DCT
1:22-cv-03333
Swirlate IP LLC v. Parsons Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Swirlate IP LLC (Texas)
- Defendant: Parsons Corporation (Delaware)
- Plaintiff’s Counsel: Direction IP Law
- Case Identification: 1:22-cv-03333, N.D. Ill., 06/27/2022
- Venue Allegations: Venue is alleged to be proper based on Defendant maintaining regular and established places of business within the Northern District of Illinois, specifically in Schaumburg and Chicago.
- Core Dispute: Plaintiff alleges that Defendant’s network characterization tool infringes two patents related to methods for improving data reliability in wireless systems by using different signal modulation schemes for initial transmissions and subsequent retransmissions.
- Technical Context: The technology, Hybrid Automatic Repeat reQuest (HARQ), is a fundamental component of modern wireless standards like LTE and 5G, enabling reliable high-speed data transfer by retransmitting corrupted data packets.
- Key Procedural History: U.S. Patent No. 7,567,622 is a continuation of the application that led to U.S. Patent No. 7,154,961. The complaint notes that during the prosecution of the '622 patent, the applicant distinguished the invention by explaining its benefits in averaging bit communication reliabilities and reducing overall data traffic compared to prior art that always transmitted data over multiple paths.
Case Timeline
| Date | Event |
|---|---|
| 2002-10-18 | Priority Date for ’961 and ’622 Patents |
| 2006-12-26 | U.S. Patent No. 7,154,961 Issued |
| 2009-07-28 | U.S. Patent No. 7,567,622 Issued |
| 2022-06-27 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,154,961 - Constellation Rearrangement for ARQ Transmit Diversity Schemes
- Patent Identification: U.S. Patent No. 7,154,961, Constellation Rearrangement for ARQ Transmit Diversity Schemes, issued December 26, 2006.
The Invention Explained
- Problem Addressed: In wireless communication systems using higher-order modulation (where multiple data bits are grouped into a single transmission symbol, like 16-QAM), the individual bits within that symbol can have different levels of transmission reliability depending on their position in the symbol's constellation map. This can lead to "degraded decoder performance" when some bits are consistently less reliable than others. (’961 Patent, col. 2:1-7).
- The Patented Solution: The invention proposes improving performance by "applying different signal constellation mappings" for transmissions sent over different diversity branches (e.g., different antennas) or for successive retransmissions of the same data. (’961 Patent, col. 2:18-23). By changing the bit-to-symbol mapping, a bit that was in an unreliable position in the first transmission can be moved to a more reliable position in the second, averaging out the reliabilities across transmissions and improving the likelihood of a successful decode at the receiver. (’961 Patent, col. 2:35-51).
- Technical Importance: This technique provides a method to enhance the robustness of data transmission without simply increasing power, making more efficient use of the radio spectrum and improving performance in systems with time-varying channel conditions. (Compl. ¶11).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 1. (Compl. ¶16).
- Independent Claim 1 recites a method with the following essential elements:
- An ARQ re-transmission method in a wireless communication system.
- Modulating data packets at a transmitter using a first modulation scheme to obtain first data symbols.
- Transmitting the first data symbols over a first diversity branch.
- Modulating the same data packets using a second modulation scheme (distinct from the first) to obtain second data symbols.
- Transmitting the second data symbols over a second diversity branch.
- Demodulating the received first and second data symbols at the receiver.
- Diversity combining the demodulated data.
U.S. Patent No. 7,567,622 - Constellation Rearrangement for ARQ Transmit Diversity Schemes
- Patent Identification: U.S. Patent No. 7,567,622, Constellation Rearrangement for ARQ Transmit Diversity Schemes, issued July 28, 2009.
The Invention Explained
- Problem Addressed: The ’622 Patent shares its specification with the ’961 Patent and addresses the same problem of unequal bit reliabilities in higher-order modulation schemes. (Compl. ¶28; ’622 Patent, col. 2:1-7).
- The Patented Solution: The solution is also centered on using different bit-to-symbol mappings for retransmissions. The claims of the ’622 Patent are specifically directed to a method where a second, different mapping is used for a retransmission that occurs in response to a repeat request from the receiver, which is sent only when the initial transmission fails. (Compl. ¶¶29-30; ’622 Patent, Claim 1).
- Technical Importance: As argued during prosecution, this approach reduces overall data traffic by employing retransmission and diversity combining only when necessary, unlike prior art systems that might always transmit data redundantly over multiple paths. (Compl. ¶30).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 1. (Compl. ¶31).
- Independent Claim 1 recites a method with the following essential elements:
- An ARQ re-transmission method using a higher order modulation scheme where more than two data bits are mapped to one symbol.
- Modulating data packets using a first mapping of the modulation scheme to get first data symbols.
- Performing a first transmission of the first data symbols.
- Receiving at the transmitter a repeat request from the receiver.
- Modulating, in response to the repeat request, the data packets using a second mapping (distinct from the first) to get second data symbols.
- Performing a second transmission of the second data symbols.
III. The Accused Instrumentality
Product Identification
The Parsons ICS-550 ("Accused Instrumentality"). (Compl. ¶16).
Functionality and Market Context
The ICS-550 is described as an "advanced network characterization tool" that passively surveys wireless network environments, including LTE and 5G NR, to record metadata from control channels. (Compl. p. 6).
The complaint alleges that the Accused Instrumentality performs the patented method by implementing the HARQ protocol found in wireless standards like LTE. This functionality is alleged to be used, at a minimum, during the product's internal testing and usage. (Compl. ¶¶17, 22). This HARQ process involves retransmitting data that was not successfully received, and the complaint alleges this is done using different modulation schemes for the initial transmission and the retransmission. (Compl. ¶¶17, 20). The complaint includes a marketing screenshot listing "LTE" as one of the ICS-550's "Operational Configurations." (Compl. p. 6).
IV. Analysis of Infringement Allegations
'961 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An ARQ re-transmission method in a wireless communication system wherein data packets are transmitted... using a first transmission and at least a second transmission based on a repeat request | The Accused Instrumentality practices a HARQ method in an LTE network where retransmissions are based on a repeat request (NAK). | ¶17 | col. 1:56-63 |
| modulating data packets at the transmitter using a first modulation scheme to obtain first data symbols | The Accused Instrumentality uses a first modulation scheme (e.g., QPSK, 16QAM, 64QAM) to modulate data packets into first data symbols. A diagram from an ETSI standard is presented as evidence of this data modulation step. (Compl. p. 9). | ¶18 | col. 9:14-16 |
| performing the first transmission by transmitting the first data symbols over a first diversity branch to the receiver | The first data symbols are transmitted over a first diversity branch, alleged to be a transmission using a first antenna port. | ¶19 | col. 9:17-19 |
| modulating said data packets at the transmitter using a second modulation scheme... which is distinct from the first modulation scheme | Upon a repeat request (NAK), the Accused Instrumentality allegedly uses a second, distinct modulation scheme via "Adaptive Re-transmission," which involves a different Modulation Coding Scheme (MCS) than the first transmission. | ¶20 | col. 10:49-61 |
| performing the second transmission by transmitting the second data symbols over a second diversity branch to the receiver | The second data symbols are transmitted over a second diversity branch, alleged to be a transmission using a different antenna port. | ¶21 | col. 9:21-24 |
| demodulating the received first and second data symbols at the receiver using the first and second modulation schemes respectively | A base station used with the Accused Instrumentality allegedly demodulates the received symbols using the respective first and second modulation schemes. | ¶22 | col. 9:25-28 |
| diversity combining the demodulated data received over the first and second diversity branches | The base station allegedly performs Hybrid ARQ soft-combining of the data received from the multiple diversity branches. A diagram illustrating HARQ processing is used to support this allegation. (Compl. p. 7). | ¶23 | col. 9:29-32 |
'622 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An ARQ re-transmission method... using a higher order modulation scheme wherein more than two data bits are mapped onto one data symbol | The Accused Instrumentality practices a HARQ method in an LTE network and uses higher order modulation like 16QAM (4 bits/symbol) and 64QAM (6 bits/symbol). A table showing QAM bits per symbol is provided as evidence. (Compl. p. 42). | ¶32 | col. 7:42-47 |
| modulating data packets at the transmitter using a first mapping of said higher order modulation scheme to obtain first data symbols | The Accused Instrumentality uses a first modulation mapping (e.g., 16QAM) to create first data symbols for the initial transmission. | ¶33 | col. 7:48-50 |
| performing the first transmission... over a first diversity branch to the receiver | The first data symbols are transmitted to a receiver over a first diversity branch, such as a first antenna port. | ¶34 | col. 7:51-53 |
| receiving at the transmitter the repeat request issued by the receiver to retransmit the data packets | The transmitter (Accused Instrumentality) receives a HARQ retransmission request in the form of a NAK from the LTE base station when data is not successfully decoded. | ¶35 | col. 8:17-21 |
| modulating, in response to the received repeat request, said data packets... using a second mapping of said higher order modulation scheme which is distinct from the first mapping | In response to the NAK, the Accused Instrumentality allegedly uses a second, distinct mapping, described as an "Adaptive Re-transmission" with a different Modulation Coding Scheme (MCS). | ¶36 | col. 8:22-26 |
| performing, in response to the received repeat request, the second transmission by transmitting the second data symbols over a second diversity branch | The re-modulated second data symbols are transmitted over a second diversity branch, such as a different antenna port. A diagram from an ETSI standard is presented showing the MAC retransmission functionality. (Compl. p. 54). | ¶37 | col. 8:27-31 |
Identified Points of Contention
- Scope Questions: The complaint alleges that the Accused Instrumentality, a "completely passive" network characterization tool (Compl. p. 6), "performs" the claimed transmission methods. A central question may be whether the operation of a passive measurement device, including its alleged "internal testing and usage" (Compl. ¶22), constitutes direct infringement of a transmission method claim in the United States.
- Technical Questions: The core of the invention involves changing symbol mappings to average bit reliabilities. The complaint alleges that using a different Modulation and Coding Scheme (MCS) for retransmission meets this limitation. This raises the question of whether a change in MCS (e.g., from 64QAM to 16QAM) is the same as the "constellation rearrangement" described in the patent specification (e.g., '961 Patent, Figs. 1-3), or if there is a technical distinction.
V. Key Claim Terms for Construction
The Term: "modulation scheme" ('961 Patent) / "mapping of said higher order modulation scheme" ('622 Patent)
Context and Importance: The invention's novelty hinges on the use of a distinct scheme or mapping for the second transmission/diversity branch. The outcome of the case may depend on whether the accused product's alleged use of a different Modulation and Coding Scheme (MCS) for retransmissions falls within the scope of this term as it is used in the patents.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification broadly describes the invention's goal as "applying different signal constellation mappings" ('961 Patent, col. 2:19-20) and refers to the use of different "mappings" or "modulation schemes" throughout. A plaintiff may argue this language covers any change in the modulation process that results in different data symbols, including a change in MCS.
- Evidence for a Narrower Interpretation: The detailed examples in the specification focus on "constellation rearrangement," showing specific bit-swapping or inversions within a given constellation size (e.g., 16-QAM). (See ’961 Patent, Figs. 1-3; col. 4:35-46). A defendant may argue that the term should be limited to these types of rearrangements intended to average bit reliabilities, and that a simple change in MCS (e.g., dropping from 16QAM to QPSK) is a different, conventional technique not contemplated by the patent.
The Term: "diversity branch"
Context and Importance: The claims require transmissions over at least a "first" and "second" diversity branch. The complaint equates these branches with transmissions from different antenna ports. (Compl. ¶¶19, 21). The viability of this infringement theory depends on this interpretation being correct.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent specification explicitly lists multiple forms of diversity, stating that "diversity branches" can be created via site diversity, "antenna diversity," polarization diversity, frequency diversity, time diversity, and multicode diversity. (’961 Patent, col. 1:25-42). This provides strong intrinsic support for a broad construction that includes using different antenna ports.
- Evidence for a Narrower Interpretation: It is unlikely a defendant could successfully argue for a narrower construction of this term, as the specification provides an explicit, non-limiting list of what constitutes a diversity branch. Any argument would have to contend with this clear language.
VI. Other Allegations
- Indirect Infringement: The complaint does not plead specific facts to support claims of induced or contributory infringement, such as knowledge and intent to encourage infringement by others.
- Willful Infringement: The complaint does not contain a specific count for willful infringement or plead facts suggesting the infringement was objectively reckless. The prayer for relief requests standard damages and does not explicitly ask for enhancement.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the patents' requirement for a distinct "modulation scheme" or "mapping"—a concept illustrated in the specification by specific constellation rearrangements designed to average bit reliabilities—be met by the accused product's alleged use of different Modulation and Coding Schemes (MCS) for retransmissions, a common feature of adaptive modulation?
- A key evidentiary question will be one of infringement by use: can Plaintiff provide sufficient evidence that the Accused Instrumentality, a passive network analysis tool, "performs" the full, multi-step transmission and retransmission method claimed in the patents within the United States, particularly as the allegations rely on "internal testing and usage"?