Low Power Multiple Channel Mixing Architecture For Detecting Wake-Up Signals and Related Falsing Protection Algorithm

• US 20090252042A1
• Filed: 02/02/2009
• Published: 10/08/2009
• Est. Priority Date: 04/07/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Bradley, Peter, Corndorf, Eric D., Rosar, George C., Dorning, Philip, Denzene, Quentin Scott, Wine, Nicholas C., Le Reverend, Remi, Bottomley, Andrew M., Dudding, Charles H., Delight, Guy A., Wentink, Robert S.
• Granted Patent: US 8,059,628 B2
• Time in Patent Office: Days
• US Class Current: 370/241
• CPC Class Codes: A61N 1/37276 characterised by means for reducing power consumption during telemetry
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A low power multiple channel receiver mixing architecture for detecting wake-up signals over multiple communication channles in sniff processing performed in an implantable medical device (IMD). The architecture includes a direct conversion real receiver configured to scan a selected center channel and a Weaver receiver configured in parallel to the direct conversion real receiver to simultaneously scan side channels, together simultaneously detecting whether a wake-up signal is being received over the center and side channels with minimal power consumption. The architecture further utilizes a falsing protection algorithm that reduces power consumption during sniff operations by inhibiting the sniffing of channels likely to provide a false indication of a wake-up signal based the presence of unwanted signals on those channels. The falsing protection algorithm restricts those channels from sniff processing likely to provide a false indication of a wake-up signal, such that sniff processing can aborted, prevented, limited or otherwise altered to conserve power consumption.

Claims

1. A low power, multiple channel mixing architecture for a receiver in an implantable medical device comprising:

a direct conversion real receiver circuit configured when activated to monitor a selected communication channel to detect whether a communication signal is being received from a remote device over the selected communication channel, and

a Weaver image rejecting mixer receiver circuit configured when activated to simultaneously monitor at least one communication channel adjacent to the selected communication channel to detect whether a communication signal is being received from a remote device over the at least one communication channel adjacent to the selected communication channel.

2. The multiple channel mixing architecture of claim 1, wherein the Weaver image rejecting mixer receiver circuit is configured to monitor a plurality of communication channels adjacent to the selected communication channel.

3. The multiple channel mixing architecture of claim 2, wherein the direct conversion real receiver circuit and the Weaver image rejecting mixer receiver circuit are configured to simultaneously monitor the selected communication channel and the plurality of adjacent communication channels to detect whether a communication signal is being received from a remote device over a specific one of the monitored communication channels.

4. The multiple channel mixing architecture of claim 1, wherein the direct conversion real receiver circuit and the Weaver image rejecting mixer receiver circuit are configured to detect whether the communication signal is a wake-up signal for the implantable medical device.

5. The multiple channel mixing architecture of claim 1, wherein the selected communication channel monitored by the direct conversion real receiver circuit is a center channel, the Weaver image rejecting mixer receiver circuit further being configured to monitor adjacent side channels to the center channel.

6. The multiple channel mixing architecture of claim 1, wherein the direct conversion real receiver circuit and the Weaver image rejecting mixer receiver circuit are configured to remain in a power off state when not activated to monitor the communication channels.

7. A method comprising:

operating an implanted medical device capable of receiving wireless communication signals;

monitoring a selected communication channel with a direct conversion real receiver in the implanted medical device to detect whether a communication signal is being received from a remote device over the selected communication channel; and

simultaneously monitoring at least one communication channel adjacent to the selected communication channel using a Weaver image rejecting mixer receiver in the implanted medical device to detect whether a communication signal is being received from a remote device over the at least one communication channel adjacent to the selected communication channel.

8. The method of claim 7, further comprising monitoring a plurality of communication channels adjacent to the selected communication channel using the Weaver image rejecting mixer receiver.

9. The method of claim 8, simultaneously monitoring the selected communication channel and the plurality of adjacent communication channels to detect whether a communication signal is being received from a remote device over a specific one of the monitored communication channels.

10. The method of claim 7, further comprising detecting whether the communication signal is a wake-up signal for the implantable medical device.

11. The method of claim 7, further comprising designating the selected communication channel monitored by the direct conversion real receiver as a center channel and the adjacent communication channels monitored by the Weaver image rejecting mixer receiver as side channels adjacent to the center channel.

12. The method of claim 11, further comprising:

selecting a different center channel and respective side channels; and

repeating the steps of simultaneously monitoring the center channel using the direct conversion real receiver and at least one adjacent side channel using the Weaver image rejecting mixer receiver to detect whether a communication signal is being received from a remote device over one of the monitored communication channels.

13. The method of claim 12, further comprising repeatedly selecting a different center channel and respective side channels and simultaneously monitoring the center channel and at least one adjacent side channel until a desired number of communication channels have been monitored.

14. The method of claim 7, further comprising operating the implantable medical device in a power off state when the direct conversion real receiver and the Weaver image rejecting mixer receiver are not activated to monitor the communication channels

15. A method comprising:

performing a plurality of different phases of sniff operations in an implantable medical device for detecting whether a wake-up communication signal is being received by the implantable medical device over a selected communication channel,

wherein one of the phases of sniff operations includes a signal strength detecting phase and at least one of the other phases of sniff operations detects the presence of the unwanted signal on the selected communication channel;

aborting all of the different phases of sniff operations on the selected communication channel if a measured signal strength in the signal strength detecting phase fails to meet a threshold value determination; and

aborting all of the different phases of sniff operations on the selected communication channel if the measured signal strength in the signal strength detecting phase meets the threshold value determination but matches a signal strength signature associated with a previously identified unwanted signal on the selected communication channel.

16. The method of claim 15, wherein the signal strength signature comprises a range of signal strength values surrounding a measured signal strength of a previously identified unwanted signal.

17. The method of claim 15, further comprising:

aborting all of the different phases of sniff operations on the selected communication channel if an unwanted signal is detected on the selected communication channel;

restricting the selected communication channel for future sniff operations;

recording the measured signal strength of the unwanted signal; and

generating a signal strength signature of a range of signal strength values surrounding the measured signal strength for use in future signal strength detecting phases.

18. The method of claim 17, when sniff operations are aborted due to a failure of the signal strength detecting phase, the method further comprising:

determining whether the selected communication channel was identified as a restricted channel during a previous sniff operation; and

if previously identified as a restricted channel, removing the restriction from the selected communication channel so that it no longer is identified as a restricted communication channel in future sniff operations.

19. The method of claim 17, wherein sniff operations are performed by a wake-up receiver including both a direct conversion real receiver and a Weaver receiver for simultaneously performing sniff operations on a plurality of selected communication channels, when it is determined that the measured signal strength satisfies the threshold value determination, the method further comprising:

determining whether the selected communication channel was identified as a restricted channel during a previous sniff operation;

if previously identified as a restricted channel, determining whether sniff operations were being performed by the direct conversion real receiver or the Weaver receiver when identified as a restricted channel in the previous sniff operation; and

if sniff operations were performed by the Weaver receiver when the selected communication channel was previously identified as a restricted channel and if Weaver receiver restrictions are configured to be ignored, allowing the other phases of sniff operations to continue.

20. The method of claim 19, wherein if sniff operations were performed by the direct conversion real receiver when the selected communication channel was previously identified as a restricted channel and if the measured signal strength falls outside of the signal strength signature, removing any prior restrictions associated with the selected communication channel so that it no longer is identified as a restricted communication channel and allowing the other phases of sniff operations to continue.

21. The method of claim 15, wherein the at least one of the other phases of sniff operations for detecting the presence of the unwanted signal comprise at least one of a frequency deviation measuring phase and a Manchester decoding phase.

22. A telemetry module in an implantable medical device comprising:

a wake-up receiver including a plurality of signal detectors configured to perform a plurality of different phases of sniff operations in an implantable medical device for detecting whether a wake-up communication signal is being received by the implantable medical device over a selected communication channel;

at least one of the plurality of signal detectors comprising an unwanted signal detector configured to detect the presence of an unwanted signal on the selected communication channel during at least one phase of sniff operations; and

at least one of the plurality of signal detectors comprising a signal strength detector configured to perform a signal strength detecting phase during one of the phases of sniff operations,

wherein the signal strength detector is further configured to;

abort all of the different phases of sniff operations on the selected communication channel if a measured signal strength in the signal strength detecting phase fails to meet a threshold value determination; and

abort all of the different phases of sniff operations on the selected communication channel if the measured signal strength in the signal strength detecting phase meets the threshold value determination but matches a signal strength signature associated with a previously identified unwanted signal on the selected communication channel.

23. The telemetry module of claim 22, wherein the signal strength signature comprises a range of signal strength values surrounding a measured signal strength of a previously identified unwanted signal.

24. The telemetry module of claim 22, wherein the at least one unwanted signal detector is further configured to:

abort all of the different phases of sniff operations on the selected communication channel if an unwanted signal is detected on the selected communication channel;

restrict the selected communication channel for future sniff operations;

record the measured signal strength of the unwanted signal; and

generate a signal strength signature of a range of signal strength values surrounding the measured signal strength for use in future signal strength detecting phases.

25. The telemetry module of claim 24, when sniff operations are aborted due to a failure of the signal strength detecting phase, the signal strength detector is further configured to:

determine whether the selected communication channel was identified as a restricted channel during a previous sniff operation; and

if previously identified as a restricted channel, remove the restriction from the selected communication channel so that it no longer is identified as a restricted communication channel in future sniff operations.

26. The telemetry module of claim 24, wherein the wake-up receiver includes both a direct conversion real receiver and a Weaver receiver for simultaneously performing sniff operations on a plurality of selected communication channels, when it is determined that the measured signal strength satisfies the threshold value determination, the signal strength detector is further configured to:

determine whether the selected communication channel was identified as a restricted channel during a previous sniff operation;

if previously identified as a restricted channel, determine whether sniff operations were being performed by the direct conversion real receiver or the Weaver receiver when identified as a restricted channel in the previous sniff operation; and

for sniff operations being performed by the direct conversion real receiver on a selected communication channel, if sniff operations were performed by the Weaver receiver when the selected communication channel was previously identified as a restricted channel and if Weaver receiver restrictions are configured to be ignored, the signal strength detector is further configured to allow the other phases of sniff operations to continue.

27. The telemetry module of claim 26, wherein if sniff operations were performed by the direct conversion real receiver when the selected communication channel was previously identified as a restricted channel and if the measured signal strength falls outside of the signal strength signature, the signal strength detector is further configured to remove any prior restrictions associated with the selected communication channel so that it no longer is identified as a restricted communication channel and to allow the other phases of sniff operations to continue.

28. The telemetry module of claim 22, wherein the at least one of the unwanted signal detectors comprise at least one of a frequency deviation measuring detector and a Manchester decoding detector.