DCT
6:20-cv-00143
UNM Rainforest Innovations v. D Link Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Stcunm (New Mexico)
- Defendant: D-LINK CORPORATION (Taiwan)
- Plaintiff’s Counsel: PARKER, BUNT & AINSWORTH, P.C.; Shore Chan Depumpo LLP
- Case Identification: 6:20-cv-00143, W.D. Tex., 02/24/2020
- Venue Allegations: Plaintiff asserts that venue is proper in any U.S. judicial district because Defendant is a foreign corporation.
- Core Dispute: Plaintiff alleges that Defendant’s networking products compliant with the IEEE 802.11ac wireless standard infringe three patents related to channel state information (CSI) feedback, data frame construction, and bit allocation for retransmissions.
- Technical Context: The patents relate to foundational technologies in Orthogonal Frequency-Division Multiple Access (OFDMA) and Multi-Input Multi-Output (MIMO) systems, which are central to modern high-speed wireless communication standards like Wi-Fi.
- Key Procedural History: The complaint details the transfer of the patents-in-suit from their original assignee, Industrial Technology Research Institute (ITRI), to Sino Matrix Technology, Inc. (SMT), and subsequently to Plaintiff Stcunm. Notably, subsequent to the filing of this complaint, Inter Partes Review (IPR) proceedings were concluded for two of the three asserted patents. The U.S. Patent and Trademark Office issued certificates canceling all asserted claims of U.S. Patent No. 8,249,204 and U.S. Patent No. 8,565,326. This development significantly narrows the potential scope of the dispute, as the viability of the infringement claims for these two patents is now in question.
Case Timeline
| Date | Event |
|---|---|
| 2007-07-12 | ’096 Patent Priority Date |
| 2008-07-08 | ’326 Patent Priority Date |
| 2008-07-11 | ’204 Patent Priority Date |
| 2012-08-21 | ’204 Patent Issue Date |
| 2012-09-11 | ’096 Patent Issue Date |
| 2013-10-22 | ’326 Patent Issue Date |
| 2020-02-24 | Complaint Filing Date |
| 2024-11-08 | IPR Certificate issues canceling asserted claims of ’204 Patent |
| 2024-12-27 | IPR Certificate issues canceling asserted claims of ’326 Patent |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,249,204 - “Apparatus and method for channel state information feedback,” Issued Aug. 21, 2012 (’204 Patent)
The Invention Explained
- Problem Addressed: In advanced Multi-Input Multi-Output (MIMO) wireless systems, a base station needs to know the condition of the communication channels—known as Channel State Information (CSI)—to optimize data transmission. The patent identifies that having the mobile device send a full, detailed CSI report back to the base station creates excessive feedback overhead, which consumes valuable uplink bandwidth (’204 Patent, col. 1:36-47).
- The Patented Solution: The invention proposes a method for the mobile station to estimate the CSI, but then to compress this information before sending it as feedback. The compression is achieved by first selecting the most significant components of the channel response ("channel taps") and then using mathematical techniques, such as least squares fitting, to represent the characteristics of these taps with a smaller set of parameters. This reduces the amount of data that must be transmitted back to the base station (’204 Patent, Abstract; col. 4:13-22).
- Technical Importance: Efficiently compressing CSI feedback is a key enabler for making complex MIMO schemes practical, as it conserves limited uplink resources while still providing the base station with sufficient information for channel-aware optimization (’204 Patent, col. 1:36-47).
Key Claims at a Glance
- The complaint asserts independent claims 1 and 11.
- Independent Claim 1 (Method) requires:
- estimating the CSI by calculating a plurality of channel responses for a plurality of communication channels;
- wherein the estimating further comprises selecting a plurality of channel taps from each of the calculated channel responses;
- compressing the estimated CSI; and
- sending the compressed CSI as the feedback to the base station.
- Independent Claim 11 (Apparatus) recites a mobile station configured to perform the elements of the method in claim 1.
- The complaint reserves the right to assert dependent claim 12 (’204 Patent, col. 12:25-28).
U.S. Patent No. 8,265,096 - “Method for constructing frame structures,” Issued Sep. 11, 2012 (’096 Patent)
The Invention Explained
- Problem Addressed: The patent describes limitations in prior art OFDMA frame structures (e.g., as defined in the IEEE 802.16e standard), noting their inflexibility for bandwidth scaling and their susceptibility to performance degradation in high-mobility scenarios where effects like Doppler shift are more pronounced (’096 Patent, col. 2:1-14).
- The Patented Solution: The invention discloses a method for constructing a hybrid data frame that allows for backward compatibility with "legacy" systems while introducing new, more robust transmission formats. The solution involves creating a frame with a "first section" containing data in a legacy format and a "second section" with data in a new format. This new format can be optimized for specific conditions, for instance by using a "shorter symbol period" to better support high-mobility users. The frame also includes a "non-data section," such as a map, to define the structure for receiving devices (’096 Patent, Abstract; col. 5:6-16).
- Technical Importance: This frame structure enables a single wireless network to simultaneously serve both older devices and newer, higher-performance devices, allowing for graceful evolution of communication standards (’096 Patent, col. 2:32-35).
Key Claims at a Glance
- The complaint asserts independent claim 1.
- Independent Claim 1 (Method) requires:
- generating a first section comprising data in a first format compatible with a first communication system;
- generating a second section with data in a second format compatible with a second communication system;
- wherein the second format is compatible with a system configured to support higher mobility than the first, and wherein each symbol in the second system has a shorter symbol period than in the first;
- generating at least one non-data section describing the data in the first and/or second sections; and
- combining the sections to form the frame structure.
- The complaint reserves the right to assert dependent claims 3, 4, 6, and/or 8 (Compl. ¶46).
U.S. Patent No. 8,565,326 - “System and Method for Bit Allocation and Interleaving,” Issued Oct. 22, 2013 (’326 Patent)
Technology Synopsis
This patent addresses improving the performance of Hybrid Automatic Repeat Request (HARQ) systems, which are used for error correction via retransmission. The invention recognizes that not all bits in an encoded data block have the same importance; some (systematic bits) are more critical for decoding than others (parity bits). The patented method involves allocating bits into different groups based on their significance, and then re-arranging or re-allocating these bits during retransmissions to maximize the probability of successful decoding at the receiver (’326 Patent, Background; Abstract).
Asserted Claims
Independent claim 1 and dependent claims 2, 4, and/or 5 (Compl. ¶52).
Accused Features
The complaint alleges the Accused Instrumentalities employ the patented data transmitter and transmission methods for bit allocation and interleaving (Compl. ¶51).
III. The Accused Instrumentality
Product Identification
The complaint identifies the "Accused Instrumentalities" as D-Link’s communications equipment, including the DAP-1860, DWA-181, DWA-171, DWA-182, COVR-C1203, and COVR-2202 models (Compl. ¶37).
Functionality and Market Context
These products are described as wireless networking devices, such as extenders, adapters, and mesh systems (Compl. ¶37). The core of the infringement allegation is that these devices are "adapted to operate in and with" wireless networks that comply with the IEEE 802.11ac standard. The complaint alleges that by operating on such networks, the products necessarily practice the methods claimed in the patents-in-suit (Compl. ¶38). The complaint does not provide further detail on the products' market positioning.
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
’204 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| estimating the CSI by calculating a plurality of channel responses each for one of the communication channels | The mobile station is configured to estimate CSI by calculating responses for each communication channel. | ¶39 | col. 4:4-6 |
| wherein the estimating further comprises selecting a plurality of channel taps from each of the calculated channel responses | The mobile station selects channel taps from each calculated channel response. | ¶39 | col. 4:7-13 |
| compressing the estimated CSI | The mobile station can also compress the estimated CSI. | ¶39 | col. 4:13-15 |
| and sending the compressed CSI as the feedback to the base station | It can send the compressed CSI as feedback to the base station. | ¶39 | col. 4:5-8 |
Identified Points of Contention (’204 Patent)
- Scope Question: A central issue would be whether the standard CSI feedback mechanisms defined in the IEEE 802.11ac standard fall within the scope of the term "compressing the estimated CSI." The complaint's allegations are conclusory and do not specify how the accused devices allegedly compress the CSI in the manner claimed.
- Evidentiary Question: The case may turn on what evidence Plaintiff presents to demonstrate that the accused products perform compression using a method covered by the claims, rather than a different, non-infringing method of reducing feedback.
’096 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| generating a first section comprising data configured in a first format compatible with a first communication system... | The accused devices "employ the patented frame structure for data transmission in which legacy communication format...[is] combined into a unitary frame structure." | ¶45 | col. 4:40-54 |
| generating a second section following the first section, the second section comprising data configured in a second format compatible with a second communication system... | The accused devices employ a "...very high throughput communication format [that is] combined into a unitary frame structure." | ¶45 | col. 5:6-16 |
| wherein the second format is compatible with the second communication system configured to support higher mobility... [and] has a shorter symbol period... | The complaint alleges the use of a "legacy" and "VHT" format but does not provide specific facts to support the "higher mobility" or "shorter symbol period" limitations. | ¶45 | col. 8:43-48 |
Identified Points of Contention (’096 Patent)
- Technical Question: A key dispute will likely focus on whether the "VHT" (Very High Throughput) format used in 802.11ac, as implemented in Defendant's products, in fact has a "shorter symbol period" and is configured for "higher mobility" relative to a "legacy" format as required by the claim. The complaint does not allege facts to support this crucial technical limitation.
- Scope Question: The parties may dispute what constitutes a "first communication system" versus a "second communication system" in the context of the 802.11ac standard, which incorporates multiple modes of operation.
V. Key Claim Terms for Construction
Term from ’204 Patent: "compressing the estimated CSI"
- Context and Importance: This term is the central novel element of the ’204 patent. Whether the standard operation of an 802.11ac device constitutes "compressing" will be determinative of infringement. Practitioners may focus on this term because its construction could read on a wide range of industry-standard products or be narrowed to the specific embodiments in the patent.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself is general. The summary of the invention also broadly recites "compressing the estimated CSI" without tying it to a specific algorithm (col. 2:50-58).
- Evidence for a Narrower Interpretation: The detailed description repeatedly and specifically describes compression using a "least squares (LS) method" (col. 4:53-56, FIGS. 3B-3C) and a "discrete cosine transform (DCT)" (col. 7:7-10, FIG. 4A). A party could argue these specific embodiments define and limit the scope of the term.
Term from ’096 Patent: "a shorter symbol period"
- Context and Importance: This is a critical limitation that technically distinguishes the "second section" of the claimed frame structure from the "first section." Plaintiff must prove the accused products' VHT format meets this requirement relative to a legacy format.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The term itself is a straightforward relative comparison, suggesting any symbol period that is measurably shorter would suffice.
- Evidence for a Narrower Interpretation: The specification explicitly links the shorter symbol period to enhancing performance in a "high-mobility environment" (col. 5:6-16). A party may argue that the term should be construed to mean not just any shorter period, but one that is implemented for the stated purpose of supporting high mobility, potentially limiting its application to specific operational modes.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement. The factual basis for inducement includes Defendant designing its products to operate on infringing networks and publishing "manuals and promotional literature describing and instructing in the operation" of the devices in an infringing manner (Compl. ¶¶ 42, 48, 54).
- Willful Infringement: The complaint seeks treble damages for willful infringement (Compl. ¶58.D). The basis for this claim appears to be post-suit knowledge, as the complaint alleges Defendant has had knowledge of infringement "since it received notice of its infringement" of each patent (Compl. ¶¶ 42, 48, 54).
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary issue is one of procedural viability: given the post-filing IPR proceedings that resulted in the cancellation of all asserted claims of the ’204 and ’326 patents, the central question for the court will be whether any viable infringement causes of action remain for two of the three patents-in-suit. The case may be effectively narrowed to the allegations concerning only the ’096 patent.
- For the remaining ’096 patent, a key evidentiary question will be one of technical proof: can the Plaintiff demonstrate that the accused 802.11ac products implement a data frame with a "second section" that meets the specific and limiting claim requirements of being configured for "higher mobility" and having a "shorter symbol period"? The complaint's allegations on this front are currently conclusory.
- Should the ’204 patent claims somehow survive, a dispositive question will be one of claim scope: can the term "compressing the estimated CSI" be construed to cover the standard feedback mechanisms of the IEEE 802.11ac standard, or is its meaning confined to the specific least-squares and DCT-based methods detailed in the patent's specification?