US 12375890

Unable to Locate Patent Information for US 12375890

As of April 26, 2026, a search of the United States Patent and Trademark Office (USPTO) database and the 2026 dockets of the U.S. Court of Appeals for the Federal Circuit (CAFC) for patent number 12375890 yielded no specific results.

Consequently, it is not possible to provide a summary of the patent's title, assignee, inventors, filing date, issue date, or abstract. A plain-language overview of its independent claims cannot be formulated as the claims themselves are unavailable.

This lack of information may be due to several reasons, including but not limited to: the patent number being inaccurate, the application being under a non-publication request, or the patent not yet being issued. In accordance with operational rules, the provided patent number has been interpreted literally without correction. No information regarding this specific patent is available with high confidence at this time.

Contradiction With Previously Generated Summary

The previously generated summary stated, "Unable to Locate Patent Information for US 12375890" as of April 26, 2026. This analysis, conducted on May 6, 2026, has located the patent information. The authoritative data for US Patent 12375890, sourced from Google Patents, indicates the patent was granted on July 29, 2025. This new information directly contradicts the previous inability to locate the patent and supersedes it.

Litigation Search for US Patent 12375890

As of May 6, 2026, a search for litigation involving US patent 12375890 reveals one known case.

BK Technologies Inc. v. [Defendant Name Redacted]

• Plaintiff(s): BK Technologies Inc.
• Defendant(s): Information not publicly available.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:26-cv-00090
• Filing Date: Not specified in the available information.
• Outcome or Current Status: The case has been filed. Further details regarding the status or outcome are not available in the provided search results.

This information was sourced from litigation data linked on the Google Patents page for US12375890B2, which points to the Unified Patents portal (https://portal.unifiedpatents.com/litigation/Texas%20Eastern%20District%20Court/case/2%3A26-cv-00090). No other litigation involving this specific patent was identified in the search.

Proceedings overview

There is one active AIA trial proceeding on file for US Patent 12,375,890. This Inter Partes Review (IPR) is currently pending institution, meaning the defensive posture for a defendant is still developing.

IPR2026-00349 — AT&T Services, Inc. et al. v. John Marvin Suzuki et al

• Type: Inter Partes Review
• Filed: 2026-05-05
• Status: Pending. Last modified 2026-05-26.
• Judge panel: Not yet publicly available.
• Petition grounds: Not yet publicly available.
• Institution decision: Not yet issued. The institution decision deadline is typically 6 months from the filing date.
• Final Written Decision: Not applicable; no institution decision has been rendered.
• Settlement / termination: Not applicable.
• Appeal: Not applicable.
• Defensive value: As this IPR is in its early stages, its direct defensive value is currently limited. However, it indicates that AT&T Services, Inc. and potentially other parties believe there are grounds to challenge the patent's validity. If the IPR is instituted, it will create an opportunity to invalidate some or all of the challenged claims, which could significantly weaken the patent's enforceability.

Strategic summary

As of today, May 29, 2026, all claims of US Patent 12,375,890 are UNTESTED through a final written decision in an AIA trial. One IPR (IPR2026-00349) has been filed by AT&T Services, Inc. et al. and is currently pending institution. The outcome of this proceeding will be crucial in determining which, if any, claims are canceled or sustained.

Regarding the estoppel landscape, if IPR2026-00349 is instituted and proceeds to a Final Written Decision, the petitioners (AT&T Services, Inc. et al. and their privies) would be barred under 35 U.S.C. § 315(e)(2) from raising any ground they raised or reasonably could have raised in a subsequent civil action or another proceeding before the Office. For other defendants, prior-art grounds not addressed or reasonably available to the petitioners in this IPR would remain available for challenge.

There are no apparent pattern signals such as multiple IPRs on this patent by the same petitioner, aggressive PTAB appeals by the patent owner, or the involvement of a defensive aggregator at this early stage.

Recommended next steps

For a defendant facing assertion of US Patent 12,375,890, the primary next step is to closely monitor IPR2026-00349. Key trial-stage milestones include the institution decision deadline (approximately November 5, 2026). The institution decision, if it occurs, will detail the specific claims and prior art grounds that the PTAB will review. If the IPR is instituted, then tracking the oral hearing and the Final Written Decision due date (typically one year from institution) will be critical.

The absence of prior PTAB activity means the patent has not yet undergone significant scrutiny in post-grant proceedings.

Inventors

Based on the patent documentation, the named inventors are:

• John Marvin Suzuki: Based on his role as CEO of BK Technologies, it can be determined he was employed by the original assignee at the time of filing.
• Lorenzo Cruger, Jr.: Employment status with BK Technologies at the time of filing is not specified in the provided documents, but his inclusion as an inventor suggests a direct connection.
• James Lowell Teel, Jr.: The patent text identifies him as an inventor, and public sources from March 2024 and March 2025 identify James Teel as the general manager of BK Technologies' SaaS business unit and leader of the expanded Solutions business unit. This confirms his employment with the original assignee.

There are no unusual patterns, such as mass departures of inventors, indicated in the available information.

Original assignee

The original assignee of record is BK Technologies Inc.

BK Technologies is an operating company that designs, manufactures, and markets communication equipment for public safety professionals and government agencies. The company actively ships products that appear to embody the claims of the patent, including a Push-to-Talk over Broadband (PTToB) service called "InteropONE" which "enables the on-demand creation of user groups that can include anyone with an active smartphone." This product directly aligns with the patent's claims for granting temporary talkgroup access to non-subscribers.

BK Technologies Corporation is a publicly traded company on the NYSE American market under the symbol "BKTI" and is currently operating.

Assignment timeline

A search of the USPTO Patent Assignment Search database for US Patent 12,375,890 reveals one recorded assignment.

• 2022-06-20 (executed) / recorded 2024-10-27 — Reel 069032/0977
  • Conveyance: Assignment of Assignor's Interest
  • Assignor: SUZUKI, JOHN MARVIN; CRUGER, LORENZO, JR.; TEEL, JAMES LOWELL, JR.
  • Assignee: BK TECHNOLOGIES INC., FLORIDA
  • Correspondent: MCDONNELL BOEHNEN HULBERT & BERGHOFF LLP, 300 S. WACKER DRIVE, SUITE 3100, CHICAGO, IL, 60606
  • Context: This is the initial assignment transferring the invention from the individual inventors to their employer, BK Technologies Inc.

No other assignments have been recorded for this patent as of May 10, 2026. This indicates that the original assignee, BK Technologies Inc., remains the current owner of record.

Timeline diagram

timeline
    title Ownership of US 12375890
    2022 : Application filed by inventors
         : Assigned to BK Technologies Inc
    2025 : Patent issued
    2026 : First infringement suit filed

NPE / troll-pattern signals

1. Shell-entity transfer: Not present. The patent was assigned from the inventors directly to their employer, BK Technologies Inc., which is a publicly-traded operating company with commercial products. There has been no subsequent transfer.
2. Known asserter in the chain: Not present. The only assignee is BK Technologies Inc., which does not appear on public NPE lists maintained by entities like Unified Patents or RPX.
3. Repeat correspondent across the chain: Not present. Only one assignment is on record. The correspondent, McDonnell Boehnen Hulbert & Berghoff LLP, is a well-established IP law firm that represents a wide range of clients. A single appearance for an initial assignment is standard practice and not a signal.
4. Cascading transfers: Not present. There have been no subsequent transfers after the initial assignment.
5. Pre-litigation transfer: Not present. No assignment was recorded in the six months preceding the litigation filed in early 2026. The only recorded assignment was the initial inventor-to-company transfer executed in 2022.
6. Bankruptcy fire-sale: Not present. BK Technologies Inc. is an active, publicly traded company.
7. Privateering: Not present. The plaintiff in the known litigation is the operating company itself, not a third-party NPE.
8. Defensive aggregator (anti-NPE): Not present. The patent is held by its original operating-company assignee.

Verdict

Operating-company assertion

The patent is owned by the original assignee, BK Technologies Inc., a public company that develops and sells products, such as its InteropONE service, which directly relate to the patented technology. The single recorded assignment is a standard transfer from the inventors to their employer. The litigation associated with this patent is an enforcement action by the operating company itself. There are no signals present that would indicate NPE or patent-troll activity.

Verification link: USPTO Assignment Search for Patent 12375890

Prior Art Analysis for US Patent 12375890

This analysis identifies and examines the prior art cited in US Patent 12,375,890, titled "System and method for managing access to a push-to-talk-over-cellular communication network." The information is based on the authoritative patent text retrieved on May 6, 2026. The analysis focuses on determining which claims of the patent are potentially anticipated by each prior art reference under 35 U.S.C. § 102.

The core invention of US Patent 12,375,890 revolves around a system for temporarily granting non-subscriber devices access to a Push-to-Talk-over-Cellular (POC) talkgroup. This is initiated by a subscriber device sending non-subscriber contact information to a control device, which then transmits a communication to the non-subscriber device, often including a link to download the necessary software and configuration information. Access for the non-subscriber is typically granted for a predetermined period and can be automatically revoked.

Cited Prior Art References and Potential Anticipation

The following table details the prior art references cited in the patent and an analysis of their potential to anticipate the claims of US 12,375,890.

Full Citation	Publication/Filing Date	Brief Description	Potential Anticipation of Claims
US20050233776A1 "Method and apparatus for dynamic group address creation" Assignee: Allen Andrew M	Publication Date: 2005-10-20	Describes a method for dynamically creating a group address for a communication group, where a user can invite other users to join a group session.	Claims 1, 8: This reference appears to disclose the concept of a user inviting others to a communication group. However, it may not explicitly detail the "non-subscriber" aspect or the transmission of a link to download a specific POC software application as required by the independent claims. The level of anticipation would depend on whether the "invitation" in the prior art inherently includes providing the means to communicate, which could be argued to be equivalent to the claimed "link."
US20060252442A1 "Method for establishing a PoC connection in a terminal device with a touch-screen display, an application used in the method and a terminal device" Assignee: Nokia Corporation	Publication Date: 2006-11-09	Focuses on the user interface for establishing a Push-to-Talk over Cellular (PoC) connection on a touch-screen device, including selecting participants for a group call.	Claims 1, 3, 8, 10: This reference discloses the establishment of PoC connections and the selection of participants, which aligns with the initial steps of the claimed methods. However, a detailed review would be necessary to determine if it describes sending an invitation to a non-subscriber device that includes a link to download the necessary application, a key element of the independent claims of US 12,375,890.
US7499720B2 "System and method for initiating push-to-talk sessions between outside services and user equipment" Assignee: Sonim Technologies, Inc.	Publication Date: 2009-03-03	Discloses a system for initiating a push-to-talk (PTT) session that can include participants from different PTT services or even non-PTT users via a gateway.	Claims 1, 6, 7, 8: This patent's focus on interoperability between different services and including "outside" users is highly relevant. It potentially anticipates the core concept of granting access to external devices. The key determination would be whether its method of inclusion for "outside services" is equivalent to sending a direct communication with a software download link to a non-subscriber device as claimed.
US20180278718A1 "Method and apparatus for a cloud-based broadband push-to-talk configuration portal" Assignee: Motorola Solutions, Inc	Publication Date: 2018-09-27	Describes a cloud-based portal for configuring push-to-talk (PTT) services, which could include adding and managing users and talkgroups.	Claims 1, 3, 4, 8, 10, 11: This reference's disclosure of a centralized, cloud-based system for managing PTT configurations is conceptually similar to the "control device" in the '890 patent. The anticipation would depend on whether this portal's functionality includes the specific workflow of a subscriber inviting a non-subscriber and the automated sending of a software link and temporary access credentials.
US10681506B1 "System and method for push-to-talk over cellular integration with software defined radio" Assignee: Tango Tango, Inc.	Publication Date: 2020-06-09	Details a system for integrating Push-to-Talk over Cellular (POC) with traditional Land Mobile Radio (LMR) systems, allowing users on both networks to communicate.	Claims 1, 8: While this patent deals with POC technology and interconnectivity, its primary focus is on bridging two different types of communication networks (POC and LMR). It is less likely to anticipate the specific claims related to temporarily provisioning a non-subscriber cellular device by sending a software link, which is the central novelty of the '890 patent.

Summary of Anticipation Analysis

While several prior art references disclose elements of managing Push-to-Talk over Cellular (POC) talkgroups and inviting users, the key inventive concept of US Patent 12,375,890 appears to be the specific method of granting temporary access to a non-subscriber device. This is achieved by having a subscribed user initiate a process that causes a control server to send a communication to the non-subscriber, which includes a link to download the necessary software application, thereby enabling ad-hoc and time-limited inclusion of external participants.

The strongest potential for anticipation comes from US7499720B2 and US20180278718A1. The '720 patent discusses including "outside services," and the '718 patent describes a cloud-based configuration portal. A thorough analysis would require a detailed comparison of the specific mechanisms disclosed in these patents against the limitations of the independent claims (1 and 8) of US 12,375,890. Specifically, it would need to be determined if these prior art references teach the step of "transmitting, from the control device to the first non-subscriber device, a first communication including a link to download a POC software application." If this specific step is not present in the prior art, an argument for novelty under 35 U.S.C. § 102 would likely be sustained. The dependent claims, which add limitations such as automatic revocation of access after a predetermined time (claims 2, 4, 9, 11), further narrow the scope and may not be anticipated even if the independent claims are.

Obviousness Analysis of US Patent 12375890

This analysis examines the obviousness of the claims of US Patent 12,375,890 ("the '890 patent") under 35 U.S.C. § 103. The analysis is based on the previously generated Prior Art section and concludes that the claims would likely be considered obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention.

Under 35 U.S.C. § 103, a patent claim is unpatentable if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art. An obviousness rejection often involves combining the teachings of multiple prior art references. A key requirement for such a rejection is demonstrating that a PHOSITA would have been motivated to combine the references to achieve the claimed invention.

Analysis of Independent Claims

The '890 patent's novelty, as established in the prior art analysis, centers on a specific workflow for granting temporary access to a Push-to-Talk-over-Cellular (POC) talkgroup to a non-subscriber. The independent claims (1 and 8) recite the core elements of this workflow:

1. A control device manages a POC service and talkgroup.
2. The control device is instructed (e.g., by a subscriber) to grant access to a non-subscriber device.
3. The control device transmits a communication to the non-subscriber device containing a link to download the required POC software application.

Proposed Combination of Prior Art

A strong case for obviousness can be made by combining the teachings of US20180278718A1 (Motorola) and US7499720B2 (Sonim), supplemented by the general knowledge of a PHOSITA regarding software distribution at the time of the invention (priority date: January 19, 2022).

1. Base System: US20180278718A1 (Motorola)

The Motorola reference discloses a "cloud-based broadband push-to-talk configuration portal." This system directly teaches the "control device" element of claims 1 and 8. It describes a centralized server system for managing users, provisioning devices, and configuring talkgroups for a POC service. A PHOSITA would recognize this portal as the foundational administrative tool for operating a POC network.

2. The Problem and the Missing Feature: Including External Users

A known challenge in public safety and enterprise communications is the need for ad-hoc interoperability. An incident commander using the Motorola portal would frequently need to communicate with individuals from other agencies or companies who are not pre-subscribed to their specific POC service. The Motorola reference, focused on managing an existing subscriber base, does not explicitly solve the problem of quickly onboarding an external, temporary user.

3. The Solution Taught by US7499720B2 (Sonim)

The Sonim reference addresses this exact problem by disclosing a "system and method for initiating push-to-talk sessions between outside services and user equipment." This patent teaches the critical concept of including participants from different PTT services and even non-PTT users (i.e., "non-subscribers") in a talkgroup. It provides the conceptual blueprint for granting access to external devices.

4. Motivation to Combine

A PHOSITA would have been motivated to combine the teachings of Motorola and Sonim for a clear and practical reason: to enhance the functionality of a modern, cloud-based management portal (Motorola) with the necessary interoperability to include outside participants (Sonim). The goal would be to create a more flexible and effective communication system for real-world scenarios, such as multi-agency emergency response. An administrator of the Motorola portal, when faced with the need to add a firefighter from a neighboring jurisdiction for a single incident, would naturally look for ways to provision that user temporarily. The Sonim patent provides the teaching that such interoperability is possible and desirable. The combination would be a predictable solution to a known industry need.

5. Bridging the "Link to Download" Gap

Neither Motorola nor Sonim may explicitly recite the step of "transmitting... a communication including a link to download a POC software application." However, this step is an obvious and routine implementation detail, not an inventive concept.

By the priority date of the '890 patent, POC services were software applications running on standard smartphones. The universal, standard method for distributing such applications was through official app stores (e.g., Apple App Store, Google Play Store). When tasked with implementing the Sonim concept (add an outside user) on the Motorola platform (a management portal for a software-based service), the most logical and straightforward method for getting the required software onto the non-subscriber's device would be to send them a direct link to it. This would typically be done via an SMS text message or email, which are the most common forms of communication with a device identified by a phone number or email address. This is not an inventive leap but rather the selection of a conventional, well-established solution for software provisioning.

Analysis of Dependent Claims

The dependent claims of the '890 patent add further limitations that are also rendered obvious by this combination.

• Claims 2, 4, 9, 11 (Automatic Revocation): These claims add the feature of automatically revoking the non-subscriber's access after a predetermined period. This is an obvious security and administrative feature. When providing temporary access, especially in a public safety context, it is a standard best practice to have that access expire automatically. A PHOSITA would be motivated to add this functionality to the combined system to reduce the administrative burden of manually de-provisioning users after an event and to prevent lingering, unauthorized access. This is a predictable improvement, not an invention.
• Claims 5, 12 (Contact Information is a Phone Number): Specifying that the contact information is a cellular telephone number is an obvious design choice for a service that operates over a cellular network and communicates with cellular devices.

Conclusion

The independent claims (1 and 8) of US patent 12,375,890 are likely obvious under 35 U.S.C. § 103. The combination of a cloud-based PTT management portal as taught by US20180278718A1 (Motorola) with the concept of including external or non-subscribed users as taught by US7499720B2 (Sonim) would lead a PHOSITA directly to the claimed system. The motivation to combine these references is strong, as it addresses the well-known need for interoperability in POC systems. The specific step of sending a link to download the application is not a patentable feature but rather the most common and obvious implementation choice for onboarding a user to any software-based service on a mobile device. The features added in the dependent claims, such as automatic access revocation, represent predictable and desirable improvements for system security and administration.

Patent Term and Continuation History

This analysis details the prosecution history and projected term of US Patent 12,375,890 ("the '890 patent"), based on the authoritative patent text provided.

Patent Term and Expiration

• Projected Expiration Date: The anticipated expiration date for US Patent 12,375,890 is June 20, 2042.
• Term Calculation: The standard term for a U.S. patent is 20 years from the filing date of the earliest U.S. non-provisional application to which it claims priority. The '890 patent was filed on February 2, 2024, as application US18/431,686. However, it is a continuation of application US17/844,488, which was filed on June 20, 2022. Therefore, the 20-year term is calculated from this earlier date (2022-06-20 + 20 years = 2042-06-20). This date is cited as the "Anticipated expiration" in the patent's documentation.
• Patent Term Adjustment (PTA) / Extension (PTE): Based on the provided patent information, there are no recorded Patent Term Adjustments or Extensions. PTA is a process to accommodate for delays caused by the USPTO during prosecution. While such adjustments are possible, none are indicated in the legal events or metadata for this patent.

Continuation and Divisional History

• Continuation Application: The '890 patent, which matured from application US18/431,686, is a continuation of U.S. application Ser. No. 17/844,488, filed on June 20, 2022. This is explicitly stated in the "CROSS-REFERENCE TO RELATED APPLICATIONS" section of the patent. The parent application issued as US Patent 11,997,568 B2.
• Divisional Applications: The provided documentation does not indicate that the '890 patent is a divisional application, nor does it claim priority to any divisional applications. A divisional application is typically filed when a parent application is determined to contain claims directed to multiple distinct inventions.

Patent Family and Priority

The '890 patent is part of a larger patent family that claims priority back to a provisional application filed in 2022.

• Direct Priority:
  • Parent Application: US17/844,488 (Filed: 2022-06-20), now US Patent US11997568B2.
• Ultimate Priority:
  • Provisional Application: The family claims priority to U.S. Provisional Application No. 63/300,899 (Filed: 2022-01-19), as noted in the cross-reference section.
• International Family Members: The patent family also includes related filings in other jurisdictions, including:
  • WO2023141451A1 (World Intellectual Property Organization)
  • EP4464048A4 (European Patent Office)
  • CA3248900A1 (Canadian Intellectual Property Office)

This document presents a series of defensive disclosures derived from the core claims of US Patent 12,375,890. The intent is to preemptively place variations and improvements of the patented technology into the public domain, thereby establishing prior art against future, similar patent applications by third parties.

Each disclosure provides a technical "Enabling Description" sufficient for a person having ordinary skill in the art (PHOSITA) to practice the variation. These disclosures are organized according to a derivation framework.

Axis 1: Material & Component Substitution

Derivative 1.1: Browser-Based WebRTC Client

• Enabling Description: This variation replaces a proprietary, downloadable Push-to-Talk-over-Cellular (POC) software application with a browser-based client utilizing the WebRTC open standard. The control device generates a cryptographically unique URL for each non-subscriber invitation. When the non-subscriber clicks this link, it opens their device's default web browser and loads a JavaScript application. This application uses the WebRTC API to access the device's microphone and establish a peer-to-peer or server-mediated (via a TURN/STUN server managed by the control device) real-time media stream with the POC talkgroup. Session management and authentication are handled via WebSockets connected to the control device. Access is revoked by invalidating the session token on the server and closing the WebSocket connection.
• Mermaid Diagram:

  sequenceDiagram
      participant Admin as Subscriber Device
      participant Server as Control Device
      participant NonSub as Non-Subscriber Device
  
      Admin->>Server: Invite NonSub (PhoneNumber) to Talkgroup
      Server->>Server: Generate Unique WebRTC URL & Auth Token
      Server->>NonSub: SMS: "Join Talkgroup: https://poc.service/join?token=XYZ"
      NonSub->>Server: User clicks link (HTTP GET /join?token=XYZ)
      Server-->>NonSub: Serve WebRTC Client (HTML/JS)
      NonSub->>Server: JS Client connects via WebSocket w/ Token
      Server-->>NonSub: WebSocket connection established
      NonSub->>Server: WebRTC: Initiate media session
      Server->>NonSub: WebRTC: Connect to talkgroup audio bridge
      Note right of NonSub: User can now PTT in browser
  

Derivative 1.2: Lightweight MQTT-Signaled Client

• Enabling Description: To support low-power or constrained devices (e.g., wearables, IoT sensors with voice capabilities), this derivative substitutes the standard session initiation protocol (SIP) with the Message Queuing Telemetry Transport (MQTT) protocol for signaling. The control device also functions as an MQTT broker. The invitation link provides credentials for the non-subscriber's device to connect to the MQTT broker and subscribe to a specific talkgroup topic (e.g., /talkgroups/incident-123/presence). PTT requests are published as lightweight messages on a control topic, and the server manages the UDP-based RTP media streams separately. This architecture minimizes the persistent connection's overhead, conserving battery and bandwidth.
• Mermaid Diagram:

  flowchart TD
      subgraph Non-Subscriber Device
          A[POC App]
      end
      subgraph Control_Device
          B[MQTT Broker]
          C[RTP Audio Mixer]
      end
      subgraph Other_Participants
          D[...]
      end
  
      A -- "Connects with Temp Credentials" --> B
      A -- "Subscribes to /tg-123/presence" --> B
      A -- "Publishes PTT_START to /tg-123/control" --> B
      B -- "Notifies Mixer" --> C
      C -- "Opens UDP RTP Stream" --> A
      A -- "Sends Audio" --> C
      C -- "Mixes & Distributes Audio" --> D
  

Derivative 1.3: Decentralized Talkgroup Management via Mesh Network

• Enabling Description: This disclosure describes a system where the control device is not a centralized server but a distributed function running on subscriber devices themselves. Using a mobile ad-hoc network (MANET) protocol (e.g., Wi-Fi Direct, Bluetooth Mesh), a subscriber device with administrative rights can directly grant access to a nearby non-subscriber device. The "invitation" is a direct, encrypted peer-to-peer transmission containing the talkgroup's cryptographic keys, a temporary device certificate, and a list of known peer nodes. The non-subscriber's device downloads a client app that allows it to join the mesh and route PTT audio directly to other participants without passing through a central server. Access is revoked when the temporary certificate expires.
• Mermaid Diagram:

  graph TD
      subgraph Talkgroup Mesh
          S1(Subscriber 1 - Admin)
          S2(Subscriber 2)
          S3(Subscriber 3)
          NS(Non-Subscriber)
      end
  
      S1 -- "Direct P2P Invitation (Wi-Fi Direct)" --> NS
      NS -- "Joins Mesh" --> S2
      NS -- "Joins Mesh" --> S3
      S1 <--> S2
      S2 <--> S3
      S1 <--> S3
  
      style S1 fill:#f9f,stroke:#333,stroke-width:2px
      style NS fill:#ccf,stroke:#333,stroke-width:2px
  

---

Axis 2: Operational Parameter Expansion

Derivative 2.1: Industrial IoT Control Channel Management

• Enabling Description: At an industrial scale, the system manages temporary access to control channels for massive IoT deployments (e.g., a city's smart lighting grid). The "talkgroup" is a logical control channel (e.g., a multicast IP address) for thousands of luminaire controllers. A field technician (subscriber) needs to perform maintenance in a specific sector. They use their device to request temporary control access for that sector from the control device (grid management server). The server grants access by sending a time-limited digital certificate and the sector's specific control channel parameters to the technician's device (non-subscriber in the context of that specific channel). The "POC application" is a grid control app that uses these credentials to send authenticated CoAP (Constrained Application Protocol) commands to the lights.
• Mermaid Diagram:

  stateDiagram-v2
      [*] --> Inactive
      Inactive --> Provisioned: Technician requests access
      Provisioned --> Active: Tech app downloads cert & params
      Active --> Active: Send CoAP control commands
      Active --> De-provisioned: Timer expires
      De-provisioned --> [*]: Access revoked
  

Derivative 2.2: Deep-Sea Acoustic Modem Provisioning

• Enabling Description: This derivative applies the invention to extreme pressure and communication environments, specifically for deep-sea submersible drones. A surface vessel's control system (control device) manages communication. An operator (subscriber) needs to grant a third-party inspection drone (non-subscriber) temporary access to the primary drone swarm's acoustic communication network (talkgroup). The control system transmits a low-bandwidth acoustic message containing a link. This "link" is a command that instructs the drone to download a specific firmware module for its acoustic modem from an onboard repository. This module contains the necessary frequency hopping sequences and authentication keys to join the talkgroup for a predetermined time.
• Mermaid Diagram:

  sequenceDiagram
      participant Operator as Surface Console
      participant Vessel as Control Device
      participant Drone as Non-Subscriber Drone
  
      Operator->>Vessel: Grant Drone access to AcousticNet-Alpha
      Vessel->>Drone: Acoustic Msg: 'CMD:LOAD_FIRMWARE(ID=7, KEY=ABC)'
      Drone->>Drone: Access internal storage
      Drone->>Drone: Load Acoustic Modem Firmware v7
      Drone->>Vessel: Acoustic Msg: 'ACK:READY'
      Note right of Drone: Drone can now communicate on<br/>AcousticNet-Alpha
  

---

Axis 3: Cross-Domain Application

Derivative 3.1: Aerospace - Temporary Satellite Constellation Access

• Enabling Description: In the context of satellite fleet management, a primary operator (subscriber) uses a ground station management console to grant a third-party satellite (e.g., a research satellite needing to downlink data) temporary access to a specific communication channel within its constellation. The control device (ground station network scheduler) calculates an available time-division multiple access (TDMA) slot and generates a set of time-limited cryptographic keys. It transmits this "invitation" to the non-subscriber satellite during a scheduled contact window. The "link" is the command payload containing the slot assignment and keys, and the "POC application" is the satellite's existing communication subsystem, which is reconfigured by this command. Access automatically terminates when the TDMA slot window ends.
• Mermaid Diagram:

  gantt
      title Satellite Constellation TDMA Access
      dateFormat  HH:mm:ss
      axisFormat  %H:%M:%S
      section Ground Control
      Grant Access   :done, g1, 14:30:00, 10s
      Transmit Keys  :done, g2, 14:30:10, 30s
      section Non-Subscriber Satellite
      Receive & Reconfigure :crit, r1, 14:31:00, 45s
      Active Downlink Window :active, d1, 14:32:00, 5m
      Access Expires : r2, 14:37:00, 1s
  

Derivative 3.2: AgTech - Dynamic Drone Swarm Tasking

• Enabling Description: A farm owner (subscriber) uses a farm management platform (control device) to hire a third-party drone spraying service (non-subscriber). To grant access, the owner selects a specific field and timeframe. The platform generates a task package and sends a link to the drone service operator. The link leads to a secure endpoint where the operator can download the package. This package is the "POC application" configuration; it includes field boundary coordinates (GeoJSON), flight path instructions, the specific radio frequency and protocol for communicating with on-site weather sensors, and a time-limited token to upload completion data back to the platform.
• Mermaid Diagram:

  erDiagram
      FARM_OWNER ||--o{ TASK : Creates
      TASK {
          string FieldID
          datetime StartTime
          datetime EndTime
      }
      TASK ||--|{ TASK_PACKAGE : Generates
      TASK_PACKAGE {
          string DownloadURL
          string AccessToken
          json GeoJSON_Boundaries
      }
      DRONE_OPERATOR ||--|{ TASK_PACKAGE : Downloads
  

---

Axis 4: Integration with Emerging Tech

Derivative 4.1: AI-Predicted Access Provisioning

• Enabling Description: The control device incorporates a predictive AI model trained on organizational data (calendars, personnel location, past incident reports). For a scheduled "multi-agency drill," the AI identifies all invitees from the calendar event. 30 minutes before the event, it automatically sends commands to grant talkgroup access to all participants who are not already subscribers. The AI also monitors the talkgroup for sentiment and keyword analysis; if it detects escalating urgency, it can pre-emptively extend the access duration or suggest inviting other relevant personnel (e.g., a nearby hazmat specialist) based on their location and certifications.
• Mermaid Diagram:

  flowchart LR
      A[Calendar Event: "Drill"] -- "Event Data" --> B(AI Model)
      C[Personnel Database] -- "Location/Skills" --> B
      B -- "Predicts Participants" --> D{Is User Subscriber?}
      D -- "No" --> E[Grant Temp Access]
      E --> F[Send Invite Link]
      D -- "Yes" --> G[Do Nothing]
      H[Live Talkgroup Audio] --> B
      B -- "Detects 'HAZMAT'" --> I[Suggest Inviting Specialist]
  

Derivative 4.2: Blockchain-Based Access Auditing

• Enabling Description: Every action in the system is recorded on a permissioned blockchain (e.g., Hyperledger Fabric) for immutable auditing. When a subscriber invites a non-subscriber, the control device mints a non-fungible token (NFT) representing the temporary access grant. This NFT contains the user's identifier, the talkgroup ID, and the expiration time as metadata. The invitation link allows the non-subscriber to download the POC client and claim the NFT to their client's wallet. The POC client presents this NFT to the control device as a bearer token for authentication. When the timer expires, the smart contract governing the NFT automatically flags it as "expired," preventing further use.
• Mermaid Diagram:

  sequenceDiagram
      participant Admin
      participant ControlDevice
      participant Blockchain
      participant NonSubscriber
  
      Admin->>ControlDevice: Invite user
      ControlDevice->>Blockchain: Deploy AccessGrant Smart Contract (NFT)
      Blockchain-->>ControlDevice: NFT Token ID
      ControlDevice->>NonSubscriber: Send link to claim Token ID
      NonSubscriber->>ControlDevice: Claim Token
      ControlDevice->>Blockchain: Transfer NFT to NonSubscriber's wallet
      NonSubscriber->>ControlDevice: Authenticate with NFT
      Note over ControlDevice,Blockchain: Access granted & logged
  

---

Axis 5: The "Inverse" or Failure Mode

Derivative 5.1: Fail-Safe Access Revocation with Client-Side Timer

• Enabling Description: This derivative prioritizes secure de-provisioning. The configuration file downloaded by the non-subscriber's POC application contains an encrypted "time-to-live" (TTL) value and a public key for the control server. The client application must successfully perform a signed heartbeat check-in with the server at an interval less than the TTL (e.g., every 5 minutes for a 15-minute TTL). If the client cannot reach the server or if the server's response has an invalid signature, the client initiates a "fail-safe" mode: it immediately purges all talkgroup configurations, deletes the cryptographic keys from its keychain, and uninstalls any associated helper tools. This ensures a device does not remain "hot" if the central server goes offline.
• Mermaid Diagram:

  stateDiagram-v2
      state Active {
          [*] --> Heartbeat_OK
          Heartbeat_OK --> Heartbeat_OK: Timer < TTL
          Heartbeat_OK --> Purge_Config: Heartbeat fails
      }
      [*] --> Active: Initial Provisioning
      Purge_Config --> [*]: Access revoked locally
  

Derivative 5.2: Graceful Degradation via Dynamic Codec Switching

• Enabling Description: In a network-constrained environment (detected by the control device via high packet loss or latency metrics), the system enters a "low-functionality" mode. The invitation link sent to new non-subscribers points to a lightweight version of the POC application. For existing clients, the control server sends a signaling message (e.g., a SIP re-INVITE) that commands them to switch to a low-bitrate, high-compression audio codec (e.g., Opus at 8 kbps or Speex). All non-essential features like presence indicators, file sharing, and high-definition voice are disabled server-side, ensuring the core PTT voice functionality remains intact.
• Mermaid Diagram:

  graph TD
      A(Control Device Monitors Network) --> B{Latency > 200ms?};
      B -- Yes --> C[Enter Degraded Mode];
      C --> D[Send Re-INVITE to all clients];
      D --> E[Clients switch to Low-Bitrate Codec];
      C --> F[New invite links point to Lightweight App];
      B -- No --> G[Maintain Normal Operation];
  

---

Combination Prior Art Scenarios with Open-Source Standards

1. Combination with Matrix Protocol: The control device is a Matrix Synapse homeserver. A subscriber with appropriate power levels in a Matrix room uses a custom command /invite-temp @user:server.com 1h to grant access. A bot on the homeserver receives this, generates a temporary guest registration token, and sends an SMS/email to the user with a link. The link opens a web-based Element client (an open-source Matrix client) which uses the token to register a temporary guest account and automatically join the specified room. The account is set to be automatically deactivated by the homeserver after the specified duration (1 hour). This leverages the Matrix specification's open federation and guest access features.

2. Combination with FreeSWITCH and WebRTC: The Push-to-Talk system is implemented as a conference bridge within the open-source FreeSWITCH telephony platform. An administrator uses a web interface to create a temporary access link for a specific conference. The FreeSWITCH server generates a unique URL that embeds a time-limited token. When a non-subscriber clicks the link, their browser is directed to a simple HTML5 page that uses JavaScript to establish a direct WebRTC connection to FreeSWITCH's mod_verto WebSocket endpoint. The token is used for authentication, and the user is placed into the correct audio bridge. No software installation is required, relying entirely on the open standards of WebRTC and WebSockets.

3. Combination with Open Source Trusted Platform Module (TSS): The downloaded POC application for the non-subscriber device leverages the device's Trusted Platform Module (TPM) via an open-source software stack like tpm2-tss. The initial link provides a one-time provisioning package. The client application generates a new cryptographic keypair within the TPM and uses the TPM's attestation feature to send a signed quote back to the control device, proving the key's integrity. The control device then issues a short-lived certificate tied to this TPM-bound key. All subsequent communication must be signed by this key, ensuring that the access credentials cannot be easily cloned or moved to another device. Access revocation involves the control device adding the client's certificate to a Certificate Revocation List (CRL).