IMPLANTABLE MEDICAL DEVICE TELEMETRY WITH ADAPTIVE FREQUENCY HOPPING

• US 20080015655A1
• Filed: 07/12/2006
• Published: 01/17/2008
• Est. Priority Date: 07/12/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Bange, Joseph E., Vallapureddy, Vineel
• Granted Patent: US 8,185,204 B2
• Time in Patent Office: Days
• US Class Current: 607/32
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: A61N 1/37254 Pacemaker or defibrillator security, e.g. to prevent or inhibit programming alterations by hackers or unauthorised individuals
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 17/318 Received signal strength

Abstract

A far-field radio-frequency (RF) telemetry system transmits data between an implantable medical device and an external system using an active channel selected from a plurality of channels each representing a frequency band within a predetermined frequency range. One or more preferred channels are identified from the plurality of channels based on channel quality indicators produced for each of the channels. When channel hopping is needed, a hop channel is selected from the one or more preferred channels and becomes the active channel.

Claims

1. A cardiac rhythm management (CRM) system, comprising:

an implantable medical device including an implant telemetry module; and

an external system communicatively coupled to the implantable medical device via a telemetry link, the external system including an external telemetry module,

wherein at least one of the implant telemetry module and the external telemetry module includes a telemetry circuit including;

an antenna;

a transceiver, coupled to the antenna, to transmit and receive data using at least one active channel during a telemetry session, the at least one active channel selected from a plurality of channels each representing a channel frequency band;

a channel selector coupled to the transceiver, the channel selector adapted to select at least one hop channel from one or more preferred channels in response to a channel selection signal;

a hop controller coupled to the channel selector, the hop controller adapted to make the at least one hop channel the active channel when the at least one hop channel is selected;

a channel quality analyzer coupled to the channel selector, the channel quality analyzer adapted to produce channel quality indicators each associated with one channel of the plurality of channels and each including at least a received signal strength indicator indicative of a strength of signal received through that channel, the channel quality analyzer including a received signal strength detector adapted to produce the received signal strength indicators; and

a preferred channel identifier coupled to the channel quality analyzer;

the preferred channel identifier adapted to identify the one or more preferred channels from the plurality of channels based on the channel quality indicators.

2. The system of claim 1, wherein the at least one active channel comprises an active transmission channel selected from the plurality of channels and an active receiving channel selected from the plurality of channels, the active transmission channel and the active receiving channel representing substantially different channel frequency bands, and the transceiver comprises:

a transmitter to transmit data using the active transmission channel;

a receiver to receive data using the active receiving channel; and

a transmit/receive switch to provide a connection between the antenna and one of the transmitter and the receiver.

3. The system of claim 1, wherein the telemetry circuit further comprises a telemetry quality monitor adapted to monitor quality of data transmission associated with the active channel and to produce the channel selection signal when the quality of data transmission fails to satisfy one or more criteria.

4. The system of claim 1, wherein the telemetry circuit further comprises a hop timer to produce the channel selection signal according to a predetermined schedule.

5. The system of claim 1, wherein the telemetry circuit further comprises a telemetry initiation module to produce the channel selection signal when or before the telemetry session begins.

6. The system of claim 1, wherein the preferred channel identifier is adapted to identify the one or more preferred channels from the plurality of channels by identifying one or more of the channel quality indicators that meet one or more predetermined requirements.

7. The system of claim 1, wherein the preferred channel identifier is adapted to produce a sequence of preferred channels by prioritizing channels according to their associated channel quality indicators.

8. The system of claim 1, wherein the channel quality indicators comprise noise floor indicators each associated with one channel of the plurality of channels and indicative of a noise floor of that channel, the channel quality analyzer comprises a noise detector adapted to produce the noise floor indicators, and the preferred channel identifier is adapted to identify the one or more preferred channels from the plurality of channels based on at least the received signal strength indicators and the noise floor indicators.

9. The system of claim 8, wherein the noise detector is adapted to produce the noise floor indicators by measuring a noise level associated with each channel of the plurality of channels when the external system is not communicatively coupled with the implantable medical device.

10. The system of claim 8, wherein the noise detector is adapted to produce the noise floor indicators by measuring a noise level associated with each channel of the plurality of channels when no data is being transmitted between the external system and the implantable medical device through that channel.

11. The system of claim 1, wherein the channel quality indicators comprise frame exchange metrics each associated with one channel of the plurality of channels, the channel quality analyzer comprises a frame exchange analyzer adapted to produce the frame exchange metrics, and the preferred channel identifier is adapted to identify the one or more preferred channels from the plurality of channels based on at least the received signal strength indicators and the frame exchange metrics.

12. The system of claim 11, wherein the frame exchange analyzer comprises a success ratio producer adapted to calculate success ratios each associated with one channel of the plurality of channels, the success ratios each being a ratio of a number of successful frame exchanges to a total number of frame exchanges.

13. The system of claim 1, wherein the channel quality indicators comprise performance history indicators each associated with one channel of the plurality of channels and indicative of a history of the channel quality indicator of that channel, the channel quality analyzer comprises a performance history tracker adapted to produce the performance history indicators, and the preferred channel identifier is adapted to identify the one or more preferred channels from the plurality of channels based on at least the received signal strength indicators and the performance history indicators.

14. The system of claim 1, wherein the external telemetry module comprises the telemetry circuit, and wherein the channel selector is adapted to transmit data specifying one or more of the at least one hop channel and the one or more preferred channels to the implantable medical device through the telemetry link.

15. The system of claim 14, wherein the channel quality analyzer comprises a quality parameter receiver adapted to receive at least one quality parameter of each of the channel quality indicators from the implantable medical device.

16. A method for transmitting data between an implantable medical device and an external system via radio-frequency telemetry, the method comprising:

receiving a channel selection signal;

selecting a hop channel from one or more preferred channels in response to the channel selection signal;

making the hop channel an active channel;

transmitting data between the implantable medical device and the external system using the active channel;

producing channel quality indicators each associated with one channel of a plurality of channels and each including at least a received signal strength indicator indicative of a strength of signal received through the one channel, each channel of the plurality of channels representing a channel frequency band; and

identifying the one or more preferred channels from the plurality of channels based on the channel quality indicators.

17. The method of claim 16, comprising:

selecting a first hop channel from one or more first preferred channels in response to the channel selection signal;

making the first hop channel a first active channel;

transmitting the data from the implantable medical device to the external system using the first active channel;

selecting a second hop channel from one or more second preferred channels in response to the channel selection signal;

making the second hop channel a second active channel; and

transmitting the data from the external system to the implantable medical device using the second active channel,

and wherein the one or more preferred channels comprise the one or more first preferred channels and the one or more second preferred channels.

18. The method of claim 16, wherein identifying the one or more preferred channels comprises identifying the one or more preferred channels from the plurality of channels by identifying one or more of the channel quality indicators that meet one or more predetermined requirements.

19. The method of claim 16, wherein identifying the one or more preferred channels comprises producing a sequence of preferred channels by prioritizing channels according to their associated channel quality indicators.

20. The method of claim 16, wherein the channel quality indicators comprise noise floor indicators each associated with one channel of the plurality of channels and indicative of a noise floor of that channel, and identifying the one or more preferred channels comprises identifying the one or more preferred channels from the plurality of channels based on the received signal strength indicators and the noise floor indicators.

21. The method of claim 20, wherein producing the channel quality indicators comprises producing the noise floor indicators by measuring a noise level associated with each channel of the plurality of channels when no data is transmitted between the external system and the implantable medical device using the each channel.

22. The method of claim 16, wherein the channel quality indicators comprise frame exchange metrics each associated with one channel of the plurality of channels, and identifying the one or more preferred channels comprises identifying the one or more preferred channels from the plurality of channels based on the received signal strength indicators and the frame exchange metrics.

23. The method of claim 22, wherein the frame exchange metrics comprise success ratios each associated with one channel of the plurality of channels and being a ratio of a number of successful frame exchanges to a total number of frame exchanges, and producing the channel quality indicators comprises calculating the success ratios.

24. The method of claim 16, wherein the channel quality indicators comprise performance history indicators each associated with one channel of the plurality of channels and indicative of a history of the channel quality indicator of that channel, and identifying the one or more preferred channels comprises identifying the one or more preferred channels from the plurality of channels based on the received signal strength indicators and the performance history indicators.

25. The method of claim 16, wherein producing the channel quality indicators comprises producing at least one quality parameter of each of the channel quality indicators using the implantable medical device.