System and method for delay measurement in fronthaul network using hardware timestamping

1 . An Open Radio Access Network (O-RAN) comprising:

an O-RAN Distributed Unit (O-DU) configured to perform baseband processing,

wherein the O-DU is configured to transmit a one-way delay measurement message to an O-RAN Radio Unit (O-RU) on a fronthaul network, wherein the one-way delay measurement message includes a value that is based on a hardware time stamp that was inserted immediately prior to transmission of the one-way delay measurement message; and

wherein the O-DU is configured to receive a response to the one-way delay measurement message from the O-RU, wherein the response includes a second value that is based on a second hardware time stamp generated when the O-RU received the one-way delay measurement message from the fronthaul network.

2 . The O-RAN of claim 1 , wherein the one-way delay measurement message comprises a packet, the packet comprising a compensation value field, and wherein the compensation value field stores the value.

3 . The O-RAN of claim 2 , wherein the response comprises a second packet, the second packet comprising a second compensation value field, and wherein the second compensation value field stores the second value.

4 . The O-RAN of claim 3 , wherein the O-DU determines a delay, based at least in part on the value in the compensation value field of the packet and the second value in the second compensation value field of the second packet.

5 . The O-RAN of claim 1 , wherein the O-DU comprises a Network Interface Card (NIC) interfacing the O-DU with the fronthaul network, and wherein the NIC generates the hardware time stamp, and

wherein the second hardware time stamp is generated by a second NIC of the O-RU interfacing the O-RU with the fronthaul network.

6 . A method for one-way delay measurement, the method comprising:

generating a one-way delay measurement message comprising a packet at an Open Radio Access Network (O-RAN) Distributed Unit (O-DU);

inserting a time stamp in an application layer of the packet;

inserting a hardware time stamp in a transport layer of the packet;

transmitting the one-way delay measurement message immediately after inserting the hardware time stamp, from the O-DU to an O-RAN Radio Unit (O-RU) over a fronthaul network;

receiving, by the O-DU from the O-RU, a response message to the one-way delay measurement message, wherein the response message comprises a second packet in which

a second time stamp and a value are inserted by the O-RU, wherein the value is a difference between the second time stamp and a second hardware time stamp generated when the O-RU received the one-way delay measurement message from the fronthaul network.

7 . The method of claim 6 , further comprising:

determining a delay, based at least in part on the time stamp, the hardware time stamp, the second time stamp, and the value.

8 . The method of claim 6 , further comprising:

inserting a second value in the packet by the O-DU, wherein the second value is the difference between the hardware time stamp and the time stamp.

9 . The method of claim 6 , wherein:

inserting the hardware time stamp comprises inserting the hardware time stamp by a Network Interface Card (NIC) that interfaces the O-DU with the fronthaul network; and

the second hardware time stamp is generated by a second NIC of the O-RU that interfaces the O-RU with the fronthaul network.

10 . A communication system comprising:

a node, configured to:

generate a message comprising a packet;

insert a time stamp in an application layer of the packet;

insert a hardware time stamp in a transport layer of the packet; and

transmit the message immediately after inserting the hardware time stamp, over a network to a second node; and

the second node, wherein the second node is configured to:

receive the message from the node over the network;

insert a second hardware time stamp in the transport layer of the packet, immediately after receiving the message;

generate a response, wherein the response comprises a second packet;

insert a second time stamp and a value in the second packet, wherein the value is a difference between the second time stamp and the second hardware time stamp; and

transmit the response to the node over the network.

11 . The communication system of claim 10 , wherein the node is further configured to:

insert a second value in a compensation value field in the application layer of the packet, and wherein the second value is a difference between the hardware time stamp and the time stamp.

12 . The communication system of claim 10 , wherein the node comprises an Open Radio Access Network (O-RAN) Distributed Unit (O-DU).

13 . The communication system of claim 12 , wherein the second node comprises an O-RAN Radio Unit (O-RU).

14 . The communication system of claim 13 , wherein the network comprises a fronthaul network.

15 . The communication system of claim 10 , wherein the second node is configured to:

insert the value in a compensation value field of the second packet.

16 . The communication system of claim 15 , wherein the second node inserts the second time stamp in an application layer of the second packet and the value in the compensation value field in the application layer of the second packet.

17 . The communication system of claim 16 , wherein the node is further configured to:

receive the response from the second node over the network, and

determine a delay based at least in part on the second time stamp, the value in the compensation value field of the second packet, the hardware time stamp, and the time stamp.

18 . The communication system of claim 10 , wherein the node comprises a Network Interface Card (NIC) configured to generate the hardware time stamp.

19 . The communication system of claim 18 , wherein the second node comprises a second NIC configured to generate the second hardware time stamp.

20 . The communication system of claim 10 , wherein the message comprises a one-way delay measurement message.