Wireless End Node Sleep Timing for Refrigeration Battery Life
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Solution Overview
Problem
Existing transport refrigeration systems face challenges in preserving the life of power sources for wireless end nodes due to continuous power draw during normal operation, which can lead to excessive battery drain and reduced lifespan, especially in mobile environments where network coordinator acknowledgment messages may not be consistently received.
Innovation Solution
Implementing a method where wireless end nodes monitor for network coordinator acknowledgment messages, increment a missed acknowledgment counter, and increase the sleep timer period when the counter reaches a threshold, allowing the node to conserve power by reducing current consumption during extended sleep modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wireless end node operates in normal operation mode continuously to monitor and communicate with the network coordinator, then the system reliability and monitoring capability are improved, but the power source lifespan deteriorates due to continuous current draw
Solution Approach 1:
The wireless end node alternates between normal operation mode and sleep mode in periodic cycles. During normal operation mode, the node monitors transport refrigeration system properties and communicates with the network coordinator. During sleep mode, the node enters a low-power state to conserve battery energy. This periodic switching resolves the contradiction by ensuring the system maintains monitoring capability when needed while preserving power source lifespan through extended sleep periods.
Solution Approach 2:
The system dynamically adjusts its operational state based on communication success. When acknowledgment messages are received from the network coordinator, the node transitions to sleep mode to conserve power. When acknowledgments are missed (indicating potential system issues), the node wakes up to re-establish communication. This dynamic state adjustment allows the system to balance between maintaining reliability and preserving power source lifespan.
2Reliability
If the wireless end node frequently wakes up to check for acknowledgment messages, then the system responsiveness and reliability are improved, but the power consumption increases reducing the power source lifespan
Solution Approach 1:
The wireless end node implements periodic wake-up cycles where it alternates between sleep mode and normal operation mode. During each cycle, the node wakes up for a brief period to monitor for acknowledgment messages from the network coordinator, then returns to sleep mode. This periodic action ensures the system remains responsive to communication while minimizing power consumption by limiting the duration of high-power operational states.
Solution Approach 2:
The system changes the time period parameter of the sleep timer based on communication status. When acknowledgment messages are successfully received, the sleep timer period is extended to reduce wake-up frequency and power consumption. When acknowledgments are missed, the sleep timer period is reduced to increase monitoring frequency and ensure system reliability. This dynamic parameter adjustment resolves the contradiction between responsiveness and power consumption.
3Duration of action of stationary object
If the sleep timer period is extended to conserve power, then the power source lifespan is improved, but the system responsiveness to network coordinator communications deteriorates
Solution Approach 1:
The wireless end node employs feedback mechanisms to monitor communication status with the network coordinator. When acknowledgment messages are received, the system feedback indicates normal operation, allowing the sleep timer period to be extended. When acknowledgments are missed, the feedback triggers a reduction in the sleep timer period to increase monitoring frequency. This feedback-driven adjustment resolves the contradiction by adapting the sleep period based on actual system communication status.
Solution Approach 2:
The sleep timer period is dynamically adjusted based on communication success rather than remaining fixed. Successful acknowledgments lead to extended sleep periods for power conservation, while missed acknowledgments trigger reduced sleep periods for increased responsiveness. This dynamic adaptation allows the system to optimize the balance between power source lifespan and system responsiveness time based on real-time communication conditions.
Data Source
AI summary
Methods and systems for preserving the life of a power source of a wireless end node of a wireless communication system for use in a mobile environment are provided. In one embodiment, a method is provided that includes wirelessly transmitting a wireless end node acknowledgment message to a network coordinator during a normal operation mode of the wireless end node. The method also includes 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. Also, the method includes 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. Further, the method includes increasing a time period of a sleep timer of the wireless end node when the missed acknowledgment counter value equals a missed acknowledgment threshold.