Impulse Radio Wakeup Circuit for Ultra-Low Power Sensor Nodes
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Solution Overview
Problem
Wireless Sensor Networks face challenges in reducing power consumption during idle states, as nodes spend a significant fraction of energy listening to the channel, and existing solutions trade off between complete integration and power consumption, with channel filtering being a key factor in achieving ultra-low power consumption.
Innovation Solution
A radio frequency device with an RF transceiver and an envelope detector circuit that generates pulses to transition out of a reduced power mode in response to a valid RF impulse signal, allowing for efficient power management without the need for complex channel filtering, using an RF impulse radio modulation protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If duty-cycling is used to reduce power consumption, then energy expenditure during idle states is reduced, but synchronization complexity increases
Solution Approach 1:
The wakeup radio autonomously detects impulse signals and generates wake-up commands without requiring external synchronization coordination. Each node independently monitors for impulses and self-determines when to wake up, eliminating the need for complex network-wide synchronization algorithms while maintaining duty-cycled power savings.
2Use of energy by moving object
If channel filtering is implemented using high-Q RF filters, then power consumption is reduced, but device complexity and size increase
Solution Approach 1:
The patent extracts and removes the complex high-Q RF filter from the wakeup radio architecture. Instead of filtering channels before detection, the system uses an impulse-based approach where the envelope detector directly processes wideband signals, identifying wake-up commands through their distinctive impulse patterns rather than frequency filtering. This eliminates the need for BAW filters or MEMS resonators.
Solution Approach 2:
The physical RF filtering mechanism (mechanical/resonant filters) is replaced with a signal processing approach using envelope detection and impulse recognition. The system substitutes hardware-based frequency selection with a detection algorithm that identifies wake-up signals through their temporal impulse characteristics rather than frequency content, enabling complete integration without external filters.
3Device complexity
If complete integration is achieved without channel filtering, then device size and cost are reduced, but power consumption increases due to noise
Solution Approach 1:
The patent converts the harmful wideband noise that would normally require filtering into a beneficial detection mechanism. By using impulse radio modulation, the wake-up signal stands out as a distinct impulse pattern against the noise background. The envelope detector exploits this impulse characteristic, allowing the system to operate without filters while the impulse signal's temporal structure provides inherent noise immunity, maintaining low power consumption despite complete integration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables low power consumption while maintaining effective communication, allowing for the integration of components into small, cost-effective nodes, reducing energy expenditure during idle states and improving network performance by distinguishing signal from noise efficiently.
Implementation Method 1
an envelope detector circuit to detect an envelope of the RF impulse signal
Data Source
AI summary
Communication networks are implemented using a variety of devices and methods. In a particular embodiment for use in a communication network having RF-communication devices that communicate using a RF protocol, an RF-communication device is implemented with an RF transceiver (110) to communicate over the network using the RF protocol and being controllable in a reduced power-consumption mode in which the RF transceiver does not communicate over the network. The device also includes an RF receiver (104, 106) including an envelope detector (104) and a pulse generator circuit (106). The envelope detector circuit (104) providing an envelope-based signal to a pulse generator circuit (106) that, in response to the envelope-based signal and after generating a number of pulses that exceeds a predetermined number of pulses, prompts the RF transceiver (110) to transition out of the reduced power-consumption mode.