Dynamic channel selection for RF telemetry with implantable device

• US 20060161223A1
• Filed: 01/19/2005
• Published: 07/20/2006
• Est. Priority Date: 01/19/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Bange, Joseph E., Von Arx, Jeffrey A., Vallapureddy, Vineel, Holmquist, Paul, Roberts, Earle, Morrissey, Cynthia
• Granted Patent: US 7,218,969 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators
• CPC Class Codes: Y10S 128/901 Suppression of noise in electric signal
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A telemetry system for radio-frequency communications between an implantable medical device and an external device providing improved noise immunity is disclosed. Multiple communications channels are used to enable establishment and re-establishment of communications between a particular pair of devices in a multiple device environment.

Claims

1. A telemetry system for enabling radio-frequency (RF) communications between an implantable medical device and an external device over a wireless medium, comprising:

an antenna, an RF transmitter, an RF receiver, and a controller incorporated into each of the implantable and external devices,

wherein the RF transmitter and receiver of each device are tunable and may be switched among a plurality of different communications channels which differ in frequency;

wherein the controller is interfaced to the RF transmitter and receiver in each device to enable establishment of a communications session and data transfer over a selected channel;

wherein the external device and implantable device controllers are programmed to switch from a first communications channel to a second communications channel upon a degradation in the quality of the first communications channel.

2. The system of claim 1 wherein the external device controller is programmed to monitor the quality of a communications channel by determining if the channel throughput over a certain time falls below a certain level.

3. The system of claim 1 wherein the external device controller is programmed to monitor the quality of a communications channel by determining if a specified number of data frames are unacknowledged.

4. The system of claim 1 wherein the external device controller is programmed to monitor the quality of a communications channel by determining if the frame error rate exceeds a threshold value.

5. The system of claim 1 wherein the implantable device and external device controllers are programmed to revert to a selected channel if a communications session is interrupted.

6. The system of claim 1 wherein the external device and implantable device controllers are programmed to use a designated control channel for initiating a communications session and to use a designated data channel for transferring data.

7. The system of claim 6 wherein the external device controller is programmed to search for an available data channel by checking the data channels for activity.

8. The system of claim 7 wherein the external device controller is programmed to tune its receiver to a particular data channel, listen for a valid preamble known to be transmitted by all devices during the transmission of data frames, and regard the data channel as unused if no such preambles are detected over a specified time period.

9. The system of claim 7 wherein the external device controller is programmed to tune its receiver to a particular data channel, measure the signal strength of the channel over a specified period of time, and regard the channel as unused if the peak signal strength over specified period of time is less than a specified value.

10. The system of claim 7 wherein the external device controller is programmed to:

tune its receiver to a particular data channel;

listen for a valid preamble known to be transmitted by all devices during the transmission of data frames;

measure the signal strength of the channel over a specified period of time; and

,

regard the data channel as unused if no such preambles are detected over a specified time period and if the peak signal strength over specified period of time is less than a specified value.

11. A method by which an implantable medical device and an external device may communicate over a wireless medium, comprising:

providing a plurality of different communications channels which differ in frequency;

establishing a communications session and data transfer between the implantable medical device and the external device over a selected channel; and

,

switching from a first communications channel to a second communications channel upon a degradation in the quality of the first communications channel.

12. The method of claim 11 further comprising monitoring the quality of a communications channel by determining if the channel throughput over a certain time falls below a certain level.

13. The method of claim 11 further comprising monitoring the quality of a communications channel by determining if a specified number of data frames are unacknowledged.

14. The method of claim 11 further comprising monitoring the quality of a communications channel by determining if the frame error rate exceeds a threshold value.

15. The method of claim 11 further comprising reverting to a selected channel if a communications session is interrupted.

16. The method of claim 11 further comprising using a designated control channel for initiating a communications session and to use a designated data channel for transferring data.

17. The method of claim 16 further comprising searching for an available data channel by checking the data channels for activity.

18. The method of claim 17 further comprising listening to a particular data channel for a valid preamble known to be transmitted by all devices during the transmission of data frames and regarding the data channel as unused if no such preambles are detected over a specified time period.

19. The method of claim 17 further comprising measuring the signal strength of a particular data channel over a specified period of time and regarding the channel as unused if the peak signal strength over specified period of time is less than a specified value.

20. The method of claim 17 further comprising:

listening to a particular data channel for a valid preamble known to be transmitted by all devices during the transmission of data frames;

measuring the signal strength of the particular data channel over a specified period of time; and

,

regarding the data channel as unused if no such preambles are detected over a specified time period and if the peak signal strength over specified period of time is less than a specified value.