Delivering precision time protocol frequency and phase synchronization over a network without on-path support
View Patent ↗Systems, methods, and computer-readable media for precision time protocol (PTP) frequency and phase synchronization to unanchored sites over non on-path supported networks are provided. In embodiments, the method includes continuously measuring one-way delay (OWD) and delay offset from a host site to an anchored site to determine a dynamic corrective offset (DCO). One of a plurality of unanchored sites is identified. In embodiments, the DCO is applied to PTP sync or PTP follow-up messages communicated from the host site to the identified unanchored site. The clocks associated with the unanchored sites are synchronized to the host clock.
1. Non-transitory computer-readable media having computer-executable instructions embodied thereon that, when executed by one or more computing devices, cause the one or more computing devices to perform operations comprising:
continuously measuring, in an asymmetric network without on-path support, one-way delay (OWD) and delay offset from a host site to an anchored site to determine a dynamic corrective offset (DCO), wherein each of the host site and the anchored site has a Primary Reference Timing Clock (PRTC) that is traceable and synchronous to a common clock;
identifying one of a plurality of unanchored small cell sites; and
applying the DCO to precision time protocol (PTP) messages communicated from the host site to the identified unanchored small cell site, wherein applying the DCO to PTP messages comprises: communicating, to the identified unanchored small cell site, a PTP sync message from the host site that indicates a point in time the host site sent the PTP sync message, the PTP sync message being received at a second point in time; indicating, to the identified unanchored small cell site, to ignore the point in time indicated in the PTP sync message; and communicating to the identified unanchored small cell site a follow-up message from the host site indicating the DCO, wherein the DCO comprises a sum of the point in time, the OWD, and the delay offset, and further wherein the follow-up message is received at a third point in time.
2. The media of claim 1 , further comprising:
determining a corrective offset by subtracting the DCO from the second point in time; and
determining an offset corrected time for the identified unanchored small cell site by adding the corrective offset to the third point in time.
3. The media of claim 1 , wherein
the DCO is indicated in the {correction_field} of the PTP sync message.
4. The media of claim 1 , wherein the PRTC is a global positioning system (GPS) receiver.
5. The media of claim 1 , wherein one or more anchored sites and one or more associated unanchored small cell sites are proximately positioned to comprise a cluster.
6. The media of claim 5 , wherein the host site synchronizes with multiple clusters.
7. The media of claim 6 , wherein the host site identifies a unique DCO for each cluster.
8. The media of claim 1 , wherein each of the anchored and unanchored small cell sites is identified by media access control (MAC) address.
9. The media of claim 1 , wherein each of the anchored and unanchored small cell sites is identified by internet protocol (IP) address.
10. A method for providing precision time protocol (PTP) frequency and phase synchronization to unanchored small cell sites over non on-path supported (NoPS) networks, the method comprising:
continuously measuring, in an asymmetric network without on-path support, one-way delay and delay offset from a host site to an anchored site to determine a dynamic corrective offset (DCO);
identifying one of a plurality of unanchored small cell sites;
communicating, to the identified unanchored small cell site, a PTP sync message from the host site that includes a time stamp indicating a point in time the host site sent the PTP sync message, the time stamp being ignored by the unanchored site and the PTP sync message being received by the unanchored site at a second point in time; and
communicating to the identified unanchored site a PTP follow-up message from the host site indicating a first offset that is the sum of the time stamp and the DCO, the PTP follow-up message being received at a third point in time.
11. The method of claim 10 , wherein each of the host site and the anchored site has a Primary Reference Timing Clock (PRTC) that is traceable and synchronous to a common clock.
12. The method of claim 10 , wherein each of the anchored and unanchored small cell sites is identified by media access control (MAC) address.
13. The method of claim 10 , wherein each of the anchored and unanchored small cell sites is identified by internet protocol (IP) address.
14. The method of claim 10 , further comprising determining a corrective offset by subtracting the second point in time from the first offset.
15. The method of claim 14 , further comprising determining an offset corrected time by adding the corrective offset to the third point in time.
16. A computer system for providing precision time protocol (PTP) frequency and phase synchronization to unanchored small cell sites over non on-path supported (NoPS) networks comprising:
a processor; and
a computer storage medium storing computer-useable instructions that, when used by the processor, cause the processor to:
continuously measure, in an asymmetric network without on-path support, one-way delay (OWD) and delay offset from a host site to an anchored site to determine a dynamic corrective offset (DCO), wherein each of the host site and the anchored site has a Primary Reference Timing Clock (PRTC) that is traceable and synchronous to a common clock;
identify one of a plurality of unanchored small cell sites;
apply the DCO to PTP messages communicated from the host site to the identified unanchored small cell site, wherein the DCO is communicated in the {correction_field} of the PTP sync message and comprises a sum of the point in time, the OWD, and the delay offset; and
communicate, to the identified unanchored small cell site, a PTP sync message that indicates a point in time the PTP sync message is communicated from the host site.
17. The computer system of claim 16 , wherein the point in time in the PTP sync message is ignored by the unanchored small cell site, and a PTP follow-up message is communicated from the host site to the unanchored small cell site that includes the DCO, the PTP sync message being received at a second point in time and the PTP follow-up message being received at a third point in time.
18. The computer system of claim 17 , wherein a corrective offset is determined by subtracting the DCO from the second point in time and an offset corrected time is determined by adding the corrective offset to the third point in time.