Stochastic Communication Protocol Method and System For Radio Frequency Identification (Rfid) Tags Based on Coalition Formation, Such as For Tag-To-Tag Communication

• US 20080252424A1
• Filed: 09/21/2006
• Published: 10/16/2008
• Est. Priority Date: 09/21/2005
• Status: Active Grant

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Nikitin, Pavel, Kodukula, Venkata, Maltseff, Paul A., Winter, Steven, Erosheva, Elena
• Granted Patent: US 8,199,689 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G06K 17/0029 the arrangement being specially adapted for wireless interrogation of grouped or bundled articles tagged with wireless record carriers
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0728 the arrangement being an optical or sound-based communication interface
• CPC Class Codes: G06K 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• CPC Class Codes: G06K 7/10297 arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092 cryptographic protocols H04L9/00; network security protocols H04L63/00; real-time communication protocols in data switching networks H04L65/00; network protocols for data switching network services H04L67/00

Abstract

Data carriers (such as RFID tags) are formed into clusters of data carriers. Each cluster has at least one bridge data carrier that can communicate with a bridge data carrier of another cluster, thereby allowing data carriers in each cluster to communicate directly or indirectly with each other using a stochastic communication protocol method. Direct tag-to-tag communication capability is provided between data carriers in each cluster and/or between clusters. The data carriers can backscatter and modulate a carrier wave from a source, thereby using the backscattered and modulated carrier wave to convey data to each other.

Claims

1. A method, comprising:

forming coalitions of clusters of distributed data carriers;

for each of said clusters, identifying a bridge data carrier that is capable to link with a bridge data carrier of another of said clusters; and

enabling communication between data carriers of the clusters, at least some of said data carriers including batteryless passive data carriers.

2. The method of claim 1 wherein at least some of said batteryless passive data carriers include passive RFID tags.

3. The method of claim 1 wherein at least some of said batteryless passive data carriers includes acoustical tags.

4. The method of claim 1 wherein forming coalitions of clusters of distributed data carriers includes forming coalitions of randomly distributed data carriers, said coalitions including a coalition between clusters, a coalition between data carriers of respective different clusters, and a coalition between data carriers in a same cluster.

5. The method of claim 1 wherein forming coalitions of distributed data carriers includes identifying candidate data carriers to place in a cluster based on whether a distance between said candidate data carriers is within a value.

6. The method of claim 5 wherein one of said identified candidate data carriers is a substantially central data carrier, wherein said distance is a distance between the central data carrier and another of said candidate data carriers.

7. The method of claim 1 wherein enabling the communication between the data carriers includes enabling indirect communication between non-bridge data carriers of different clusters using their respective bridge data carriers, enabling direct or indirect communication between data carriers in a same cluster, or enabling communication between data carriers of different clusters using their respective bridge data carriers and at least one intermediate cluster and the bridge data carriers of the intermediate cluster.

8. The method of claim 1 wherein enabling communications between data carriers of the clusters includes:

providing a carrier wave that can be backscattered;

modulating the backscattered carrier wave with a first of said data carriers to generate an interrogation signal; and

modulating the backscattered carrier wave with a second of said data carriers to generate a return signal in response to the interrogation signal.

9. The method of claim 8 wherein the first of said data carrier initiates modulation of the backscattered carrier wave by:

receiving power from the carrier wave;

monitoring for a query signal associated with the carrier wave for a period of time;

if the query signal is not detected after expiration of the period of time, generating and sending the interrogation signal to query the second of said data carriers; and

if the query signal is detected prior to expiration of the period of time, responding to the query signal.

10. The method of claim 8 wherein providing the carrier wave includes providing the carrier wave from a portable data collection or communication device.

11. The method of claim 8 wherein providing the carrier wave includes providing the carrier wave from another data carrier that is adapted to generate the carrier wave.

12. The method of claim 11 wherein said another data carrier is embedded in a business card, an advertisement, or a document.

13. The method of claim 1 wherein identifying a bridge data carrier includes identifying a bridge data carrier based on a power output level from at least one of said data carriers.

14. The method of claim 13 wherein identifying the bridge data carrier based on the power output level from at least one of said data carriers includes:

defining a bridge zone as a region where the power output level from said at least one of said data carriers in a first cluster, which is sensed by another one of said data carriers in a second cluster, exceeds a cumulative power that is sensed by said another one of said data carriers from all of the data carriers in the first cluster by a threshold value.

15. The method of claim 1 wherein forming coalitions of clusters of distributed data carriers includes forming a cluster having only one data carrier.

16. The method of claim 1 wherein forming coalitions of clusters of distributed data carriers includes forming coalitions having a mix of battery powered active data carriers and said passive data carriers.

17. The method of claim 1 wherein enabling communication between data carriers of the clusters includes enabling communication using a stochastic communication protocol that includes synchronization of communication.

18. The method of claim 17 wherein the synchronization of communication includes localized time synchronization between at least two data carriers.

19. The method of claim 17 wherein the synchronization of communication includes global time synchronization between data carriers of a plurality of said clusters.

20. The method of claim 17 wherein the synchronization of communication includes global-based time synchronization in which communication time between data carriers is set in accordance with a common time clock.

21. The method of claim 17 wherein the synchronization of communication includes time-stamped data communication in which data received by a recipient data carrier from a sender data carrier includes a time of transmission of the data.

22. The method of claim 17 wherein the synchronization of communication includes data carrier-to-data carrier synchronization includes:

setting a time, and propagating the set time from one data carrier to another;

or

using one of the data carriers designated as a managerial data carrier to set the time, and propagating the set time from the managerial data carrier to neighbor data carriers.

23. The method of claim 17 wherein the synchronization of communication includes multiple-hop time synchronization in which time error is compensated for during communication.

24. The method of claim 17 wherein the synchronization of communication includes:

providing a plurality of different synchronization modes; and

allowing at least some of the data carriers to identify one of said synchronization modes and to corroborate with neighbor data carriers in accordance with the identified synchronization mode.

25. A system, comprising:

clusters of distributed data carriers,

wherein for each of said clusters, a bridge data carrier is identified that is capable to link with a bridge data carrier of another of said clusters; and

means for enabling communication between data carriers of the clusters, some of said data carriers including batteryless passive carriers.

26. The system of claim 25 wherein said means for enabling communication between data carriers of the clusters includes:

source means for providing a carrier wave that can be backscattered; and

means for modulating the backscattered carrier wave to generate interrogation and return signals therefrom, said interrogation and return signals being communicated between at least two of said data carriers.

27. The system of claim 26 wherein one of said data carriers includes means for independently generating the interrogation signal after an expiration of time, alternatively or additionally to generating the interrogation signal using the carrier wave.

28. The system of claim 25 wherein said clusters includes a candidate data carrier placed in a particular cluster based on a distance between said candidate data carrier and a substantially central data carrier in the particular cluster.

29. The system of claim 25 wherein said bridge data carrier is identified according to:

a region where a power output level from said at least one of said data carriers in a first cluster, which is sensed by another one of said data carriers in a second cluster, exceeds a cumulative power that is sensed by said another one of said data carriers from all of the data carriers in the first cluster by a threshold value.

30. A system, comprising:

a plurality of clusters of distributed data carriers, some of said data carriers including batteryless passive data carriers; and

for each of said clusters, a bridge data carrier that is capable to link with a bridge data carrier of another of said clusters to enable communication between data carriers of the clusters, said communication including modulation of a backscattered carrier wave to convey interrogation and return signals between data carriers of the clusters.

31. The system of claim 30, further comprising a carrier wave source to generate the carrier wave.

32. The system of claim 31 wherein said carrier wave source includes portable wireless communication device, one of said data carriers embedded in an object, or an automatic data collection device.

33. The system of claim 31 wherein said one of said data carriers embedded in the object is adapted to generate the carrier wave to interrogate at least another one of said data carriers in response to expiration of a specified time period.

34. The system of claim 30 wherein said clusters include dynamically formed clusters of randomly distributed data carriers that can communicate with each other using a stochastic communication protocol.

35. The system of claim 30 wherein each of the clusters includes a substantially central data carrier, wherein a candidate data carrier is adapted to be considered to include in a particular cluster based on a distance between the candidate data carrier and the central data carrier of the particular cluster.

36. The system of claim 30 wherein the bridge data carriers are determined based at least in part on a cumulative output power that is sensed by a bridge data carrier of a first cluster, the cumulative output power corresponding to output power of data carriers in a second cluster different from the first cluster.

37. An article of manufacture, comprising:

a storage medium usable with a plurality of distributed data carriers arranged into clusters, the storage medium having instructions stored thereon that are executable by a processor to provide communication between passive ones of said data carriers, by;

monitoring for a carrier wave and powering a first passive data carrier if the carrier wave is detected;

starting a timer;

if an interrogation signal is not received by the first passive data carrier before expiration of the timer, generating the interrogation signal from the first passive data carrier by modulating the carrier wave;

sending the interrogation signal to at least a second data carrier; and

continuing to send the interrogation signal to the second data carrier until a response signal is received from the second data carrier.

38. The article of manufacture of claim 37 wherein the second data carrier is in a different cluster than the first passive data carrier, said instructions to send the interrogation signal including instructions that are executable by said processor to provide communication between passive ones of said data carriers, by:

sending the interrogation signal to a bridge data carrier associated with the cluster of the second data carrier.

39. The article of manufacture of claim 37 wherein the storage medium further includes instructions stored thereon that are executable by said processor to provide communication between passive ones of said data carriers, by:

identifying the bridge data carrier associated with the cluster of the second data carrier based at least in part on a cumulative output power level of at least some of the data carries in the cluster of the second data carrier.

40. The article of manufacture of claim 37 wherein the first and second data carriers are both passive RFID data carriers of a same or different cluster.

41. The article of manufacturing of claim 37 wherein said storage medium is at least partially integrated with a sensor.

42. The article of manufacturing of claim 41 wherein said sensor is adapted to detect and collect data regarding at least one of a plurality of parameters related to temperature, humidity, air pressure, lighting levels, presence of certain chemical substances, presence and strength of electromagnetic or other types of signals, or other environmental condition.

43. The article of manufacturing of claim 37 wherein the first passive data carrier is adapted to generate a broadcast signal.

44. The article of manufacturing of claim 37 wherein the response signal of the second data carrier is a broadcast signal.