CRC based on the field using a first CRC generation scheme, the first CRC generation scheme, specified by a first communication protocol, for a corresponding field in a PHY preamble format defined by the first communication protocol;
• generating, at the wireless network interface device, a second CRC based on the field using a second CRC generation scheme, the second CRC generation scheme specified, specified by a second communication protocol, for a corresponding field in a PHY preamble format defined by the second communication protocol;
• comparing, at the wireless network interface device, the received CRC to (i) the first generated CRC and (ii) the second generated CRC;
• and
• determining, at the wireless network interface device, whether the PHY protocol data unit conforms to the second communication protocol based on the comparison of the received CRC to (i) the first generated CRC and (ii) the second generated CRC.

An apparatus, comprising:

• a wireless network interface having one or more integrated circuit (IC) devices configured to:
• receive a physical layer (PHY) protocol data,
• decode a field of a PHY preamble of the PHY protocol data unit, including decoding a received cyclic redundancy check (CRC) included in the field,
• generate, based on the field, a first CRC using a first CRC generation scheme, the first CRC generation scheme, specified by a first communication protocol, for a corresponding field in a PHY preamble format defined by the first communication protocol,
• generate, based on the field, a second CRC using a second CRC generation scheme, the second CRC generation scheme specified, specified by a second communication protocol, for a corresponding field in a PHY preamble format defined by the second communication protocol,
• compare the received CRC to (i) the first generated CRC and (ii) the second generated CRC, and
• determine whether the PHY protocol data unit conforms to the second communication protocol based on the comparison of the received CRC to (i) the first generated CRC and (ii) the second generated CRC.