Wakeup radio for low power nodes in Bluetooth

1. A method performed by a low-power node (LPN) in a wireless mesh network, wherein the LPN comprises a main receiver and a wakeup receiver, and wherein the method comprises:

performing the following first operations in response to an event trigger:

activating the wakeup receiver while maintaining the main receiver in an inactive state, and

sending a polling message to a second node in the wireless mesh network;

for a predetermined duration after sending the polling message, determining whether a wakeup signal has been received from the second node via the wakeup receiver; and

performing second operations based on determining that the wakeup signal has been received, the second operations including: activating the main receiver, and receiving, from the second node via the main receiver, a response to the polling message.

2. The method of claim 1 , wherein the second operations also include deactivating the wakeup receiver.

3. The method of claim 2 , wherein the second operations also include, after receiving a response to the polling message, deactivating the main receiver while maintaining the wakeup receiver in an inactive state.

4. The method of claim 1 , further comprising, based on determining that the wakeup signal was not received during the predetermined duration, deactivating the wakeup receiver while maintaining the main receiver in an inactive state.

5. The method of claim 1 , wherein sending the polling message comprises sending one or more repetitions of the polling message on respective one or more channels.

6. The method of claim 5 , wherein:

determining whether the wakeup signal has been received is performed in response to each of the repetitions; and

the method further comprises, based on determining that the wakeup signal was received in response to a particular repetition, refraining from sending subsequent repetitions of the polling message.

7. The method of claim 1 , wherein receiving the response to the polling messages comprises monitoring for one or more repetitions of the response on respective one or more channels.

8. The method of claim 1 , wherein:

determining whether the wakeup has been received comprises monitoring a predetermined channel; and

the predetermined channel is one of the following: a pre-defined channel, and a channel determined between the LPN and the second node before performing the first operations.

9. The method of claim 1 , wherein:

the polling message comprises an indication of a channel to carry the wakeup signal; and

determining whether the wakeup has been received comprises monitoring the indicated channel.

10. The method of claim 1 , wherein the wireless mesh network is a Bluetooth Mesh network; and the second node is a Friend node with respect to the LPN.

11. A method performed by a second node in association with a low-power node (LPN) in a wireless mesh network, the method comprises:

monitoring for polling messages from the LPN while the LPN's main receiver is in an inactive state;

based on determining that a polling message was received from the LPN, determining whether there are any messages intended for the LPN that are buffered at the second node;

based on determining that there are messages intended for the LPN that are buffered at the second node, sending a wakeup signal to the LPN's wakeup receiver; and

subsequently sending a response to the polling message to the LPN's main receiver, which is activated based on the wakeup signal.

12. The method of claim 11 , further comprising, based on determining that there are no messages intended for the LPN that are buffered at the second node:

refraining from sending both the wakeup signal and the response to the polling message; and monitoring for further polling messages from the LPN.

13. The method of claim 11 , wherein monitoring for polling messages comprises monitoring for one or more repetitions of a polling message on respective one or more channels.

14. The method of claim 13 , further comprising, based on determining that a particular repetition of the polling message was received on a particular channel, refraining from monitoring for subsequent repetitions of the polling message.

15. The method of claim 11 , wherein sending the response to the polling message comprises sending one or more repetitions of the response on respective one or more channels.

16. The method of claim 11 , wherein:

the wakeup signal is sent on a predetermined channel; and

the predetermined channel is one of the following: a pre-defined channel, or a channel determined between the second node and the LPN before monitoring for the polling messages.

17. The method of claim 11 , wherein: the received polling message comprises an indication of a channel to carry the wakeup signal; and the wakeup signal is sent on the indicated channel.

18. The method of claim 11 , further comprising:

receiving, from a further node in the wireless mesh network, a message intended for the LPN; and

buffering the received message.

19. The method of claim 11 , wherein:

the wireless mesh network is a Bluetooth Mesh network; and

the second node is a Friend node with respect to the LPN.

20. A low-power node (LPN) in a wireless mesh network, wherein the LPN comprises:

a wireless transceiver configured to communicate with at least a second node in the wireless mesh network, wherein the wireless transceiver includes a main receiver and a wakeup receiver; and

processing circuitry operatively coupled to the wireless transceiver, whereby the processing circuitry and the wireless transceiver are configured to perform operations corresponding to the method of claim 1 .

21. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry comprising a low-power node (LPN) in a wireless mesh network, configure the LPN to perform operations corresponding to the method of claim 1 .

22. A second node in a wireless mesh network, wherein the second node comprises:

a wireless transceiver configured to communicate with at least a low-power node (LPN) in the wireless mesh network; and

processing circuitry operatively coupled to the wireless transceiver, whereby the processing circuitry and the wireless transceiver are configured to perform operations corresponding to the method of claim 11 .

23. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry comprising a second node in a wireless mesh network, configure the second node to perform operations corresponding to the method of claim 11 .

24. A wireless mesh network comprising:

the low-power node (LPN) of claim 20 ;

a second node comprising processing circuitry and a wireless transceiver that are configured to:

monitor for polling messages from the LPN while the LPN's main receiver is in the inactive state;

based on determining that a polling message was received from the LPN, determine whether there are any messages intended for the LPN that are buffered at the second node;

based on determining that there are messages intended for the LPN that are buffered at the second node, send a wakeup signal to the LPN's wakeup receiver; and

subsequently send a response to the polling message to the LPN's main receiver, which is activated based on the wakeup signal; and

one or more further nodes configured to send messages to the LPN via the second node.