Time-keeping between devices using power distribution line communications
First Claim
1. A method for communicating time-based data in a power line communication system having a command center, a collector device and a plurality of endpoint devices, the method comprising:
- communicating, from the collector device, downstream data to a plurality of endpoint devices, the downstream data communication using a communication protocol that is relative to a collector network time and that is over a set of power distribution lines carrying alternating current (AC), the collector network time using a local oscillator as a time base; and
for each endpoint device,communicating, from the endpoint device, upstream data to the collector device, the upstream data communication using a communication protocol that is relative to a corresponding endpoint network time and that is over the set of power distribution lines carrying alternating current (AC), the endpoint network time using the AC as a time base, wherein the upstream data is time-sensitive relative to a location-based time that is dependent on a geographic location of the endpoint device, that uses the AC as a time base and that is offset relative to the endpoint network time; and
adjusting and synchronizing the collector network time and the endpoint network time according to a network time derived from a time server;
(i) to facilitate system-wide downstream data communication over the set of power distribution lines and (ii) to track, via upstream data communication over the set of power distribution lines, with time-based events reported relative to the location-based times used by the endpoint devices.
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Accused Products
Abstract
Particular embodiments are directed towards a method for communicating time-based data in a power line communication system. The communication system utilized in the method includes: a command center; a collector device; and a plurality of endpoint devices. The method includes communicating, from the collector device, downstream data to the plurality of endpoint devices. This downstream communication utilizes a communication protocol that is relative to a collector network time, and is over a set of power distribution lines carrying alternating current (AC). The collector network time uses the local oscillator. The AC zero-crossing event can be used as a time base for other versions of the network time. Conceptually, the AC can be thought of as acting as a reference clock for maintaining these other network times, although the clocking function can be carried out in the digital realm, e.g., using a digital-signal processor (DSP).
47 Citations
20 Claims
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1. A method for communicating time-based data in a power line communication system having a command center, a collector device and a plurality of endpoint devices, the method comprising:
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communicating, from the collector device, downstream data to a plurality of endpoint devices, the downstream data communication using a communication protocol that is relative to a collector network time and that is over a set of power distribution lines carrying alternating current (AC), the collector network time using a local oscillator as a time base; and for each endpoint device, communicating, from the endpoint device, upstream data to the collector device, the upstream data communication using a communication protocol that is relative to a corresponding endpoint network time and that is over the set of power distribution lines carrying alternating current (AC), the endpoint network time using the AC as a time base, wherein the upstream data is time-sensitive relative to a location-based time that is dependent on a geographic location of the endpoint device, that uses the AC as a time base and that is offset relative to the endpoint network time; and adjusting and synchronizing the collector network time and the endpoint network time according to a network time derived from a time server;
(i) to facilitate system-wide downstream data communication over the set of power distribution lines and (ii) to track, via upstream data communication over the set of power distribution lines, with time-based events reported relative to the location-based times used by the endpoint devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A utility reporting system comprising:
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a plurality of endpoints, each endpoint configured and arranged to maintain local metrological time in response to timing data received over power distribution lines by adjusting a local clock and by adding timing offsets for one or more of time zones and daylight savings; receive utility usage data from utility meters; tag the utility usage data with the local metrological time; maintain an endpoint network time using a frequency of AC power carried on the power distribution lines as a timing reference; transmit the tagged utility usage data over the power distribution lines using the endpoint network time as a reference for timing the transmission of data carrying symbols; a collector including a plurality of blades, each blade configured and arranged to maintain a collector network time using a local oscillator circuit as a timing reference; adjust the collector network time in response to timing data received from a time server; transmit, over the power distribution lines, the maintained collector network time to one or more of the plurality of endpoints; receive, over the power distribution lines, a signal modulated to include the data carrying symbols and to represent the tagged utility usage data; and demodulate the modulated signal using the collector network time as a reference for identifying the data carrying symbols.
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14. A method comprising:
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receiving a signal carried on a power distribution line; decoding the signal to generate data; extracting time-of-day information from the generated data; detecting a start symbol in the signal; and setting, in response to detecting the start symbol, a network time to a time corresponding to the extracted time-of-day information. - View Dependent Claims (15, 16)
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17. An apparatus comprising:
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a transceiver circuit configured and arranged to receive and transmit signals carried on a power distribution line; a processing circuit configured and arranged to receive a signal carried on the power distribution line; decode the signal to generate data; extract time-of-day information from the generated data; detect a start symbol in the signal; and set, in response to detecting the start symbol, a network time to a time indicated by the extracted time-of-day information. - View Dependent Claims (18, 19)
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20. An apparatus for communicating time-based data in a power line communication system having a command center, a collector device and a plurality of endpoint devices, the apparatus comprising:
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means for communicating, from the collector device, downstream data to a plurality of endpoint devices, the downstream data communication using a communication protocol that is relative to a collector network time and that is over a set of power distribution lines carrying alternating current (AC), the collector network time using a local oscillator as a time base; and for each endpoint device, means for communicating, from the endpoint device, upstream data to the collector device, the upstream data communication using a communication protocol that is relative to a corresponding endpoint network time and that is over the set of power distribution lines carrying alternating current (AC), the endpoint network time using the AC as a time base, wherein the upstream data is time-sensitive relative to a location-based time that is dependent on a geographic location of the endpoint device, that uses the AC as a time base and that is offset relative to the endpoint network time; and means for adjusting and synchronizing the collector network time and the endpoint network time according to a network time derived from a time server;
(i) to facilitate system-wide downstream data communication over the set of power distribution lines and (ii) to track, via upstream data communication over the set of power distribution lines, with time-based events reported relative to the location-based times used by the endpoint devices.
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Specification