Low-Power Wireless Beacon for Fluorescent Lamp Control
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Solution Overview
Problem
Existing ZigBee-based lighting control systems for low-power wireless networks face high power consumption due to protocol overhead and latency issues, making them expensive and inefficient for cost-sensitive battery-powered applications.
Innovation Solution
A low-power wireless network with a master unit transmitting synchronizing RF beacons at infrequent intervals, allowing endpoint units to operate in a low-power sleep mode most of the time, and using a 'Count Until Action' field to schedule actions like turning off fluorescent lamps without frequent beacon transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a full ZigBee protocol stack is implemented in the coordinator and endpoint devices, then the system achieves standardized wireless communication and device control, but power consumption increases and device cost increases
Solution Approach 1:
The patent extracts and removes unnecessary protocol layers from the ZigBee stack, implementing only a simplified protocol with physical layer, synchronization layer, and application layer. This extraction eliminates the network layer and other overhead components that consume power, while retaining essential wireless communication functionality for beacon reception and command execution.
Solution Approach 2:
The patent applies local quality by implementing different protocol complexity levels at different device locations/roles. The coordinator uses a simplified protocol suitable for its beacon transmission function, while endpoint devices use an even more minimal protocol for receiving commands and reporting status, optimizing power consumption at each location according to its specific functional requirements.
2Loss of time
If beacon transmission intervals are shortened to reduce latency, then the system responds more quickly to commands, but power consumption increases
Solution Approach 1:
The patent implements periodic beacon transmissions at optimized intervals (e.g., every 15 minutes or 900 seconds) that balance responsiveness with power conservation. The coordinator transmits beacons periodically rather than continuously, and endpoint devices synchronize their wake-sleep cycles to these periodic beacons, achieving acceptable latency while minimizing active radio time and power consumption.
3Reliability
If endpoint devices remain in active reception mode continuously, then the system achieves immediate response to commands, but battery life decreases
Solution Approach 1:
The patent implements preliminary action by having endpoint devices wake up just in time to receive beacons based on synchronized timing information embedded in previous beacons. Devices calculate their wake time in advance and enter low-power sleep mode between beacons, yet remain reliably responsive because they wake synchronously with each beacon transmission, achieving both battery conservation and command responsiveness.
4Loss of time
If the coordinator transmits beacons frequently, then the system maintains better synchronization and reduces latency, but network power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the beacon interval parameter based on system conditions and requirements. The beacon interval is set to optimized values (such as 900 seconds) that provide adequate synchronization accuracy while minimizing power consumption. This parameter optimization allows the network to maintain time synchronization for command responsiveness without the energy cost of frequent beacon transmissions.
Data Source
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AI summary
A low-power wireless network involves a plurality of RF-enabled fluorescent lamp starter units. In each of a plurality of intervals, a receiver of a starter unit operates in a receive mode during a beacon slot time, and for the majority of the rest of the interval operates in a low-power sleep mode. The starter unit wakes up and listens for a beacon each beacon slot time, regardless of whether a beacon is transmitted during that interval or not. A starter unit can be commanded to schedule a future action (for example, for a time between widely spaced synchronizing beacons) by making one of the beacons a scheduling beacon. The scheduling beacon includes a field that the starter unit uses to schedule the future action. If the scheduled action is to be canceled before the next widely spaced synchronizing beacon, then an action-canceling beacon is communicated in the next interval.