M-CMTS, Edge-QAM and upstream receiver core timing synchronization

Patent metadata

Field	Value
Publication number	US-9787768-B1
Application number	US-201313832756-A
Country	US
Kind code	B1
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

Systems and methods of this disclosure can operate to synchronize timing between communication devices and can include a timing server. The timing server can provide a communications interface for the exchange of timing messages to a first communication device. Using existing protocol messages defined in the M-CMTS architecture, additional communication devices can intercept, snoop, and extract timing information from messages between the first communication device and the timing server to adjust their internal clocks to maintain timing synchronization thereby reducing the number of communication interfaces required from a timing server.

First claim

What is claimed:

1. A system, comprising:
a timing server operable for two-way communication through a broadcast device to a first timing client, the broadcast device residing between the timing server and the first timing client;
the timing server further operable to generate one or more timing messages for the first timing client, the one or more timing messages comprising a change in timing information to the first timing client-based on a time difference identified between the timing server and the first timing client;
the broadcast device operable to communicate with one or more additional timing clients, wherein the one or more timing messages sent from the timing server to the first timing client, the one or more timing messages comprising the change in timing information based on communication between the timing server and the first timing client, are replicated and broadcast to the one or more additional timing clients,
wherein the one or more additional timing clients are operable to receive and process the one or more replicated timing messages though the one or more timing messages were generated based on the time difference identified between the timing server and the first timing client,
wherein process the one or more replicated timing messages includes:
extracting one or more timing correction values from the replicated timing messages; and
adjusting internal timing based on the extracted timing correction values.

2. The system of claim 1 , wherein the timing server generates the one or more timing messages defined by the Data-Over-Cable Interface Specification (DOCSIS) Timing Interface Specification (DTI).

3. The system of claim 2 , wherein the timing server is implemented by a modular cable modem termination system (M-CMTS).

4. The system of claim 1 , wherein the additional timing clients comprise one or more Edge-QAM(s).

5. The system of claim 1 , wherein the additional timing clients comprise one or more upstream receiver(s).

6. The system of claim 1 , wherein the one of the additional timing clients comprises a modular cable modem termination system (M-CMTS).

7. The system of claim 1 , wherein the first timing client comprises one of a modular cable modem termination system (M-CMTS), Edge-QAM, and upstream receiver.

8. The system of claim 1 , wherein the broadcast device communicates with the one or more additional communication devices through one of dedicated, shared and a combination of dedicated and shared communication links.

9. The system of claim 1 , wherein the broadcast device is implemented with a standard ethernet hub.

10. A method, comprising:
transmitting, by a timing server, one or more timing correction messages through a broadcast device to a first timing client based on a time difference identified between the timing server and the first timing client, wherein the broadcast device provides two-way communication between the timing server and the first timing client;
replicating and transmitting, by the broadcast device, the timing correction messages to one or more additional timing clients, the timing correction messages including a timing correction value based on the time difference identified between the timing server and the first timing client;
processing, by the one or more additional timing client, the timing correction message includes:
snooping the replicated timing correction messages;
extracting one or more timing correction values from the snooped timing correction messages; and
adjusting internal timing based on the extracted timing correction values.

11. The method of claim 10 , wherein redundant broadcast devices are used to replicate and transmit the timing correction messages.

12. The method of claim 10 , wherein a broadcast device is used to replicate and transmit the timing correction messages, wherein the delay between the broadcast device and the first timing client approximates the communication path delay between the broadcast device and the additional timing clients.

13. The method of claim 10 , wherein redundant communication links are used to transmit the timing correction messages to the first timing client and additional timing clients.

14. The method of claim 10 , wherein a local timing correction factor is applied in conjunction with the timing correction values for adjusting internal timing.

15. The method of claim 10 , wherein the timing correction value is one of a clock correction value and time stamp.

Assignees

• Arris Group Inc
• Arris Entpr Llc

Inventors

• Wheelock Ian

Classifications

• H04L12/2801 Primary

  Broadband local area networks · CPC title

• H04L7/0037

  Delay of clock signal · CPC title

• H04L67/1095 Primary

  Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes · CPC title

• H04J3/0664

  unidirectional timestamps · CPC title

• H04L69/28

  Timers or timing mechanisms used in protocols · CPC title