L1/L2 Triggered Mobility Signaling with Next-Hop Key Chaining

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing mobility and security signaling in heterogeneous networks, particularly in 5G networks, leading to inefficiencies and potential security vulnerabilities.

Innovation Solution

Implementing a mechanism for signaling security information in mobility management, utilizing advanced protocols and configurations in the NR user plane and control plane to enhance security and mobility management in 5G networks, including the use of gNBs and ng-eNBs to manage multiple technologies and releases, and employing flexible criteria for implementing protocols based on device and network configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing wireless communication systems use traditional mobility management protocols, then device compatibility is maintained, but security vulnerabilities and inefficiency increase

Engineering Contradiction:
ImprovesecurityVSAvoidsignaling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments security information signaling into specific mobility management messages (Handover Request, Handover Accept, Handover Confirm) rather than using separate security procedures. This integrates security into the existing mobility signaling flow, reducing overall signaling complexity while maintaining security functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent makes existing mobility management messages multi-functional by incorporating security information (security indicators, security keys, security algorithms) into standard handover messages. This allows a single message to simultaneously handle mobility transition and security establishment, eliminating the need for separate security signaling.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If security information is added to mobility signaling messages, then security is improved, but message size and processing complexity increase

Engineering Contradiction:
ImprovesecurityVSAvoidmessage size
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges security information with mobility management information in the same signaling messages. For example, the Handover Request message contains both handover command elements and security indicator elements, eliminating the need for separate security messages and reducing overall message volume.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses compact parameter representations for security information, such as security indicators that identify security algorithms and keys using efficient encoding schemes. This minimizes the additional bytes required while conveying necessary security parameters.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If heterogeneous networks support multiple technologies and releases, then versatility is improved, but signaling efficiency decreases

Engineering Contradiction:
Improvetechnology compatibilityVSAvoidsignaling efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements dynamic security parameter selection where security algorithms and keys are chosen based on the specific technology type (NR, E-UTRA, NR-LTE) and release version of the target cell. This allows the system to adapt security signaling to the specific technology context, maintaining efficiency across heterogeneous networks.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies technology-specific and release-specific security configurations at each target cell level. Each cell can have customized security parameters appropriate to its technology type and release version, while the overall system maintains a unified handover signaling framework that works across all technologies.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4672792A1Signaling of security information for mobility
Publication Date: 2025.12.31 OFINNO LLC
  • EP4672792A1 patent drawingFigure 1A~1B
  • EP4672792A1 patent drawingFigure 2A~2B
  • EP4672792A1 patent drawingFigure 3

AI summary

A method can include transmitting, by a first base station to a wireless device, a radio resource control (RRC) message including a layer 1/ layer 2 triggered mobility (LTM) configuration of a cell of a second base station. The method can also include receiving, by a distributed unit (DU) of the first base station from a central unit (CU) of the first base station, a message indicating a next hop chaining count (NCC) for deriving a key of the second base station and an identifier of the cell. The method can further include determining to execute the LTM, of the wireless device, to the cell. The method can additionally include transmitting, to the wireless device, an LTM cell switch medium access control (MAC) control element (CE) for the LTM, indicating the NCC, wherein the LTM cell switch MAC CE comprises an identifier of an LTM candidate configuration of the cell.