Peninsula Tech LLC v. AT&T Mobility LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Peninsula Technologies, LLC (Texas)
  • Defendant: AT&T Mobility LLC (Delaware)
  • Plaintiff's Counsel: Nelson Bumgardner Conroy PC
• Case Identification: 2:26-cv-283, E.D. Tex., 04/07/2026
• Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant is subject to personal jurisdiction, has committed acts of infringement in the district, and maintains "regular and established places of business" in the district, including retail stores and infringing base station equipment.
• Core Dispute: Plaintiff alleges that Defendant's 4G and 5G mobile networks infringe four patents related to wireless communication procedures, including network slicing for handovers, access management for non-public networks, and cell configuration.
• Technical Context: The technology at issue concerns the management of mobile device connections and resources in modern 5G cellular networks, which is fundamental to network efficiency and the support of diverse services.
• Key Procedural History: The complaint alleges that Plaintiff provided Defendant with pre-suit notice of the Asserted Patents and its infringement via a letter on February 10, 2025. It further alleges that claim charts for three of the four patents were made available in a private data room, which was subsequently accessed and its contents downloaded by IP addresses associated with Defendant on February 24, 2025, and March 12, 2025. These allegations form the basis for a claim of willful infringement.

Case Timeline

Date	Event
2017-05-04	'470 Patent Priority Date
2017-09-28	'668 Patent Priority Date
2018-05-04	'470 Patent Application Date
2019-03-27	'273 and '521 Patents Priority Date
2020-08-11	'668 Patent Application Date
2020-12-02	'273 Patent Application Date
2021-09-14	'470 Patent Issue Date
2021-11-29	'521 Patent Application Date
2021-12-07	'273 Patent Issue Date
2023-01-31	'668 Patent Issue Date
2023-10-24	'521 Patent Issue Date
2025-02-10	Notice Letter Sent to Defendant
2025-02-24	Claim Charts Made Available; Allegedly Downloaded by Defendant
2025-03-12	Files Allegedly Downloaded by Defendant
2026-04-07	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,122,470 - "Network slice information for handover procedure"

The Invention Explained

• Problem Addressed: In cellular networks that use "network slicing"-the creation of virtual, customized networks for different services-a technical challenge arises when a mobile device must be handed over from one base station to another that may not support the same network slices or have the necessary resources. US 11,122,470, col. 17:24-34
• The Patented Solution: The patent describes a method for a "first base station" to manage a handover for a device requiring a specific network slice. If the station receives a request for session resources for a slice it cannot provide, it initiates a handover to a "second base station." Crucially, it sends a handover request message that contains a "cause information element" explicitly stating that the reason for the handover is the unavailability of the requested session resources for that network slice. This allows the receiving base station to understand the context and make an informed decision on whether to accept or reject the handover. US 11,122,470, abstract US 11,122,470, fig. 20
• Technical Importance: This method aims to improve handover reliability and efficiency in sliced networks by explicitly communicating the reason for the handover, which may prevent service interruptions or connection failures. Compl. ¶25

Key Claims at a Glance

• The complaint asserts independent claim 1 Compl. ¶25
• The essential elements of claim 1 are:
  • Receiving, by a first base station from a core network entity, a first message requesting session resources for a first network slice.
  • Initiating a handover to a second base station, based on the requested slice resources not being available at the first base station.
  • Sending a second message to the second base station indicating a handover request, which includes a packet flow identifier, a network slice identifier, and a cause information element stating the requested resources are not available.
  • Receiving a third message from the second base station indicating acceptance or rejection of the handover.
• The complaint reserves the right to assert additional claims Compl. ¶25, fn. 1

U.S. Patent No. 11,197,273 - "Cell information for access management"

The Invention Explained

• Problem Addressed: The patent addresses the management of Non-Public Networks (NPNs), which are private cellular networks. In a modern, disaggregated base station architecture (split into a central unit and a distributed unit), there is a need for a structured process to communicate which cells belong to an NPN and manage device access to them.
• The Patented Solution: The invention claims a base station distributed unit (gNB-DU) that performs a three-step method. First, it receives a "first indication" from a base station central unit (gNB-CU) that a cell is associated with an NPN. Second, it transmits a "second indication" (e.g., via a broadcast message) to inform wireless devices that the cell is part of that NPN. Third, it receives a random access preamble from a wireless device that is "associated with" the NPN, signifying an access attempt. US 11,197,273, abstract US 11,197,273, col. 59:9-19
• Technical Importance: This method provides an orderly mechanism within a disaggregated 5G base station (gNB) for advertising private network availability and processing access requests from authorized devices. Compl. ¶37

Key Claims at a Glance

• The complaint asserts independent claim 9 Compl. ¶36
• The essential elements of claim 9 are a base station distributed unit configured to:
  • Receive, from a base station central unit, a first indication that a cell is associated with a first non-public network (NPN).
  • Transmit, via the cell, a second indication that the cell is associated with the first NPN.
  • Receive, via the cell, a random access preamble from a wireless device that is associated with the first NPN.
• The complaint reserves the right to assert additional claims Compl. ¶25, fn. 1

U.S. Patent No. 11,570,668 - "Release of a second session of a wireless device by an access and mobility management function"

Technology Synopsis

The patent describes a method for managing the release of a wireless device's session during a handover between two different Access and Mobility Management Functions (AMFs) in a 5G core network. The invention details a sequence of messages where the source AMF initiates the handover with the target AMF, receives a message back from the target AMF causing the release of the session resources, and then sends requests to both the target AMF and the source Session Management Function (SMF) to finalize the release, ensuring that network resources are efficiently cleaned up after the device has moved. US 11,570,668, abstract

Asserted Claims

The complaint asserts at least claim 1 Compl. ¶46

Accused Features

Plaintiff alleges that Defendant's 5G core network equipment, specifically its AMF and SMF components, infringe by performing the claimed method steps during N2-based inter-AMF handovers as defined by 3GPP standards Compl. ¶¶47-51

U.S. Patent No. 11,800,521 - "Cell configuration"

Technology Synopsis

This patent relates to the configuration of a cell for a Non-Public Network (NPN) within a disaggregated base station architecture. The method involves a base station central unit (gNB-CU) sending a first indication to a base station distributed unit (gNB-DU) that a cell is associated with an NPN. The gNB-CU then receives a second indication from the core network (AMF) that a specific wireless device is authorized for that NPN. Based on this device-specific authorization, the gNB-CU sends a request to the gNB-DU to configure the cell specifically for that wireless device. US 11,800,521, abstract

Asserted Claims

The complaint asserts at least claim 1 Compl. ¶58

Accused Features

Plaintiff alleges that Defendant's 5G base station equipment, including its gNB-CU and gNB-DU components, infringe by performing the claimed NPN cell configuration methods in accordance with 3GPP standards Compl. ¶¶59-61

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Defendant AT&T's 4G and 5G cellular networks, which include core network equipment (such as Access and Mobility Management Functions and Session Management Functions) and radio access network equipment (such as base stations, or gNBs, which are composed of central and distributed units) (Compl. ¶11; Compl. ¶12).

Functionality and Market Context

• The complaint alleges that the accused networks operate in compliance with 3GPP standards, including features from Releases 15, 16, and 17, which define functionalities for network slicing, Non-Public Networks (NPNs), and handover procedures Compl. ¶12 The infringement allegations center on the standardized operation of these network components in managing device sessions and mobility (Compl. ¶25; Compl. ¶26; Compl. ¶27; Compl. ¶28; Compl. ¶29). The complaint presents a diagram from a 3GPP technical specification to illustrate the message flow for a PDU session resource setup, which is alleged to be part of the infringing activity Compl. p. 8
• AT&T is identified as one of the three largest mobile network operators in the United States, serving over 118 million subscribers, positioning the accused networks as commercially significant Compl. ¶10

IV. Analysis of Infringement Allegations

11,122,470 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
receiving, by a first base station from a core network entity, a first message indicating a request for session resources for a wireless device, wherein the session resources are for a first network slice;	The first base station (gNB) receives a PDU Session Resource Setup Request message from a core network entity (AMF), where the message contains an S-NSSAI element identifying the network slice.	¶26	col. 27:19-25
initiating, by the first base station and based on the requested session resources for the first network slice not being available for the wireless device at the first base station, a handover for the wireless device towards a first cell of a second base station;	Upon determining that the resources for the requested network slice are unavailable, the first base station (source NG-RAN) initiates a handover to a second base station (target NG-RAN).	¶27	col. 27:26-31
sending, to the second base station and based on the initiating, a second message indicating a handover request, the second message comprising: a packet flow identifier of a packet flow associated with the first network slice; a network slice identifier of the first network slice for the handover request; and a cause information element indicating that a cause for the handover request is that the requested session resources are not available, at the first base station, for the first network slice identified by the network slice identifier;	The first base station sends a Handover Request message to the second base station. This message allegedly includes a PDU Session ID (packet flow identifier), an S-NSSAI (network slice identifier), and a Cause IE indicating that resources are unavailable (e.g., "Radio resources not available" or "Slice(s) not supported"). The complaint provides a visual from a technical standard highlighting the Cause IE and its potential values Compl. p. 10	¶28	col. 27:32-43
receiving, from the second base station, a third message indicating an acceptance or a rejection based on the second message.	The first base station receives either a Handover Request Acknowledgement (acceptance) or a Handover Preparation Failure (rejection) message from the second base station.	¶29	col. 27:40-43

• Identified Points of Contention:
  • Scope Questions: A potential point of contention may be whether the Cause IE values cited in the complaint, such as "Slice(s) not supported," meet the specific claim requirement that the cause is "that the requested session resources are not available." The court may need to determine if these are functionally and legally equivalent for the purposes of this claim.
  • Technical Questions: The infringement theory relies on the 3GPP standards. A key evidentiary question will be whether AT&T's network, in its actual operation, initiates handovers because of slice resource unavailability and populates the Cause IE with the specific values alleged, or if handovers are triggered for other reasons not covered by the claim.

11,197,273 Infringement Allegations

Claim Element (from Independent Claim 9)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
receive, from a base station central unit, a first indication that a cell is associated with a first non-public network (NPN);	The base station distributed unit (gNB-DU) receives a GNB-DU Configuration Update Acknowledge message from the central unit (gNB-CU). This message allegedly includes an Available SNPN ID List information element, which serves as the claimed "first indication."	¶37	col. 59:13-15
transmit, via the cell, a second indication that the cell is associated with the first NPN;	The gNB-DU broadcasts a System Information Block 1 (SIB1) message, which contains an npn-IdentityInfoList field. This broadcast serves as the "second indication" to wireless devices that the cell supports the NPN. The complaint includes a visual depicting the structure of the SIB1 message Compl. p. 17	¶38	col. 59:16-17
receive, via the cell, a random access preamble from a wireless device that is associated with the first NPN.	After processing the SIB1 message, an NPN-capable wireless device sends a random access preamble on the Physical Random Access Channel (PRACH) to the gNB-DU to initiate access to the NPN.	¶39	col. 59:18-19

• Identified Points of Contention:
  • Scope Questions: The construction of "wireless device that is associated with the first NPN" may be a focal point. It raises the question of whether the device must be pre-authorized with the network before sending the preamble, or if simply being an "NPN-Capable" device that has read the broadcasted NPN information is sufficient to meet the limitation.
  • Technical Questions: The case may turn on evidence showing that AT&T's disaggregated base stations (gNB-CUs and gNB-DUs) actually perform this specific sequence of communication. While the standards describe these messages and information elements, demonstrating their use in AT&T's commercial network to manage NPN access will be a key evidentiary hurdle.

V. Key Claim Terms for Construction

The Term: "cause information element indicating that a cause for the handover request is that the requested session resources are not available" ('470 Patent, Claim 1)

• Context and Importance: This term is central to the infringement theory for the '470 Patent, as it defines the specific reason for the handover that must be communicated between base stations. The dispute will likely focus on what specific message contents satisfy this limitation. Practitioners may focus on this term because the complaint's own evidence points to related but textually different cause values, such as "Slice(s) not supported" Compl. p. 12
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent abstract states the handover request is "to provide at least one network slice for the wireless device," which may support an argument that any cause value communicating a slice-related resource issue fulfills the claim's purpose US 11,122,470, abstract
  • Evidence for a Narrower Interpretation: The claim language itself is highly specific, reciting the exact reason. A defendant may argue that this precise wording was chosen to distinguish it from other, more general cause values, thereby limiting the claim scope to only that explicit reason US 11,122,470, col. 27:38-41

The Term: "wireless device that is associated with the first NPN" ('273 Patent, Claim 9)

• Context and Importance: This term in the final step of claim 9 defines the characteristic of the device from which the preamble is received. Its construction is critical because it determines the required state or capability of the device at the moment of the access attempt. Practitioners may focus on this term because it dictates the evidentiary requirements for proving the final element of the claim.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification does not appear to provide an explicit definition. A plaintiff may argue that in the context of access management, a device becomes "associated with" the NPN by virtue of receiving the broadcasted NPN information and subsequently attempting to access it, without requiring prior network-side authorization.
  • Evidence for a Narrower Interpretation: A defendant may argue that the term implies a pre-existing relationship, such as being on an access control list or having a subscription for that NPN. The context of NPNs as private, restricted networks could be used to support an interpretation requiring some form of pre-authorization before a device can be considered "associated with" it.

VI. Other Allegations

• Indirect Infringement: The complaint focuses on direct infringement under 35 U.S.C. § 271(a) by Defendant's operation of its cellular network and does not plead specific facts to support claims of induced or contributory infringement.
• Willful Infringement: Willfulness is alleged for all four asserted patents. The allegations are based on pre-suit knowledge stemming from a notice letter delivered on February 10, 2025, and Defendant's alleged downloading of related claim charts from a data room on two separate occasions thereafter, followed by continued infringing conduct Compl. ¶¶20-21 Compl. ¶32 Compl. ¶42 Compl. ¶54 Compl. ¶64

VII. Analyst's Conclusion: Key Questions for the Case

• Evidentiary Burden: A primary question will be one of evidentiary sufficiency: can the Plaintiff demonstrate that Defendant's commercially deployed network performs the specific, multi-step methods recited in the claims? The complaint relies heavily on the capabilities described in 3GPP technical standards, and a central issue will be bridging the gap between what the standards allow and what can be proven to occur in Defendant's actual network operations.
• Causality and Claim Scope: The case for the '470 Patent will likely involve a key question of causality and construction: does the claim require that the unavailability of slice-specific resources is the actual trigger for the handover, and must the "cause information element" communicate this exact reason? The court's interpretation of this limitation will be critical to determining the scope of infringement.
• System-Level Operation: For the NPN-related patents ('273 and '521), a core issue will be one of integrated system function: does the evidence show that Defendant's disaggregated base station components (the gNB-CU and gNB-DU) operate together as a cohesive system to perform the full sequence of claimed steps, from internal configuration messaging to external broadcasting and receiving access requests from appropriately "associated" devices?