Methods and apparatus for range measurement

An apparatus, comprising:

• a network interface device associated with a first communication device, the network interface device having one or more integrated circuit devices configured to:
• generate a physical layer (PHY) protocol data unit having i) a beginning portion and ii) an ending portion, wherein
• the beginning portion includes a PHY protocol header having a PHY protocol preamble,
• the ending portion includes a reference signal, and
• the PHY protocol data unit is configured to prompt a second communication device to record a reception time corresponding to reception of the reference signal by the second communication device;
• wherein the one or more integrated circuit devices are further configured to:
• transmit the PHY protocol data unit,
• record a transmission time corresponding to transmission of the reference signal by the first communication device, and
• at least one of:
• i) receive the reception time from the second communication device and calculate a time of flight of the PHY protocol data unit using the reception time and the transmission time, and
• ii) transmit the transmission time to one or more of a) the second communication device, and b) a third communication device that receives the reception time, to facilitate calculation of the time of flight of the PHY protocol data unit using the reception time and the transmission time.

A method for facilitating time of flight measurements in a communication network, the method comprising:

• receiving, at a first communication device, a physical layer (PHY) protocol data unit having i) a beginning portion and ii) an ending portion, wherein
• the beginning portion includes a PHY protocol header having a PHY protocol preamble,
• the ending portion includes a reference signal, and
• the PHY protocol data unit is configured to prompt the first communication device to record a reception time corresponding to reception of the reference signal by the first communication device;
• recording, at the first communication device, the reception time corresponding to reception of the reference signal by the first communication device;
• and
• at least one of:
• i) receiving a transmission time corresponding to transmission of the reference signal by a second communication device and calculating, at the first communication device, a time of flight of the PHY protocol data unit using the reception time and the transmission time, and
• ii) causing the first communication device to transmit the reception time to the second communication device to facilitate calculation of the time of flight of the PHY protocol data unit using the reception time and the transmission time.

An apparatus, comprising:

• a network interface device associated with a first communication device, the network interface device having one or more integrated circuit devices configured to:
• receive a physical layer (PHY) protocol data unit having i) a beginning portion and ii) an ending portion, wherein
• the beginning portion includes a PHY protocol header having a PHY protocol preamble,
• the ending portion includes a reference signal, and
• the PHY protocol data unit is configured to prompt the first communication device to record a reception time corresponding to reception of the reference signal by the first communication device;
• wherein the one or more integrated circuit devices are further configured to:
• record the reception time corresponding to reception of the reference signal by the first communication device, and
• at least one of:
• i) receive a transmission time corresponding to transmission of the reference signal by a second communication device and calculate a time of flight of the PHY protocol data unit using the reception time and the transmission time, and
• ii) cause the first communication device to transmit the reception time to the second communication device to facilitate calculation of the time of flight of the PHY protocol data unit using the reception time and the transmission time.