Telemetry protocol for ultra low error rates useable in implantable medical devices

• US 20070049990A1
• Filed: 08/30/2005
• Published: 03/01/2007
• Est. Priority Date: 08/30/2005
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Klostermann, Daniel, Rahman, Md.Mizanur
• Granted Patent: US 8,265,768 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data

Abstract

An improved telemetry protocol for an implantable medical device is disclosed. The sending device forms a block of information to be telemetered to the receiving device in a typical fashion, including a header, a message, and an error detection data, such as a Cyclic Redundancy Code (CRC) for that data. This CRC, called CRC1, is preferably computed using a first CRC polynomial. Then, the entirety of the block is divided into smaller packets of a predetermined byte size. Each packet, regardless of its contents, has a CRC computed for it (CRC2) preferably computed using a second CRC polynomial. Each packet with its appended CRC2 is sent to the receiving device, which deduces a CRC2 and compares it with the appended CRC2. If not valid, that packet is again requested to be resent. If valid, the next packet is requested to be sent, its CRC2 checked, etc., until all packets are received and verified. The receiving device then discards the CRC2s to reconstitute the original block. The receiving device then deduces CRC1 and compares it with the CRC1 appended to the block. If valid, the block is accepted, and if not, the procedure is repeated for the block.

Claims

1. A method for receiving and processing telemetry of a block transmitted between an external component and an implantable medical device, wherein one of the external component and the implantable medical device comprises a receiving device for the telemetered block, the block comprising payload data and first error detection data relevant to at least the payload data, the method comprising:

receiving a plurality of packets at the receiving device, each packet comprising at least a portion of the block and second error detection data relevant to at least its associated block portion;

assessing the second error detection data for each received packet, and if valid, accepting the packet at the receiving device;

reconstituting the block at the receiving device, the reconstituted block comprising the accepted packets; and

assessing the first error detection data for the block, and if valid accepting the block at the receiving device.

2. The method of claim 1, wherein the receiving device comprises the implantable medical device.

3. The method of claim 1, wherein the first and second error detection data are cyclic redundancy codes.

4. The method of claim 1, wherein the first and second cyclic redundancy codes are formed using different cyclic redundancy polynomials.

5. The method of claim 1, wherein the block includes header information.

6. The method of claim 5, wherein the first error detection data is relevant only to the payload data and not the header.

7. The method of claim 1, wherein the received packets further comprise start codes, and wherein the second error detection data for each packet is relevant to its start code and to its associated block portion.

8. The method of claim 1, wherein the received packets further comprise start codes, and wherein the second error detection data for each packet is relevant only to its associated block portion but not its start code.

9. The method of claim 1, wherein the packets are of fixed size.

10. A method for telemetering a block of information between an external component and an implantable medical device, wherein one of the external component and the implantable medical device comprises a sending device for the block of information and the other comprises a receiving device, the method comprising:

forming the block of information at the sending device, the block comprising payload data for the receiving device and first error detection data relevant to at least the payload data;

dividing the entirety of the block into a plurality of sequential first packets;

associating second error detection data with each of the first packets to form second packets; and

serially broadcasting the plurality of second packets to the receiving device.

11. The method of claim 10, wherein the sending device comprises the external component.

12. The method of claim 10, wherein the first and second error detection data are cyclic redundancy codes.

13. The method of claim 10, wherein the first and second cyclic redundancy codes are formed using different cyclic redundancy polynomials.

14. The method of claim 10, wherein the block includes header information.

15. The method of claim 14, wherein the first error detection data is relevant only to the payload data and not the header.

16. The method of claim 10, further comprising associating start code with each of the first packets when forming the second packets, and wherein the second error detection data for each second packet is relevant to its start code and to its associated block portion.

17. The method of claim 10, further comprising associating start code with each of the first packets when forming the second packets, and wherein the second error detection data for each second packet is relevant only to its associated block portion but not its start code.

18. A data structure for telemetry between an implantable medical device and an external component comprising a plurality of sequential packets, each packet comprising a sequential portion of a block of information, the block comprising at least payload data relevant to the operation of the implantable medical device and first error detection data relevant at least to the payload data, wherein each packet further comprises second error detection data relevant to at least its sequential portion.

19. The data structure of claim 18, wherein the first and second error detection data are cyclic redundancy codes.

20. The data structure of claim 18, wherein the first and second cyclic redundancy codes are formed using different cyclic redundancy polynomials.

21. The data structure of claim 18, wherein the block includes header information.

22. The data structure of claim 21, wherein the first error detection data is relevant only to the payload data and not the header.

23. The data structure of claim 18, wherein each packet further comprises a start code, and wherein the second error detection data is relevant to its start code and to its sequential portion.

24. The data structure of claim 18, wherein each packet further comprises a start code, and wherein the second error detection data is relevant only to its sequential portion but not its start code.