Ranking and switching of wireless channels in a body area network of medical devices

• US 8,755,269 B2
• Filed: 12/23/2009
• Issued: 06/17/2014
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Jollota, James
• Primary Examiner(s): Mesfin, Yemane
• Assistant Examiner(s): DAVENPORT, MON CHERI S
• Application Number:
  US12/646,754
• Publication Number:
  US 20110149759A1
• Time in Patent Office: 1,637 Days
• Field of Search: 370/216, 370225-228, 370/241, 370/242, 370/245, 370/248, 370/252, 370/329, 370/332, 370/333, 370/338, 370/348, 370/431, 370/433, 370/437
• US Class Current: 370/225
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0024 for multiple sensor units attached to the patient, e.g. using a body or personal area network
• CPC Class Codes: A61B 5/1112 Global tracking of patients, e.g. by using GPS
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks

Abstract

Operating techniques and methodologies for a body area network of medical devices are provided. One technique relates to an intelligent channel hopping scheme that detects loss of wireless synchronization on an initial wireless channel, thereafter obtains a measure of quality for the initial wireless channel, and then selects a new wireless channel when the obtained measure of quality fails to satisfy a threshold criteria. Another operating technique dynamically adapts an ordered list of available wireless channels in accordance with a quality measure of the available wireless channels. Thus, when quality degradation associated with a first wireless channel is detected, the ordered list can be updated to indicate a lower preference for the first wireless channel and to indicate a higher preference for a second wireless channel that does not suffer from quality degradation. Another channel hopping or switching technique selects wireless channels in a manner that is influenced by the current geographic position of the medical device.

Claims

1. A method of operating a wireless coordinator device in a wireless local insulin infusion system comprising a body area network of wireless medical devices, the method comprising:

detecting loss of wireless synchronization, for a current wireless data communication channel, between the wireless coordinator device and a wireless glucose sensor transmitter device of the wireless local insulin infusion system, wherein detecting loss of wireless synchronization comprises determining that the wireless coordinator device missed at least a threshold number of expected wireless pings in sequence from the wireless end node device, wherein wireless pings are sent from the wireless glucose sensor transmitter device using the current wireless data communication channel, wherein the wireless pings are sent from the wireless glucose sensor transmitter device according to a transmit schedule of which both the wireless glucose sensor transmitter device and the wireless coordinator device are aware, and wherein each wireless ping is a glucose data packet that conveys glucose data when glucose sensor data is available, or a dummy packet that conveys no data when glucose sensor data is unavailable;

in response to detecting loss of wireless synchronization, obtaining a measure of quality for the current wireless data communication channel;

when the obtained measure of quality fails to satisfy a threshold criteria, selecting a new wireless data communication channel for the wireless coordinator device; and

thereafter, transmitting wireless beacons with the wireless coordinator device, using the new wireless data communication channel.

2. The method of claim 1, further comprising obtaining, for a plurality of available wireless data communication channels, a respective measure of wireless channel quality, wherein the new wireless data communication channel is selected from the plurality of available wireless data communication channels based upon its respective measure of wireless channel quality.

3. The method of claim 2, wherein the respective measure of wireless channel quality for the new wireless data communication channel indicates highest quality among the plurality of available wireless data communication channels.

4. The method of claim 1, further comprising:

prior to detecting loss of wireless synchronization, sending initial wireless beacons from the wireless coordinator device, using the current wireless data communication channel; and

prior to obtaining the measure of quality for the current wireless data communication channel, ceasing the sending of the initial wireless beacons.

5. The method of claim 1, further comprising:

saving, at the wireless coordinator device, ping timing information corresponding to the wireless glucose sensor transmitter device; and

synchronizing the wireless coordinator device for receipt of wireless pings from the wireless glucose sensor transmitter device in accordance with the saved ping timing information, wherein detecting loss of wireless synchronization utilizes the saved ping timing information.

6. The method of claim 5, further comprising receiving the ping timing information from the wireless glucose sensor transmitter device.

7. A method of operating a wireless coordinator device in a wireless local insulin infusion system that includes a wireless glucose sensor transmitter device, the method comprising:

obtaining, at the wireless coordinator device, a ping schedule for the wireless glucose sensor transmitter device, the ping schedule indicating time slots during which the wireless coordinator device should expect to receive pings from the wireless glucose sensor transmitter device, wherein each ping is a glucose data packet that conveys glucose data when glucose sensor data is available, or a dummy packet that conveys no data when glucose sensor data is unavailable;

configuring the wireless coordinator device to monitor for pings sent by the wireless glucose sensor transmitter device in accordance with the ping schedule;

the wireless coordinator device performing wireless data communication with the wireless glucose sensor transmitter device, using a current wireless data communication channel;

detecting that the wireless coordinator device missed at least a threshold number of expected wireless pings in sequence as indicated by the ping schedule, the wireless pings sent from the wireless glucose sensor transmitter device using the current wireless data communication channel;

in response to the detecting step, testing quality of the current wireless data communication channel;

when the quality of the current wireless data communication channel is below a threshold quality measure, selecting a new wireless data communication channel; and

thereafter, the wireless coordinator device using the new wireless data communication channel to transmit wireless beacons and to receive wireless pings from the wireless glucose sensor transmitter device.

8. The method of claim 7, further comprising obtaining, for a plurality of available wireless data communication channels including the new wireless data communication channel, a respective measure of wireless channel quality, wherein the new wireless data communication channel is selected from the plurality of available wireless data communication channels based upon its respective measure of wireless channel quality.

9. The method of claim 7, further comprising:

obtaining, at the wireless coordinator device, a second ping schedule for a wireless end node device operating in the wireless local insulin infusion system, the second ping schedule indicating time slots during which the wireless coordinator device should expect to receive pings from the wireless end node device;

configuring the wireless coordinator device to monitor for pings sent by the wireless end node device in accordance with the second ping schedule; and

the wireless coordinator device performing wireless data communication with the wireless end node device, using the current wireless data communication channel.

10. A wireless medical device for a wireless local insulin infusion system comprising a body area network of medical devices, the wireless medical device comprising:

a processor;

a memory element coupled to the processor and configured to store a ping schedule for a wireless glucose sensor transmitter device; and

a wireless communication module coupled to the processor and configured to receive ping messages from the wireless glucose sensor transmitter device using a current wireless data communication channel, wherein each wireless ping message is a glucose data packet that conveys glucose data when glucose sensor data is available, or a dummy packet that conveys no data when glucose sensor data is unavailable;

wherein the processor is configured to;

detect when the wireless communication module has missed at least a threshold number of expected ping messages in sequence from the wireless glucose sensor transmitter device, as indicated by the ping schedule;

test a quality characteristic of the current wireless data communication channel when the wireless communication module has missed at least the threshold number of expected ping messages in sequence; and

switch from the current wireless data communication channel to a new wireless data communication channel when the quality characteristic fails to satisfy predetermined quality criteria.

11. The wireless medical device of claim 10, wherein the wireless communication module is configured to transmit wireless beacons using the new wireless data communication channel.

12. The wireless medical device of claim 10, wherein the processor is configured to obtain, for a plurality of available wireless data communication channels including the new wireless data communication channel, a respective measure of wireless channel quality, and is further configured to select the new wireless data communication channel from the plurality of available wireless data communication channels based upon its respective measure of wireless channel quality.

13. The wireless medical device of claim 10, wherein the wireless communication module is configured to receive the ping schedule from the wireless glucose sensor transmitter device.