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Methods and systems for preserving the life of a power source of a wireless end node in a transport refrigeration system

  • US 9,060,337 B2
  • Filed: 03/21/2013
  • Issued: 06/16/2015
  • Est. Priority Date: 03/21/2012
  • Status: Active Grant
First Claim
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1. A method for preserving the life of a power source of a wireless end node of a wireless communication system for use in a mobile environment, the wireless end node including an electrical assembly powered by a power source, the electrical assembly including an operation sensor configured to sense an operation of a transport refrigeration system, a transceiver configured to transmit a data signal to and receive a data signal from the network coordinator, a memory storage, a sleep timer configured to count down a time period that the wireless end node operates in a sleep mode, and a controller including the sleep timer, the controller being connected to the operation sensor, the transceiver and the memory storage, and the controller configured to manage, command, direct and regulate behavior of the wireless end node and configured to operate the wireless end node in a normal operation mode and the sleep mode, the method comprising:

  • deploying, installing, pairing and setting the wireless end node in the normal operation mode, wherein in the normal operation mode the electrical assembly drawing current from the power source, the operating sensor monitoring a portion of the transport refrigeration system and the transceiver transmitting data to and receiving data from the network coordinator;

    the wireless end node wirelessly transmitting a wireless end node acknowledgment message to a network coordinator during a normal operation mode of the wireless end node;

    the wireless end node monitoring for a network coordinator acknowledgment message from a network coordinator in response to the wireless end node acknowledgement message during the normal operation mode of the wireless end node;

    incrementing a missed acknowledgment counter value stored in a memory storage of the wireless end node when the network coordinator acknowledgment message is not received;

    switching from the normal operation mode to the sleep mode for a first time period after incrementing the missed acknowledgement counter value or after the wireless end node receiving the network acknowledgement message from the network coordinator, wherein in the sleep mode the electrical assembly powering down and reducing the amount of current drawn from the power source to a level sufficient for operating the sleep timer, for receiving an interrupt request via the transceiver, and for powering up the electrical assembly from the sleep mode back to the normal operation mode; and

    increasing a time period of the sleep timer of the wireless end node from the first time period to a second time period when the missed acknowledgment counter value equals a missed acknowledgment threshold in order to reduce current being drawn from the power source of the wireless end node;

    the wireless end node receiving a network coordinator acknowledgement message from the network coordinator during the normal operation mode;

    clearing the missed acknowledgement counter and returning the time period of the sleep timer from the second time period to the first time period when the wireless end node receives the network coordinator acknowledgement message from the network coordinator;

    the wireless end node receiving the interrupt request from a user; and

    clearing the missed acknowledgement counter and returning the time period of the sleep timer from the second time period to the first time period when the wireless end node receives the interrupt request from the user.

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