DCT
2:25-cv-00854
TurboCode LLC v. Touchbistro Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: TurboCode LLC (Texas)
- Defendant: TouchBistro, Inc. (Canada)
- Plaintiff’s Counsel: Direction IP Law
- Case Identification: 2:25-cv-00854, E.D. Tex., 08/25/2025
- Venue Allegations: Venue is based on Defendant being a non-U.S. resident, which permits suit in any judicial district under 28 U.S.C. § 1391(c)(3).
- Core Dispute: Plaintiff alleges that Defendant’s point-of-sale products, which utilize 4G/LTE cellular connectivity, infringe a patent related to high-speed decoder architectures for error correction in wireless communications.
- Technical Context: The technology at issue involves "turbo codes," a class of high-performance forward error correction codes essential for reliable data transmission in modern wireless standards like 4G/LTE.
- Key Procedural History: The patent-in-suit was the subject of an Ex Parte Reexamination requested in 2006, which concluded with the issuance of a Reexamination Certificate in 2009, confirming the patentability of amended claims.
Case Timeline
| Date | Event |
|---|---|
| 2001-01-02 | ’742 Patent Priority Date |
| 2004-11-02 | ’742 Patent Issue Date |
| 2006-07-13 | Reexamination Request Filed for ’742 Patent |
| 2009-02-10 | Ex Parte Reexamination Certificate Issued for ’742 Patent |
| 2025-08-25 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,813,742 - High Speed Turbo Codes Decoder for 3G Using Pipelined SISO Log-Map Decoders Architecture
- Patent Identification: U.S. Patent No. 6,813,742, High Speed Turbo Codes Decoder for 3G Using Pipelined SISO Log-Map Decoders Architecture, issued November 2, 2004.
The Invention Explained
- Problem Addressed: The patent’s background section describes prior art decoders for turbo codes, particularly those using the Maximum a Posteriori (MAP) algorithm, as being computationally complex, requiring many multiplications that result in costly, power-hungry, and slow hardware implementations unsuitable for consumer mobile devices (’742 Patent, col. 1:45-61).
- The Patented Solution: The invention proposes a decoder architecture using two pipelined Soft-In/Soft-Out (SISO) Log-MAP decoders connected in a feedback loop (’742 Patent, Abstract; FIG. 4). This structure allows for iterative decoding where data is passed back and forth between the decoders to improve accuracy. By operating in the logarithmic ("Log") domain, the design replaces complex multiplications with simpler binary adder circuits, which enables a faster, lower-power, and more cost-effective implementation in silicon (ASICs) (’742 Patent, col. 2:54-58).
- Technical Importance: This pipelined, Log-MAP approach was intended to make powerful turbo decoding technology practical for high-throughput 3G wireless applications by increasing processing speed while reducing power consumption and hardware complexity (’742 Patent, col. 2:32-41).
Key Claims at a Glance
- The complaint asserts independent claim 6, as amended by the Ex Parte Reexamination Certificate (Compl. ¶13).
- Essential elements of asserted independent claim 6 include:
- A method of iteratively decoding received baseband signals.
- Providing an input buffer with at least three shift registers to generate first, second, and third shifted input signals.
- Providing first and second soft decision decoders serially coupled in a circular circuit, with specific inputs from the input buffer assigned to each decoder.
- Providing at least one memory module coupled to the output of each decoder, where the output of the second decoder's memory is fed back to the first decoder.
- Processing systematic and extrinsic information data using a MAP or logarithm approximation algorithm.
- Generating a soft decision based on a MAP or logarithm approximation algorithm.
- Weighing and storing the soft decision information into the memory module.
- Performing iterative decoding for a predetermined number of times, with output from the last decoder fed back to the first in a circular circuit.
- The complaint does not explicitly reserve the right to assert dependent claims (Compl. ¶12-13).
III. The Accused Instrumentality
Product Identification
- The "TouchBistro point of sale products," which include the "TD Move/5000" payment terminal (Compl. ¶12, p. 4).
Functionality and Market Context
- The complaint alleges that the Accused Instrumentalities are infringing by "using and/or testing" products that comply with 4G/LTE cellular communication standards (Compl. ¶12). The infringement theory is not based on the point-of-sale software features, but on the underlying hardware's wireless data processing capabilities. A product datasheet for the Move/5000 is included in the complaint, which states the device has "4G/LTE" wireless connectivity (Compl. p. 8). The complaint alleges that compliance with these standards necessitates the use of a turbo decoder that performs the patented method (Compl. ¶14).
IV. Analysis of Infringement Allegations
’742 Patent Infringement Allegations
| Claim Element (from Independent Claim 6) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| providing an input buffer comprising at least three shift registers, for receiving an input signal and generating first, second, and third shifted input signals | The accused products allegedly provide an input buffer that receives an input signal and generates first, second, and third shifted input signals ("soft data," "soft parity 1," and "soft parity 2") for the turbo decoder. | ¶15 | col. 4:11-14 |
| providing first and second soft decision decoders serially coupled in a circular circuit, wherein each decoder processes soft decision from the preceding decoder output data... | The accused products allegedly implement first and second soft decision decoders connected in series, where each decoder processes soft information from the other in a looped manner to refine accuracy through iterative feedback. A technical diagram of this architecture is provided (Compl. p. 15). | ¶16 | col. 4:9-11 |
| providing at least one memory module coupled to an output of each of the first and second soft decision decoders, wherein the output of the memory module associated with the second soft decision decoder is fed back as an input of the first soft decision decoder | The accused products allegedly include memory modules (e.g., an "interleaver" and "deinterleaver") coupled to the decoders, where the output from the second decoder's module is fed back to the input of the first. The complaint references a diagram showing this feedback path (Compl. p. 19). | ¶17 | col. 4:10-13 |
| processing systematic information data and extrinsic information data using the maximum a posteriori (AP) probability algorithm, and/or logarithm approximation algorithm | The accused products allegedly use a MAP probability algorithm, such as the BCJR algorithm, to process systematic and extrinsic data during turbo decoding. | ¶18 | col. 2:49-54 |
| generating soft decision based on the maximum a posteriori (MAP) probability algorithm, and/or logarithm approximation algorithm | The accused products allegedly generate soft decisions (probabilistic outputs) using at least the BCJR algorithm. | ¶19 | col. 5:29-32 |
| weighing and storing soft decision information into the corresponding memory module | The accused products allegedly weigh (e.g., normalize) and store soft decision information in a memory module, with the complaint asserting this is a necessary step in any viable MAP algorithm. | ¶20, ¶26 | col. 6:25-32 |
| performing, for a predetermined number of times, iterative decoding from the first to the last of multiple decoders, wherein an output from the last soft decision decoder is fed back as an input to the first soft decision decoder...and propagate to the last decoder in a circular circuit | The accused products allegedly perform iterative decoding for a set number of iterations, where the output of the second decoder is fed back to the first in a circular loop to improve accuracy. A diagram illustrating this iterative process is included (Compl. p. 29). | ¶21 | col. 4:22-26 |
Identified Points of Contention
- Scope Questions: A primary question will be whether mere compliance with the 4G/LTE standard is sufficient to prove infringement of every element of the claimed method. The complaint's theory rests on the premise that the standard dictates the claimed implementation, which raises the question of whether alternative, non-infringing decoder designs are permissible under the same standard.
- Technical Questions: The complaint provides extensive documentation on how LTE turbo decoders work in general, but offers no direct evidence from the accused products themselves. This raises the evidentiary question of how Plaintiff will prove that the TouchBistro devices actually perform specific steps like "weighing and storing soft decision information" in the manner required by the claim, as opposed to using a technically distinct process.
V. Key Claim Terms for Construction
The Term: "serially coupled in a circular circuit"
Context and Importance: This term defines the core iterative architecture of the claimed method. Its construction will be critical for determining whether the accused LTE decoders, which are inherently iterative, use the specific feedback structure claimed in the patent.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself is general, suggesting any architecture where two decoders are linked in a series loop for feedback could be covered. The patent's summary describes the invention as performing "re-iterative decoding of data back-and-forth between the two Log-MAP decoders" (’742 Patent, col. 2:58-60).
- Evidence for a Narrower Interpretation: FIG. 4, the primary system block diagram, shows a specific arrangement where Decoder A's output is sent to an Interleaver Memory (43), which feeds Decoder B (44), whose output is then sent to a De-Interleaver Memory (45) that feeds back to Decoder A. A defendant may argue the claim should be limited to this precise pipelined structure with distinct interleaver and de-interleaver memory modules in the feedback path.
The Term: "weighing and storing soft decision information"
Context and Importance: This is an active processing step whose meaning is not explicitly defined in the patent. Practitioners may focus on this term because the complaint equates "weighing" with "normalization" required by MAP algorithms (Compl. ¶26), a connection that will need to be established through claim construction.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent specification describes a process of calculating, comparing, and selecting probabilities (e.g., using "MAX" functions) to arrive at a final decision (’742 Patent, col. 7:51-8:18). Plaintiff may argue that these selection and comparison steps constitute a form of "weighing."
- Evidence for a Narrower Interpretation: The patent does not use the term "weighing" or "normalization" in its detailed description. A defendant may argue that the term has no antecedent basis in the specification and should be found indefinite, or that it must be limited to a specific mathematical operation that is absent from both the patent and the accused devices.
VI. Other Allegations
The complaint does not contain allegations of indirect or willful infringement.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of evidentiary sufficiency: can Plaintiff prove, without direct technical evidence from the accused devices, that compliance with the 4G/LTE standard necessarily requires implementation of every specific step of the method of claim 6? This hinges on whether the standard dictates a single, infringing implementation or allows for non-infringing design choices.
- A key legal and technical question will be one of definitional scope: does the accused devices' process for handling probabilistic data in their decoders constitute "weighing" as required by the claim? The outcome may depend on whether the court construes this term broadly to mean any form of value selection or normalization, or narrowly based on its absence from the patent’s detailed description.