DCT
2:25-cv-00841
Empire Technology Development LLC v. AT&T Services Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Empire Technology Development LLC (Delaware)
- Defendant: AT&T Services, Inc., AT&T Mobility LLC, AT&T Enterprises, LLC (Delaware)
- Plaintiff’s Counsel: Capshaw DeRieux, LLP; Milbank LLP
- Case Identification: 2:25-cv-00841, E.D. Tex., 08/21/2025
- Venue Allegations: Plaintiff alleges venue is proper based on Defendant AT&T maintaining regular and established places of business in the district, committing acts of infringement in the district, and having previously admitted to proper venue in the district in prior litigation.
- Core Dispute: Plaintiff alleges that Defendant’s U.S. cellular networks, which support 4G LTE and 5G services, infringe patents related to dynamic load balancing between heterogeneous networks and power control for network control channels.
- Technical Context: The technologies at issue address fundamental challenges in modern cellular networks: managing user transitions (handovers) between different network types (e.g., 5G and 4G LTE) and optimizing power allocation to prevent interference and ensure reliable communication.
- Key Procedural History: The complaint references prior litigation involving AT&T in the Eastern District of Texas to support jurisdictional and venue allegations, but mentions no substantive procedural history, such as prior challenges or licensing, related to the patents-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 2010-09-07 | ’957 Patent Priority Date |
| 2011-05-09 | ’839 Patent Priority Date |
| 2014-09-09 | ’957 Patent Issued |
| 2015-02-17 | ’839 Patent Issued |
| 2025-08-21 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,830,957 - "DYNAMIC INTERNETWORK LOAD BALANCING," Issued Sep. 9, 2014
The Invention Explained
- Problem Addressed: The patent describes the challenge of managing wireless devices in areas with overlapping coverage from different types of "heterogeneous" networks (e.g., Wi-Fi and cellular). A network can become congested, but simply handing off a single device to another network may not be possible if that other network is also busy. The patent states that existing systems lack a coordinated approach to manage access between such networks. (’957 Patent, col. 1:10-40).
- The Patented Solution: The invention proposes a coordinated "swap" of wireless devices between two different networks to balance the load. A "vertical handover manager" identifies a triggering event (e.g., signal degradation for one device) and, instead of a simple one-way handover, coordinates a first handover for a first device (e.g., from Network A to B) with a second handover for a second device (from Network B to A). (’957 Patent, col. 2:42-55). This coordination is managed using a "multiuser table" that contains network, core, and user information for devices on both networks. (’957 Patent, col. 7:59-col. 8:5; Fig. 3).
- Technical Importance: This approach aims to improve overall network efficiency and user experience by treating load balancing as a systemic, multi-device problem rather than a series of independent, single-device handovers. (Compl. ¶ 27).
Key Claims at a Glance
- Independent Claim 1: A method for vertical handovers.
- Receiving an indication of one or more triggering events associated with vertical handovers.
- Determining candidates for vertical handovers, including a first device on a first network and a second device on a second network.
- Performing the handovers by executing a first handover (device 1 from network 1 to 2) and a second handover (device 2 from network 2 to 1).
- Maintaining, by multiple vertical handover managers at respective access nodes, a "multiuser table" containing network, user, and core information from both networks.
- The complaint asserts at least claim 1 and does not explicitly reserve the right to assert other claims. (Compl. ¶ 40).
U.S. Patent No. 8,958,839 - "POWER CONTROL OF CONTROL CHANNELS IN AN LTE SYSTEM," Issued Feb. 17, 2015
The Invention Explained
- Problem Addressed: In cellular systems like LTE, base stations transmit scheduling information on a Physical Downlink Control Channel (PDCCH). The patent notes that if base stations in neighboring cells transmit the PDCCH at the same power level, it can cause interference, making it difficult for user equipment (UE), especially near cell edges, to decode critical network instructions. (’839 Patent, col. 1:9-20).
- The Patented Solution: The invention proposes separating the PDCCH into two parts and controlling their transmission power independently. First, scheduling data intended for all users (in a "common search space") is transmitted with a first power. Second, scheduling data for a specific user (in a "specific search space") is transmitted with a second, independently determined power. (’839 Patent, Abstract; col. 2:51-57). This allows the network to adjust the power for a specific user based on their unique conditions (e.g., distance or channel quality) without altering the power for the common broadcast information.
- Technical Importance: This method seeks to reduce inter-cell interference and improve system performance by applying power more efficiently, boosting it only when necessary for specific users rather than for all control transmissions. (Compl. ¶ 35).
Key Claims at a Glance
- Independent Claim 1: A method for power control.
- Transmitting first scheduling data in a common search space of a PDCCH with a first transmission power.
- Transmitting second scheduling data in a specific search space of the PDCCH with a second transmission power.
- Determining the magnitude of the first transmission power based on one or more first criteria.
- Determining the magnitude of the second transmission power based on one or more second criteria independent from the first criteria.
- The complaint asserts at least claims 1 and 4. (Compl. ¶ 84). Dependent claim 4 adds the limitation that the "second criteria" for the specific search space power includes a received Channel Quality Indicator (CQI) from the user equipment. (’839 Patent, col. 16:34-38).
III. The Accused Instrumentality
- Product Identification: AT&T's U.S. cellular networks, including base stations and related equipment that support 4G LTE and 5G services. (Compl. ¶ 8). For the ’839 Patent, the complaint specifically identifies Ericsson base station antennas as part of the accused instrumentalities. (Compl. ¶ 93).
- Functionality and Market Context:
- The complaint alleges that the accused networks perform "vertical handovers" to manage mobility between different network technologies, such as 5G and 4G LTE. (Compl. ¶ 47). This includes procedures like Evolved Packet System ("EPS") fallback, where a device moves from 5G to 4G to handle a voice call. (Compl. ¶ 49). A diagram in the complaint illustrates a user equipment (UE) mobility path moving between the smaller coverage footprint of a 5G base station (gNB) and the larger footprint of a co-located 4G base station (eNB). (Compl. ¶ 50).
- The complaint further alleges the networks perform power control on the PDCCH, using features like "PDCCH power boost" to adjust transmission power based on factors including network resource allocation and channel quality feedback from user devices. (Compl. ¶¶ 105, 110, 115).
IV. Analysis of Infringement Allegations
’957 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| receiving an indication of one or more triggering events associated with vertical handovers of wireless devices; determining candidates for vertical handovers... | AT&T's network determines that a UE is a candidate for handover by monitoring for triggering events, such as moving out of 5G coverage or initiating an IMS voice call that requires fallback to 4G LTE, as defined by 3GPP standards. | ¶¶ 51, 53, 56-57 | col. 2:45-48 |
| performing the vertical handovers including: executing a first vertical handover... from the first wireless network to the second... [and] a second vertical handover... from the second wireless network to the first... | The network executes handovers between 5G (NG-RAN) and 4G (E-UTRAN) networks in both directions, as described in 3GPP technical specifications for inter-system mobility. | ¶¶ 61-62, 64 | col. 2:49-52 |
| maintaining, by multiple vertical handover managers each collocated at a respective access node, a multiuser table including network information and user information... and core information from a core network... | Base stations (access nodes) allegedly function as "vertical handover managers" that use "Neighbor Cell Relation" (NCR) tables, managed by the Automatic Neighbor Relation (ANR) function, to store network and user data. The complaint alleges these NCR tables are the claimed "multiuser table." The N26 interface is alleged to be the "core network" that is separately coupled and stores core information. | ¶¶ 66, 70-71, 76 | col. 2:53-61 |
- Identified Points of Contention:
- Scope Question: Does the accused functionality of performing standard, sequential handovers between 4G and 5G networks meet the claim limitation of "executing a first vertical handover ... [and] executing a second vertical handover," which the patent specification describes as a coordinated, concurrent "swap"? (’957 Patent, col. 4:56-62).
- Technical Question: Does the 3GPP-standard "Neighbor Cell Relation" (NCR) table, used for managing adjacent cell information for routine mobility, perform the same function as the claimed "multiuser table," which the patent describes as a tool to coordinate a swap between two specific devices on different heterogeneous networks? (’957 Patent, col. 6:31-36; Fig. 3). The complaint presents a diagram from a 3GPP standard showing the ANR function, which "allows OAM [the operator] to manage the NCRT." (Compl. ¶ 72).
’839 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| transmitting, with a first transmission power, first scheduling data in a common search space of a Physical Downlink Control Channel (PDCCH) | AT&T's networks transmit System Information Block 1 ("SIB1") in the "common search space CORESET 0" in accordance with 3GPP standards. | ¶ 95 | col. 1:27-29 |
| transmitting, with a second transmission power, second scheduling data in a specific search space of the PDCCH | AT&T's networks assign each UE a "specific search space" for monitoring the PDCCH for its own control information. | ¶¶ 99-101 | col. 1:29-32 |
| determining a magnitude of the first transmission power... based on one or more first criteria | The network determines the power for the common search space based on the number of needed Control Channel Element ("CCE") resources, which triggers a "PDCCH power boost feature." | ¶¶ 110-113 | col. 15:61-63 |
| determining a magnitude Pi of the second transmission power... based on one or more second criteria independent from the first criteria | The network determines the power for the UE-specific search space based on channel quality, including the Block Error Rate ("BLER") target and the Channel Quality Indicator ("CQI") input from the UE, which also triggers the "PDCCH power boost feature." | ¶¶ 115-117 | col. 16:1-4 |
- Identified Points of Contention:
- Scope Question: Do the alleged "first criteria" (CCE resource allocation) and "second criteria" (channel quality/CQI) constitute criteria that are "independent" as required by the claim, or are they inherently related aspects of a single goal of ensuring reliable transmission? The complaint presents a 3GPP standards table showing distinct "Common" and "UE-specific" search spaces for PDCCH candidates. (Compl. ¶ 96).
- Technical Question: Does the accused "PDCCH power boost feature" represent two distinct power determination processes for two different power levels, or is it a single feature that adjusts power based on a combination of inputs? The complaint alleges the feature is triggered by CCE needs for the common space and by CQI/BLER for the specific space. (Compl. ¶¶ 113, 117).
V. Key Claim Terms for Construction
’957 Patent: "multiuser table"
- Context and Importance: This term is central to the invention's mechanism for coordinating handovers. Its definition will determine whether standard network management tools like the accused NCR tables fall within the claim scope.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim itself broadly defines the table's contents as "network information and user information from the first and second wireless networks, and core information from a core network." (’957 Patent, col. 16:55-61). This could arguably encompass any data structure holding such information.
- Evidence for a Narrower Interpretation: The specification repeatedly links the table to the specific function of identifying and coordinating swaps. Figure 3 provides a specific embodiment of the table with columns for "Trigger Event?", "Swap Can.?", and "Swap NW," suggesting its purpose is more specific than general network neighbor management. (’957 Patent, Fig. 3; col. 7:59-col. 8:5).
’839 Patent: "independent from the first criteria"
- Context and Importance: This limitation distinguishes the invention from prior art power control methods. The dispute will likely hinge on whether the criteria for setting the common search space power and the specific search space power are sufficiently distinct.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent does not explicitly define "independent." One could argue that if the determinations use different inputs (e.g., system-wide parameters vs. UE-specific feedback) and are performed as separate logical steps, they are "independent" even if they serve a related purpose.
- Evidence for a Narrower Interpretation: A defendant may argue "independent" requires that the criteria be unrelated in both their nature and their effect on the system. The specification distinguishes between a first power for the common space and a second power for the specific space, where the second power determination can be based on a CQI from the UE, a factor entirely unrelated to the system-level needs governing the common space. (’839 Patent, col. 2:58-63).
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement for both patents, stating AT&T "directs and controls all aspects of the... Accused Instrumentalities" and encourages and instructs users to use the infringing services. (Compl. ¶¶ 42, 44, 86, 88).
- Willful Infringement: Willfulness allegations for both patents are based on alleged knowledge of the patents and their infringement "at least since the filing and service of this Complaint." (Compl. ¶¶ 78, 123).
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary issue for the ’957 Patent will be one of technical and functional equivalence: Can Plaintiff demonstrate that standardized network functions for managing neighbor cell lists (ANR/NCR) and executing routine, sequential handovers are equivalent to the patent's specific disclosure of using a "multiuser table" to actively coordinate a concurrent "swap" between two devices to balance load?
- A central question for the ’839 Patent will be one of claim construction and proof: Does the term "independent" require the criteria for setting the two power levels to be functionally and causally distinct? Further, does the accused "PDCCH power boost feature" in AT&T's network actually implement two separate power determination methods based on such independent criteria, or is it a single, integrated power adjustment mechanism?