Patent ID: 8369235

Claim:
A method of exchanging messages in a transmitting device to measure a round trip time between a transmitting device and a receiving device in a wireless network, the method comprising: generating an echo request command by an audio video control (AVC) layer and transferring the echo request command to a medium access control (MAC) layer, the echo request command including a first identifier for identifying the transmitting device, a second identifier for identifying the receiving device, and a third identifier; transferring a MAC message from the MAC layer to a physical layer, the MAC message including a message preamble, a message type, and the echo request command; transmitting a first physical layer data unit from the physical layer to the receiving device, the first physical layer data unit including at least one header, the MAC message, and audio/video (A/V) data; and receiving a second physical layer data unit from the receiving device, the second physical layer data unit including an echo report command in response to the echo request command, the echo report command including the third identifier, wherein the first physical layer data unit is a downlink physical layer data unit (DLPDU), and the second physical layer data unit is an uplink control physical layer data unit (ULCPDU).