User Equipment Handling Non-Integrity-Protected Reject Messages
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Solution Overview
Problem
Current 5G NR technology specifications do not define specific behaviors for User Equipment (UE) to handle non-integrity-protected reject messages, leading to indeterminate behavior or operation errors when registered with different 3GPP core networks over various access types.
Innovation Solution
A UE with a wireless transceiver and controller, configured to receive reject messages without integrity protection and search for alternative cells or access points, ensuring seamless communication and service continuity by ignoring non-integrity-protected reject messages when registered with 3GPP core networks over 3GPP or non-3GPP access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE follows current 3GPP specifications for handling reject messages, then the UE can operate in standard-compliant mode, but the UE behavior becomes indeterminate or errors occur when receiving non-integrity-protected reject messages while registered over different accesses
Solution Approach 1:
The patent inverts the traditional approach by not treating the reject message as authoritative when integrity protection is absent. Instead of following the reject message instructions, the UE ignores them and maintains its current registration state, effectively inverting the normal message-processing logic to handle this specific security concern.
Solution Approach 2:
The patent changes the parameter of message integrity verification by checking whether integrity protection is present before processing the reject message. This parameter change allows the UE to differentiate between secure and insecure message sources, enabling conditional behavior that resolves the contradiction between standard compliance and operational reliability.
2Reliability
If the UE ignores non-integrity-protected reject messages, then service continuity is maintained and cyberattacks are prevented, but the UE may miss legitimate network instructions
Solution Approach 1:
The patent introduces an intermediary verification step (integrity protection check) between receiving the reject message and acting on it. This intermediary mechanism allows the UE to filter out potentially malicious messages while preserving the ability to process legitimate ones, thus maintaining service continuity without losing important information.
Solution Approach 2:
The patent applies preliminary anti-action by proactively checking for integrity protection before processing the reject message. This preemptive measure prevents potential cyberattacks by blocking unverified messages before they can disrupt service, while still allowing legitimate messages with proper integrity protection to pass through.
3Reliability
If the UE searches for another suitable cell or AP upon receiving reject message, then service continuity is maintained, but additional time and resources are consumed
Solution Approach 1:
The patent applies partial action by conditionally triggering the cell/AP search only when specific conditions are met (integrity-protected reject message received and currently registered). This partial approach avoids unnecessary searching in cases where the reject message is likely malicious, thus reducing time loss while maintaining service continuity when actually needed.
Data Source
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AI summary
A User Equipment (UE) communicates with one or both of a first 3GPP core network and a second 3GPP core network over one or both of a 3GPP access and a non-3GPP access. The communication includes: receiving, from the first 3GPP core network, a reject message; and searching for another suitable cell or another suitable Access Point (AP), when the reject message is received over the 3GPP access or the non-3GPP access and the UE is registered with the first 3GPP core network or the second 3GPP core network over the 3GPP access or the non-3GPP access.