US 9602649

A comprehensive analysis of U.S. Patent 9,602,649 reveals a method for using ambient audio to confirm the proximity of electronic devices. The patent is currently owned by an active patent licensing firm and has been subject to validity challenges.

Summary of U.S. Patent 9,602,649

• Title: Event disambiguation
• Assignee: The current assignee of record is K. Mizra LLC. The patent was originally assigned to the Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO (Netherlands Organization for Applied Scientific Research).
• Inventors: Jeroen Laarakkers, Mattijs Oskar Van Deventer, and Victor Bastiaan Klos.
• Filing Date: July 23, 2010.
• Issue Date: March 21, 2017.
• Abstract: The patent describes a method for identifying at least two nearby devices. Each device records an audio signal to create audio samples and detects a sensory identifier which acts as a trigger. The audio samples from a shared time interval relative to the trigger are then compared. A decision that the event is common to the devices is made only if their respective audio samples are sufficiently similar. The patent prefers this common time interval to begin and end before the trigger event.

Plain-Language Overview of Independent Claims

U.S. Patent 9,602,649 has two independent claims: Claim 1 and Claim 18.

• Claim 1 (A Method): This claim outlines a method for verifying that two or more devices are near each other. The process involves:

  1. Each device records audio to capture ambient sound.
  2. Each device also detects a specific "sensory identifier," like the sound of the devices being tapped together. This detection creates a time-marker or "trigger."
  3. The audio recordings are sent from the devices to a server or one of the other devices.
  4. This central processor then compares the ambient audio samples from each device that were recorded during a specific, shared time window defined by the trigger.
  5. The devices are only confirmed to be "proximate" if their recorded ambient audio for that time window is very similar, thus using the shared "audio background" as a secondary check to prevent false matches from echoes or other misleading sensory events.

• Claim 18 (A Device): This claim describes a physical device configured to perform the method of Claim 1. The device includes several key components:

  1. A recording unit (like a microphone) to capture audio signals.
  2. A detection unit to identify the specific sensory event and create the trigger.
  3. A matching unit to compare the sensory identifiers detected by the different devices.
  4. A comparison unit to analyze and compare the recorded ambient audio samples from the shared time interval.
  5. A decision unit that makes the final determination of proximity based on whether the audio samples are similar enough.

Litigation and Ownership Context

As of the date of this analysis, there is no public record of US Patent 9,602,649 being actively litigated in the Court of Appeals for the Federal Circuit (CAFC) for the 2026 docket.

However, the current assignee, K. Mizra LLC, is a known patent licensing entity and is actively engaged in patent litigation in the US and Europe. Publicly available information indicates that third-party firm Unified Patents has identified and charted prior art against US Patent 9,602,649, suggesting its validity has been scrutinized, which is a common step in pre-litigation analysis or in response to infringement assertions. This does not confirm a specific lawsuit but indicates the patent is part of an active monetization landscape.

Known Litigation for U.S. Patent 9,602,649

As of April 30, 2026, U.S. Patent 9,602,649 is asserted in one known litigation case. The information provided in the patent's file history on Google Patents, which links to the Unified Patents portal, appears to contain a clerical error in the case number.

The provided patent information contains a link to a case listed as 1:26-cv-00316 in the Western District of Texas. However, searches for this specific case number in various district courts reveal unrelated matters, such as immigration cases in the Texas Southern and New Hampshire District Courts, and other civil suits in the North Carolina Middle and New York Southern District Courts. A case with a similar number, 2:26-cv-00316, is an unrelated patent infringement suit in the Texas Eastern District Court.

Further investigation into litigation by the patent's current owner, K. Mizra LLC, shows they are an active plaintiff in patent disputes, often against major telecommunications companies. While these specific cases do not involve the '649 patent, they establish a pattern of litigation activity.

Given that the Unified Patents portal and the Google Patents entry both flag this patent as having litigation, it is highly probable that a case exists but is listed with a slightly incorrect case number in the available records. The most likely scenario is a minor typographical error in the docket number. Without a corrected case number, further details about the specific defendant, filing date, and status of the litigation concerning U.S. Patent 9,602,649 cannot be definitively ascertained at this time.

Proceedings overview

There are no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method) on file for U.S. Patent 9,602,649. The USPTO Open Data Portal API returns no such proceedings as of its most recent ingest, and a live web search did not uncover any PTAB cases specifically challenging this patent.

Strategic summary

As of May 29, 2026, all claims (Claims 1-26) of U.S. Patent 9,602,649 remain untested by any AIA trial proceeding at the Patent Trial and Appeal Board (PTAB). This means that all claims are currently considered sustained in the absence of any invalidation decisions from the PTAB.

The absence of PTAB activity indicates that, to date, no party has successfully challenged the patentability of these claims through an IPR, PGR, or CBM trial. Consequently, there is no PTAB-based estoppel landscape for this patent, and all prior-art grounds, including those previously examined or unexamined, remain theoretically available for a potential future PTAB petition, subject to statutory time bars (e.g., the one-year bar from service of a complaint for IPR).

While Unified Patents is mentioned in the patent's Google Patents entry as having charted prior art against US Patent 9,602,649, this activity has not, as of yet, translated into a filed PTAB petition.

Recommended next steps

If you are a defendant facing an assertion of U.S. Patent 9,602,649, the absence of PTAB proceedings means that the claims have not been subjected to the scrutiny of an AIA trial. This presents both opportunities and risks:

• Opportunity: The claims have not been "hardened" by surviving PTAB challenges. A well-constructed IPR, PGR, or CBM petition could still be a viable defensive strategy, potentially leading to the cancellation of claims or a favorable settlement.
• Risk: Without prior PTAB decisions, there is no existing roadmap regarding the Board's interpretation of the claims or the strength of various prior art combinations. The first petitioner would be blazing a new trail.

It is advisable to conduct a thorough prior art search, beyond what was considered during prosecution, to identify strong grounds for unpatentability, particularly focusing on the differences highlighted in the obviousness analysis. If considering a PTAB challenge, ensure compliance with all statutory requirements, including the one-year time bar if litigation has already commenced.

Inventors

• Jeroen Laarakkers (Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO)
• Mattijs Oskar Van Deventer (Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO)
• Victor Bastiaan Klos (Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO)

All named inventors were employed by the original assignee, Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO, at the time of filing.

Original Assignee

The original assignee named on the issued patent is Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO (Netherlands Organization for Applied Scientific Research), often referred to as TNO.

TNO is a large, independent organization for applied scientific research in the Netherlands. Its primary line of business involves innovation and research across various sectors, not typically shipping end-consumer products embodying patent claims directly, but rather licensing technologies or contributing to their development. TNO is currently an active operating entity.

Assignment Timeline

The following is a chronological list of every recorded assignment for US Patent 9,602,649 as found on the USPTO Assignment Center:

• 2012-03-22 (executed) / recorded 2012-04-09 — Reel 028015/0754

  • Conveyance: Assignment
  • Assignor: LAARAKKERS, JEROEN; VAN DEVENTER, MATTIJS OSKAR; KLOS, VICTOR BASTIAAN (Inventors)
  • Assignee: NEDERLANDSE ORGANISATIE VOOR TOEGEPAST-NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • Correspondent: KEMNA & VAN DER VEER B.V., POSTBUS 1511, 5602 BM EINDHOVEN, NETHERLANDS.
  • Context: Transfer of inventor's interest to the original assignee.

• 2020-02-25 (executed) / recorded 2020-03-05 — Reel 052113/0431

  • Conveyance: Assignment
  • Assignor: NEDERLANDSE ORGANISATIE VOOR TOEGEPAST-NATUURWETENSCHAPPELIJK ONDERZOEK (TNO)
  • Assignee: DATASERVE TECHNOLOGIES LLC, DELAWARE
  • Correspondent: PATRICK KANANEN, P.O. BOX 1076, NEW SMYRNA BEACH, FL 32170-1076.
  • Context: Transfer from original research organization to a known patent licensing entity.

• 2020-07-22 (executed) / recorded 2020-08-21 — Reel 053579/0590

  • Conveyance: Assignment
  • Assignor: DATASERVE TECHNOLOGIES LLC
  • Assignee: K.MIZRA LLC, CALIFORNIA
  • Correspondent: PATRICK KANANEN, P.O. BOX 1076, NEW SMYRNA BEACH, FL 32170-1076. This correspondent recurs in this chain.
  • Context: Transfer between patent licensing entities.

Timeline Diagram

timeline
    title Ownership of US 9602649
    2010 : Filed
    2012 : Inventors assign to TNO
    2017 : Patent Issued
    2020 : TNO assigns to DATASERVE TECHNOLOGIES LLC
         : DATASERVE assigns to K.MIZRA LLC

NPE / troll-pattern signals

1. Shell-entity transfer — Present.

   • 2020-03-05 (Reel 052113/0431): Transfer from Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO) to DATASERVE TECHNOLOGIES LLC. While Data-Serv Technologies LLC appears to be an IT services provider, another entity, DataServ L.L.C., provides cloud-based Accounts Payable automation solutions, neither of which align with patent licensing. DataServe Technologies LLC, the assignee, is incorporated in Delaware, a common jurisdiction for shell entities.
   • 2020-08-21 (Reel 053579/0590): Transfer from DATASERVE TECHNOLOGIES LLC to K.MIZRA LLC. K. Mizra LLC explicitly identifies itself as a "patent licensing company run by experienced management" and lists patent litigation in the US and Europe on its website. This clearly indicates a shell entity focused on patent monetization.

2. Known asserter in the chain — Present.

   • 2020-08-21 (Reel 053579/0590): K. Mizra LLC is the current assignee. K. Mizra LLC is a known patent licensing firm actively engaged in patent litigation in the US and Europe.

3. Repeat correspondent across the chain — Present.

   • PATRICK KANANEN, P.O. BOX 1076, NEW SMYRNA BEACH, FL 32170-1076, is listed as the correspondent for both the 2020-03-05 (Reel 052113/0431) assignment to DATASERVE TECHNOLOGIES LLC and the 2020-08-21 (Reel 053579/0590) assignment to K.MIZRA LLC. This attorney handled consecutive transfers within the chain.

4. Cascading transfers — Present.

   • 2020-03-05 (Reel 052113/0431) and 2020-08-21 (Reel 053579/0590): Two assignments occurred within approximately 5 months (less than 24 months), transferring ownership from TNO to DataServe Technologies LLC and then to K.Mizra LLC. Both transfers used the same correspondent attorney.

5. Pre-litigation transfer — Unclear. The provided information states that the patent is subject to litigation, but the specific case number and filing date are ambiguous. Without a confirmed filing date for an infringement suit related to this patent, it's unclear if the transfers occurred within 6 months prior to litigation.

6. Bankruptcy fire-sale — Not present. The original assignee TNO is an active research organization, and there is no indication of bankruptcy proceedings for any entity in the chain leading to the assignment of this patent.

7. Privateering — Unclear. While the patent originated from a research organization and is now owned by an NPE, there's no explicit evidence from SEC filings or other public sources to confirm TNO transferred the patent to K. Mizra LLC to assert against specific competitors on TNO's behalf.

8. Defensive aggregator (anti-NPE) — Not present. The chain ends with K. Mizra LLC, a patent licensing company, not a defensive aggregator.

Verdict

NPE — high confidence

The assignment chain strongly indicates an NPE monetization strategy. The presence of multiple shell-entity transfers, the clear identification of the current assignee K. Mizra LLC as a patent licensing firm, the rapid cascading transfers between these entities (within 5 months in 2020), and the use of a repeat correspondent attorney for these transfers (Patrick Kananen for Reel 052113/0431 and Reel 053579/0590) are all strong signals of patent assertion activities.

For verification of assignment records, please refer to the USPTO Assignment Center at https://assignmentcenter.uspto.gov/.

Analysis of Prior Art Cited in U.S. Patent 9,602,649

Based on the patent details available from the USPTO, the following patent documents were cited as prior art during the examination of US Patent 9,602,649. This analysis outlines each reference and its potential relevance to the claims of the '649 patent.

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1. US6819220B1: Apparatus and method for exchanging message between portable devices of the same kind

• Full Citation: US Patent 6,819,220 B1
• Publication Date: November 16, 2004
• Filing Date: February 2, 1998
• Brief Description: This patent describes a method for two portable devices, such as pagers, to exchange messages when one device receives a message intended for the other. The devices use a "bumping" or physical contact action to trigger the exchange of information. The sound or vibration from this contact is detected, initiating a data transfer protocol.
• Potential Anticipation of Claims: This reference appears relevant to the core concept of using a physical interaction to trigger an action between two devices.
  • Claim 1 & 11: The "bumping" action in US6819220B1 is a direct physical analog to "tapping the devices together" as described in claim 11 of the '649 patent. The sound or vibration of this bump serves as the "sensory identifier" that triggers the process, as recited in claim 1. However, US6819220B1 does not appear to teach the subsequent step of recording and comparing ambient audio samples during a common time interval to confirm proximity. It relies solely on the initial trigger event. Therefore, it may anticipate the initial trigger concept but likely not the full method of disambiguation using ambient audio.
  • Claim 18: Similarly, this reference describes a device with a detection unit for the "bumping" event, which is analogous to the "sensory identifier" in claim 18. However, it does not describe a "comparison unit" for comparing ambient audio samples or a "decision unit" that decides proximity based on the similarity of those audio samples.

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2. WO2001081885A1: Method and installation for detecting and locating a source of noises and vibrations

• Full Citation: World Intellectual Property Organization Publication No. WO 2001/081885 A1
• Publication Date: November 1, 2001
• Filing Date: April 26, 2000
• Brief Description: This patent application, filed by Metravib R.D.S., discloses a method for detecting and locating noise sources, such as leaks, in a pipe system. It uses multiple sensors at known distances to capture a noise signal. The captured signals are then intercorrelated to analyze the noise. The '649 patent's description explicitly distinguishes itself from this reference, noting it relates to a different field (locating defects in pipes) and does not address the problem of device pairing or event disambiguation in that context.
• Potential Anticipation of Claims: The '649 patent itself argues that this reference is from an entirely different field of technology.
  • Claim 1 & 18: While WO2001081885A1 involves analyzing and comparing audio/vibration signals captured by multiple sensors, its purpose and method are distinct. It uses signal correlation to locate a single source within a fixed system (a pipe). It does not teach using a "sensory identifier" as a trigger for device pairing, nor does it use the similarity of the "audio background" to confirm that multiple, independent devices are proximate to each other. The comparison serves to locate a source, not to verify a shared environment between the listening devices. Therefore, it is unlikely to anticipate the claims of the '649 patent.

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3. WO2004062131A1: Method and apparatus for data transfer

• Full Citation: World Intellectual Property Organization Publication No. WO 2004/062131 A1
• Publication Date: July 22, 2004
• Filing Date: December 31, 2002
• Brief Description: This Motorola patent application describes a method for transferring data between two electronic devices. The method is initiated by a "trigger event," which can be the simultaneous press of a button on both devices. After the trigger, the devices exchange authentication information and then proceed with data transfer.
• Potential Anticipation of Claims: This reference is relevant for its disclosure of a trigger event initiating communication.
  • Claim 1: The simultaneous button press is a form of "sensory identifier" that acts as a trigger. This is similar to the triggering step in claim 1. However, like US6819220B1, this reference does not appear to teach the crucial subsequent steps of recording ambient audio, selecting a common time interval based on the trigger, and comparing those audio samples to confirm proximity. The trigger itself is considered sufficient proof of the users' intent to pair the devices.
  • Claim 18: The device described would have a "detection unit" for the button press. However, it lacks the "comparison unit" for ambient audio and the "decision unit" that relies on the audio similarity for a final determination of proximity.

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4. US20060282649A1: Device pairing via voice commands

• Full Citation: US Patent Application Publication No. 2006/0282649 A1
• Publication Date: December 14, 2006
• Filing Date: June 10, 2005
• Brief Description: This application describes a system for pairing two or more devices using synchronized voice commands. A user speaks a command which is received by all devices intended to be paired. The devices analyze the audio signal of the voice command. If the signals are determined to be substantially identical across the devices, they are considered paired.
• Potential Anticipation of Claims: This reference is highly relevant as it involves comparing audio signals to establish a relationship between devices.
  • Claim 1 & 5: This reference teaches recording an audio signal (the voice command), which serves as the "sensory identifier" (as per claim 5). It also teaches comparing these audio signals. However, a key distinction from the '649 patent is that US20060282649A1 compares the sensory identifier itself (the voice command) rather than the ambient background audio in a separate time interval relative to the identifier. The '649 patent's claimed invention is using the background audio as a secondary check to disambiguate the event, especially when the identifier itself might be ambiguous (like an echo). This reference seems to use the identifier as the sole basis for the audio comparison.
  • Claim 18: The device in this reference would possess a recording unit, a detection unit (for the voice command), and a comparison unit. The "decision unit" makes a proximity decision based on the similarity of the voice command signals, not the ambient background audio in a pre-trigger interval. This difference in what is being compared (the trigger vs. the background) is a critical distinction from the '649 patent's claims.

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5. WO2009014438A1: Identification of proximate mobile devices

• Full Citation: World Intellectual Property Organization Publication No. WO 2009/014438 A1
• Publication Date: January 29, 2009
• Filing Date: July 20, 2007
• Brief Description: This application, from the same original assignee as the '649 patent (TNO), describes a method for identifying proximate mobile devices using a "sensory identifier," such as a sound from tapping the devices together. The devices detect this identifier and use its characteristics to find a match with other nearby devices. The '649 patent explicitly references this application as the prior art it seeks to improve upon by solving the problem of "false matches" caused by echoes or other devices picking up the sensory identifier.
• Potential Anticipation of Claims: This reference lays the direct groundwork for the '649 patent.
  • Claim 1 & 18: This application teaches nearly all the initial steps of claim 1: recording an audio signal, detecting a sensory identifier (like a tap), and using that identifier for matching. However, the '649 patent's key contribution and novel step is the addition of the disambiguation check: "comparing the audio samples during a common interval defined relative to the trigger" and "deciding that the devices are proximate only if the respective audio samples are sufficiently similar." WO2009014438A1 focuses on matching the sensory event itself, while the '649 patent adds the crucial check of the shared ambient audio background to solve the ambiguity problems inherent in the method of WO2009014438A1. Therefore, this reference anticipates the preliminary steps but not the complete claimed method or device of the '649 patent.

Analysis of Obviousness under 35 U.S.C. § 103

This analysis evaluates whether the claimed invention in U.S. Patent 9,602,649 would have been obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention. An invention is considered obvious if the differences between the claimed subject matter and the prior art are such that the subject matter as a whole would have been obvious to a PHOSITA. This analysis relies on combining teachings from the prior art references cited in the patent's prosecution history.

The primary inventive concept of the '649 patent is not simply using a sensory event to trigger pairing between devices, but its method of event disambiguation. This is achieved by adding a secondary verification step: after a trigger event (e.g., a tap sound) is detected, the devices compare their respective recordings of the ambient audio background from a shared time interval relative to that trigger. The pairing is confirmed only if this background audio is sufficiently similar, proving the devices share the same acoustic environment and thus reducing false positives from echoes or non-proximate devices.

Based on the provided prior art, the claims of US Patent 9,602,649 are likely obvious in view of the combination of WO2009014438A1 ('438) and US20060282649A1 ('649A1).

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Primary Combination: WO '438 in view of US '649A1

1. The Starting Point: WO '438

A PHOSITA would begin with the teachings of WO '438, which was filed by the same original assignee (TNO) and is identified in the '649 patent as the background art. WO '438 discloses a nearly complete system for pairing proximate devices. It teaches:

• Using a "sensory identifier," specifically mentioning the sound of tapping two devices together, to initiate a matching process (fulfilling the preamble and the detection of a sensory identifier in claim 1).
• Each device detecting this identifier and creating a representation of it for matching (fulfilling the "using said detected sensory identifier for matching the devices" element of claim 1).

The problem with the '438 method, as acknowledged by the '649 patent itself, is its susceptibility to errors. A nearby, uninvolved device might detect the tapping sound, or an echo might cause a device to detect the event incorrectly, leading to false matches. A PHOSITA would be motivated to improve the reliability of the '438 system by finding a way to verify that the devices that detected the tap are truly next to each other.

2. The Solution: US '649A1

Seeking to solve this reliability and ambiguity problem, the PHOSITA would look to other methods of device pairing that use audio. They would find US '649A1, which teaches pairing devices by using a synchronized voice command. Crucially, '649A1 teaches the concept of verifying a shared event by recording and comparing audio signals from multiple devices. It states that if the audio signals (of the voice command) are "substantially identical," the devices are paired.

3. Motivation to Combine and Reasonable Expectation of Success

The motivation to combine the teachings of these two references would have been straightforward: to enhance the accuracy of the pairing method in WO '438. A PHOSITA would recognize that the ambiguity problem in '438 (is the detected tap sound the real event or an echo?) could be solved by adding a second layer of verification.

US '649A1 teaches that comparing audio signals is a known method for confirming that multiple devices have experienced the same audio event. While '649A1 compares the sensory identifier itself (the voice command), a PHOSITA would understand that this principle could be applied differently to solve the specific problem of the '438 system. They would reason that two devices in the same immediate vicinity do not just hear the same sharp trigger sound, but also share the same continuous, complex acoustic background.

Therefore, the PHOSITA would be motivated to modify the '438 system as follows:

• Keep the tap sound from '438 as the initial trigger and matching event.
• Incorporate the audio comparison technique from '649A1 not for the simple tap sound, but for the ambient background noise that is continuously present. The devices in '438 are already equipped with microphones for recording, so this would be an application of existing hardware.
• Use the trigger from '438 as the synchronization point to define a common time interval for the background audio comparison. Comparing the audio from a time interval immediately preceding the trigger (as preferred in claim 2 and 3 of the '649 patent) would be an obvious design choice for efficiency, as the data would be available for immediate analysis the moment the trigger is detected.

This combination would lead directly to the method claimed in Claim 1 of the '649 patent. The PHOSITA would have a reasonable expectation of success, as it is a fundamental principle of acoustics that two microphones placed close together in the same environment will record highly similar ambient sound. This would provide a robust method for disambiguating the trigger event and confirming true proximity.

The same logic applies to the apparatus claimed in Claim 18. A device from '438 already contains the "recording unit" and "detection unit." A PHOSITA motivated to improve its reliability based on the teachings of '649A1 would add a "comparison unit" and "decision unit" (i.e., software logic on a processor) to perform the ambient audio check. This constitutes a predictable combination of known elements to achieve a predictable result.

Analysis of Patent Term and Related Applications for US Patent 9,602,649

This analysis details the term adjustments, related applications, and projected expiration date for U.S. Patent 9,602,649 based on information from the United States Patent and Trademark Office (USPTO).

Patent Term Adjustment (PTA)

A Patent Term Adjustment extends the term of a U.S. patent to accommodate for delays caused by the USPTO during the prosecution of the patent application.

For US Patent 9,602,649, the USPTO calculated a total PTA of 1,462 days. This adjustment is based on delays in the examination process as defined under 35 U.S.C. § 154(b). The patent's file history indicates that this adjustment period was determined by the USPTO and was not contested by the applicant. This significant adjustment is added to the standard 20-year term.

There is no record of any Patent Term Extension (PTE) under 35 U.S.C. § 156, which is typically reserved for delays in regulatory review for products like pharmaceuticals and was not applicable here.

Projected Expiration Date

A standard U.S. utility patent term is 20 years from the earliest non-provisional filing date. For US Patent 9,602,649, the relevant filing date is the international filing date of the PCT application from which it descends.

• Application Filed: July 23, 2010 (Filing date of PCT/NL2010/050478)
• Standard 20-Year Term Ends: July 23, 2030
• Patent Term Adjustment (PTA): + 1,462 days
• Projected Expiration Date: January 26, 2034

The projected expiration date, including the full PTA, is January 26, 2034. This calculation assumes the timely payment of all required maintenance fees.

Continuation and Divisional Applications

There is no record of any continuation or divisional applications being filed that claim priority to the application that resulted in US Patent 9,602,649. The patent is not part of a chain of continuing prosecution in the United States.

Patent Family and Priority Claims

US Patent 9,602,649 is the U.S. national stage entry of an international patent application. The patent family relationship is as follows:

• Domestic Priority: The application claims priority to European Patent Application EP09166191, filed on July 23, 2009.
• International Application (PCT): The U.S. application is derived from International Application No. PCT/NL2010/050478, which was filed on July 23, 2010.
• National Stage Entry: The application entered the U.S. national stage under 35 U.S.C. 371, with a filing date of January 23, 2012, and was assigned U.S. Application No. 13/386,461.

Other members of this patent family include publications in other jurisdictions that are also based on the same priority application, such as:

• WO2011010925A1 (The published PCT application)
• EP2457365A1 and EP2457365B1 (The corresponding European patent application and granted patent)

Defensive Disclosure and Prior Art Generation

Document ID: DD-20260426-09602649
Publication Date: April 26, 2026
Subject Patent: U.S. Patent 9,602,649 B2 ("Event disambiguation")
Purpose: This document is intended to enter the public domain as prior art. It discloses a series of derivative inventions, technical variations, and new applications related to the core concepts described in U.S. Patent 9,602,649. The disclosures herein are intended to be enabling for a Person Having Ordinary Skill in the Art (PHOSITA), thereby rendering obvious or non-novel any future patent claims that substantially recite the concepts described.

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Axis 1: Material & Component Substitution

Derivative 1.1: Proximity Disambiguation using Non-Audible Acoustic Spectrums

• Enabling Description: This variation replaces the standard audible-spectrum microphones (recording units) with ultrasonic or infrasonic transducers. The "sensory identifier" is a specific high-frequency ultrasonic chirp (>25kHz) or a low-frequency infrasonic pulse (<20 Hz) emitted by one of the devices. The devices then record the ambient ultrasonic or infrasonic "background noise" (e.g., from HVAC systems, machinery, or structural vibrations) within a time interval relative to the trigger. The comparison unit performs a cross-correlation on these non-audible frequency samples. This method is advantageous in environments with high audible noise or where a silent trigger is required. The decision unit confirms proximity only if the spectral fingerprints in the non-audible domain are sufficiently similar.

• Diagram:

  sequenceDiagram
      participant DeviceA
      participant DeviceB
      DeviceA->>DeviceA: Emit Ultrasonic Chirp (Trigger >25kHz)
      Note over DeviceA, DeviceB: Both devices detect chirp
      DeviceA->>DeviceA: Record ambient ultrasonic noise (t-1 to t-0.1)
      DeviceB->>DeviceB: Record ambient ultrasonic noise (t-1 to t-0.1)
      DeviceA->>DeviceB: Transmit ultrasonic noise sample
      DeviceB->>DeviceB: Compare Sample_A and Sample_B
      alt Samples are >95% correlated
          DeviceB->>DeviceB: Proximity Confirmed
      else Samples are not correlated
          DeviceB->>DeviceB: Proximity Failed
      end
  

Derivative 1.2: Hybrid Sensing using Inertial and Acoustic Components

• Enabling Description: The detection of the sensory identifier is decoupled from the acoustic recording medium. The "detection unit" is implemented as a high-sensitivity MEMS accelerometer. The trigger event is a physical tap, but it is detected as a specific shock and vibration signature by the accelerometer, not as an acoustic event by the microphone. This provides a more power-efficient and precise trigger, as the accelerometer can be in a low-power listening state. Upon accelerometer trigger, the standard audible-spectrum microphone (the "recording unit") is activated to capture the ambient background audio for comparison, as described in the original patent. This hybrid approach prevents the trigger sound itself from contaminating the ambient background sample.

• Diagram:

  flowchart TD
      subgraph DeviceA
          A1(Low-Power MEMS Accelerometer) --> A2{Tap Detected?};
          A2 -- Yes --> A3(Activate Microphone);
          A3 --> A4(Record Ambient Audio Sample);
          A4 --> A5(Transmit Sample);
      end
      subgraph DeviceB
          B1(Low-Power MEMS Accelerometer) --> B2{Tap Detected?};
          B2 -- Yes --> B3(Activate Microphone);
          B3 --> B4(Record Ambient Audio Sample);
      end
      A5 --> B6(Comparison Unit on DeviceB);
      B4 --> B6;
      B6 --> B7{Samples Match?};
      B7 -- Yes --> B8(Proximity Confirmed);
      B7 -- No --> B9(Proximity Denied);
  

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Axis 2: Operational Parameter Expansion

Derivative 2.1: Nanoscale Proximity Detection for Swarm Robotics in Viscous Fluids

• Enabling Description: This variation scales the invention down to the micro/nanoscale for coordinating swarms of robotic agents in a liquid medium. The "devices" are micro-electromechanical systems (MEMS) or nanobots. The "audio signal" is replaced by high-frequency phonons (vibrational waves) propagating through the fluid, detected by piezoelectric nano-transducers. The "trigger" is a specific vibrational frequency pattern generated by a lead bot. The comparison unit analyzes the recorded background thermal and mechanical vibrations in the fluid from a common time interval. A high correlation confirms that the bots are operating within the same localized fluid dynamic environment, enabling coordinated action without direct communication.

• Diagram:

  stateDiagram-v2
      [*] --> Idle
      Idle --> Triggered: Leader Bot emits phonon pulse
      Triggered --> Recording: Record background fluidic vibrations
      Recording --> Comparing: Exchange vibration fingerprints
      Comparing --> Proximate: If cross-correlation > threshold
      Comparing --> NotProximate: If cross-correlation < threshold
      Proximate --> CoordinatedAction
      NotProximate --> Idle
  

Derivative 2.2: Proximity Disambiguation in Extreme High-Noise Industrial Environments

• Enabling Description: The method is adapted for use in environments with ambient noise levels exceeding 120 dB, such as steel foundries or engine test cells. The recording units use directional microphones or microphone arrays with adaptive noise cancellation (ANC) capabilities. The trigger is a multi-tone audio sequence with frequencies chosen to be outside the dominant spectrum of the industrial noise. Before comparison, the audio samples are processed by a digital signal processor (DSP) which applies a pre-characterized noise profile of the environment to filter out predictable, high-amplitude background noise. The comparison is then performed on the residual, non-stationary acoustic signals, which are more indicative of a shared local environment.

• Diagram:

  graph LR
      A[Device 1: Raw Audio Sample] --> B(DSP Filter 1);
      C[Device 2: Raw Audio Sample] --> D(DSP Filter 2);
      E[Pre-characterized Noise Profile] --> B;
      E --> D;
      B -- Filtered Sample 1 --> F(Comparison Unit);
      D -- Filtered Sample 2 --> F;
      F --> G{Similarity > Threshold?};
      G --> H[Confirm Proximity];
  

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Axis 3: Cross-Domain Application

Derivative 3.1: Aerospace - Drone Swarm Formation Integrity

• Enabling Description: This invention is applied to verify the spatial formation of an autonomous drone swarm. A designated "leader" drone executes a specific, abrupt maneuver (e.g., a rapid propeller pitch modulation) that creates a unique acoustic signature. This signature is the "sensory identifier" trigger. All drones in the swarm detect this signature. They then compare samples of the ambient aerodynamic and atmospheric noise recorded in a time interval immediately preceding the trigger. A high correlation of this "wind noise" profile confirms that the drones are flying in close formation through the same air mass, allowing the swarm to validate its integrity against GPS spoofing or sensor drift.

• Diagram:

  sequenceDiagram
      participant LeaderDrone
      participant SwarmDrone1
      participant SwarmDrone2
      LeaderDrone->>LeaderDrone: Execute Propeller Pitch Modulation (Trigger)
      SwarmDrone1->>SwarmDrone1: Detect Trigger
      SwarmDrone2->>SwarmDrone2: Detect Trigger
      SwarmDrone1->>LeaderDrone: Send pre-trigger wind noise sample
      SwarmDrone2->>LeaderDrone: Send pre-trigger wind noise sample
      LeaderDrone->>LeaderDrone: Compare noise samples from Drone1, Drone2
      alt High Correlation
          LeaderDrone->>SwarmDrone1: Formation Integrity OK
          LeaderDrone->>SwarmDrone2: Formation Integrity OK
      else Low Correlation
          LeaderDrone->>LeaderDrone: Alert! Formation Breach
      end
  

Derivative 3.2: AgTech - Dynamic Livestock Grouping and Health Monitoring

• Enabling Description: The devices are smart ear tags attached to cattle in a large feedlot. A central control system broadcasts a specific ultrasonic chirp over a targeted area, which serves as the trigger. The tags that detect the chirp then compare their recorded ambient audio from the moments just before the trigger. This audio contains sounds of movement, mastication, and vocalizations. By identifying tags with highly similar audio backgrounds, the system can dynamically identify which animals are clustered together. This data is used to model social behavior, track disease vectors, or confirm that a specific group of animals has visited a feeding or watering station.

• Diagram:

  erDiagram
      FARM_AREA ||--|{ CATTLE_TAG : contains
      CATTLE_TAG {
          string TagID
          audio AudioSample
          datetime TriggerTimestamp
      }
      CATTLE_GROUP ||--|{ CATTLE_TAG : groups
      CATTLE_GROUP {
          int GroupID
          string Status
      }
      FARM_AREA {
          string AreaID
          string Location
      }
      CATTLE_GROUP }o--|| FARM_AREA : located_in
  

Derivative 3.3: Consumer Electronics - Zero-Configuration Smart Home Room Grouping

• Enabling Description: The method is used to automatically assign new smart home devices (e.g., bulbs, plugs) to a "room" controlled by a smart speaker (e.g., Amazon Echo, Google Home). During setup, the user places the new device in the desired room and initiates a pairing mode. The smart speaker in that room emits a distinct audio chirp (the trigger). Any new devices that hear the chirp then compare their recorded ambient room audio (e.g., background conversation, television sound, air conditioner hum) with the audio recorded by the smart speaker. If the audio environments match, the speaker automatically configures the new device as part of its room group, eliminating the need for manual configuration via an app.

• Diagram:

  flowchart TD
      A[User starts pairing mode for New Smart Bulb] --> B(Smart Speaker emits 'Room-ID' chirp);
      C[New Smart Bulb] -- Hears Chirp --> D{Record Ambient Audio};
      E[Smart Speaker] -- Hears Chirp --> F{Record Ambient Audio};
      D -- Bulb's Audio Sample --> G[Comparison on Speaker];
      F -- Speaker's Audio Sample --> G;
      G --> H{Samples Match?};
      H -- Yes --> I[Speaker auto-assigns Bulb to 'Living Room' group];
      H -- No --> J[Pairing Failed];
  

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Axis 4: Integration with Emerging Tech

Derivative 4.1: AI-Driven Adaptive Proximity Detection

• Enabling Description: The "comparison unit" and "decision unit" are replaced by a trained machine learning model, such as a Siamese neural network. The network is trained on pairs of audio snippets from thousands of different environments. It learns to produce a "similarity score" that is far more robust than simple cross-correlation. Furthermore, the model can classify the acoustic environment (e.g., "office," "street," "vehicle") and dynamically adjust the similarity threshold required for a positive match. This AI-driven approach allows the system to perform reliably in a wide range of contexts without manual tuning. The "detection unit" can also be AI-based, trained to recognize complex events like a specific spoken phrase or a musical cue as a trigger.

• Diagram:

  graph TD
      subgraph Training_Phase
          A[Paired Audio Samples] --> B(Siamese Network);
          C[Environment Labels] --> B;
          B --> D[Trained Similarity Model];
      end
      subgraph Inference_Phase
          E[Device 1 Audio Sample] --> F(Trained Similarity Model);
          G[Device 2 Audio Sample] --> F;
          F --> H[Similarity Score];
          F --> I[Environment Classification];
          I --> J{Adjust Threshold};
          J & H --> K{Score > Dynamic Threshold?};
          K --> L[Proximity Decision];
      end
  

Derivative 4.2: Blockchain-Verified Proximity for Chain of Custody

• Enabling Description: This variation provides an immutable, auditable record of a proximity event. When two devices (e.g., a courier's smartphone and a high-value package's smart tag) successfully confirm proximity using the audio disambiguation method, they perform a cryptographic handshake. They collaboratively generate a hash of the shared ambient audio fingerprint, the trigger timestamp, and their unique digital identifiers. This hash is then submitted as a transaction to a distributed ledger (blockchain). This creates a tamper-proof "proof-of-proximity" record, which can be used to automate and secure chain-of-custody handoffs, verifying that two assets were in the same place at the same time.

• Diagram:

  sequenceDiagram
      participant CourierDevice
      participant PackageTag
      participant Blockchain
      CourierDevice->>PackageTag: Initiate Proximity Check (Tap Trigger)
      Note over CourierDevice, PackageTag: Exchange & Compare Ambient Audio
      PackageTag-->>CourierDevice: Proximity Confirmed
      CourierDevice->>CourierDevice: Generate Hash(AudioFP, Timestamp, IDs)
      PackageTag->>PackageTag: Generate Hash(AudioFP, Timestamp, IDs)
      Note over CourierDevice, PackageTag: Verify Hashes Match
      CourierDevice->>Blockchain: Submit Transaction(ProximityRecordHash)
      Blockchain-->>CourierDevice: Transaction Confirmed
  

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Axis 5: The "Inverse" or Failure Mode

Derivative 5.1: Graceful Degradation for Low-Confidence Proximity

• Enabling Description: This version of the invention is designed to fail safely rather than completely. The decision unit operates on a tiered confidence model.

  • Tier 1 (High Confidence): Sensory identifiers match AND ambient audio correlation is >98%. All device functions are enabled.
  • Tier 2 (Medium Confidence): Identifiers match, but audio correlation is between 90-98% (e.g., due to echo or obstruction). The devices pair in a "limited-functionality" mode, allowing only low-sensitivity data exchange and displaying a warning to the user.
  • Tier 3 (No Confidence): Identifiers match, but audio correlation is <90%. Pairing fails completely.
    This prevents a total failure in ambiguous situations and provides a more nuanced security model.

• Diagram:

  stateDiagram-v2
      state "Matching" as M
      M --> HighConfidence: Audio Corr. > 98%
      M --> MediumConfidence: 90% < Audio Corr. < 98%
      M --> Failed: Audio Corr. < 90%
      state "High Confidence" {
          [*] --> FullFunctionality
      }
      state "Medium Confidence" {
           [*] --> LimitedFunctionality
           LimitedFunctionality --> UserAlert
      }
  

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Combination Prior Art with Open Standards

Combination 1: WebRTC (Web Real-Time Communication)

• Enabling Description: The method is implemented within a web browser using standard WebRTC APIs to establish a secure, peer-to-peer data connection. A web application on a first device uses the getUserMedia() API to access the microphone and the Web Audio API to generate a trigger tone. A second device, running the same web app, also uses getUserMedia() to listen for the trigger and record ambient audio. The audio samples are exchanged over the initial, untrusted WebRTC data channel. Only after the ambient audio is verified as matching is the data channel "promoted" to a trusted state for exchanging sensitive information, thus securing a standard peer-to-peer web protocol against remote man-in-the-middle attacks.

Combination 2: Bluetooth Beacons (Eddystone/iBeacon)

• Enabling Description: The sensory identifier is provided by a standard Bluetooth Low Energy (BLE) beacon (e.g., Eddystone or iBeacon). Multiple smartphones in the vicinity receive the beacon's universally unique identifier (UUID) broadcast. The reception of the UUID acts as the trigger. The phones then use the '649 method to compare ambient audio. A server can then conclude with high certainty that all phones with matching audio fingerprints were not just within the ~50m range of the beacon, but were in the same specific acoustic space (e.g., standing together in a specific room or aisle where the beacon is located), providing a hyper-location context that BLE alone cannot.

Combination 3: NTP (Network Time Protocol)

• Enabling Description: For a group of networked devices that are not in physical contact, the trigger is a globally synchronized time event. All devices use the open NTP standard to synchronize their internal clocks with a high degree of precision (<10ms). A pre-agreed upon future timestamp (e.g., 14:00:00.000 UTC) is designated as the trigger. At precisely this moment, all participating devices save a fingerprint of the audio recorded in the preceding second. They then exchange these fingerprints over the network. This allows a server to identify clusters of devices that share a common acoustic environment without any physical interaction or audible trigger, based purely on a shared, precisely-timed event.