ADAPTABLE COMMUNICATION SENSITIVITY FOR AN IMPLANTABLE MEDICAL DEVICE

• US 20100023085A1
• Filed: 07/24/2008
• Published: 01/28/2010
• Est. Priority Date: 07/24/2008
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Wu, Yongjian, Tieu, Thanh, Panescu, Dorin, Persson, Benjamin T., Shah, Devanshi, Weaver, Lyle Frank
• Granted Patent: US 8,554,333 B2
• Time in Patent Office: Days
• US Class Current: 607/30
• CPC Class Codes: A61N 1/37276 characterised by means for reducing power consumption during telemetry
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless communication threshold for an implantable medical device is automatically adapted in an attempt to maintain optimum signal detection sensitivity. In some aspects, a threshold level may be adapted to account for current environmental conditions, implant conditions, device conditions, or other conditions that may affect the reception of wireless signals at the device. In some aspects, the determination of an optimum level for the threshold involves a tradeoff relating to effectively detecting target signals while avoiding detection of noise and/or interference. In some aspects, adaptation of a threshold may be based on maximum energy levels associated with one or more sets of RF energy sample data. In some aspects, adaptation of a threshold may be based on the number of false wakeups that occur during a period of time.

Claims

1. A communication method for an implantable medical device, comprising:

intermittently sensing radio frequency energy to generate a sample set comprising a defined number of energy sample values;

determining a maximum energy level for the sample set based on at least one of the energy sample values; and

adapting a threshold based on the maximum energy level, wherein the adaptation of the threshold adjusts detection sensitivity associated with identifying target radio frequency signals in a current environment.

2. The method of claim 1, wherein the adaptation of the threshold is further based on a determination of whether a defined number of false wakeups occurred within a defined period of time.

3. The method of claim 2, further comprising temporarily suspending the sensing if the defined number of false wakeups occurred within the defined period of time.

4. The method of claim 3, further comprising:

resuming the sensing at a specified point in time; and

acquiring a new set of energy sample values upon resumption of the sensing to re-adapt the threshold.

5. The method of claim 1, wherein:

the sample set comprises a plurality of subsets; and

the determination of the maximum energy level comprises;

determining a maximum sample value for each subset;

identifying a maximum of the maximum sample values for the subsets; and

setting the maximum energy level to the identified maximum.

6. The method of claim 5, wherein the subsets are defined based on sliding sample windows that partially overlap.

7. The method of claim 1, wherein the sample set comprises a histogram.

8. The method of claim 7, wherein the maximum energy level is based on a first tail of the histogram.

9. The method of claim 7, wherein:

the histogram includes a low-end non-zero contiguous set of values; and

the maximum energy level is based on a maximum value of the low-end non-zero contiguous set of values.

10. The method of claim 1, wherein the adaptation of the threshold further comprises setting the threshold to a maximum value to prevent false wakeups for a period of time.

11. The method of claim 10, further comprising acquiring a new set of sample values to change the threshold from the maximum value to a new value.

12. The method of claim 1, further comprising disabling the adaptation of the threshold based on the maximum energy level if a defined number of false wakeups occurred during a defined period of time.

13. The method of claim 1, further comprising:

performing a sniff operation to detect radio frequency signal energy during a low power operational mode;

performing a radio frequency scan operation if the detected radio frequency signal energy is greater than or equal to the threshold, wherein the radio frequency scan operation is longer in duration and/or consumes more power than the sniff operation; and

determining, based on the radio frequency scan operation, whether to commence communicating with a device that generated the detected radio frequency signal energy.

14. The method of claim 1, wherein:

the sensing comprises sensing environmental and/or intrinsic noise;

the energy sample values relate to energy levels of discrete samples of the environmental and/or intrinsic noise; and

the determination of the maximum energy level comprises taking a statistical measure of the energy sample values, whereby the adaptation of the threshold is further based on the statistical measure.

15. The method of claim 1, further comprising:

performing the sensing during a clear channel assessment operation; and

transmitting the threshold to the implantable medical device.

16. An implantable medical apparatus, comprising:

a receiver configured to intermittently sense radio frequency energy to generate a sample set comprising a defined number of energy sample values;

a sample processor configured to determine a maximum energy level for the sample set based on at least one of the energy sample values; and

a threshold adapter configured to adapt a threshold based on the maximum energy level, wherein the adaptation of the threshold adjusts detection sensitivity associated with identifying target radio frequency signals in a current environment.

17. The apparatus of claim 16, further comprising a false wakeup detector configured to determine whether a defined number of false wakeups occurred within a defined period of time, wherein the threshold adapter is further configured to adapt the threshold if the defined number of false wakeups occurred within the defined period of time.

18. The apparatus of claim 17, wherein the receiver is further configured to temporarily suspend the sensing if the defined number of false wakeups occurred within the defined period of time.

19. The apparatus of claim 16, wherein:

the sample set comprises a plurality of subsets; and

the sample processor is further configured to define the maximum energy level by;

determining a maximum sample value for each subset;

identifying a maximum of the maximum sample values for the subsets; and

setting the maximum energy level to the identified maximum.

20. The apparatus of claim 19, wherein the subsets are defined based on sliding sample windows that partially overlap.

21. The apparatus of claim 16, wherein the sample set comprises a histogram.

22. The apparatus of claim 21, wherein the sample processor is further configured to define the maximum energy level based on a first tail of the histogram.

23. The apparatus of claim 16, wherein the threshold adapter is further configured to set the threshold to a maximum value to prevent false wakeups for a period of time.

24. The apparatus of claim 16, wherein the threshold adapter is further configured to disable the adaptation of the threshold based on the maximum energy level if a defined number of false wakeups occurred during a defined period of time.

25. The apparatus of claim 16, wherein:

the receiver is further configured to perform a sniff operation to detect radio frequency signal energy during a low power operational mode;

the receiver is further configured to perform a radio frequency scan operation if the detected radio frequency signal energy is greater than or equal to the threshold;

the radio frequency scan operation is longer in duration and/or consumes more power than the sniff operation; and

the apparatus further comprises a communication processor configured to determine, based on the radio frequency scan operation, whether to commence communicating with a device that generated the detected radio frequency signal energy.

26. A wireless communication method, comprising:

sensing radio frequency energy;

obtaining information relating to a transmission by an external communication device; and

defining, based on the sensed energy and the information, a threshold for identifying target radio frequency signals at an implanted medical device.

27. The method of claim 26, wherein the obtained information relates to timing of the transmission and/or an energy level of the transmission.

28. The method of claim 26, wherein the definition of the threshold comprises correlating an energy distribution associated with the sensed energy with transmission patterns of the external communication device that are indicated by the obtained information.

29. The method of claim 26, further comprising:

determining an energy level of an environmental signal spectrum associated with the sensed energy; and

determining, based on the obtained information, an energy level of a signal spectrum associated with the transmission,

wherein the definition of the threshold comprises setting the threshold to a level that is higher than the energy level of the environmental signal spectrum and lower than the energy level of a signal spectrum associated with the transmission.

30. The method of claim 26, further comprising:

determining a relative margin between an environmental signal spectrum associated with the sensed energy and a signal spectrum associated with the transmission; and

determining, based on the relative margin, whether to use the obtained information to adapt the threshold.

31. The method of claim 26, further comprising:

transmitting information based on the sensed energy to the external communication device;

defining a threshold adjustment at the external communication device based on the transmitted information and the obtained information; and

transmitting the threshold adjustment to the implanted device.

32. A wireless communication system, comprising:

an implantable medical device configured to;

sense radio frequency energy; and

transmitting information based on the sensed energy; and

a communication device configured to;

obtain information relating to a transmission by the communication device;

define threshold information for identifying target radio frequency signals at the implanted medical device based on the transmitted information and the obtained information; and

transmit the threshold information to the implantable medical device.

33. The system of claim 32, wherein the obtained information relates to timing of the transmission by the communication device and/or an energy level of the transmission by the communication device.

34. The system of claim 32, wherein the definition of the threshold information comprises correlating an energy distribution associated with the sensed energy with transmission patterns of the communication device that are indicated by the obtained information.

35. The system of claim 32, further comprising:

determining an energy level of an environmental signal spectrum associated with the sensed energy; and

determining, based on the obtained information, an energy level of a signal spectrum associated with the transmission by the communication device,

wherein the definition of the threshold information comprises setting a threshold to a level that is higher than the energy level of the environmental signal spectrum and lower than the energy level of a signal spectrum associated with the transmission by the communication device.

36. The system of claim 32, further comprising:

determining a relative margin between an environmental signal spectrum associated with the sensed energy and a signal spectrum associated with the transmission by the communication device; and

determining, based on the relative margin, whether to use the obtained information to define the threshold information.