Multiple implant communications with adjustable load modulation using modulation indices

Patent metadata

Field	Value
Publication number	US-10568513-B2
Application number	US-201815907457-A
Country	US
Kind code	B2
Filing date	Feb 28, 2018
Priority date	Mar 7, 2017
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

A medical system and method of communicating between a telemetry controller and a plurality of medical devices implanted within a patient is provided. Communication links are respectively established between the telemetry controller and the implanted medical devices. The communication links are respectively amplitude modulated by the implanted medical devices at modulation levels using load modulation. Received signal strength indicators (RSSIs) of the amplitude modulated communication links for the implanted medical devices are measured. A variation of the RSSIs is decreased by modifying, based on the measured RSSIs, at least one modulation level at which the respective at least one communication link is amplitude modulated by the respective implanted medical device(s).

First claim

What is claimed is:

1. A medical system for use with a patient, comprising:
a plurality of implantable medical devices; and
a telemetry controller configured for establishing communication links between the implantable medical devices and the telemetry controller;
wherein the implantable medical devices are configured for amplitude modulating the communication links at modulation levels; and
wherein the telemetry controller is further configured for respectively measuring received signal strength indicators (RSSIs) of the amplitude modulated communication links, and decreasing a variation of the RSSIs by comparing the RSSIs to each other, determining the lowest one of the RSSIs, selecting one of the implantable medical devices not associated with the lowest RSSI, and commanding, based on the comparison of the measured RSSIs, the selected implantable medical device to modify a respective modulation level of the modulation levels at which a respective communication link is amplitude modulated by the selected implanted medical device to an equalizing modulation level, such that the RSSI of the respective communication link amplitude modulated at the modified respective modulation level by the selected implantable medical device matches the lowest RSSI.

2. The medical system of claim 1 , wherein the telemetry controller is configured for commanding the selected implantable medical device to modify the respective modulation level to the equalizing modulation level by decrementing the respective modulation level by a predetermined amount at least one time.

3. The medical system of claim 1 , wherein the telemetry controller is configured for commanding the selected implantable medical device to modify the respective modulation level to the equalizing modulation level by approximating a modulation level at which the RSSI of the respective communication link amplitude modulated at the approximated modulation level by the selected implantable medical device is likely to match the lowest RSSI.

4. The medical system of claim 1 , wherein the telemetry controller is configured for commanding the selected implantable medical device to modify the respective modulation level to the equalizing modulation level by:
measuring the RSSI of the respective communication link amplitude modulated at the respective modified modulation level by the selected implantable medical device;
comparing the measured RSSI with the lowest RSSI; and
repeating the respective modulation level modifying, the RSSI measuring, and the measured RSSI comparison until the RSSI of the respective communication link amplitude modulated between the telemetry controller and the selected implantable medical device matches the lowest RSSI.

5. The medical system of claim 1 , wherein the telemetry controller is further configured:
for selecting another one of the implantable medical devices not associated with the lowest RSSI; and
commanding the other selected implantable medical device to modify another respective modulation level to another equalizing modulation level, such that the RSSI of the respective communication link amplitude modulated at the other equalizing modulation level by the other selected implantable medical device matches the lowest RSSI.

6. The medical system of claim 5 , wherein the telemetry controller is configured for repeating the selection of one of the implantable medical devices and the modification of the respective modulation level for all remaining ones of the implantable medical devices not associated with the lowest RSSI.

7. The medical system of claim 1 ,
wherein the implantable medical devices are configured for initially amplitude modulating the communication links at maximum modulation levels; and
wherein the telemetry controller is configured for commanding the selected implantable medical device to modify the respective modulation level to the equalizing modulation level by reducing a maximum modulation level of the maximum modulation levels at which the selected implantable medical device initially amplitude modulates the respective communication link to the respective equalizing modulation level.

8. The medical system of claim 1 , wherein decreasing the variation between the RSSIs results in substantial uniformity between the RSSIs.

9. The medical system of claim 8 , wherein the variation of the RSSIs is less than 50%.

10. The medical system of claim 8 , wherein the variation of the RSSIs is less than 20%.

11. The medical system of claim 1 ,
wherein the implantable medical devices are further configured for respectively storing modulation indices that respectively set the modulation levels at which the implantable medical devices amplitude modulate the communication links; and
wherein the telemetry controller is further configured for commanding the selected implantable medical device to modify the respective modulation level by commanding the selected implantable medical device to modify a modulation index respectively of the modulation indices stored by the selected implantable medical device.

12. The medical system of claim 1 ,
wherein the implantable medical devices are further configured for generating data and sequentially amplitude modulating the communication links with the data by the implantable medical devices after the variation of the RSSIs has been decreased; and
wherein the telemetry controller is further configured for amplitude demodulating the communication links to acquire the data from the implantable medical devices.

13. The medical system of claim 12 , wherein the data is physiological data acquired from the patient by the implantable medical devices.

14. The medical system of claim 12 , wherein the data is operational status data of the implantable medical devices.

15. The medical system of claim 1 ,
wherein the telemetry controller comprises:
a primary coil; and
a coil driver configured for applying a primary carrier signal having an envelope to the primary coil; and

each of the implantable medical devices comprises:
a secondary coil on which a secondary carrier signal having an envelope may be induced in response to the application of the primary carrier signal on the primary coil, thereby establishing the respective communication link between the each implantable medical device and the telemetry controller; and
an uplink modulator configured for amplitude modulating the secondary carrier signal envelope at the respective modulation level, thereby inducing an amplitude modulation of the primary carrier signal envelope on the primary coil.

16. The medical system of claim 15 ,
wherein the telemetry controller further comprises:
an amplitude detector configured for detecting a peak-to-peak amplitude of the induced amplitude modulations of the primary carrier signal envelope;
control circuitry configured for determining the RSSIs from the detected peak-to-peak amplitudes, and generating a command based on the measured RSSIs; and
a downlink modulator configured for amplitude modulating the primary carrier signal envelope on the primary coil with the command, thereby inducing an amplitude modulation of the secondary carrier signal envelope, encoded with the respective command, on the secondary coil of the selected implantable medical device; and

the selected implantable medical device further comprises:
a downlink demodulator configured for amplitude demodulating the amplitude modulated secondary carrier signal envelope to acquire the command; and
control circuitry configured for modifying the respective modulation level in accordance with the command.

Assignees

• The Alfred E Mann Foundation For Scient Research

Inventors

• Lee Edward K F
• Suri Harshit R

Classifications

• A61F2/583

  Hands; Wrist joints · CPC title

• A61B2560/0219

  of externally powered implanted units · CPC title

• H04Q9/00

  Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom · CPC title

• H04Q2209/40

  using a wireless architecture · CPC title

• A61B5/0031 Primary

  Implanted circuitry · CPC title