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Systems and methods for synchronizing optical transmitters

  • US 9,654,933 B2
  • Filed: 02/10/2014
  • Issued: 05/16/2017
  • Est. Priority Date: 02/10/2014
  • Status: Active Grant
First Claim
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1. An asset tracking system, comprising:

  • a wireless network having a plurality of nodes configured to communicate wireless electrical signals via a first electrical channel, the nodes having optical transmitters configured to transmit wireless optical signals via an optical channel that is time-division multiplexed among the nodes, wherein messages communicated via the first electrical channel hop from node-to-node through the wireless network, and wherein one of the wireless optical signals from one of the nodes includes a room identifier identifying a room of a building in which the one node is located;

    a tag configured to receive the wireless optical signals, including the one wireless optical signal having the room identifier, the tag further configured to transmit a first message via a wireless electrical signal to one of the nodes via a second electrical channel, wherein the first message includes the room identifier, and wherein the nodes are configured to transmit the first message via the first electrical channel; and

    a server configured to receive the first message from the nodes and to determine a location of the tag based on the room identifier, the server further configured to transmit a second message for controlling the tag to the nodes via the first electrical channel, wherein at least one of the nodes is configured to transmit the second message to the tag via the second electrical channel,wherein the nodes are configured to transmit an electrical synchronization signal via the first electrical channel and to synchronize the optical transmitters based on the electrical synchronization signal.

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