Wireless sensor network wake-up range extension via energy harvesting and edge devices
An enhanced, ultra low power passive wake-up radio-based sensor includes a passive wake-up radio-based sensor node having an energy harvester and low power wake-up circuit to improve the wake-up range for passive wake-up radio sensor nodes without the need for local power. The wake-up sensor may additionally include a transmitter for providing a wake-up signal to nodes that are outside the wake-up range of a base.
1. A wake-up radio sensor node, comprising:
an energy harvesting circuit for collecting energy from a wireless signal and outputting a voltage based on said collected energy;
a wake-up circuit comprising a wake-up pulse generator interconnected to said energy harvesting circuit for receiving said output voltage of said energy harvesting signal and using said output voltage to generate a wake-up signal;
a wireless sensor having a sleep mode and an active mode interconnected to said wake-up circuit to receive said wake-up signal, wherein said sensor is programmed to enter said active mode from said sleep mode in response to receiving said wake-up signal; and
a power source interconnected to said wireless sensor.
2. The node of claim 1 , wherein said wake-up pulse generator generates said wake-up signal after said voltage exceeds a predetermined threshold.
3. The node of claim 2 , wherein predetermined threshold is 1.5 volts.
4. The node of claim 1 , wherein said wireless sensor is programmed to send any data when said wireless sensor enters said active mode from said sleep mode.
5. The node of claim 4 , wherein said wireless sensor is programmed to enter said sleep mode after sending data when in said active mode.
6. The node of claim 1 , wherein said power source only supplies power to said wireless sensor for sensing and data communication.
7. A multi-hop wireless wake-up radio sensor node, comprising:
an energy harvesting circuit for collecting energy from a wireless signal and outputting a voltage based on said collected energy;
a wake-up circuit comprising a wake-up pulse generator interconnected to said energy harvesting circuit for receiving said output voltage of said energy harvesting signal and using said output voltage to generate a wake-up signal;
a wireless sensor interconnected to said wake-up circuit to receive said wake-up signal and configured to output a node wake-up signal when said wake-up signal is received;
a wireless transmitter interconnected to said wireless sensor module for transmitting said node wake-up signal; and
a power source interconnected to said wireless sensor module and said wireless transmitter.
8. The node of claim 7 , wherein said wireless transmitter comprises a radio-frequency identification reader and a dual-channel power distribution switch.
9. The node of claim 7 , wherein said wireless sensor includes a timer for counting a predetermined period of time that commences after said node wake-up signal is transmitted.
10. The node of claim 9 , wherein said wireless sensor is programmed to receive data from a nearby node before said predetermined period of time elapses.
11. The node of claim 10 , wherein said wireless sensor is set to a multi-hop mode if data is received from a nearby node prior to said predetermined period of time elapsing.
12. A method of extending the wake-up range of a radio sensor node, comprising the steps of:
using an energy harvesting circuit to collect energy from a wireless signal;
outputting a voltage based on said collected energy;
using said output voltage to generate a wake-up signal;
providing said signal to a wireless sensor having a sleep mode and an active mode; and
wherein said sensor enters said active mode from said sleep mode in response to receiving said wake-up signal.
13. The method of claim 12 , further comprising the step of supplying power to just said wireless sensor from a power source.
14. The method of claim 12 , wherein said wake-up signal is generated after said voltage exceeds a predetermined threshold.
15. The method of claim 14 , wherein predetermined threshold is 1.5 volts.
16. The method of claim 15 , wherein said wireless sensor transmits data after said wireless sensor enters said active mode from said sleep mode.
17. The method of claim 15 , wherein said wireless sensor enters said sleep mode after sending data in said active mode.