PDCP State Variable Handling for Wireless Handover Security

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Solution Overview

Problem

In wireless communication systems, there is a challenge in securely handling state variables during handover procedures, particularly in ensuring that the same COUNT value is not used for security when reporting handover failures to the source network.

Innovation Solution

The method involves a user equipment (UE) receiving a handover command with COUNT values from a first network, establishing a second PDCP entity for a target network while maintaining the first PDCP entity, and upon detecting handover failure, setting state variables for the first PDCP entity using the indicated COUNT values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the UE reuses the same COUNT value for reporting handover failure to the source network, then the handover failure can be reported efficiently, but security issues arise due to potential replay attacks

Engineering Contradiction:

Improvehandover failure reporting efficiencyVSAvoidsecurity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-incrementing the COUNT value before reporting handover failure. When the UE detects handover failure, it increments the COUNT value stored in the first PDCP entity before using it to report the failure to the source network. This ensures that the COUNT value used for reporting is already updated and different from the one used during the failed handover, preventing replay attacks while maintaining efficient failure reporting.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the UE maintains the first PDCP entity during handover, then security context is preserved for failure reporting, but the risk of COUNT value reuse increases

Engineering Contradiction:

Improvesecurity context preservationVSAvoidCOUNT value reuse vulnerability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the COUNT value parameter in the first PDCP entity. Instead of discarding the first PDCP entity or using the same COUNT value for failure reporting, the UE increments the COUNT value parameter before using it for handover failure reporting. This parameter change ensures that the security context is preserved while eliminating the vulnerability to COUNT value reuse attacks.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12302179B2Method and apparatus for handling state variables for security during handover procedure in wireless communication system

Publication Date: 2025.05.13 LG ELECTRONICS INC

AI summary

The present invention relates to a method of performing a handover procedure by a user equipment (UE) in a wireless communication system. Especially, the method includes the steps of receiving a handover command containing information about at least one COUNT value from a first network; establishing a first Packet Data Convergence Protocol (PDCP) entity associated with a second network while maintaining a second PDCP entity associated with the first network; performing a random access procedure with the second network; and based on a handover failure with the second network being detected, transmitting a message for informing the handover failure to the first network with setting at least one state variable for the first PDCP entity according to the at least one COUNT value.