DCT
0:14-cv-04671
Regents Of University Of Minnesota v. T-Mobile USA Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Regents of the University of Minnesota (Minnesota)
- Defendant: T-Mobile USA, Inc. (Delaware)
- Plaintiff’s Counsel: Fish & Richardson P.C.
- Case Identification: 0:14-cv-04671, D. Minn., 01/30/2015
- Venue Allegations: Plaintiff alleges venue is proper in the District of Minnesota because Defendant conducts continuous business in the state, operates a wireless communication network including 4G LTE services, and employs sales representatives there.
- Core Dispute: Plaintiff alleges that Defendant’s 4G LTE wireless communication network and services infringe five patents related to improving the reliability and efficiency of high-speed wireless data transmission.
- Technical Context: The patents address fundamental challenges in wireless communications, such as signal fading and interference, which are critical to the performance of modern standards like 4G LTE.
- Key Procedural History: The complaint is a First Amended Complaint. Plaintiff alleges that Defendant had knowledge of the asserted patents no later than November 6, 2014, a fact that may be relevant to potential claims of willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 2002-04-22 | Earliest Priority Date for ’768 and ’230 Patents |
| 2003-05-21 | Earliest Priority Date for ’317, ’185, and ’309 Patents |
| 2007-07-31 | ’768 Patent Issued |
| 2013-11-19 | ’317 Patent Issued |
| 2014-05-06 | ’185 Patent Issued |
| 2014-07-08 | ’309 Patent Issued |
| 2014-11-04 | ’230 Reissue Patent Issued |
| 2014-11-06 | Date of Defendant’s Alleged Knowledge of Asserted Patents |
| 2015-01-30 | First Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,251,768: “Wireless Communication System Having Error-Control Coder and Linear Precoder” (Issued Jul. 31, 2007)
The Invention Explained
- Problem Addressed: In high-rate wireless systems like Orthogonal Frequency Division Multiplexing (OFDM), signal fading can create frequency "nulls" or deep fades that corrupt data transmission, while multipath propagation causes intersymbol interference (ISI) (’768 Patent, col. 1:28-51). While error-control (EC) coding can combat these effects, achieving a high degree of diversity (resilience to fading) often requires an exponential increase in decoding complexity (’768 Patent, col. 2:3-12).
- The Patented Solution: The invention proposes a joint coding and precoding scheme that combines standard error-control coding with a "linear precoder" that operates in the complex field (’768 Patent, Abstract; col. 2:15-20). As shown in FIG. 1, an error-control unit (12) encodes the data, which is then mapped to constellation symbols and processed by a linear pre-coder (18) before modulation (’768 Patent, FIG. 1). This combination is designed to achieve maximum diversity with only a modest increase in complexity, offering a "multiplicative benefit" compared to using either technique alone (’768 Patent, col. 2:38-42).
- Technical Importance: This technique offered a method to improve the robustness of high-speed wireless transmissions against fading without incurring the prohibitive computational costs typically associated with high-diversity error correction codes (’768 Patent, col. 2:23-32).
Key Claims at a Glance
- The complaint asserts infringement of one or more claims of the ’768 Patent (Compl. ¶32). Independent claim 1 is representative.
- Claim 1 Elements:
- An error-control coder that applies an error correction code to produce an encoded data stream.
- A bit interleaver to produce an interleaved data stream.
- A mapping unit to map the interleaved data stream to constellation symbols.
- A precoder that applies a linear transformation to the constellation symbols to produce precoded symbols.
- A symbol interleaver to process the precoded symbols to produce permuted blocks.
- A modulator to produce an output waveform for transmission.
- The complaint does not explicitly reserve the right to assert dependent claims but makes a general allegation of infringement of "one or more claims" (Compl. ¶32).
U.S. Reissue Patent No. RE45,230: “Wireless Communication System Having Linear Encoder” (Issued Nov. 4, 2014)
The Invention Explained
- Problem Addressed: The patent addresses the same fundamental problem of making multicarrier systems like OFDM robust against frequency-selective fading, where channel nulls can make symbol detection difficult or impossible (’230 Patent, col. 2:1-6).
- The Patented Solution: The invention describes a "linear complex-field encoding" technique that introduces memory across the subcarriers (’230 Patent, Abstract). Instead of sending a single data symbol on each subcarrier, the "linear encoder" (10) ensures that each subcarrier carries a "linear combination" of multiple information symbols (’230 Patent, col. 2:48-53; FIG. 1). This spreads the information across the subcarriers, providing diversity gain so that a fade on a single subcarrier does not result in the complete loss of a data symbol.
- Technical Importance: This encoding method provided a way to build signal diversity directly into the transmission structure at the physical layer, making the system inherently more resilient to the frequency-selective fading common in wireless environments (’230 Patent, col. 2:45-53).
Key Claims at a Glance
- The complaint asserts infringement of one or more claims of the ’230 Patent (Compl. ¶38). Independent claim 1 is representative.
- Claim 1 Elements:
- A first encoder that encodes a data stream based on an error-control code.
- An interleaver to interleave the encoded symbols.
- A constellation mapper to map symbols into blocks of K information bearing symbols.
- A second encoder that applies a matrix to linearly transform the blocks of K symbols to produce blocks of N precoded symbols.
- A modulator to generate a multicarrier waveform.
- The complaint generally alleges infringement of "one or more claims" (Compl. ¶38).
Multi-Patent Capsule: ’317, ’185, and ’309 Patents
- Patent Identification:
- U.S. Patent No. 8,588,317, “Estimating Frequency-Offsets and Multi-Antenna Channels in MIMO OFDM Systems,” Issued Nov. 19, 2013.
- U.S. Patent No. 8,718,185, “Estimating Frequency-Offsets and Multi-Antenna Channels in MIMO OFDM Systems,” Issued May 6, 2014.
- U.S. Patent No. 8,774,309, “Estimating Frequency-Offsets and Multi-Antenna Channels in MIMO OFDM Systems,” Issued Jul. 8, 2014.
- Technology Synopsis: These related patents address the problem of accurately estimating channel conditions and carrier frequency offsets (CFO) in complex MIMO-OFDM systems (’317 Patent, Abstract). The inventions describe methods that use training symbols and "hopping" null subcarriers (zero-value symbols that change position from block to block) to decouple the estimation of CFO from the estimation of the channel itself, which can improve the accuracy and efficiency of the overall system (’317 Patent, col. 2:19-35).
- Asserted Claims: The complaint asserts infringement of one or more claims of each patent (Compl. ¶44).
- Accused Features: The allegations target Defendant's LTE wireless communications systems and methods (Compl. ¶43-44).
III. The Accused Instrumentality
Product Identification
Defendant's "4G LTE network" and the wireless communication services provided over that network (Compl. ¶28).
Functionality and Market Context
The complaint alleges that Defendant owns, operates, imports, makes, and/or uses LTE wireless communication systems that provide 4G LTE services to its customers (Compl. ¶28, ¶29). The infringing activities are alleged to relate to the "operation of the radio access portion of Defendant's LTE wireless communication systems" (Compl. ¶29). The complaint does not provide specific technical details on the operation of Defendant's network, instead alleging that the network as a whole embodies the patented inventions (Compl. ¶29).
IV. Analysis of Infringement Allegations
’768 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| an error-control coder that applies an error correction code to produce an encoded data stream of information bearing symbols | Operation of the radio access portion of Defendant's 4G LTE network, which uses error correction coding. | ¶29, ¶32 | col. 3:24-32 |
| a bit interleaver to produce an interleaved data stream... | Operation of the radio access portion of Defendant's 4G LTE network, which uses bit interleaving. | ¶29, ¶32 | col. 3:32-35 |
| a mapping unit to map the interleaved data stream to the constellation symbols... | Operation of the radio access portion of Defendant's 4G LTE network, which maps bits to constellation symbols (e.g., QAM). | ¶29, ¶32 | col. 3:36-42 |
| a precoder that applies a liner transformation to the constellation symbols to produce precoded symbols... | Operation of the radio access portion of Defendant's 4G LTE network, which allegedly performs linear precoding. | ¶29, ¶32 | col. 3:43-48 |
| a symbol interleaver to process the precoded symbols... | Operation of the radio access portion of Defendant's 4G LTE network, which uses symbol interleaving. | ¶29, ¶32 | col. 3:50-55 |
| a modulator to produce an output waveform... for transmission through a wireless channel | Operation of the radio access portion of Defendant's 4G LTE network, which modulates signals for transmission. | ¶29, ¶32 | col. 3:55-60 |
Identified Points of Contention
- Scope Questions: A central question will be whether signal processing performed in Defendant's standard-compliant 4G LTE network meets the specific definition of a "linear pre-coder" that applies a "liner transformation" as claimed. The dispute may focus on whether this term should be interpreted broadly to cover any linear signal processing before modulation or narrowly to the specific unitary precoders discussed in the patent's embodiments (’768 Patent, col. 7:8-24).
- Technical Questions: The complaint provides no specific evidence detailing how Defendant’s network operates. A key question for discovery will be to determine the exact signal processing steps performed within the accused network and whether they map onto the sequence of elements required by claim 1.
’230 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a first encoder that encodes a data stream based on an error-control code to produce encoded symbols | Operation of Defendant's 4G LTE network, which uses error correction coding. | ¶29, ¶38 | col. 27:56-62 |
| an interleaver that interleaves the encoded symbols to produce interleaved symbols | Operation of Defendant's 4G LTE network, which uses interleaving. | ¶29, ¶38 | col. 28:1-3 |
| a constellation mapper that maps the interleaved symbols to produce blocks of K information bearing symbols... | Operation of Defendant's 4G LTE network, which maps data to constellation symbols. | ¶29, ¶38 | col. 28:4-7 |
| a second encoder that applies a matrix to linearly transform the blocks of K information bearing symbols...to produce blocks of N precoded symbols... | Operation of Defendant's 4G LTE network, which allegedly performs a linear encoding transformation on blocks of symbols. | ¶29, ¶38 | col. 28:8-12 |
| a modulator that generates a multicarrier waveform... | Operation of Defendant's 4G LTE network, which generates a multicarrier (OFDM) waveform. | ¶29, ¶38 | col. 28:13-14 |
No probative visual evidence provided in complaint.
Identified Points of Contention
- Scope Questions: The analysis will likely focus on the construction of "second encoder that applies a matrix to linearly transform" the symbol blocks. The question will be whether this term covers any matrix-based signal processing inherent in the 4G LTE standard or is limited to the specific types of Vandermonde or Cosine encoders disclosed in the patent (’230 Patent, col. 11:7-19).
- Technical Questions: As with the ’768 patent, the complaint lacks factual detail linking the claim elements to specific operations in Defendant's network. An evidentiary question will be whether Defendant's system performs two distinct encoding steps that correspond to the claimed "first encoder" (for error control) and "second encoder" (for linear transformation).
V. Key Claim Terms for Construction
- The Term: "linear pre-coder" (’768 Patent, claim 1) / "linearly transform" (’230 Patent, claim 1)
- Context and Importance: These terms are foundational to the asserted claims of both lead patents. The infringement case will hinge on whether the signal processing performed in Defendant’s 4G LTE network falls within the scope of these terms. Practitioners may focus on these terms because they represent the core of the inventions, and their construction will likely determine whether a standard-compliant LTE system infringes.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The ’768 patent specification describes the precoder as operating "over a complex field with no restriction on the input symbol alphabet or the precoded symbol alphabet" (’768 Patent, col. 2:28-32). The ’230 patent describes the linear transformation generally as creating "different linear combinations of the information symbols on the subcarriers" (’230 Patent, col. 2:51-53). This language could support a broad, functional definition.
- Evidence for a Narrower Interpretation: Both patents disclose specific mathematical structures for the precoder/encoder. The ’768 patent provides examples of specific unitary precoder matrices (’768 Patent, col. 7:8-24). The ’230 patent describes specific Vandermonde and Cosine encoders (’230 Patent, col. 11:7-19). A defendant may argue that the claims should be limited to these disclosed embodiments or structures with similar properties.
VI. Other Allegations
Indirect Infringement
The complaint alleges both induced and contributory infringement. The allegations state that Defendant encourages infringement by requiring customer devices to operate on its LTE network in an infringing manner and through marketing and advertising (Compl. ¶33, ¶39, ¶45). It further alleges Defendant sells components, such as mobile devices, knowing they are "especially made or especially adapted for use in the infringement" and are not staple articles of commerce (Compl. ¶30, ¶33).
Willful Infringement
The complaint alleges Defendant had knowledge of all asserted patents "no later than November 6, 2014," prior to the filing of the amended complaint (Compl. ¶30, ¶33, ¶39, ¶45). It also alleges willful blindness, stating Defendant "knows there is a high probability that the use of its LTE wireless communication systems constitutes direct infringement... but has taken deliberate actions to avoid learning of these facts" (Compl. ¶33).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: How will the court construe the key inventive concepts of "linear pre-coder" and "linear encoder"? The outcome of the case may depend on whether these terms are interpreted broadly to encompass signal processing inherent in the 4G LTE standard, or more narrowly to reflect the specific mathematical embodiments disclosed in the patents.
- A key evidentiary question will be one of technical implementation: Assuming a claim construction is established, what evidence will discovery yield about the specific hardware and software implementation of Defendant's radio access network? The complaint's theory appears to be that compliance with the 4G LTE standard equates to infringement, raising the question of whether infringement is automatic for any LTE network or depends on non-standardized implementation choices made by the operator.