Invalidity dossier

US 7154961

Constellation rearrangement for ARQ transmit diversity schemes

Current assignee: Althearidge LLC

Added 4/27/2026, 4:52:27 PM

IndustryWireless Technologies
At a glanceNo PTAB challenges2 lawsuits on fileasserted by Althearidge LLCWireless Technologies

Active provider: Google · gemini-2.5-flash

Patent summary

Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.

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Analysis of U.S. Patent No. 7,154,961

Date of Analysis: April 28, 2026

This report provides a summary of United States Patent No. 7,154,961, including its bibliographic details and a plain-language explanation of its independent claims. Information is based on the patent's official text.

Bibliographic Information

  • Title: Constellation rearrangement for ARQ transmit diversity schemes
  • Assignee: The current assignee of record is SWIRLATE IP LLC. The original assignee was Matsushita Electric Industrial Co., Ltd.
  • Inventors: Christian Wengerter, Alexander Golitschek Edler Von Elbwart, Eiko Seidel
  • Filing Date: October 18, 2002
  • Issue Date: December 26, 2006
  • Abstract: An ARQ (re-) transmission method of transmitting data in a wireless communication system wherein data packets are transmitted from a transmitter to a receiver, using a first transmission and a second transmission based on a repeat request. The method comprises the steps of modulating data at the transmitter using a first signal constellation pattern to obtain a first data symbol. The first data symbol is transmitted as the first transmission to the receiver using a first diversity branch. Further, the data is modulated at the transmitter using a second signal constellation pattern to obtain a second data symbol. Then, the second data symbol is transmitted as the second transmission to the receive over a second diversity branch. Finally, the received first and second data symbol data symbol are diversity combined at the receiver. The invention further relates to a transmitter and a receiver embodied to carry out the method of the invention.

Litigation Status

As of today's date, this patent has been the subject of numerous litigation proceedings. It has been asserted in various U.S. District Courts, including cases in Texas, Delaware, and Washington, by the current assignee, SWIRLATE IP LLC. No active cases for 2026 in the Court of Appeals for the Federal Circuit (CAFC) were immediately identified in the preliminary search.

Plain-Language Summary of Independent Claims

This patent contains two independent claims: Claim 1 (and its various dependent claims which add specificity) and Claim 11.

Independent Claim 1 (and related claims 2-10): A Method for Reliable Data Retransmission

Independent claim 1 describes a method for re-transmitting data in a wireless system when the first attempt fails (a process known as Automatic Repeat reQuest or ARQ). The core idea is to improve the reliability of the retransmission by using different modulation schemes for the original transmission and the subsequent retransmission, which are sent over different "diversity branches" (e.g., different antennas or frequencies).

In simple terms, the process is as follows:

  1. A data packet is modulated using a first "modulation scheme" (like 16-QAM) to create data symbols.
  2. These symbols are sent to a receiver over a first communication path (a "diversity branch").
  3. If the receiver requests a retransmission, the same data packet is modulated again, but this time using a second, different modulation scheme.
  4. These new symbols are sent over a second communication path.
  5. The receiver, knowing which modulation scheme was used for each transmission, demodulates both sets of symbols.
  6. Finally, it combines the information from both transmissions to reconstruct the original data with a higher chance of success.

Dependent claims add further specifics:

  • Claim 1 itself specifies that the modulation is 16-QAM and that a specific number of different modulation schemes are used.
  • Claim 2 focuses on the outcome: the different modulation schemes are chosen specifically to reduce differences in the "reliability" of the bits after they are combined, effectively averaging out potential errors.
  • Claims 3 & 4 specify whether the same data (a "single redundancy version") or slightly different data ("multiple redundancy versions") is sent in the transmissions.
  • Claim 5 explains how to create the different modulation schemes: either by "interleaving" (shuffling the order of the bits within a symbol) or "inverting" (flipping the bit values).
  • Claims 7-10 detail more complex scenarios involving more than two diversity branches and transmissions, and prioritizing certain types of data bits ("systematic bits") to have higher reliability.

Independent Claim 11: A Transmitter for Implementing the Method

This claim describes the physical transmitter device built to perform the method outlined above. The transmitter must include:

  1. An interleaver or inverter: A component that can change the bit patterns to create the different modulation schemes.
  2. A mapping unit (modulator): This part takes the data packets and, using the different modulation schemes, converts them into the data symbols for transmission.
  3. A transmission unit: This component sends the first set of symbols over a first diversity branch and the second set of symbols over a second diversity branch.

Generated 4/28/2026, 2:40:06 AM

Cases on file (2)

Group view →

Specific litigation cases in our database that name US patent 7154961. The free-form analysis below may also discuss cases beyond this list.

  • Althearidge LLC v. Cipherlab Co Ltdfiled Apr 17, 2026
    2:26-cv-00308Texas Eastern District CourtOpen

    Defendants: Cipherlab Co Ltd

    Other patents asserted: 7567622

    The accused technology is a method for improving the reliability of wireless communications by changing how data is encoded when it has to be re-transmitted due to an error.

  • Althearidge LLC v. Viasat Incfiled Apr 17, 2026
    7:26-cv-00154Texas Western District CourtJudge David Countsterminated Apr 21, 2026Closed

    Defendants: Viasat Inc

    Other patents asserted: 7567622

    The infringement involves a method of re-transmitting wireless data that alters the signal's structure to correct errors and improve the reliability of the connection.

Litigation summary

Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.

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Based on the patent documentation and associated litigation records, U.S. Patent No. 7,154,961 has been the subject of extensive litigation, primarily initiated by the current assignee, SWIRLATE IP LLC. The following is a list of known court cases involving this patent.

Litigation History of US Patent 7,154,961

Below are cases filed in various U.S. District Courts where SWIRLATE IP LLC was the plaintiff. The information is sourced from the litigation data linked in the patent's public record.

Cases Filed in Texas

Cases Filed in Delaware

Cases Filed in Washington

Numerous other cases have been filed in various jurisdictions, including Illinois, California, and Colorado, against a wide range of technology and automotive companies. The pattern of litigation suggests a broad assertion campaign by the patent owner in the years leading up to the patent's expiration in late 2022. The current status or final outcome for most of these cases is not detailed in the publicly aggregated data.

Generated 4/28/2026, 2:55:07 AM

Proceedings on file (0)

All PTAB activity →

AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.

Current assignee: Althearidge LLC

No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.

PTAB challenges

AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.

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Proceedings overview

The USPTO Open Data Portal does not list any AIA trial proceedings for US patent 7154961 as of the most recent ingest. Therefore, there are no active, invalidated, sustained, settled, or institution-denied PTAB proceedings on file. This indicates that the patent's claims have not been challenged via IPR, PGR, or CBM trials at the PTAB.

Strategic summary

As of today's date, the claims of US 7154961 have not been tested or challenged through any AIA trial proceedings at the Patent Trial and Appeal Board (PTAB). This means all claims (Claims 1-11) of the patent remain untested by these particular post-grant review mechanisms. There is no estoppel landscape from PTAB decisions to consider, as no petitions have been filed or instituted.

The absence of PTAB activity is a notable signal. Given the patent's expiration in October 2022 and the extensive litigation history (as noted in the Patent Summary and Litigation Summary), it is unusual for a frequently asserted patent to have no record of AIA trial proceedings, especially IPRs, which are common defensive tools against asserted patents. This could indicate several possibilities, such as: the patent owner consistently settling cases before an IPR could be instituted, defendants choosing other invalidity avenues, or the patent's claims being considered less susceptible to IPR challenges based on their specific scope and the available prior art.

Recommended next steps

Since there are no PTAB proceedings on file for US 7154961, there are no institution decisions, final written decisions, or appeal statuses to track from the PTAB. If a defendant is currently being asserted against, the absence of PTAB challenges means that all prior-art grounds remain potentially available for a new IPR petition, subject to the statutory deadlines for filing such petitions.

Given the patent's expiration, any new IPR would primarily serve to potentially invalidate claims for the purpose of challenging past damages, rather than preventing future infringement. However, the lack of PTAB hardening also means that if a strong prior art argument exists, a new IPR could be an effective strategy to invalidate the claims.

Generated 5/30/2026, 12:47:36 AM

Ownership chain (7)

Asserters network →

Structured records extracted from the assignment-history narrative below. Each entity links to its full ownership-network profile.

  1. 2004-09-15 · recorded 2004-12-06 · reel 016820/0331 · ASSIGNMENT OF ASSIGNORS INTEREST

    WENGERTER, CHRISTIAN; GOLITSCHEK EDLER VON ELBWART, ALEXANDER; SEIDEL, EIKOMATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.

    internal reorg

  2. 2008-10-01 · recorded 2008-11-20 · reel 021930/0876 · CHANGE OF NAME

    MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.PANASONIC CORPORATION

    change of name only

  3. 2014-05-27 · reel 033033/0163 · ASSIGNMENT OF ASSIGNORS INTEREST

    PANASONIC CORPORATIONPANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA

    internal reorg

  4. 2015-12-02 · recorded 2016-01-10 · reel 037471/0227 · ASSIGNMENT OF ASSIGNORS INTEREST

    PANASONIC CORPORATION; PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA; PANASONIC SYSTEM NETWORKS CORPORATIONGRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST I

    defensive aggregation

  5. 2015-12-02 · recorded 2018-09-05 · reel 047015/0263 · CORRECTIVE ASSIGNMENT

    PANASONIC SYSTEM NETWORKS CO., LTD.; PANASONIC CORPORATION; PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICAGRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST I

    correction

  6. 2017-02-01 · recorded 2017-03-02 · reel 041443/0083 · ASSIGNMENT OF ASSIGNORS INTEREST

    GRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST IINTERTECHNOLOGY GLOBAL LLC

    transfer-to-asserter

  7. 2020-04-22 · recorded 2020-04-27 · reel 052506/0513 · ASSIGNMENT OF ASSIGNORS INTEREST

    INTERTECHNOLOGY GLOBAL LLCSWIRLATE IP LLC

    transfer-to-asserter

Assignment history

Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.

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Inventors

  • Christian Wengerter: Employee of Matsushita Electric Industrial Co., Ltd. at the time of filing.
  • Alexander Golitschek Edler Von Elbwart: Employee of Matsushita Electric Industrial Co., Ltd. at the time of filing.
  • Eiko Seidel: Employee of Matsushita Electric Industrial Co., Ltd. at the time of filing.

All inventors were likely employees of the original assignee, Matsushita Electric Industrial Co., Ltd., at the time of the patent application filing.

Original assignee

The entity named on the issued patent (US7154961B2) was Matsushita Electric Industrial Co., Ltd..
This company was a major global manufacturer of electronics, renowned for products under the Panasonic brand. Its primary line of business involved consumer electronics, industrial equipment, and housing. Matsushita Electric Industrial Co., Ltd. shipped a wide range of products, including wireless communication devices, which would embody the claims of this patent. The company subsequently changed its name to Panasonic Corporation in 2008. Panasonic Corporation is currently an operating company.

Assignment timeline

  • 2004-09-15 (executed) / recorded 2004-12-06 — Reel 016820/0331

    • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
    • Assignor: WENGERTER, CHRISTIAN; GOLITSCHEK EDLER VON ELBWART, ALEXANDER; SEIDEL, EIKO
    • Assignee: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    • Correspondent: Not determinable from the provided data.
    • Context: Transfer from individual inventors to their corporate employer.

  • 2008-10-01 (executed) / recorded 2008-11-20 — Reel 021930/0876

    • Conveyance: CHANGE OF NAME
    • Assignor: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    • Assignee: PANASONIC CORPORATION
    • Correspondent: Not determinable from the provided data.
    • Context: Corporate name change from Matsushita Electric Industrial Co., Ltd. to Panasonic Corporation.

  • 2014-05-27 (executed) / recorded 2014-05-27 — Reel 033033/0163

    • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
    • Assignor: PANASONIC CORPORATION
    • Assignee: PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA
    • Correspondent: Not determinable from the provided data.
    • Context: Internal corporate reorganization for intellectual property management.

  • 2015-12-02/04 (executed) / recorded 2016-01-10 — Reel 037471/0227

    • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
    • Assignor: PANASONIC CORPORATION; PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA; PANASONIC SYSTEM NETWORKS CORPORATION
    • Assignee: GRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST I
    • Correspondent: Not determinable from the provided data.
    • Context: Portfolio sale from Panasonic entities to a specific series of Allied Security Trust, likely for monetization or defensive aggregation.

  • 2017-02-01 (executed) / recorded 2017-03-02 — Reel 041443/0083

    • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
    • Assignor: GRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST I
    • Assignee: INTERTECHNOLOGY GLOBAL LLC
    • Correspondent: Not determinable from the provided data.
    • Context: Transfer from a potential defensive aggregator vehicle to a new, likely licensing-focused entity.

  • 2015-12-02/04 (executed) / recorded 2018-09-05 — Reel 047015/0263

    • Conveyance: CORRECTIVE ASSIGNMENT
    • Assignor: PANASONIC SYSTEM NETWORKS CO., LTD.; PANASONIC CORPORATION; PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA
    • Assignee: GRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST I
    • Correspondent: Not determinable from the provided data.
    • Context: Corrective assignment confirming the previous transfer to Grand Mesa.

  • 2020-04-22 (executed) / recorded 2020-04-27 — Reel 052506/0513

    • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
    • Assignor: INTERTECHNOLOGY GLOBAL LLC
    • Assignee: SWIRLATE IP LLC
    • Correspondent: Not determinable from the provided data.
    • Context: Transfer between shell entities, leading to the current litigious owner.

Timeline diagram

timeline
    title Ownership of US 7154961
    2004 : Assigned to Matsushita Electric
    2008 : Name change to Panasonic Corp
    2014 : Assigned to Panasonic IP Corp Amer
    2015 : Assigned to Grand Mesa AST I
    2017 : Assigned to Intertechnology Global LLC
    2018 : Corrective assignmt to Grand Mesa AST I
    2020 : Assigned to Swirlate IP LLC

NPE / troll-pattern signals

  1. Shell-entity transfer — PRESENT
    • INTERTECHNOLOGY GLOBAL LLC, TEXAS (assignee on 2017-03-02, Reel 041443/0083; assignor on 2020-04-27, Reel 052506/0513) and SWIRLATE IP LLC, TEXAS (assignee on 2020-04-27, Reel 052506/0513) both have names indicative of licensing entities and are registered in Texas, a common jurisdiction for NPEs. Swirlate IP LLC is confirmed as a frequent plaintiff in the provided litigation summary.
  2. Known asserter in the chain — PRESENT
    • SWIRLATE IP LLC (current assignee, 2020-04-27, Reel 052506/0513) is explicitly identified as the plaintiff in numerous infringement lawsuits related to this patent, as detailed in the patent's litigation summary.
  3. Repeat correspondent across the chain — NOT PRESENT
    • Correspondent information is not explicitly provided in the "Legal Events" section of the Google Patents record, thus preventing assessment of recurrence.
  4. Cascading transfers — NOT PRESENT
    • While there are multiple transfers, the intervals between subsequent assignments (e.g., ~13 months from Grand Mesa to Intertechnology Global, ~3 years from Intertechnology Global to Swirlate IP) do not meet the "multiple consecutive assignments ... in <24 months" criterion.
  5. Pre-litigation transfer — PRESENT
    • The patent was assigned to SWIRLATE IP LLC on 2020-04-27 (Reel 052506/0513). The first recorded litigation case with Swirlate IP LLC as plaintiff, Swirlate IP LLC v. TCL MOKA Manufacturing, S. de R.L. de C.V. et al, was filed on 2020-11-23. This places the first lawsuit approximately 7 months after the assignment, strongly indicating the transfer was in preparation for assertion.
  6. Bankruptcy fire-sale — NOT PRESENT
    • The original assignee and its direct corporate successors (Matsushita/Panasonic) are large, operating companies and there is no indication of bankruptcy proceedings related to the patent transfer.
  7. Privateering — UNCLEAR
    • While the initial transfer from Panasonic to Grand Mesa (an AST-related entity) could potentially have privateering elements as part of a broader monetization strategy, the subsequent transfers to Intertechnology Global LLC and Swirlate IP LLC, followed by aggressive assertion, complicate this interpretation. There's no explicit evidence in the provided text to confirm a privateering arrangement where Panasonic is benefiting from Swirlate's assertions.
  8. Defensive aggregator (anti-NPE) — INVERSE SIGNAL
    • GRAND MESA, SERIES 57 OF THE ALLIED SECURITY TRUST I (assignee on 2016-01-10, Reel 037471/0227) is related to Allied Security Trust, a known defensive aggregator. However, the patent was subsequently transferred away from this entity to known asserters (Intertechnology Global LLC and Swirlate IP LLC), rather than terminating there. This suggests that for this specific patent, the defensive purpose (if any) did not hold, and it moved into an assertion pathway.

Verdict

NPE — high confidence

The assignment chain clearly demonstrates a pattern consistent with patent assertion entities. Key signals include the transfer to shell entities (Intertechnology Global LLC and Swirlate IP LLC) which bear typical NPE naming conventions and registered addresses in Texas. Most critically, Swirlate IP LLC, the current owner (Reel 052506/0513, recorded 2020-04-27), is extensively engaged in litigation asserting this patent, with the first lawsuit filed approximately 7 months after acquisition, indicating a pre-litigation transfer for assertion purposes. While an AST-related entity was briefly in the chain, the patent's ultimate trajectory was towards aggressive assertion.

USPTO Assignment Center Search for US7154961

Generated 5/30/2026, 12:48:02 AM

Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

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Analysis of Prior Art for U.S. Patent No. 7,154,961

The following analysis details the most relevant prior art references cited during the prosecution of U.S. Patent No. 7,154,961 ("the '961 patent"). The analysis focuses on the potential for these references to anticipate the independent claims of the '961 patent under 35 U.S.C. § 102, based on their disclosures relative to the '961 patent's priority date of October 18, 2002.

Key Prior Art References and Potential Anticipation

The core invention of the '961 patent is the use of different modulation schemes (constellation rearrangements) for an initial transmission and subsequent ARQ retransmissions, where these transmissions are sent over different diversity branches to improve reliability at the receiver.

1. WO2002067491A1 ("'491 application")

  • Full Citation: WO2002067491A1, "Hybrid arq method with single constellation rearrangement", Matsushita Electric Industrial Co., Ltd.
  • Publication Date: August 29, 2002 (Prior art to the '961 patent).
  • Description: This international application, from the same original assignee as the '961 patent, discloses a method for Hybrid Automatic Repeat Request (HARQ) where the signal constellation mapping is changed for retransmissions. The stated goal is to average the reliability of the bits mapped to a modulation symbol. For example, a first transmission uses a standard 16-QAM mapping, and if a retransmission is requested, a different 16-QAM mapping is used for the subsequent transmission. This change in mapping helps to ensure that bits that were in low-reliability positions in the first transmission are moved to high-reliability positions in the retransmission, improving the overall decoding performance after the receiver combines the two attempts.
  • Potential Anticipation of Claim(s): High potential to anticipate the core method, but may lack a key element.
    • The '491 application clearly discloses the central concept of using a first modulation scheme for a first transmission and a second, different modulation scheme for an ARQ retransmission to improve bit reliability. This appears to anticipate the majority of the steps in Claim 1 and the dependent claims that focus on averaging bit reliabilities (like Claim 2).
    • However, the '961 patent claims specify that the first and second transmissions are performed over a first diversity branch and a second diversity branch, respectively. If the '491 application only describes constellation rearrangement for retransmissions over a single channel or does not explicitly teach sending the differently-modulated signals over distinct diversity branches, it would not fully anticipate the claimed combination. The invention of the '961 patent can be seen as the specific application of the '491 method in a transmit diversity context.

2. EP0735701A2 ("'701 patent")

  • Full Citation: EP0735701A2, "Switched antenna diversity transmission method and system using ARQ techniques", AT&T IPM Corp.
  • Publication Date: October 2, 1996 (Prior art to the '961 patent).
  • Description: The '701 patent describes a system that combines switched antenna diversity with an ARQ protocol. In this system, if a data packet transmitted from a first antenna is not received correctly, the receiver sends a retransmission request. The transmitter then re-sends the packet from a different antenna. This process leverages spatial diversity to overcome localized fading or interference that may have affected the first transmission path.
  • Potential Anticipation of Claim(s): Partial anticipation; likely does not anticipate the key inventive step.
    • This reference clearly teaches using ARQ in combination with transmit diversity, specifically sending an initial transmission on a first diversity branch (antenna 1) and a retransmission on a second diversity branch (antenna 2). This anticipates the "diversity branch" and "ARQ re-transmission" elements of Claim 1 and Claim 11.
    • However, the '701 patent does not appear to teach or suggest using different modulation schemes or constellation rearrangements for the initial transmission and the retransmission. It focuses on changing the physical transmission path (the antenna), not the signal's modulation characteristics. Therefore, it would not anticipate the complete combination of elements claimed in the '961 patent.

3. US 6,769,085 B2 ("'085 patent")

  • Full Citation: US 6,769,085 B2, "Method for modifying a bit sequence in an ARQ restransmission, receiver and transmitter therefor", Matsushita Electric Industrial Co., Ltd.
  • Filing Date: November 16, 2001 (Prior art to the '961 patent).
  • Description: This patent, also from Matsushita, discloses a method for modifying a bit sequence during an ARQ retransmission. The modification is achieved by inverting or reordering (interleaving) the bits of the data packet before it is modulated and re-sent. This modification effectively changes the mapping of bits to modulation symbols between the first and second transmissions. The transmitter described includes components for performing this bit modification.
  • Potential Anticipation of Claim(s): High potential to anticipate claims related to implementation.
    • This reference directly teaches the methods described in Claim 5 (obtaining different modulation schemes by interleaving or inverting bits) and the transmitter structure of Claim 11 (a transmitter with an "interleaver or inverter to obtain different modulation schemes").
    • Similar to the '491 application, the key question for full anticipation of Claim 1 and Claim 11 is whether the '085 patent explicitly teaches sending the initial transmission and the modified (interleaved/inverted) retransmission over separate and distinct diversity branches as part of a combined diversity scheme. If it does not, it anticipates the method of creating different modulations but not the full claimed method of applying it across diversity branches.

4. US 6,356,528 B1 ("'528 patent")

  • Full Citation: US 6,356,528 B1, "Interleaver and deinterleaver for use in a diversity transmission communication system", Qualcomm Incorporated.
  • Filing Date: April 15, 1999 (Prior art to the '961 patent).
  • Description: The '528 patent describes the use of an interleaver in a communication system that employs transmit diversity. The system transmits data over multiple antennas. Interleaving is used to reorder symbols before transmission to mitigate the effects of burst errors. The receiver performs the corresponding de-interleaving.
  • Potential Anticipation of Claim(s): Partial anticipation; likely does not anticipate the ARQ-based scheme.
    • This patent links the concepts of "interleaving" and "diversity transmission," which are elements of claims in the '961 patent (specifically Claim 5 and Claim 11).
    • However, the context in the '528 patent is typically for a single, initial transmission spread across multiple antennas (e.g., space-time coding) rather than for an ARQ retransmission scheme where the modulation property is deliberately changed in response to a repeat request. It lacks the crucial element of using different modulation schemes for a first transmission and a subsequent second transmission based on a repeat request.

Summary of Prior Art Analysis

The cited prior art establishes that the individual components of the '961 invention were known before its priority date. Specifically:

  • Using different antennas for ARQ retransmissions (diversity) was known ('701 patent).
  • Changing the signal constellation (modulation scheme) for ARQ retransmissions was known ('491 application).
  • Implementing this change via bit interleaving or inverting was known ('085 patent).

The novelty of the '961 patent, as allowed by the examiner, appears to reside in the specific combination of these known techniques: applying constellation rearrangement to an ARQ retransmission scheme and transmitting the original and rearranged signals over separate diversity branches. While references like the '491 application and '085 patent are very close, they may not explicitly disclose this combined diversity and constellation rearrangement strategy for ARQ, which forms the basis of the independent claims of the '961 patent.

Generated 4/28/2026, 2:55:41 AM

Obviousness

Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.

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Obviousness Analysis of U.S. Patent No. 7,154,961 under 35 U.S.C. § 103

This analysis evaluates whether the invention claimed in U.S. Patent No. 7,154,961 ("the '961 patent") would have been obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention, based on the prior art references cited during the patent's prosecution.

A PHOSITA in this technical field as of the priority date (October 18, 2002) would be an electrical engineer or computer scientist with a graduate degree in a relevant field and/or several years of experience in digital wireless communication systems, particularly in the areas of modulation techniques, error control coding (including ARQ and FEC schemes), and multiple-antenna (diversity) systems.

The independent claims of the '961 patent are likely obvious under 35 U.S.C. § 103 in view of a combination of prior art references, most notably the combination of EP0735701A2 ('701 patent) and WO2002067491A1 ('491 application) or, alternatively, '701 patent in combination with US 6,769,085 B2 ('085 patent).

Primary Obviousness Combination: '701 patent and '491 application

1. Summary of the References:

  • EP0735701A2 ('701 patent): This reference teaches a system that explicitly combines switched antenna diversity with an ARQ protocol. It discloses transmitting a data packet from a first antenna (a first diversity branch) and, upon receiving a retransmission request from the receiver, re-transmitting the packet from a second, different antenna (a second diversity branch). The '701 patent thus establishes the foundational framework of using transmit diversity within an ARQ scheme to improve reliability. The primary element it lacks is the use of different modulation schemes for the separate transmissions.

  • WO2002067491A1 ('491 application): This reference teaches a method for improving HARQ performance by changing the signal constellation mapping for retransmissions. It explains that for higher-order modulations like 16-QAM, bits mapped to different positions in a symbol have different reliability levels. The '491 application discloses that by using a second, different constellation mapping for a retransmission, the bit reliabilities can be averaged, leading to a better overall chance of successful decoding. It teaches the "why" and "how" of constellation rearrangement for ARQ but does not explicitly require the retransmission to be sent over a different diversity branch.

2. Motivation to Combine:

A PHOSITA starting with the transmit diversity ARQ system taught by the '701 patent would be motivated to find ways to further enhance its performance. The goal of any diversity or retransmission scheme is to maximize the probability of correct decoding. The '491 application provides a known, documented solution for improving the performance of ARQ systems by rearranging the signal constellation.

A skilled artisan would have recognized that the two techniques address different, yet complementary, aspects of transmission reliability:

  • The '701 patent's antenna switching combats large-scale fading and interference specific to a physical path.
  • The '491 application's constellation rearrangement combats errors related to the inherent properties of the modulation scheme itself.

Therefore, a PHOSITA would have been motivated to apply the known performance-enhancing technique from the '491 application to the known diversity ARQ system of the '701 patent. This combination would be a predictable and logical step to create a more robust system that leverages both spatial diversity (different paths) and modulation diversity (different bit-to-symbol mappings). The expected result would be a system with a lower error rate than a system using either technique alone.

3. Mapping the Combination to the Claims:

  • Independent Claim 1: This method claim is rendered obvious by the combination.

    • "modulating data packets ... using a first modulation scheme...": Disclosed by both '701 and '491 as part of a standard initial transmission.
    • "transmitting the first data symbols over a first diversity branch...": Explicitly taught by the '701 patent's use of a first antenna.
    • "modulating said data packets ... using a second modulation scheme...": This is the key contribution of the '491 application, which teaches using a different constellation for the ARQ retransmission.
    • "transmitting the second data symbols over a second diversity branch...": This is taught by the '701 patent's instruction to re-transmit from a second antenna upon receiving an ARQ request.
    • "diversity combining the demodulated data...": This is an inherent and necessary step at the receiver in any system using transmit diversity and retransmissions, as described in both references.
    • The dependent claims are likewise obvious. Claim 2 (reducing differences in bit reliabilities) is the explicit purpose stated in the '491 application. Claim 5 (using interleaving or inverting) is a known method for achieving constellation rearrangement, as further detailed in the '085 patent.

  • Independent Claim 11: This claim for a transmitter is also obvious. The '701 patent teaches a transmitter with a "transmission unit" capable of sending signals over a first and a second diversity branch. The '491 application teaches the use of a "mapping unit" that can apply different modulation schemes. The '085 patent goes further, explicitly disclosing a transmitter with an "interleaver or inverter to obtain different modulation schemes." Combining these teachings would lead a PHOSITA to a straightforward design of a transmitter that incorporates both the antenna-switching capability of the '701 patent's transmitter and the re-mapping/interleaving capability of the '491/'085 transmitter to implement the combined method.

Conclusion

The core inventive concept of the '961 patent lies in the specific combination of transmit diversity for ARQ retransmissions with the use of constellation rearrangement for those same retransmissions. The prior art shows that both of these techniques were individually known in the art as methods to improve wireless communication reliability. The '701 patent taught using diversity for ARQ, and the '491 application and '085 patent taught using constellation rearrangement for ARQ. Combining these known techniques to achieve their expected benefits would have been an obvious design choice for a person of ordinary skill in the art seeking to create a more robust communication system. Therefore, the independent claims of U.S. Patent No. 7,154,961 are rendered obvious by the combination of the cited prior art.

Generated 4/28/2026, 2:56:04 AM

Extensions

Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.

✓ Generated

Term, Application History, and Family of Patent 7,154,961

Based on a detailed analysis of the patent documentation for U.S. Patent No. 7,154,961, the following information outlines the patent's term, application history, and related family members.

Patent Term and Projected Expiration

  • Filing Date: The application for this patent, US10/501,906, was filed on October 18, 2002.
  • Term Calculation: For utility patents filed on or after June 8, 1995, the term is 20 years from the earliest non-provisional application filing date.
  • Projected Expiration Date: Based on the October 18, 2002, filing date, the 20-year term concluded on October 18, 2022.
  • Patent Term Adjustment/Extension (PTA/PTE): There is no record of any Patent Term Adjustment (PTA) or Patent Term Extension (PTE) being granted for this patent. The official status of the patent is "Expired - Lifetime," which is consistent with the calculated expiration date.
  • Maintenance Fees: Legal event records show the patent temporarily lapsed in January 2019 for failure to pay maintenance fees. However, it was officially reinstated in December 2019 after the late fee was accepted, and it remained active until its natural expiration in 2022.

Continuation and Divisional Applications

The '961 patent is part of a chain of related U.S. applications that claim priority to the same initial filing date.

  • Continuation Application: The "Related Child Applications" section of the patent record explicitly identifies application US11/633,421 (which issued as patent US 7,567,622 B2) as a continuation of the application that led to the '961 patent.
  • Chain of Continuing Applications: The patent family data shows a succession of applications claiming priority to the original 2002 filing, creating a series of related patents and applications:
    1. US10/501,906 (Issued as US 7,154,961 B2, the patent in question)
    2. US11/633,421 (Issued as US 7,567,622 B2)
    3. US12/490,096 (Published as US 2009/0262858 A1; listed as abandoned)
    4. US13/034,348 (Issued as US 8,325,845 B2)

No divisional applications were explicitly identified in the provided records.

Patent Family Members

The initial application was filed internationally under the Patent Cooperation Treaty (PCT), leading to a family of patents in various countries, all sharing the same priority date of October 18, 2002.

  • PCT Application: WO2004036818A1
  • European Patent: EP1552639B1
  • Japanese Patent: JP3885078B2
  • Chinese Patent: CN1620776B
  • Korean Patent: KR100789042B1
  • Other Jurisdictions: The patent family also includes filings in Australia (AU2002368296A1), Austria (ATE383689T1), and Germany (DE60224588T2).

All members of this patent family are now expired due to having reached the end of their statutory term.

Generated 4/28/2026, 2:56:31 AM

Derivative works

Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.

✓ Generated

This Defensive Disclosure document provides a series of technical variations and extensions to the core concepts described in U.S. Patent No. 7,154,961. The purpose of this disclosure is to place these derivative concepts into the public domain, thereby establishing them as prior art for future patent applications. Each disclosure is accompanied by an enabling description and a visual diagram.

Reference Patent: US 7,154,961
Title: Constellation rearrangement for ARQ transmit diversity schemes
Core Concept: The combination of using different signal constellation mappings (modulation schemes) for an initial transmission and a subsequent ARQ retransmission, where these transmissions are sent over separate diversity branches (e.g., different antennas, frequencies, or paths) and combined at the receiver to improve decoding reliability.

Derivative Disclosures

1. Material & Component Substitution

1.1. Quantum-Seeded Scrambling for Constellation Rearrangement

  • Enabling Description: The standard bit-level interleaver or inverter described in claim 11 is replaced by a hardware module containing a Quantum Random Number Generator (QRNG). For each ARQ retransmission, the QRNG generates a true random seed. This seed is used to initialize a cryptographic-grade pseudo-random number generator (PRNG), which in turn dictates the bit-scrambling pattern applied to the data packet before modulation. This method generates a virtually infinite set of unique and non-deterministic constellation mappings. The seed used for each retransmission is communicated to the receiver via a robust, low-rate side channel, allowing it to apply the identical scrambling pattern to the received soft bits before combining. This architecture drastically increases the unpredictability of the constellation rearrangement, enhancing security against eavesdropping while still achieving the desired bit-reliability averaging.
  • Mermaid Diagram:
    flowchart TD
    subgraph Transmitter
        A[Data Packet] --> B{QRNG};
        B --> C[Generate Seed];
        C --> D{PRNG};
        A --> E[Bit Scrambler];
        D --> E;
        E --> F[QAM Modulator];
        F --> G[Transmit on Diversity Branch N];
        C --> H[Send Seed on Side Channel];
    end
    subgraph Receiver
        I[Receive Signal on Branch N] --> J[QAM Demodulator];
        K[Receive Seed] --> L{PRNG};
        J --> M[Bit Descrambler];
        L --> M;
        M --> N[Combine with Previous Attempts];
    end

1.2. Analog I/Q Phase Rotation Array

  • Enabling Description: Constellation rearrangement is performed in the analog domain post-modulation. The baseband modulator produces standard I/Q (In-phase and Quadrature) signals. These signals are fed into a dynamically controlled analog phase rotator circuit, which can be implemented using a Gilbert cell mixer or a vector modulator. For each ARQ retransmission, a controller applies a different rotation angle (e.g., 45° for the first retransmission, 30° for the second) to the I/Q signal pair before up-conversion. This action rotates the entire signal constellation in the complex plane, effectively creating a new modulation scheme. The sequence of rotation angles is predetermined or signaled to the receiver, which applies the inverse rotation to the received I/Q samples before demodulation and combining. This method avoids digital logic changes and performs the rearrangement at the analog front-end.
  • Mermaid Diagram:
    sequenceDiagram
    participant TX as Transmitter
    participant RX as Receiver
    Note over TX: Initial Transmission (Tx1)
    TX->>TX: Modulate Data (Mapping 1)
    TX->>RX: Transmit on Branch 1
    Note over RX: Decode Fails, ARQ Request
    RX-->>TX: NACK
    Note over TX: Retransmission (Tx2)
    TX->>TX: Modulate Data (Mapping 1)
    TX->>TX: Apply Analog Phase Rotation (e.g., +45°)
    TX->>RX: Transmit on Branch 2
    Note over RX: Demodulation of Tx2
    RX->>RX: Apply Inverse Rotation (e.g., -45°)
    RX->>RX: Demodulate and Combine with Tx1

2. Operational Parameter Expansion

2.1. Constellation Hopping for Deep Space Communications

  • Enabling Description: This method is designed for communication channels with extremely low Signal-to-Noise Ratio (SNR), such as deep-space links. The system uses a large, predefined set of several hundred distinct 16-QAM constellation mappings stored in both the transmitter and receiver. For a single data packet, the transmitter sends out a continuous stream of retransmissions over different diversity branches (achieved through frequency hopping or using multiple spacecraft antennas). Each retransmission uses the next constellation mapping from the stored sequence in a round-robin fashion. The receiver accumulates the soft information (LLRs) from dozens or even hundreds of these differently-mapped retransmissions over a long period. The constant "hopping" of constellation patterns ensures that every bit's reliability is averaged over a massive number of channel states and mapping positions, allowing for successful decoding far below the normal Shannon limit for a single transmission.
  • Mermaid Diagram:
    stateDiagram-v2
    [*] --> Tx_1
    Tx_1: Transmit w/ Mapping_1 on Branch_1
    Tx_1 --> Tx_2: ARQ_Req_1
    Tx_2: Transmit w/ Mapping_2 on Branch_2
    Tx_2 --> Tx_3: ARQ_Req_2
    Tx_3: Transmit w/ Mapping_3 on Branch_3
    Tx_3 --> Tx_N: ...
    Tx_N: Transmit w/ Mapping_N on Branch_N
    Tx_N --> Decode_Success: Soft-Combining Threshold Met
    Decode_Success --> [*]

2.2. Proactive Diversity for Ultra-Low Latency Links

  • Enabling Description: To minimize latency for applications like high-frequency trading, this method eliminates the wait time for an ARQ request. The transmitter proactively sends two versions of the same data packet simultaneously. The first version uses mapping_1 and is sent on diversity_branch_1. Concurrently, the second version uses mapping_2 and is sent on diversity_branch_2. The receiver is configured to always expect both transmissions and immediately combines them for a single, low-latency decoding attempt. This provides the reliability benefits of the core invention on the very first transmission. A traditional ARQ request-and-retransmit cycle is only initiated if this initial combined decoding fails, at which point a third transmission with mapping_3 on branch_3 would occur.
  • Mermaid Diagram:
    flowchart TD
    subgraph Time T0
        A[Data Packet] --> B[Modulate w/ Mapping 1];
        A --> C[Modulate w/ Mapping 2];
        B --> D[Transmit on Branch 1];
        C --> E[Transmit on Branch 2];
    end
    subgraph Receiver at T0+delta
        F[Receive on Branch 1]
        G[Receive on Branch 2]
        F & G --> H{Combine & Decode};
        H -- Success --> Z[Done];
        H -- Failure --> I[Send ARQ Request];
    end

3. Cross-Domain Application

3.1. Aerospace: Peer-to-Peer ARQ in UAV Swarms

  • Enabling Description: In a UAV swarm, the "diversity branches" are other UAVs. A Ground Control Station (GCS) sends a command packet to the swarm using a primary constellation map. Drones that fail to decode the packet (e.g., due to signal blockage by another drone) broadcast a NACK. Neighboring drones that successfully decoded the packet act as relays. They re-modulate the original data using a secondary constellation map and transmit it to the drone that failed. The failing drone then combines the weak, original signal from the GCS (Branch 1) with the strong, re-mapped signal from its peer (Branch 2) to successfully decode the command.
  • Mermaid Diagram:
    sequenceDiagram
    participant GCS
    participant UAV_A as UAV A (Success)
    participant UAV_B as UAV B (Fails)
    GCS->>+UAV_A: Command (Mapping 1)
    GCS->>-UAV_B: Command (Mapping 1, weak signal)
    UAV_B-->>UAV_A: NACK / Peer Request
    UAV_A->>UAV_A: Re-modulate w/ Mapping 2
    UAV_A->>UAV_B: Relayed Command (Mapping 2)
    UAV_B->>UAV_B: Combine GCS signal and UAV A signal

3.2. AgTech: Time-Frequency Diversity in Sub-Soil Networks

  • Enabling Description: For sensors buried in soil, where the channel is highly variable, diversity is achieved across time and frequency. A sensor makes its first transmission attempt using mapping_1 on frequency channel f1 at time t1. If the hub station fails to decode the data and requests a retransmission, the sensor waits for a short, randomized backoff period and retransmits the data using mapping_2 on a different frequency channel f2 at time t2. The hub station stores the soft information from the first attempt and combines it with the second. This leverages both frequency and time diversity to combat the complex multi-path and attenuation characteristics of the soil channel, while the constellation rearrangement averages bit reliability.
  • Mermaid Diagram:
    flowchart LR
    subgraph Sensor
        A[Sensor Data] --> B{Modulate w/ Map 1};
        B --> C[Transmit on Freq 1, Time 1];
        D{Receive NACK} --> E{Modulate w/ Map 2};
        E --> F[Transmit on Freq 2, Time 2];
    end
    subgraph Hub
        G[Receive on F1,T1] --> H{Store LLRs};
        I[Receive on F2,T2] --> J[Combine LLRs];
        C --> G
        F --> I
        J --> K{Decode};
        K -- Failure --> L[Send NACK] --> D;
    end

4. Integration with Emerging Tech

4.1. AI-Generated Constellations for HARQ

  • Enabling Description: The transmitter integrates a generative neural network (GNN) that designs custom constellations in real-time. Before each retransmission, the transmitter's AI model analyzes the Channel State Information (CSI) feedback from the receiver. Based on this analysis, it generates an optimal, non-uniform constellation mapping specifically tailored to the current channel conditions. The goal is to maximize the minimum Euclidean distance between points and simultaneously maximize the reliability of the specific bits that were weakest in the previous attempt. The compact mathematical description of this newly generated constellation is then sent to the receiver over a control channel, which uses it to demodulate the subsequent retransmission.
  • Mermaid Diagram:
    graph TD
    A[CSI Feedback from Receiver] --> B(Generative AI Model);
    C[Data from Previous Failed Tx] --> B;
    B --> D{Generate Optimized Constellation Map};
    D --> E[Modulator];
    F[Data Packet] --> E;
    E --> G[Transmit on Diversity Branch N];
    D -- Constellation Description --> H[Transmit on Control Channel];

4.2. Blockchain-Verified Retransmission Chain

  • Enabling Description: In a decentralized wireless network, a blockchain is used to verify and log all transmission attempts. When a device transmits data (Tx1) using mapping_1 on branch_1, it records the transaction (containing a data hash, mapping ID, and branch ID) on a distributed ledger. If a retransmission is needed, the new transmission (Tx2) with mapping_2 on branch_2 is logged as a new transaction cryptographically linked to the first. The receiver queries the ledger to verify the authenticity and sequence of the transmission chain before it combines the signals. This prevents spoofing and creates an immutable audit trail for network usage and billing.
  • Mermaid Diagram:
    erDiagram
    TRANSMITTER ||--o{ TRANSMISSION : sends
    TRANSMISSION {
        string tx_id PK
        string data_hash
        string mapping_id
        string branch_id
        string previous_tx_id FK
    }
    RECEIVER ||--o{ TRANSMISSION : receives
    BLOCKCHAIN ||--|{ TRANSMISSION : logs
    TRANSMITTER {
        string device_id PK
    }
    RECEIVER {
        string device_id PK
    }

5. The "Inverse" or Failure Mode

5.1. Graceful Degradation for Low-Power States

  • Enabling Description: In a low-battery state, a device enters a power-saving mode. It disables transmit diversity, using only a single antenna to save power. However, it continues to use constellation rearrangement for ARQ retransmissions to preserve some coding gain. Furthermore, it employs a graceful degradation strategy for the modulation itself. The first transmission is 16-QAM. The first retransmission uses a different 16-QAM map. If that fails, the second retransmission drops the modulation order to QPSK. A final attempt might use robust BPSK. This tiered approach trades data rate for robustness, ensuring that as power fades, the link's chance of success on a lower-rate transmission increases.
  • Mermaid Diagram:
    stateDiagram-v2
    state "Full Power" as P1
    state "Low Power" as P2

    [*] --> P1
    P1: Tx Diversity ON
    P1: 16-QAM HARQ w/ Rearrangement
    P1 --> P2 : Low Battery Trigger

    P2: Tx Diversity OFF
    P2 --> S1 : Start Transmission
    state "1st Attempt" as S1
    S1: Tx 16-QAM (Map 1)
    S1 --> S2 : NACK
    state "2nd Attempt" as S2
    S2: Tx 16-QAM (Map 2)
    S2 --> S3 : NACK
    state "3rd Attempt" as S3
    S3: Tx QPSK
    S3 --> S4 : NACK
    state "4th Attempt" as S4
    S4: Tx BPSK

    S1 --> [*] : ACK
    S2 --> [*] : ACK
    S3 --> [*] : ACK
    S4 --> [*] : ACK

Combination Prior Art with Open-Source Standards

C.1. Combination with IEEE 802.11be (Wi-Fi 7) Multi-Link Operation (MLO)

  • Enabling Description: The core invention is integrated into the Wi-Fi 7 MLO framework. A Wi-Fi access point (AP) transmits a data frame to a client over a primary link (e.g., the 6 GHz band), which serves as the first diversity branch. If the transmission is unsuccessful (no BlockACK received), the AP retransmits the same frame over a secondary link (e.g., the 5 GHz band), which serves as the second diversity branch. Crucially, this retransmission uses a different 1024-QAM constellation mapping than the original transmission. The client device, aware of the MLO-HARQ session, is configured to buffer the soft-decision bits from the 6 GHz attempt and combine them with the soft-decision bits from the re-mapped 5 GHz attempt, significantly improving the probability of successful decoding in congested environments.

C.2. Combination with 3GPP 5G-NR URLLC

  • Enabling Description: The technique is applied to 5G New Radio for Ultra-Reliable Low-Latency Communication. A gNodeB (base station) transmits a data block to a UE using a primary beam/antenna port set (branch_1) and a standard 256-QAM mapping (mapping_1). If the UE signals a NACK for this transmission, the gNodeB performs a retransmission using a different, spatially distinct beam (branch_2). This retransmission uses a rearranged 256-QAM mapping (mapping_2), where the mapping ID is signaled in the Downlink Control Information (DCI). This combines spatial diversity (different beams) with modulation diversity (rearranged constellation), providing an additional layer of robustness critical for URLLC applications like factory automation and remote surgery.

C.3. Combination with LoRaWAN Protocol

  • Enabling Description: The concept is adapted for the Chirp Spread Spectrum (CSS) modulation used in LoRaWAN. A LoRa end-device transmits a packet on channel_A with a specific spreading factor; this is the first transmission. If the gateway fails the CRC check, it commands a retransmission. The end-device then retransmits on channel_B (frequency diversity branch). For this retransmission, it applies a "bit-to-chirp re-mapping." Normally, a block of bits maps directly to an initial chirp frequency. In the re-mapped version, the bits are first passed through a simple, pre-defined XOR function or a lookup table before being mapped to the initial chirp frequency. The LoRaWAN gateway, knowing this is a retransmission, applies the inverse mapping to the received signal before combining it with the initial attempt, thus achieving a coding gain analogous to QAM constellation rearrangement.

Generated 4/28/2026, 2:57:39 AM

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