Time-keeping between devices using power distribution line communications

摘要

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).

主权项

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; andadjusting 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.