Safe identification and association of wireless sensors

• US 7,924,150 B2
• Filed: 11/04/2005
• Issued: 04/12/2011
• Est. Priority Date: 11/08/2004
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Sanchez Sanchez, David, Klabunde, Karin, Falck, Thomas, Baldus, Heribert
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): Thompson; Bradley E
• Application Number:
  US11/718,554
• Publication Number:
  US 20090062626A1
• Time in Patent Office: 1,985 Days
• Field of Search: 340/539.12, 341/174, 375/130
• US Class Current: 340/539.12
• CPC Class Codes: A61B 2560/0431 Portable apparatus, e.g. comprising a handle or case
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• 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 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: H03K 2217/94089 Wireless transmission
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A wireless sensor network for wirelessly monitoring a medical subject includes a plurality of sensor nodes (22, 24, 26, 122, 124, 126). Each sensor node includes a wireless transceiver (46) for sending and receiving wireless messages, a sensor (40, 42, 130, 132, 140, 142) monitoring a characteristic of the medical subject, and a processor (50). The processor is programmed to at least perform an authentication method including: (i) acquiring sensor data via the sensor for a predetermined time (76) responsive to receiving a wireless trigger message; (ii) storing an association code (60, 150, 152, 160, 162) computed from the acquired sensor data; and (iii) authenticating a subsequently received wireless message containing an association code tag by comparing the association code tag with the stored association code. The processor further attaches the stored association code as the association code tag in messages sent to other sensors.

Claims

1. A wireless sensor network for wirelessly monitoring a medical subject, the wireless sensor network comprising:

a plurality of sensor nodes, each sensor node including a wireless transceiver for sending and receiving wireless messages, a sensor monitoring a characteristic of the medical subject, and a processor programmed to at least perform an authentication method including;

(i) acquiring sensor data via the sensor for a predetermined time responsive to receiving a wireless trigger message,

(ii) storing an association code computed from the acquired sensor data, and

(iii) authenticating a subsequently received wireless message containing an association code tag by comparing the association code tag with the stored association code.

2. The wireless sensor network as set forth in claim 1, wherein the processor is further programmed to perform a wireless message sending method including:

attaching the stored association code with a message as an association code tag, and

wirelessly sending the message including the attached association code tag,

at least one other sensor node receiving the wirelessly sent message including the attached association code tag and performing the authenticating (iii) to authenticate the received message including the attached association code tag.

3. The wireless sensor network as set forth in claim 1, wherein the association code includes a data set derived from the acquired sensor data, and the authenticating includes:

computing a correlation of the association code and the association code tag; and

comparing the correlation with a predetermined authentication standard.

4. The wireless sensor network as set forth in claim 3, wherein the comparing includes:

determining a peak of the correlation; and

comparing the peak with an authentication peak threshold.

5. The wireless sensor network as set forth in claim 1, wherein the computing of the association code from the acquired sensor data includes Fourier transforming the acquired sensor data, and the authenticating includes:

computing a multiplicative combination of the association code and the association code tag; and

comparing the multiplicative combination with a predetermined authentication standard.

6. The wireless sensor network as set forth in claim 1, wherein the computing of the association code from the acquired sensor data includes Fourier transforming the acquired sensor data, and the authenticating includes:

pointwise multiplying Fourier frequencies of the association code and the association code tag to produce a pointwise product data set;

determining a peak of the pointwise product data set; and

comparing the peak with an authentication peak threshold.

7. The wireless sensor network as set forth in claim 1, wherein (i) the acquired sensor data includes a set of samples spanning the predetermined time, and (ii) the association code includes a plurality of data points computed from the set of samples.

8. The wireless sensor network as set forth in claim 7, wherein the plurality of data points are computed by amplitude normalizing the set of samples.

9. The wireless sensor network as set forth in claim 7, wherein the plurality of data points are computed by sub-sampling the set of samples.

10. The wireless sensor network as set forth in claim 7, wherein the plurality of data points are computed by Fourier transforming the set of samples.

11. The wireless sensor network as set forth in claim 1, wherein:

at least a first sensor node of the plurality of sensor nodes include a sensor monitoring a first characteristic of the medical subject but does not include a sensor monitoring a second characteristic of the medical subject, the authentication method of the first sensor node employing the sensor monitoring the first characteristic;

at least a second sensor node of the plurality of sensor nodes include a sensor monitoring the second characteristic of the medical subject but does not include a sensor monitoring the first characteristic of the medical subject, the authentication method of the second sensor node employing the sensor monitoring the second characteristic, and

at least a third sensor node of the plurality of sensor nodes includes sensors monitoring both the first and second characteristics of the medical subject, the processor of the third sensor node being programmed to perform the authentication method to generate first and second stored association codes corresponding to the first and second characteristics and further performing a message relay method including;

(iv) subsequent to authenticating a received wireless message containing an association code tag corresponding to one of the stored first association code and the stored second association code, modifying the message by replacing the tag with the other of the first association code and the second association code, and

(v) wirelessly sending the modified message.

12. The wireless sensor network as set forth in claim 1, wherein the plurality of sensor nodes define an autonomous wireless sensor network that autonomously:

(i) acquires and stores sensor data pertaining to a plurality of characteristics of the medical subject, and (ii) wirelessly transmits the stored sensor data to an external device.

13. The wireless sensor network as set forth in claim 1, wherein at least one of the plurality of sensor nodes includes:

a data memory storing sensor data pertaining to the monitoring of the characteristic of the medical subject, the processor being further programmed to perform a data dump method including;

constructing a data message containing stored sensor data pertaining to the monitoring of the characteristic of the medical subject,

attaching the stored association code with the data message as an association code tag, and

wirelessly sending the data message with the attached association code tag,

the data dump method being performed responsive to receiving and authenticating a wireless data dump request message.

14. The wireless sensor network as set forth in claim 1, wherein at least one sensor of the plurality of sensor nodes includes:

a second sensor monitoring a second characteristic of the medical subject that is different from the characteristic monitored by the other sensor; and

a data memory storing sensor data pertaining to the monitoring of the second characteristic of the medical subject, the processor being further programmed to perform a data dump method including;

constructing a data message containing stored second sensor data pertaining to the monitoring of the characteristic of the medical subject,

attaching the stored association code with the data message as an association code tag, and

wirelessly sending the data message with the attached association code tag,

the data dump method being performed responsive to receiving and authenticating a wireless data dump request message.

15. A wireless sensor node for use in the network of claim 1.

16. A wireless sensor network method performed by a plurality of sensor nodes wirelessly monitoring a medical subject, the wireless sensor network method comprising:

performing at each sensor node an authentication process including;

(i) acquiring sensor data pertaining to a characteristic of the medical subject for a predetermined time responsive to a receiving wireless trigger message,

(ii) storing an association code identifying the medical subject, the association code being computed from the acquired sensor data, and

(iii) authenticating that a subsequently received wireless message containing an association code tag is associated with the medical subject by comparing the association code tag with the stored association code.

17. The wireless sensor network method as set forth in claim 16, further including:

performing at a sensor node a wireless message send process including;

attaching the stored association code to a message as an association code tag, and

wirelessly sending the message including the attached association code tag,

at least one other sensor node receiving the wirelessly sent message including the attached association code tag and performing the authenticating (iii) to authenticate the received message including the attached association code tag.

18. The wireless sensor network method as set forth in claim 16, wherein the association code includes a data set derived from the acquired sensor data, and the authenticating includes:

combining the association code and the association code tag to generate an authentication measure using one of (ii) a correlation and (ii) Fourier transforming and multiplying of the association code and the association code tag; and

comparing the authentication measure with a predetermined authentication standard.

19. The wireless sensor method as set forth in claim 16, further including:

acquiring and storing sensor data pertaining to a plurality of characteristics of the medical subject, and

wirelessly transmitting the stored sensor data to an external device.

20. The wireless sensor method as set forth in claim 19, wherein the plurality of characteristics that are acquired, stored, and wirelessly transmitted include the characteristic used in the authentication process.

21. A wireless sensor network for wirelessly monitoring a medical subject, the wireless sensor network comprising:

a plurality of sensor nodes, each sensor node including a wireless transceiver for sending and receiving wireless messages, a sensor monitoring a characteristic of the medical subject, and a processor programmed to at least perform an authentication method including;

(i) acquiring sensor data pertaining to the characteristic of the medical subject via the sensor for a predetermined time responsive to receiving a wireless trigger message,

(ii) computing an association code identifying the medical subject from the acquired sensor data,

(iii) storing the computed association code at the sensor, and

(iv) authenticating that a wireless message subsequently received by the sensor node is associated with the medical subject by comparing an association code tag contained in the received wireless message with the stored association code.