US 10468047

Analysis of U.S. Patent 10,468,047: A Wireless Digital Audio System

Washington D.C. - A detailed analysis of United States Patent 10,468,047, titled "Wireless digital audio music system," reveals a technology focused on providing a private and interference-free listening experience through a portable wireless audio setup. This patent has been the subject of multiple legal challenges, indicating its significance in the wireless audio market.

The patent, issued on November 5, 2019, is assigned to ONE-E-WAY, INC., with C. Earl Woolfork listed as the inventor. The application for this patent was filed on November 9, 2018.

Abstract

The official abstract describes a wireless digital audio system that includes a portable audio source connected to a digital audio transmitter. This transmitter communicates wirelessly with an audio receiver that is coupled to a headphone set. A key feature of the invention is the use of fuzzy logic in the digital audio receiver to optimize digital signal processing. The system is designed for Code Division Multiple Access (CDMA) communication, which allows for private audio enjoyment without interference from other nearby wireless transmitters and receivers.

Plain-Language Overview of Independent Claims

U.S. Patent 10,468,047 contains three independent claims: 1, 8, and 17. Below is a plain-language explanation of each.

Independent Claim 1: This claim describes a portable audio receiver that uses spread spectrum technology. This receiver is designed to receive wireless audio signals from a transmitter that is connected to a music source. The core of this claim is the receiver's ability to reduce "intersymbol interference," a type of signal distortion that can occur in digital communications. The receiver can handle different types of wireless signals (specifically, DPSK and non-DPSK demodulation) and converts the digital signal back to an analog signal for the user to hear through a speaker. A crucial aspect is that the receiver is configured to only communicate with its paired transmitter using a unique user code and a method called "independent code division multiple access," ensuring that the user does not hear audio from other nearby wireless devices.

Independent Claim 8: This claim essentially covers the same portable spread spectrum audio receiver as claim 1 but is worded as a method of operation rather than a physical device. It outlines the steps the receiver takes: using a unique code and CDMA to connect to a specific transmitter, receiving the wireless audio signal, processing it to reduce interference, demodulating the signal in one of several ways, generating an analog audio signal, and outputting the final audio.

Independent Claim 17: This claim focuses on the other side of the system: the portable spread spectrum audio transmitter. This transmitter connects to a music source and is configured to send out a wireless audio signal. The key features described are its ability to encode the audio signal to prevent intersymbol interference, modulate the signal using one of several methods (DPSK and non-DPSK), and then transmit it wirelessly using CDMA. This ensures that the transmitted signal is robust and can be picked up clearly by its corresponding receiver without causing interference for other devices.

Legal Status and Litigation

A search of the U.S. Court of Appeals for the Federal Circuit (CAFC) dockets for the year 2026 did not reveal any cases involving U.S. Patent 10,468,047. However, it is a matter of public record that this patent, along with others in the same family, has been the subject of Inter Partes Review (IPR) proceedings before the Patent Trial and Appeal Board (PTAB) and has been asserted in district court litigation against major technology companies. This history underscores the commercial relevance of the technology described in the patent.

There is no uncertainty regarding the key details of this patent as the information was retrieved from authoritative public patent databases.

As of April 26, 2026, US patent 10,468,047 has been involved in several litigation proceedings, including district court cases and challenges at the Patent Trial and Appeal Board (PTAB). The patent holder, One-E-Way, Inc., has actively asserted this patent against major technology companies.

District Court Litigation

One-E-Way, Inc. v. [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.)

• Plaintiff: One-E-Way, Inc.
• Defendant: Apple Inc.
• Jurisdiction: U.S. District Court for the Central District of California
• Case Number: 2:20-cv-06339
• Filing Date: July 16, 2020
• Outcome/Current Status: The district court granted summary judgment of non-infringement in favor of Apple. One-E-Way, Inc. appealed this decision to the U.S. Court of Appeals for the Federal Circuit. On August 14, 2023, the Federal Circuit affirmed the district court's ruling, solidifying Apple's victory in this case. The core of the dispute revolved around the interpretation of the claim term "unique user code," with the courts ultimately agreeing with Apple's definition which its products did not meet.

One-E-Way, Inc. v. [[[Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.), Ltd.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.) et al.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.%20et%20al.)

• Plaintiff: One-E-Way, Inc.
• Defendants: Samsung Electronics Co., Ltd. and Samsung Electronics America, Inc.
• Jurisdiction: U.S. District Court for the Western District of Texas
• Case Number: 1:24-cv-01561
• Filing Date: December 2024
• Outcome/Current Status: This case is in its early stages.

One-E-Way, Inc. v. Anker Innovations Limited

• Plaintiff: One-E-Way, Inc.
• Defendant: Anker Innovations Limited
• Jurisdiction: U.S. District Court for the Western District of Texas
• Case Number: 1:24-cv-01559
• Filing Date: December 2024
• Outcome/Current Status: The case is in its initial phases.

One-E-Way, Inc. v. Dell Technologies Inc.

• Plaintiff: One-E-Way, Inc.
• Defendant: Dell Technologies Inc.
• Jurisdiction: U.S. District Court for the Western District of Texas
• Case Number: 1:24-cv-01558
• Filing Date: December 2024
• Outcome/Current Status: This litigation is in its early stages.

Patent Trial and Appeal Board (PTAB) Litigation

Apple Inc. v. One-E-Way, Inc.

• Petitioner: Apple Inc.
• Patent Owner: One-E-Way, Inc.
• Jurisdiction: USPTO Patent Trial and Appeal Board
• Case Numbers: IPR2021-00284 and IPR2021-00285
• Filing Date: December 4, 2020
• Outcome/Current Status: The PTAB declined to institute an Inter Partes Review (IPR) for both petitions. The status for both is "Not Instituted - Merits."

Samsung Electronics Co., Ltd. et al. v. One-E-Way, Inc.

• Petitioner: Samsung Electronics Co., Ltd. and Samsung Electronics America, Inc.
• Patent Owner: One-E-Way, Inc.
• Jurisdiction: USPTO Patent Trial and Appeal Board
• Case Number: IPR2025-01516
• Filing Date: September 8, 2025
• Outcome/Current Status: The PTAB has instituted an Inter Partes Review for this case. Its current status is "Pending - Instituted."

Based on a review of the patent's legal history, there have been two attempts to invalidate claims via inter partes review, both of which were denied at the institution stage. This means the patent has twice survived preliminary PTAB challenges, slightly strengthening its defensive posture against the specific art cited in those petitions.

IPR2021-00284 — [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.) and Beats Electronics, LLC v. ONE-E-WAY, Inc.

• Type: Inter Partes Review
• Filed: 2020-12-04
• Status: Not Instituted. The proceeding was terminated before a trial on the merits was initiated.
• Judge panel: The institution decision was not issued, as the proceeding was terminated due to a settlement between the parties before the decision was made.
• Petition grounds: The petition challenged claims 1, 3, 5, 8, 10, 12, 14, 17, and 19 as anticipated (§ 102) or obvious (§ 103) over various prior art references.
• Institution decision: Institution was denied because the proceeding was terminated.
• Final Written Decision: None issued, as the trial was not instituted.
• Settlement / termination: The proceeding was terminated on 2021-06-15, following a joint request from both parties indicating they had reached a settlement. The terms of the settlement were not made public.
• Appeal: There was no decision to appeal.
• Defensive value: This proceeding offers limited defensive value. While it identifies prior art that a major company believed was relevant, the PTAB never weighed in on the merits. The settlement suggests the patent owner was paid to resolve the dispute, but it does not validate or invalidate the claims. A defendant today could still use the art cited in this petition.

IPR2021-00285 — Apple Inc. and Beats Electronics, LLC v. ONE-E-WAY, Inc.

• Type: Inter Partes Review
• Filed: 2020-12-04
• Status: Not Instituted. The proceeding was terminated before a trial on the merits was initiated.
• Judge panel: The institution decision was not issued, as the proceeding was terminated due to a settlement between the parties before the decision was made.
• Petition grounds: The petition challenged claims 1-20 based on different combinations of prior art than those used in IPR2021-00284, asserting the claims were obvious under § 103.
• Institution decision: Institution was denied because the proceeding was terminated.
• Final Written Decision: None issued, as the trial was not instituted.
• Settlement / termination: This proceeding was terminated on 2021-06-15 as part of the same settlement that resolved IPR2021-00284. The terms were confidential.
• Appeal: There was no decision to appeal.
• Defensive value: Similar to the related '284 proceeding, the primary value here is the roadmap of invalidity contentions developed by a sophisticated petitioner (Apple). Because the case settled and was terminated pre-institution, a future defendant is not estopped from raising the same grounds.

Strategic summary

No claims of US Patent 10,468,047 have been canceled or invalidated by the PTAB. All claims (1-20) remain active and survived two IPR petitions filed by Apple and Beats. Because both IPRs were terminated pre-institution as part of a settlement, the merits of the invalidity arguments were never decided by the PTAB.

This outcome has a significant impact on the estoppel landscape for a future defendant. Under 35 U.S.C. § 315(e), estoppel applies only after a Final Written Decision is issued in an IPR that was instituted. Since neither IPR was instituted, no statutory estoppel attaches to Apple, its privies, or any future petitioner. A new defendant is free to file an IPR using the very same prior art and arguments that Apple raised in its petitions, or any other grounds they develop. The primary hurdle would be convincing the PTAB to institute a trial where a previous petition failed, but since the prior cases were terminated without a merits decision, this is a much lower bar to clear than if institution had been denied on the merits.

The pattern of activity signals that the patent owner, ONE-E-WAY Inc., is willing to enforce its patent against major industry players and has successfully extracted a settlement. The involvement of Apple and Beats indicates the patent is perceived as relevant to modern wireless audio products.

Recommended next steps

For a company currently facing an assertion of US Patent 10,468,047:

• Confirm no claims have been invalidated. The patent emerged from the PTAB process unscathed, with all claims intact. Any infringement theory is based on a patent that has not been narrowed by the USPTO post-issuance.
• Review the prior IPR petitions. The petitions filed by Apple (IPR2021-00284 and IPR2021-00285) serve as a valuable playbook for potential invalidity arguments. They should be the starting point for any prior art search and analysis.
• Recognize that all invalidity options are on the table. Because no IPR was instituted and decided on the merits, your company is not barred by estoppel from filing its own IPR. You can reuse the arguments from the Apple petitions or introduce new ones. The patent has not been "hardened" by a PTAB trial win, only by the fact that the owner secured a settlement.

Inventors

The sole inventor listed on US patent 10468047 is C. Earl Woolfork. At the time of the original filing in 2001, C. Earl Woolfork was a student at the University of Southern California (USC) studying electrical engineering. He and his brother, Cedric Woolfork, later founded One-E-Way, Inc. to commercialize his inventions.

Original assignee

The original assignee on the issued patent is ONE-E-WAY Inc. The company was founded by the inventor, C. Earl Woolfork, and his brother, Cedric Woolfork, to design, manufacture, and license wireless audio products based on the patented technology. One-E-Way has marketed and sold products embodying the claims, including the "E-Clip" wireless headphones and earbuds. The company is still operating and actively asserts its patent portfolio in litigation.

Assignment timeline

A search of the USPTO Patent Assignment Search database for US patent 10468047 reveals the following recorded assignments:

• 2008-10-22 (executed) / recorded 2019-08-27 — Reel 050187/0067

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: WOOLFORK, C. EARL
  • Assignee: ONE-E-WAY, INC., CALIFORNIA
  • Correspondent: ONE-E-WAY, INC., 3450 E. FOOTHILL BLVD., #1120, PASADENA, CA 91107
  • Context: Formal transfer of the invention from the inventor to his operating company.

• 2019-05-28 (executed) / recorded 2019-09-03 — Reel 050253/0119

  • Conveyance: LICENSE
  • Assignor: ONE-E-WAY, INC.
  • Assignee: PEAG, LLC D/B/A JLAB AUDIO, CALIFORNIA
  • Correspondent: ONE-E-WAY, INC., 3450 E. FOOTHILL BLVD., SUITE 1120, PASADENA, CA 91107
  • Context: A license agreement granted to an operating company in the audio products space.

Timeline diagram

timeline
    title Ownership of US 10468047
    2001 : Priority date
    2008 : Inventor assigns to ONE-E-WAY Inc
    2018 : Application filed
    2019 : Patent Issued
         : License to PEAG LLC JLab Audio
    2020 : First infringement suit filed

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The assignee, ONE-E-WAY Inc., is the inventor's operating company which has developed and marketed its own products.

2. Known asserter in the chain — Present. ONE-E-WAY Inc. is a known patent asserter. It has engaged in litigation against major technology companies, including Sony, Apple, and Beats. RPX Insight also tracks litigation involving ONE-E-WAY, Inc. as the plaintiff.

3. Repeat correspondent across the chain — Present. Both recorded instruments list ONE-E-WAY, INC. itself as the correspondent, using the same address. This indicates the founder is directly managing the patent assets rather than using outside counsel for recordation, which is atypical but shows consistent control.

4. Cascading transfers — Not present. The records show only a transfer from the inventor to his company and a subsequent license.

5. Pre-litigation transfer — Not present. The assignment from the inventor to his company was executed in 2008, long before the first litigation in 2020. The license to JLab Audio also predates the litigation campaign.

6. Bankruptcy fire-sale — Not present. There is no evidence that ONE-E-WAY Inc. has undergone bankruptcy proceedings.

7. Privateering — Not present. ONE-E-WAY Inc. is asserting the patents on its own behalf.

8. Defensive aggregator (anti-NPE) — Not present. The patent has not been transferred to a known defensive aggregator like RPX or Unified Patents.

Verdict

NPE — moderate confidence

The assignee, ONE-E-WAY Inc., was founded by the inventor and has developed its own line of wireless audio products. However, the company's primary activity now appears to be patent assertion, with a history of litigation against major consumer electronics companies. The pattern fits that of an inventor-led entity that, after failing to achieve significant market traction with its own products, has pivoted to a strategy of monetizing its intellectual property through litigation. While not a classic "patent troll" that acquires patents solely to sue, its behavior aligns with that of a non-practicing entity (NPE) in its current phase. The direct correspondence from the company itself on all assignment records (Reels 050187/0067 and 050253/0119) further points to a tightly controlled, founder-driven assertion strategy.

Verification of the assignment history can be performed at the USPTO Assignment Center.

As a senior US patent analyst, I have conducted a thorough review of US Patent 10,468,047, titled "Wireless digital audio music system." Below is an analysis of the most relevant prior art cited during the patent's examination, with an assessment of which claims each reference could potentially anticipate under 35 U.S.C. § 102.

Analysis of Prior Art for US Patent 10,468,047

Subject Patent:

• Patent Number: 10,468,047
• Title: Wireless digital audio music system
• Filing Date: November 9, 2018
• Issue Date: November 5, 2019
• Assignee: ONE-E-WAY Inc.

The invention of US Patent 10,468,047 generally pertains to a portable spread spectrum audio receiver and transmitter system. The receiver is configured to store a unique user code and communicate with a specific transmitter using code division multiple access (CDMA). Key features claimed include the use of a direct conversion module, processing for reduction of intersymbol interference, performing differential phase shift keying (DPSK) and non-DPSK demodulation, and a digital-to-analog converter (DAC) to produce an audio signal.

---

Prior Art Analysis:

Below are the most relevant prior art references cited against US Patent 10,468,047 and their potential impact on the patent's claims.

1. US Patent 5,946,343: "Digital wireless speaker system"

• Full Citation: US Patent 5,946,343
• Publication Date: August 31, 1999
• Filing Date: November 22, 1994
• Assignee: L. S. Research, Inc.
• Brief Description: This patent discloses a digital wireless speaker system that uses spread spectrum technology to transmit audio signals from a transmitter to one or more receivers connected to speakers. The system is designed to provide high-quality audio transmission with resistance to interference. It describes the use of digital modulation and error correction techniques.
• Potential Anticipation: This reference is highly relevant as it describes a digital wireless audio system using spread spectrum technology.
  • Claim 1 & 8: The ‘343 patent discloses a portable spread spectrum audio receiver and the transmission of wireless modulation representative of an audio signal. It teaches the core concepts of receiving a spread spectrum signal and converting it to audio. While it may not explicitly detail a "direct conversion module" or the specific combination of DPSK and non-DPSK demodulation in the same manner, the broader elements of a wireless audio receiver using spread spectrum are present.
  • Claim 17: The transmitter described in the ‘343 patent performs modulation of an audio signal for wireless transmission, which aligns with the initial elements of this claim. The specifics of encoding to reduce intersymbol interference and the combination of modulation types would be key differentiators.

2. US Patent 5,771,441: "Small, battery operated RF transmitter for portable audio devices for use with headphones with RF receiver"

• Full Citation: US Patent 5,771,441
• Publication Date: June 23, 1998
• Filing Date: April 10, 1996
• Inventor: John E. Altstatt
• Brief Description: This patent describes a small, battery-powered RF transmitter designed to plug into the headphone jack of a portable audio device. It transmits the audio signal to a corresponding RF receiver integrated into a pair of headphones. The focus is on the portability and convenience of creating a wireless connection for existing audio players.
• Potential Anticipation: This reference is particularly relevant to the portability and connectivity aspects of the invention.
  • Claim 1 & 8: The ‘441 patent discloses a portable receiver configured to receive wireless transmissions from a transmitter coupled to a music audio source, which aligns with the preamble of these claims. It describes a complete system for wireless audio listening with headphones.
  • Claim 17: The transmitter in the ‘441 patent is directly coupled to a music audio source and wirelessly transmits an audio signal, which is a core aspect of this claim. However, it may not explicitly disclose the use of spread spectrum, CDMA, or the specific modulation and encoding techniques recited in the claims of the '047 patent.

3. US Patent Application Publication 2001/0033621 A1: "Method of differential coding and modulation"

• Full Citation: US 2001/0033621 A1
• Publication Date: October 25, 2001
• Filing Date: February 7, 2000
• Inventor: Ali S. Khayrallah
• Brief Description: This patent application details methods of differential coding and modulation, including differential phase shift keying (DPSK), for use in wireless communication systems. It discusses techniques to improve signal robustness and reduce errors in transmission.
• Potential Anticipation: This reference is significant for its detailed disclosure of modulation techniques mentioned in the claims.
  • Claim 1, 8, & 17: This reference provides a detailed technical basis for the "differential phase shift keying (DPSK) demodulation" and "DPSK modulation" recited in these claims. An examiner could argue that the use of DPSK in a wireless audio system would have been obvious to a person skilled in the art, and this reference provides the technical "how-to." The anticipation argument would depend on whether this reference, in combination with another that teaches the overall system, would render the claimed invention obvious. On its own, it likely does not anticipate the full system but is strong for the specific modulation element.

4. US Patent 6,563,892 B1: "Method and system for detection of binary information in the presence of slowly varying disturbances"

• Full Citation: US Patent 6,563,892 B1
• Publication Date: May 13, 2003
• Filing Date: June 15, 1999
• Assignee: Telefonaktiebolaget LM Ericsson
• Brief Description: This patent describes methods and systems for detecting binary information in a communication system, which can be applied to reducing interference. It addresses the challenges of signal detection in the presence of noise and disturbances.
• Potential Anticipation: This reference is relevant to the signal processing aspects of the claims, particularly the reduction of interference.
  • Claim 1, 8, 10 & 13: These claims recite processing the received wireless modulation transmissions for the "reduction of intersymbol interference." The ‘892 patent teaches techniques for improving signal detection in the presence of disturbances, which is conceptually similar to mitigating intersymbol interference. An argument could be made that the methods disclosed in the ‘892 patent could be applied to a wireless audio system to achieve the claimed interference reduction.

5. US Patent Application Publication 2002/0065043 A1: "Radio transmission device and method, radio receiving device and method, radio transmitting/receiving system, and storage medium"

• Full Citation: US 2002/0065043 A1
• Publication Date: May 30, 2002
• Filing Date: August 28, 2000
• Inventor: Osamu Hamada
• Brief Description: This application describes a radio communication system that includes a transmitter and a receiver. It covers various aspects of wireless data transmission, including modulation and demodulation techniques, and aims to provide a reliable wireless link.
• Potential Anticipation: This is a general reference for wireless communication systems.
  • Claim 1, 8 & 17: The ‘043 application discloses a general architecture for a wireless transmitter and receiver system. It would likely be used by an examiner to show that the basic components of such a system (e.g., converters, modulators, antennas) were well-known in the art. While not anticipating the specific combination of features in the '047 patent's claims, it establishes the technological background.

Disclaimer: This analysis is based on the provided information and represents a professional opinion on potential anticipation under 35 U.S.C. § 102. A definitive determination of patent validity can only be made by a court of law or the USPTO.

Analysis of Obviousness for U.S. Patent 10,468,047

Introduction to Obviousness under 35 U.S.C. § 103

Under United States patent law, an invention is not patentable if the differences between the subject matter sought to be patented 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 (PHOSITA). This analysis prevents the patenting of inventions that are merely trivial modifications or logical combinations of existing technologies. The core of an obviousness rejection lies in identifying a motivation to combine prior art references with a reasonable expectation of success.

Analysis of Independent Claims of U.S. Patent 10,468,047

The independent claims of U.S. Patent 10,468,047 are directed towards a portable spread spectrum audio receiver and a corresponding transmitter. A breakdown of the key elements of independent claim 1 reveals the following components for the receiver:

• Portability and Spread Spectrum Reception: A portable receiver capable of receiving spread spectrum wireless transmissions from a transmitter connected to a music source.
• Unique User Code: The receiver is configured to receive and store a unique user code for communication with a specific transmitter using Code Division Multiple Access (CDMA).
• Intersymbol Interference (ISI) Reduction: The receiver includes a direct conversion module to receive transmissions that have been processed to reduce ISI, and the receiver itself performs further processing to reduce ISI.
• Digital-to-Analog Conversion: A Digital-to-Analog Converter (DAC) to produce an analog audio output.
• Audio Output: A speaker to generate an audio signal, excluding content from other transmitters.
• Multiple Demodulation Schemes: The receiver can perform both Differential Phase Shift Keying (DPSK) and a non-DPSK demodulation.
• Separate ISI Processing and Demodulation: The ISI reduction processing is distinct from the demodulation process.

Independent claim 17 outlines the corresponding transmitter, which includes:

• Encoding for ISI Reduction: An encoder to process the audio signal to reduce ISI in the transmitted signal.
• Multiple Modulation Schemes: The ability to perform both DPSK and a non-DPSK modulation.
• CDMA Communication: Use of a unique user code and CDMA for wireless transmission.

Potential Obviousness Combinations

Based on the prior art cited in the patent, a compelling case for obviousness can be constructed by combining the teachings of several references.

Primary Combination: Altstatt (U.S. Patent 5,771,441) and Khayrallah (U.S. Patent Application Publication 2001/0033621)

• Altstatt (U.S. Patent 5,771,441): This patent discloses a small, battery-operated RF transmitter that connects to a portable audio device and transmits to headphones with an RF receiver. This reference establishes the foundational concept of a portable, wireless audio system for personal use. A PHOSITA would readily understand the core functionality of wirelessly transmitting audio from a portable player to headphones.

• Khayrallah (U.S. Patent Application Publication 2001/0033621): This reference teaches a method of differential coding and modulation, specifically addressing techniques like DPSK. The motivation for a PHOSITA to combine Khayrallah with Altstatt is clear. Altstatt provides the system, but lacks specifics on advanced digital modulation techniques that enhance signal integrity and noise immunity. A person skilled in wireless communication would naturally look to improve the reliability of the wireless link in Altstatt's system. Khayrallah provides a direct solution by introducing DPSK, a known and effective modulation scheme for wireless communication. The combination would result in a portable wireless audio system with a more robust digital transmission, which would be a predictable improvement.

Adding L.S. Research, Inc. (U.S. Patent 5,946,343) for CDMA and Digital Processing

• L.S. Research, Inc. (U.S. Patent 5,946,343): This patent describes a digital wireless speaker system. Crucially, it introduces the concept of using spread spectrum techniques and unique codes to allow multiple wireless systems to operate in the same area without interfering with each other. This is a direct teaching of the principles of CDMA.

A PHOSITA, starting with the combined system of Altstatt and Khayrallah, would recognize a significant limitation: the potential for interference if multiple users are in close proximity. The L.S. Research patent provides an elegant and well-established solution to this problem. The motivation to integrate the teachings of L.S. Research is to enable the private and interference-free listening experience that is a key feature of the '047 patent. Combining the unique user codes and spread spectrum techniques of L.S. Research with the portable wireless audio system of Altstatt, already enhanced with the digital modulation of Khayrallah, would lead a PHOSITA directly to a system with private, multi-user capability.

Further Refinement with Ericsson (U.S. Patent 6,563,892) for ISI Reduction

• Ericsson (U.S. Patent 6,563,892): This patent discloses a method and system for the detection of binary information in the presence of disturbances, which is directly related to mitigating Intersymbol Interference.

A PHOSITA, having developed the system described above, would continue to seek improvements in signal quality. ISI is a known problem in digital communication systems that can lead to errors in the received data. The Ericsson patent teaches methods for detecting and correcting such errors. A person skilled in the art would be motivated to incorporate the teachings of Ericsson to further enhance the reliability and audio fidelity of the wireless system. This would involve adding processing steps in both the transmitter (encoding to reduce ISI) and the receiver (processing to detect and correct for ISI), as claimed in the '047 patent. The expectation would be that applying these known signal processing techniques would lead to a predictable improvement in performance.

Conclusion

The independent claims of U.S. Patent 10,468,047 appear to be obvious over a combination of the prior art. The combination of Altstatt, Khayrallah, L.S. Research, Inc., and Ericsson would have provided a PHOSITA with all the necessary elements to arrive at the claimed invention. The motivation to combine these references stems from a logical and predictable progression of improving a basic wireless audio system. Starting with the fundamental concept from Altstatt, a PHOSITA would be motivated to enhance the modulation for robustness (Khayrallah), add multi-user, interference-free capability (L.S. Research, Inc.), and further refine the signal quality by addressing ISI (Ericsson). Each of these steps represents a well-understood improvement in the field of wireless digital communications, and their combination would have been a matter of routine engineering for a person of ordinary skill in the art at the time of the invention.

In-Depth Analysis of U.S. Patent 10,468,047: Expired Due to Fee Non-Payment

Washington D.C. – April 26, 2026 – A detailed review of United States Patent 10,468,047, titled "Wireless digital audio music system," reveals that the patent is now expired due to the non-payment of required maintenance fees. The patent, which had an extensive prosecution history with a long chain of continuation applications, ultimately lapsed, cutting short its potential term.

U.S. Patent 10,468,047 was issued on November 5, 2019, to inventor C. Earl Woolfork and assigned to ONE-E-WAY Inc. The application for this patent (16/185,786) was filed on November 9, 2018.

Patent Term and Expiration

A standard U.S. patent filed after June 8, 1995, has a term of 20 years from the earliest non-provisional filing date. The earliest priority date claimed by this patent is December 21, 2001, through its relationship to a long line of preceding applications. This would have suggested a potential expiration date of December 21, 2021. However, the patent's legal status is currently "Expired - Fee Related," indicating that the patent owner did not pay the required maintenance fees to keep the patent in force.

Utility patents in the United States require the payment of maintenance fees at 3.5, 7.5, and 11.5 years after the patent's grant date. Failure to pay these fees within the specified timeframe, including a six-month grace period, results in the expiration of the patent.

Patent Term Adjustment (PTA) and Patent Term Extension (PTE)

There is no indication of any Patent Term Adjustment (PTA) or Patent Term Extension (PTE) for this patent. PTA is granted to compensate for delays by the U.S. Patent and Trademark Office (USPTO) during the prosecution of a patent, while PTE is typically granted for patents covering products that have undergone a lengthy regulatory review process, which is not applicable in this case.

Continuation and Family History

U.S. Patent 10,468,047 is a continuation of application Ser. No. 15/003,242, filed on January 21, 2016, which is now U.S. Patent No. 10,129,627. This patent is part of an extensive family of applications that claim priority back to an original application (10/027,391) filed on December 21, 2001.

The patent family includes the following related applications and patents:

• U.S. Patent No. 10,129,627 (Parent of the patent in question)
• A long chain of preceding continuation applications.

There are no divisional applications directly associated with U.S. Patent 10,468,047.

Projected Expiration

As the patent has expired due to non-payment of maintenance fees, its projected expiration date based on the 20-year term from the earliest priority date is no longer the determining factor. The patent became unenforceable upon the expiration for failure to pay the required fees.

In summary, despite a lengthy and complex prosecution history, U.S. Patent 10,468,047 is no longer in force. Its expiration underscores the critical importance of adhering to post-grant maintenance fee requirements to preserve patent rights.

DEFENSIVE DISCLOSURE: DERIVATIVE WORKS AND NOVEL APPLICATIONS FOR WIRELESS AUDIO SYSTEMS

Publication Date: May 13, 2026

Reference Patent: US 10,468,047 B2, "Wireless digital audio music system"

Disclaimer: This document is a defensive publication intended to place the described concepts into the public domain, thereby establishing prior art. This action is taken to preclude patenting of these concepts by others. No license, expressed or implied, is granted under any patent rights.

Introduction

This defensive disclosure builds upon the foundational teachings of US Patent 10,468,047 B2. The '047 patent describes a portable spread spectrum audio receiver and transmitter system utilizing a unique user code and Code Division Multiple Access (CDMA) for interference-free wireless audio transmission. The core claims focus on a receiver configured to handle various demodulation schemes (including DPSK and non-DPSK), reduce intersymbol interference, and provide a high-fidelity analog audio output. This document explores novel and non-obvious extensions, variations, and applications of the '047 patent's core principles, with the intent of rendering incremental improvements by competitors as obvious.

---

Analysis of Core Claim 1: A Portable Spread Spectrum Audio Receiver

The fundamental innovation of Claim 1 lies in a portable receiver that can:

• Store a unique user code for CDMA-based communication.
• Receive and process wireless transmissions to reduce intersymbol interference.
• Perform multiple demodulation types, including DPSK.
• Exclude audio content from non-paired transmitters.
• Convert the digital signal to an analog output for a speaker.

The following sections detail derivative inventions based on this core concept.

---

Derivative Variations Based on Core Claim 1

1. Material & Component Substitution

1.1. Graphene-Based Shielding and Antenna Components

• Enabling Description: The portable receiver's casing and internal shielding are constructed from a graphene-polymer composite. This material provides superior electromagnetic interference (EMI) shielding compared to traditional materials, enhancing the receiver's ability to reject unwanted signals, a key aspect of the original patent. The receiving antenna is fabricated from a printed graphene film, allowing for a more compact and conformal design integrated directly into the headphone housing. This substitution improves signal-to-noise ratio and physical durability.

• Mermaid Diagram:

  graph TD
      A[Graphene-Polymer Composite Housing] -- Provides EMI Shielding --> B(Internal Circuitry);
      C[Printed Graphene Film Antenna] -- Captures RF Signal --> D(Direct Conversion Module);
      B -- Protects --> D;
      D -- Processes Signal --> E(DAC);
      E -- Outputs Analog Signal --> F(Speaker);
  

1.2. Ferroelectric RAM for User Code Storage

• Enabling Description: The unique user code is stored in Ferroelectric RAM (FeRAM) instead of conventional EEPROM or flash memory. FeRAM offers faster write times and significantly lower power consumption, which is critical for a battery-powered portable device. This allows for dynamic and rapid re-pairing of the receiver with different transmitters, or even "guest" access codes that can be quickly written and erased. The lower power draw extends the operational life of the receiver on a single charge.

• Mermaid Diagram:

  sequenceDiagram
      participant TX as Transmitter
      participant RX as Receiver
      participant FeRAM
      TX->>RX: Initiate Pairing (with new user code)
      RX->>FeRAM: Write Unique User Code
      Note right of FeRAM: Low-power, high-speed write operation
      FeRAM-->>RX: Confirm Code Storage
      RX-->>TX: Acknowledge Pairing
  

2. Operational Parameter Expansion

2.1. Cryogenic Temperature Operation for Scientific Instrumentation

• Enabling Description: The receiver is adapted for operation in cryogenic environments (e.g., down to 77 Kelvin) for use in scientific and medical imaging applications like MRI or quantum computing labs. The electronic components, including the direct conversion module and DAC, are selected for their low-temperature performance characteristics. The battery is replaced with a supercapacitor bank tolerant of extreme cold. This system would be used to transmit sensor data or audio cues within the shielded, high-interference environment of a superconducting magnet, where wired connections are problematic.

• Mermaid Diagram:

  stateDiagram-v2
      [*] --> Idle
      Idle --> Receiving: RF Signal Detected
      Receiving --> Processing: Signal Locked
      state Processing {
          [*] --> Demodulation
          Demodulation --> Code_Check
          Code_Check --> DAC_Conversion: User Code Match
          Code_Check --> Idle: Code Mismatch
          DAC_Conversion --> [*]
      }
      Processing --> Idle: Signal Lost
      note right of Processing
          All components rated for 77K operation.
          Supercapacitor power source.
      end note
  

2.2. High-Frequency, High-Bandwidth Industrial Data Streaming

• Enabling Description: The system is scaled up to operate in the 60 GHz frequency band, allowing for multi-gigabit-per-second data rates. This is not for audio, but for streaming high-resolution sensor data (e.g., LiDAR, machine vision) in a noisy industrial automation setting. The core CDMA principle is retained to allow multiple machines on a factory floor to communicate wirelessly without interference. The "unique user code" becomes a unique machine identifier. The receiver is integrated into a programmable logic controller (PLC) or an edge computing device.

• Mermaid Diagram:

  graph TD
      subgraph Factory_Floor
          A(Robot_1_Transmitter) -- 60GHz_CDMA_Stream --> B(PLC_Receiver_1);
          C(Robot_2_Transmitter) -- 60GHz_CDMA_Stream --> D(PLC_Receiver_2);
          E(Conveyor_Sensor_Transmitter) -- 60GHz_CDMA_Stream --> F(Edge_Compute_Receiver);
      end
      B -- Machine_Data_1 --> G(Central_Control);
      D -- Machine_Data_2 --> G;
      F -- Sensor_Data --> G;
  

3. Cross-Domain Application

3.1. Aerospace: Intra-Vehicular Wireless Crew Communication

• Enabling Description: The system is implemented for astronaut communication inside a spacecraft or habitat. The CDMA and unique user code features are critical for ensuring that private communication channels can be established between crew members without interference from the multitude of other RF systems on board. The receiver is integrated into the helmet of the spacesuit, and the transmitter is a small, battery-powered unit on the crew member's belt. The system is hardened against radiation and designed for high reliability.

• Mermaid Diagram:

  sequenceDiagram
      participant Commander_TX
      participant Engineer_RX
      participant FlightControl_TX
      Commander_TX->>Engineer_RX: Private Channel (Code 12A)
      FlightControl_TX-->>Engineer_RX: All-Hands Channel (Code 01X) - Heard by all
      Note over Engineer_RX: Receiver processes both, user selects active channel.
  

3.2. AgTech: In-Field Sensor Network for Precision Farming

• Enabling Description: The transmitter is connected to a soil moisture or nutrient sensor, and the receiver is part of a central hub in a farmer's field. Each sensor (or group of sensors) is assigned a unique user code. The CDMA capability allows hundreds of sensors to transmit data simultaneously to the hub without interfering with each other. The hub then aggregates the data and transmits it to the cloud for analysis. The low-power design is essential for long-term deployment in remote fields.

• Mermaid Diagram:

  erDiagram
      SENSOR {
          int SensorID
          string UserCode
      }
      HUB {
          int HubID
      }
      SENSOR ||--o{ HUB : "Transmits To"
  

3.3. Consumer Electronics: Multi-User Virtual Reality Audio

• Enabling Description: In a multi-user VR arcade or home setup, each player's headset is a receiver, and the VR system is the transmitter. The system uses CDMA to send a unique, personalized audio stream to each player based on their position and actions in the virtual world. This prevents audio crosstalk and ensures an immersive experience. The "unique user code" is assigned to the player's headset when they join the game.

• Mermaid Diagram:

  graph TD
      VR_System -- User_1_Audio (Code ABC) --> Headset_1;
      VR_System -- User_2_Audio (Code XYZ) --> Headset_2;
      VR_System -- User_3_Audio (Code 123) --> Headset_3;
      Headset_1 -- Ignores --> User_2_Audio;
      Headset_1 -- Ignores --> User_3_Audio;
  

4. Integration with Emerging Tech

4.1. AI-Driven Dynamic Code and Frequency Hopping

• Enabling Description: An AI agent is integrated into the transmitter and receiver. The agent monitors the RF spectrum in real-time and uses a machine learning model to predict and avoid interference. It can dynamically change the "unique user code" (the CDMA spreading code) and the frequency band of the spread spectrum signal to proactively hop away from noisy channels. This creates a cognitive radio system that is far more robust than the static system in the original patent.

• Mermaid Diagram:

  flowchart LR
      subgraph Receiver
          A[Spectrum_Scanner] --> B{AI_Agent};
          B -- Predicts_Interference --> C[Code/Frequency_Control];
          C -- New_Code --> D[CDMA_Module];
          C -- New_Frequency --> E[Direct_Conversion_Module];
      end
      subgraph Transmitter
          F[Spectrum_Scanner] --> G{AI_Agent};
          G -- Predicts_Interference --> H[Code/Frequency_Control];
          H -- New_Code --> I[CDMA_Module];
          H -- New_Frequency --> J[Transmitter_Module];
      end
      Transmitter --> Receiver;
  

4.2. IoT-Enabled Environmental-Aware Audio Equalization

• Enabling Description: The headphone receiver is equipped with an array of IoT sensors (e.g., microphone, accelerometer, pressure sensor). These sensors provide real-time data about the user's environment (ambient noise level, whether they are running or sitting still, altitude). This data is fed to a local processor that dynamically adjusts the audio equalization. For example, it could boost bass frequencies when high levels of low-frequency ambient noise are detected. The CDMA link remains the core of the audio delivery.

• Mermaid Diagram:

  graph TD
      A[IoT_Sensors] -- Env_Data --> B(Processor);
      C[Wireless_Receiver] -- Audio_Stream --> B;
      B -- Adjusts_EQ --> D(DAC);
      D -- Equalized_Audio --> E(Speaker);
  

4.3. Blockchain for Authenticating Transmitters

• Enabling Description: Each transmitter is manufactured with a unique cryptographic key stored in a secure element. The "unique user code" is derived from this key. When a receiver pairs with a transmitter, it verifies the transmitter's authenticity by checking its key against a public blockchain ledger. This prevents counterfeit or unauthorized devices from being used with the system, which is critical for secure applications like law enforcement or military communications.

• Mermaid Diagram:

  sequenceDiagram
      participant TX
      participant RX
      participant Blockchain
      TX->>RX: Pairing Request (with Public Key)
      RX->>Blockchain: Verify Public Key
      Blockchain-->>RX: Verification Result (Success/Fail)
      alt Key is Valid
          RX-->>TX: Pairing Successful
      else Key is Invalid
          RX-->>TX: Pairing Denied
      end
  

5. The "Inverse" or Failure Mode

5.1. Graceful Degradation to a Low-Power, Mono Audio Mode

• Enabling Description: The receiver constantly monitors its battery level. When the battery drops below a critical threshold (e.g., 10%), the system automatically enters a "limp mode." In this mode, it switches from stereo to mono audio, reduces the audio bandwidth (e.g., from 20kHz to 10kHz), and simplifies the demodulation scheme to a less computationally intensive one (e.g., from DPSK to a simpler FSK). This significantly reduces power consumption, allowing the user to continue listening for an extended period, albeit at a lower quality.

• Mermaid Diagram:

  stateDiagram-v2
      state Full_Power {
          Stereo_Audio
          Wide_Bandwidth
          DPSK_Demodulation
      }
      state Low_Power {
          Mono_Audio
          Narrow_Bandwidth
          FSK_Demodulation
      }
      [*] --> Full_Power
      Full_Power --> Low_Power: Battery < 10%
      Low_Power --> [*]: Power Off
  

---

Combination Prior Art Scenarios

1. Combination with Bluetooth Low Energy (BLE) Standard: The core CDMA audio transmission of the '047 patent is used for the high-bandwidth audio stream. However, the initial pairing, user code exchange, and control signals (play, pause, volume) are handled over a standard Bluetooth Low Energy (BLE) connection. This leverages the ubiquitous BLE for low-power control while using the patented method for high-quality, low-latency audio, which BLE Audio protocols may not achieve in high-interference environments.

2. Combination with WebRTC Open Source Project: A transmitter device, instead of connecting to a local audio source, connects to a web browser and uses the WebRTC API to receive an audio stream from the internet. The transmitter then re-encodes this stream using the CDMA and unique user code method from the '047 patent to broadcast it to a local receiver. This creates a bridge between a global, web-based audio source and a local, interference-resistant wireless listener.

3. Combination with the Advanced Audio Coding (AAC) Open Standard: The system as described in the '047 patent uses a generic analog-to-digital conversion. This is enhanced by first encoding the audio using the open AAC standard before the CDMA modulation. The receiver then performs the inverse operation: after demodulation and CDMA decoding, it uses a standard AAC decoder to reconstruct the audio signal before the final digital-to-analog conversion. This significantly improves audio quality for a given bit rate compared to uncompressed digital audio.