Clock synchronization over a powerline modem network for multiple devices

• US 6,577,231 B2
• Filed: 04/03/2001
• Issued: 06/10/2003
• Est. Priority Date: 04/03/2001
• Status: Expired due to Term

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Ramaswamy, Kumar, Litwin, Louis Robert Jr.
• Primary Examiner(s): LA, ANH V
• Application Number:
  US09/825,233
• Publication Number:
  US 20020140547A1
• Time in Patent Office: 798 Days
• Field of Search: 340/310.01, 340/309.15, 368/46, 368/52, 368/47, 368/59, 368/1, 368/184, 368/185, 368/204, 968/920
• US Class Current: 375/356
• CPC Class Codes: G04G 7/00 Synchronisation radio-controlled time-pieces G04R
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/542 the information being in digital form

Abstract

An apparatus and method of clock synchronization of a powerline modem network for a plurality of devices are provided. A plurality of devices are provided having a powerline modem and a clock (100). The powerline modem permits communication between the plurality of devices over a powerline network. A synchronization message is provided over the powerline network (102). The synchronization message includes an instruction for each of the plurality of devices to update their clock in accordance with a clock time provided in the synchronization message (104). A synchronization device may be provided to update device clocks on a powerline network.

Claims

1. A method of clock synchronization of a powerline modem network for a plurality of devices, comprising the steps of:

providing a plurality of devices having a powerline modem and a clock, the powerline modem operable for digital communication and communication between the plurality of devices over a powerline network; and

providing a synchronization message over the powerline network from a local master device the synchronization message including an instruction for each of the plurality of devices to update their clock in accordance with a clock time provided in the synchronization mess age.

2. The method as recited in claim 1, wherein the step of providing a synchronization message includes providing the synchronization message after an interval of elapsed time.

3. The method as recited in claim 1, wherein the step of providing a synchronization message includes providing the synchronization message after a power outage.

4. The method as recited in claim 1, further comprising the step of updating a clock on the synchronization device by invoking an external clock source.

5. The method as recited in claim 1, wherein the step of providing a synchronization message includes the steps of requesting the synchronization message by one of the plurality of devices and issuing the synchronization message in accordance with the request.

6. A synchronization device to update device clocks on a powerline network, comprising:

a plug which connects to a powerline network and powers the synchronization device;

a clock which maintains time;

a powerline modem of a local master device coupled to the plug, said powerline modem operable for digital communication and sending a synchronization message to devices with clocks in the powerline network, the synchronization message enables the devices to update their clocks in accordance with the clock of the synchronization device.

7. The synchronization device as recited in claim 6, further comprising a battery which powers the clock of the synchronization device to maintain the time during a power outage.

8. The synchronization device as recited in claim 6, further comprising a timing circuit, which measures elapsed time to enable reissuance of the synchronization message.

9. The synchronization device as recited in claim 6, further comprising a receiver, which receives a time from an external source to update the clock of the synchronization device.

10. The synchronization device as recited in claim 6, wherein the devices with clocks include at least one of a media player, a television, an answering machine, a thermostat, a clock, a stereo, a microwave and a security system.

11. A method of clock synchronization of a powerline modem network for a plurality of devices, comprising the steps of:

providing a plurality of devices having a powerline modem and a clock, the powerline modem permitting communication between the plurality of devices over a powerline network;

requesting a synchronization message by one of the plurality of devices;

providing the synchronization message over the powerline network from a local master device in accordance with said step of requesting, the synchronization message including an instruction for each of the plurality of devices to update their clock in accordance with a clock time provided in the synchronization message.

12. A synchronization device to update device clocks on a powerline network, comprising:

a plug which connects to a powerline network and powers the synchronization device;

a clock which maintains time;

a powerline modem of a local master device coupled to the plug, which is operable to issue a synchronization message to devices with clocks in the powerline network in response to and in accordance with a request for the synchronization message by at least one of the devices in the powerline network, the synchronization message enabling the devices to update their clocks in accordance with the clock of the synchronization device.